c-peptide and Insulin-Resistance

Despite advances in the characterization of partial clinical remission (PR) of type 1 diabetes, an accurate definition of PR remains problematic. Two recent studies in children with new-onset T1D demonstrated serious limitations of the present gold standard definition of PR, a stimulated C-peptide (SCP) concentration of >300 pmol/L. The first study employed the concept of insulin sensitivity score (ISS) to show that 55% of subjects with new-onset T1D and a detectable SCP level of >300 pmol/L had low insulin sensitivity (IS) and thus might not be in remission when assessed by insulin-dose adjusted A1c (IDAA1c), an acceptable clinical marker of PR. The second study, a randomized controlled trial of vitamin D (ergocalciferol) administration in children and adolescents with new-onset T1D, demonstrated no significant difference in SCP between the ergocalciferol and placebo groups, but showed a significant blunting of the temporal trend in both A1c and IDAA1c in the ergocalciferol group. These two recent studies indicate the poor specificity and sensitivity of SCP to adequately characterize PR and thus call for a re-examination of current approaches to the definition of PR. They demonstrate the limited sensitivity of SCP, a static biochemical test, to detect the complex physiological changes that occur during PR such as changes in insulin sensitivity, insulin requirements, body weight, and physical activity. These shortcomings call for a broader definition of PR using a combination of functional markers such as IDAA1c and ISS to provide a valid assessment of PR that reaches beyond the static changes in SCP alone.

Topics: Adolescent; Biomarkers; Body Weight; C-Peptide; Child; Diabetes Mellitus, Type 1; Ergocalciferols; Exercise; Glycated Hemoglobin; Health Status Indicators; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Randomized Controlled Trials as Topic; Remission Induction

Women's metabolism during pregnancy undergoes numerous changes that can lead to gestational diabetes mellitus (GDM). The cause and pathogenesis of GDM, a heterogeneous disease, are not completely clear, but GDM is increasing in prevalence and is associated with the modern lifestyle. Most diagnoses of GDM are made

Topics: Biomarkers; Blood Glucose; C-Peptide; Diabetes, Gestational; Female; Humans; Insulin; Insulin Resistance; Pregnancy

It is well known that type 2 diabetes mellitus (T2D) is a globally increasing health burden. Despite recent therapeutic advances and the availability of many different classes of antihyperglycemic therapy, a large proportion of people do not achieve glycemic control. A decline in pancreatic beta-cell function has been defined as a key contributing factor to progression of T2D. In fact, a significant proportion of beta-cell secretory capacity is thought to be lost well before the diagnosis of T2D is made. Several models have been proposed to explain the reduction in beta-cell function, including reduced beta-cell number, beta-cell exhaustion, and dedifferentiation or transdifferentiation into other cell types. However, there have been reports that suggest remission of T2D is possible, and it is believed that beta-cell dysfunction may be, in part, reversible. As such, the question of whether beta cells are committed to failure in people with T2D is complex. It is now widely accepted that early restoration of normoglycemia may protect beta-cell function. Key to the successful implementation of this approach in clinical practice is the appropriate assessment of individuals at risk of beta-cell failure, and the early implementation of appropriate treatment options. In this review, we discuss the progression of T2D in the context of beta-cell failure and describe how C-peptide testing can be used to assess beta-cell function in primary care practice. In conclusion, significant beta-cell dysfunction is likely in individuals with certain clinical characteristics of T2D, such as long duration of disease, high glycated hemoglobin (≥9%), and/or long-term use of therapies that continuously stimulate the beta cell. In these people, measurement of beta-cell status could assist with choice of appropriate therapy to delay or potentially reverse beta-cell dysfunction and the progression of T2D.

Topics: Biomarkers; C-Peptide; Diabetes Mellitus, Type 2; Disease Progression; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Incretins; Insulin; Insulin Resistance; Insulin-Secreting Cells; Oxidative Stress

Long-term exposure to high dietary acid load has been associated with insulin resistance and type 2 diabetes in epidemiological studies. However, it remains unclear whether the acid load of the diet translates to mild metabolic acidosis and whether it is responsible for the impairment in glucose regulation in humans. Previously, in a cross-sectional study we have reported that dietary acid load was not different between healthy individuals with normal weight and those with overweight/obesity, irrespective of insulin sensitivity. However, 4-week high acid load diet increased plasma lactate (a small component of the anion gap) and increased insulin resistance in healthy participants. The change in plasma lactate correlated significantly with the change in insulin resistance. Because cause-and-effect could not be evaluated in these settings, we sought to directly test the effect of an alkalizing treatment preload on postprandial glucose regulation. In a randomized placebo-controlled study with a crossover design, we administered sodium bicarbonate (NaHCO

Topics: Blood Glucose; C-Peptide; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Glucose; Humans; Insulin; Insulin Resistance; Postprandial Period; Randomized Controlled Trials as Topic

Insulin clearance has recently been highlighted as a fundamental aspect of glucose metabolism, as it has been hypothesized that its impairment could be related to an increased risk of developing type 2 diabetes. This review focuses on methods used to calculate insulin clearance: from the early surrogate indices employing C-peptide:insulin molar ratio, to direct measurement methods used in animal models, to modeling-based techniques to estimate the components of insulin clearance (hepatic versus extrahepatic). The methods are explored and interpreted by critically highlighting advantages and limitations.

Topics: Animals; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Diagnostic Techniques, Endocrine; Humans; Inactivation, Metabolic; Insulin; Insulin Resistance; Liver

Current knowledge suggests a complex role of C-peptide in human physiology, but its mechanism of action is only partially understood. The effects of C-peptide appear to be variable depending on the target tissue, physiological environment, its combination with other bioactive molecules such as insulin, or depending on its concentration. It is apparent that C-peptide has therapeutic potential for the treatment of vascular and nervous damage caused by type 1 or late type 2 diabetes mellitus. The question remains whether the effect is mediated by the receptor, the existence of which is still uncertain, or whether an alternative non-receptor-mediated mechanism is responsible. The Institute of Endocrinology in Prague has been paying much attention to the issue of C-peptide and its metabolic effect since the 1980s. The RIA methodology of human C-peptide determination was introduced here and transferred to commercial production. By long-term monitoring of C-peptide oGTT-derived indices, the Institute has contributed to elucidating the pathophysiology of glucose tolerance disorders. This review summarizes the current knowledge of C-peptide physiology and highlights the contributions of the Institute of Endocrinology to this issue.

Topics: Animals; C-Peptide; Diabetes Mellitus, Type 2; Humans; Insulin Resistance; Nervous System Diseases; Vascular Diseases

To evaluate the comparative effects of incretin-based therapies, including glucagon-like peptide-1 receptor agonists (GLP-1 RAs) and dipeptidyl peptidase-4 inhibitors (DPP-4Is), on β-cell function and insulin resistance in patients with type 2 diabetes mellitus (T2DM).. Medline, Embase, the Cochrane Library and www.clinicaltrials.gov were searched for randomized controlled trials (RCTs) with a duration of at least 4 weeks. Network meta-analysis was performed, followed by subgroup analysis and meta-regression. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used to assess the quality of evidence. Outcomes of interest include homeostasis model assessment for β cell function (HOMA-β) and insulin resistance (HOMA-IR), fasting C-peptide and fasting plasma glucose (FPG). Weighted mean difference (WMD) with 95% confidence interval (CI) was calculated as the measure of effect size.. A total of 360 RCTs (74% at least double-blinded) with 157 696 patients were included. Incretin-based therapies were compared with six other classes of glucose-lowering drugs or with placebo. Compared with placebo, a significant increase in HOMA-β and fasting C-peptide was detected for GLP-1RAs (WMD = 20.31 [95% CI, 16.34-24.39] with low quality; WMD = 0.16 ng/mL [95% CI, 0.03-0.29] with low quality) and for DPP-4Is (WMD = 9.90 [95% CI, 8.27-11.61] with moderate quality; WMD = 0.09 ng/mL [95% CI, 0.04-0.14] with moderate quality) separately, while a significant reduction in HOMA-IR and FPG were found in favour of GLP-1RAs (WMD = -0.67 [95% CI, -1.08 to -0.27] with low quality; WMD = -1.04 mmol/L [95% CI, -1.26 to -0.83] with moderate quality) and DPP-4Is (WMD = -0.23 [95% CI, -0.38 to -0.08] with low quality; WMD = -0.77 mmol/L [95% CI, -0.98 to -0.57] with moderate quality), respectively.. Incretin-based therapies not only show an increase in HOMA-β and fasting C-peptide level, but also achieve a reduction in HOMA-IR and FPG in comparison with placebo. Although GRADE scores indicate low to moderate for most comparisons, incretin-based therapies seem to be an advisable option for long-term treatment to preserve β-cell function.

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Glucagon-Like Peptide-1 Receptor; Humans; Incretins; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Network Meta-Analysis

We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) assessing the effect of programmed exercise for at least 12 weeks, in postmenopausal women on insulin sensitivity-related outcomes (ISROs), including fasting insulin, C-peptide, insulin growth factor (IGF-1) and IGF-binding protein (IGFBP-3), Homeostatic Model Assessment-Insulin Resistance (HOMA-IR), and anthropometric variables.. Searches were conducted in PubMed-Medline, Embase, Scopus, Web of Science, and Cochrane Library from inception through May 3, 2016, for studies published in all languages. Extracted data included characteristics of the study design, study participants, intervention, and outcome measures. Types of exercise were classified into "mid-term exercise intervention" (MTEI, 3-4 months exercise duration) and a "long-term exercise intervention" (LTEI, 6-12 months exercise duration). Risk of bias in RCTs was evaluated with the Cochrane tool. We used random-effects models for meta-analyses. We adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.. Seven RCTS (n = 580) evaluating the effects of programmed exercise on ISROs were included. In three RCTs, MTEI significantly lowered insulin levels (mean difference [MD] -6.50 pmol/L, 95% confidence interval [CI] -11.19, -1.82, P = 0.006) and HOMA-IR values (MD -0.18, 95% CI -0.34, -0.03, P = 0.02) when compared with controls. LTEI had no significant effect on insulin levels (P = 0.19) or HOMA-IR values (P = 0.68) in four and three RCTs, respectively. There were no significant differences between exercise intervention versus controls in circulating IGF-1, glucose, triglycerides with both MTEI and LTEI, and in IGFBP-3 with LTEI. There were significant reductions in body mass index (BMI, kg/m) (MD -1.48, 95% CI -2.48, -0.48, P = 0.004) and in body fat percentage (MD -2.99, 95% CI -4.85, -1.14, P = 0.01) after MTEI; and in waist circumference after both MTEI (MD -1.87, 95% CI -3.02, -0.72, P = 0.001) and LTEI (MD -3.74, 95% CI -6.68, -0.79). Heterogeneity of effects among studies was moderate to low.. Exercising for 3 to 4 months significantly lowered insulin levels and HOMA-IR values, BMI waist circumference, and percentage body fat mass; exercising for 6 to 12 months lowered waist circumference in postmenopausal women.

Topics: Body Composition; Body Mass Index; C-Peptide; Exercise; Fasting; Female; Humans; Insulin; Insulin Resistance; Insulin-Like Growth Factor Binding Protein 3; Insulin-Like Growth Factor I; Life Style; MEDLINE; Postmenopause; Randomized Controlled Trials as Topic; Waist Circumference

In this review, we present findings that support autocrine cell protection by C-peptide in the context of clinical studies of type 1 diabetes (T1D), which universally measure C-peptide serum levels as a surrogate for β cell functional mass. Over the last decade, evidence has accumulated that supports models in which C-peptide, cosecreted with insulin by pancreatic β cells, acts on peripheral targets including the vascular endothelium to reduce oxidative stress and apoptosis subsequent to exposure to diabetic insults. In parallel, as assays have become more sensitive, C-peptide has been detected in the circulation of most subjects with T1D where higher C-peptide levels are associated with fewer and slower development of diabetic microvascular complications, consistent with antioxidant protection by C-peptide. Clinical trials investigating C-peptide-replacement therapy effects have demonstrated amelioration of T1D nephropathy and neuropathy. Recently, the antioxidant action of C-peptide was extended to the β cells secreting it, that is an autocrine mechanism. Autocrine protection has major implications for the treatment of diabetes because the more C-peptide secreted, the more protection provided to the same β cells resulting in a slower decay in β cell functional mass over the time course of disease. Why β cells evolved to cosecrete an antioxidant C-peptide hormone together with the glycaemia-lowering insulin hormone is explored in the context of proposed evolutionary advantages of physiologically transient oxidative stress and insulin resistance as an adaptation for survival through times of fuel scarcity. The importance of recognizing autocrine C-peptide protection of functional β cell mass in observational clinical studies, and its therapeutic implications in interventional C-peptide-replacement studies, will be discussed.

Topics: Animals; C-Peptide; Diabetes Mellitus, Type 1; Disease Models, Animal; Endothelial Cells; Humans; Insulin Resistance; Insulin-Secreting Cells; Reactive Oxygen Species

Insulin resistance is common among obese adolescents; however, the extent of this problem is not clear. We conducted a systematic review of PubMed-Medline, CINAHL, The Web of Science, EMBASE and Scopus for observational studies evaluating components defining insulin resistance (insulin, C-peptide and homeostatic model assessment-insulin resistance [HOMA-IR]) in obese adolescents (12-18 years) versus non-obese adolescents. Our systematic review and meta-analysis followed the PRISMA guidelines. Data were combined using a random-effects model and summary statistics were calculated using the mean differences (MDs). 31 studies were included (n = 8655). In 26 studies, fasting insulin levels were higher in obese adolescents when compared to non-obese adolescents (MD = 64.11 pmol/L, 95%CI 49.48-78.75, p < 0.00001). In three studies, fasting C-peptide levels were higher in obese adolescents when compared to non-obese adolescents (MD = 0.29 nmol/L, 95%CI 0.22-0.36, p < 0.00001). In 24 studies, HOMA-IR values were higher in obese adolescents when compared to non-obese adolescents (MD = 2.22, 95%CI 1.78-2.67, p < 0.00001). Heterogeneity of effects among studies was moderate to high. Subgroup analyses showed similar results to the main analyses. Circulating insulin and C-peptide levels and HOMA-IR values were significantly higher in obese adolescents compared to those non-obese.

Topics: Adolescent; Adolescent Nutritional Physiological Phenomena; Biomarkers; C-Peptide; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Metabolic Syndrome; Observational Studies as Topic; Pediatric Obesity; Reproducibility of Results

Concomitant confluent and reticulated papillomatosis (CRP) and acanthosis nigricans (AN) is rare. We present a case of concomitant CRP and obesity-associated AN in a 12-year-old obese Japanese girl. Curiously, oral minocycline therapy, which has been shown to be effective for CRP, was effective against both CRP and AN. Possible mechanisms by which minocycline could have improved skin lesions of CRP and obesity-associated AN are discussed. In addition, reports of concomitant CRP and obesity-associated AN are reviewed. CRP and obesity-associated AN share common clinicopathological features and some reports have described concomitant CRP and obesity-associated AN. Together with the observation that skin lesions of CRP and obesity-associated AN in the present case responded to oral minocycline therapy, these facts suggest a tight relationship or a common pathogenetic pathway between these pathologies.

Topics: Acanthosis Nigricans; Alkaline Phosphatase; Anti-Bacterial Agents; Biopsy; Blood Glucose; C-Peptide; Child; Female; Humans; Insulin Resistance; Minocycline; Obesity; Papilloma; Rare Diseases; Skin; Skin Neoplasms; Syndrome; Treatment Outcome

Diabetes is not a single homogeneous disease but composed of many diseases with hyperglycaemia as a common feature. Four factors have, historically, been used to identify this diversity: the age at onset; the severity of the disease, i.e. degree of loss of beta cell function; the degree of insulin resistance and the presence of diabetes-associated autoantibodies. Our broad understanding of the distinction between the two major types, type 1 diabetes mellitus and type 2 diabetes mellitus, are based on these factors, but it has become apparent that they do not precisely capture the different disease forms. Indeed, both major types of diabetes have common features, encapsulated by adult-onset autoimmune diabetes and maturity-onset diabetes of the young. As a result, there has been a repositioning of our understanding of diabetes. In this review, drawing on recent literature, we discuss the evidence that autoimmune type 1 diabetes has a broad clinical phenotype with diverse therapeutic options, while the term non-autoimmune type 2 diabetes obscures the optimal management strategy because it encompasses substantial heterogeneity. Underlying these developments is a general progression towards precision medicine with the need for precise patient characterisation, currently based on clinical phenotypes but in future augmented by laboratory-based tests.

Topics: Age Factors; Alleles; Autoantibodies; Autoimmunity; C-Peptide; Diabetes Mellitus; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Disease Progression; Genotype; Humans; Hyperglycemia; Insulin; Insulin Resistance; Phenotype

Recent research in nutritional control of aging suggests that cytosolic increases in the reduced form of nicotinamide adenine dinucleotide and decreasing nicotinamide adenine dinucleotide metabolism plays a central role in controlling the longevity gene products sirtuin 1 (SIRT1), adenosine monophosphate-activated protein kinase (AMPK) and forkhead box O3 (FOXO3). High nutrition conditions, such as the diabetic milieu, increase the ratio of reduced to oxidized forms of cytosolic nicotinamide adenine dinucleotide through cascades including the polyol pathway. This redox change is associated with insulin resistance and the development of diabetic complications, and might be counteracted by insulin C-peptide. My research and others' suggest that the SIRT1-liver kinase B1-AMPK cascade creates positive feedback through nicotinamide adenine dinucleotide synthesis to help cells cope with metabolic stress. SIRT1 and AMPK can upregulate liver kinase B1 and FOXO3, key factors that help residential stem cells cope with oxidative stress. FOXO3 directly changes epigenetics around transcription start sites, maintaining the health of stem cells. 'Diabetic memory' is likely a result of epigenetic changes caused by high nutritional conditions, which disturb the quiescent state of residential stem cells and impair tissue repair. This could be prevented by restoring SIRT1-AMPK positive feedback through activating FOXO3.

Topics: Aging; AMP-Activated Protein Kinases; Animals; C-Peptide; Diabetes Complications; Diabetic Angiopathies; Disease Models, Animal; Epigenesis, Genetic; Feedback, Physiological; Forkhead Box Protein O3; Humans; Hypoxia; Insulin Resistance; NAD; Oxidation-Reduction; Oxidative Stress; Signal Transduction; Sirtuin 1

Independent epidemiological studies have evaluated the association between markers of glucose metabolism (including fasting glucose, fasting insulin, homeostasis model of risk assessment-insulin resistance (HOMA-IR), glycated haemoglobin (HbA1c) and C peptide) and the risk of colorectal cancer (CRC). However, such associations have not been systematically analysed and no clear conclusions have been drawn. Therefore, we addressed this issue using a meta-analysis approach.. Systematic review and meta-analysis.. PubMed and EMBASE were searched up to May 2015.. Either a fixed-effects or random-effects model was adopted to estimate overall ORs for the association between markers of glucose metabolism and the risk of CRC. In addition, dose-response, meta-regression, subgroup and publication bias analyses were conducted.. 35 studies involving 25 566 patients and 5 706 361 participants were included. Higher levels of fasting glucose, fasting insulin, HOMA-IR, HbA1c and C peptide were all significantly associated with increased risk of CRC (fasting glucose, pooled OR=1.12, 95% CI 1.06 to 1.18; fasting insulin, pooled OR=1.42, 95% CI 1.19 to 1.69; HOMA-IR, pooled OR=1.47, 95% CI 1.24 to 1.74; HbA1c, pooled OR=1.22, 95% CI 1.02 to 1.47 (with borderline significance); C peptide, pooled OR=1.27, 95% CI 1.08 to 1.49). Subgroup analysis suggested that a higher HOMA-IR value was significantly associated with CRC risk in all subgroups, including gender, study design and geographic region. For the relative long-term markers, the association was significant for HbA1c in case-control studies, while C peptide was significantly associated with CRC risk in both the male group and colon cancer.. The real-time composite index HOMA-IR is a better indicator for CRC risk than are fasting glucose and fasting insulin. The relative long-term markers, HbA1c and C peptide, are also valid predictors for CRC risk. Considering the included case-control studies in the current analysis, more cohort studies are warranted to enhance future analysis.

Topics: Biomarkers; C-Peptide; Colorectal Neoplasms; Diabetes Mellitus, Type 2; Glucose; Glucose Tolerance Test; Glycated Hemoglobin; Homeostasis; Humans; Insulin Resistance; Risk Assessment; Risk Factors

Insulin stimulates cell proliferation and inhibits apoptosis. While epidemiologic studies have investigated associations between markers of insulin resistance/hyperinsulinemia (i.e., circulating insulin, homeostasis model assessment-insulin resistance (HOMA-IR), C-peptide) and risk of colorectal adenoma (CRA), the effect size has not yet been quantified.. We aimed to summarize the association between hyperinsulinemia/insulin resistance and risk of CRA, including whether the association is independent of adiposity.. Pubmed and Embase were searched through April, 2015 to identify observational studies investigating the associations between insulin, C-peptide and HOMA-IR and CRA risk. Using the highest versus lowest category meta-analysis and dose-response meta-analysis based on a random-effects model, we estimated summary odds ratio (OR) and the corresponding 95% confidence interval (95% CI).. A total of 27 studies (insulin: 16 studies including 14,007 cases; C-peptide: 11 studies including 8639 cases; HOMA-IR: 8 studies including 11,619 cases) were included in this meta-analysis. The summary ORs of CRA comparing the highest with the lowest quantile were 1.33 for insulin (95% CI=1.12-1.58, I(2)=73.9%, Pheterogeneity<0.001), 1.44 for C-peptide (95% CI=1.13-1.83, I(2)=63.5%, Pheterogeneity=0.003), and 1.33 for HOMA-IR (95% CI=1.10-1.60, I(2)=69.1%, Pheterogeneity=0.004). Upon stratification by ethnicity, higher levels of insulin and C-peptide were significantly associated with increased risk of CRA in non-Asian ethnicity (summary OR for insulin=1.67 [95% CI=1.28-2.17], I(2)=34.9%, Pheterogeneity=0.16; summary OR for C-peptide=1.59 [95% CI=1.22-2.08], I(2)=21.5%, Pheterogeneity=0.27) but not in Asians (summary OR for insulin=1.10 [95% CI=0.92-1.33], I(2)=76.6%, Pheterogeneity=0.001; summary OR for C-peptide=1.27 [95% CI=0.84-1.91], I(2)=72.6, Pheterogeneity=0.01). We observed evidence for the existence of publication bias for insulin (P=0.01 by Egger test) and HOMA-IR (P=0.05 by Egger test). The results were confirmed in linear dose-response meta-analysis. These significant positive associations generally persisted even after adjustment for adiposity, although the effect size was substantially attenuated.. Independent of adiposity, higher levels of insulin, C-peptide, and HOMA-IR were significantly associated with increased risk of CRA. The weaker associations and high heterogeneity in Asian studies warrant further research. These results indicate that insulin resistance and hyperinsulinemia may contribute in part to the association between obesity and CRA risk.

Topics: Adenoma; Adiposity; Blood Glucose; C-Peptide; Colorectal Neoplasms; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Obesity; Risk Factors

It has been suggested that chronic hyperinsulinemia from insulin resistance is involved in the etiology of endometrial cancer (EC). We performed a systematic review and meta-analysis to assess whether insulin resistance is associated with the risk of EC.. We searched PubMed-Medline, Embase, Scopus, and Web of Science for articles published from database inception through 30th September 2014. We included all observational studies evaluating components defining insulin resistance in women with and without EC. Quality of the included studies was assessed by Newcastle-Ottawa scale. Random-effects models and inverse variance method were used to meta-analyze the association between insulin resistance components and EC.. Twenty-five studies satisfied our inclusion criteria. Fasting insulin levels (13 studies, n = 4088) were higher in women with EC (mean difference [MD] 33.94 pmol/L, 95% confidence interval [CI] 15.04-52.85, p = 0.0004). No differences were seen in postmenopausal versus pre- and postmenopausal subgroup analysis. Similarly, non-fasting/fasting C-peptide levels (five studies, n = 1938) were also higher in women with EC (MD 0.14 nmol/L, 95% CI 0.08-0.21, p < 0.00001). Homeostatic model assessment - insulin resistance (HOMA-IR) values (six studies, n = 1859) in EC patients were significantly higher than in women without EC (MD 1.13, 95% CI 0.20-2.06, p = 0.02). There was moderate-to-high heterogeneity among the included studies.. Currently available epidemiologic evidence is suggestive of significantly higher risk of EC in women with high fasting insulin, non-fasting/fasting C-peptide and HOMA-IR values.

Topics: Adult; Aged; Biomarkers; Blood Glucose; C-Peptide; Chi-Square Distribution; Endometrial Neoplasms; Fasting; Female; Humans; Insulin; Insulin Resistance; Life Style; Middle Aged; Risk Assessment; Risk Factors; Risk Reduction Behavior

The simultaneous assessment of insulin action, secretion, and hepatic extraction is key to understanding postprandial glucose metabolism in nondiabetic and diabetic humans. We review the oral minimal method (i.e., models that allow the estimation of insulin sensitivity, β-cell responsivity, and hepatic insulin extraction from a mixed-meal or an oral glucose tolerance test). Both of these oral tests are more physiologic and simpler to administer than those based on an intravenous test (e.g., a glucose clamp or an intravenous glucose tolerance test). The focus of this review is on indices provided by physiological-based models and their validation against the glucose clamp technique. We discuss first the oral minimal model method rationale, data, and protocols. Then we present the three minimal models and the indices they provide. The disposition index paradigm, a widely used β-cell function metric, is revisited in the context of individual versus population modeling. Adding a glucose tracer to the oral dose significantly enhances the assessment of insulin action by segregating insulin sensitivity into its glucose disposal and hepatic components. The oral minimal model method, by quantitatively portraying the complex relationships between the major players of glucose metabolism, is able to provide novel insights regarding the regulation of postprandial metabolism.

Topics: Adolescent; Blood Glucose; C-Peptide; Child; Food; Glucose; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Liver; Models, Biological; Postprandial Period

Type 2 Diabetes is a heterogeneous disease which harbors several different pathomechanistic entities. For a successful prevention, it is important to understand the exact pathomechanisms. Overt type 2 Diabetes usually develops through an intermediary state called prediabetes, which is also heterogeneous. This state is especially important, because it already confers a higher risk for diabetes-associated complications. Therefore, detection of prediabetes and prevention of its progression to diabetes would be desirable. In this review, we describe the phenotypes of prediabetes and type 2 diabetes. We also try to envision the first steps of a future phenotype-oriented diabetes therapy.

Topics: Blood Glucose; C-Peptide; Diabetes Complications; Diabetes Mellitus, Type 2; Disease Progression; Early Diagnosis; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Prediabetic State; Prognosis; Risk Factors; Transcription Factor 7-Like 2 Protein

This study was undertaken to evaluate the association between components defining insulin resistance and breast cancer in women.. We conducted a systematic review of four databases (PubMed-Medline, EMBASE, Web of Science, and Scopus) for observational studies evaluating components defining insulin resistance in women with and without breast cancer. A meta-analysis of the association between insulin resistance components and breast cancer was performed using random effects models.. Twenty-two studies (n = 33,405) were selected. Fasting insulin levels were not different between women with and without breast cancer (standardized mean difference, SMD -0.03, 95%CI -0.32 to 0.27; p = 0.9). Similarly, non-fasting/fasting C-peptide levels were not different between the two groups (mean difference, MD 0.07, -0.21 to 0.34; p = 0.6). Using individual odds ratios (ORs) adjusted at least for age, there was no higher risk of breast cancer when upper quartiles were compared with the lowest quartile (Q1) of fasting insulin levels (OR Q2 vs. Q1 0.96, 0.71 to 1.28; OR Q3 vs. Q1 1.22, 0.91 to 1.64; OR Q4 vs. Q1 0.98, 0.70 to 1.38). Likewise, there were no differences for quartiles of non-fasting/fasting C-peptide levels (OR Q2 vs. Q1 1.12, 0.91 to 1.37; OR Q3 vs. Q1 1.20, 0.91 to 1.59; OR Q4 vs. Q1 1.40, 1.03 to 1.92). Homeostatic model assessment (HOMA-IR) levels in breast cancer patients were significantly higher than in people without breast cancer (MD 0.22, 0.13 to 0.31, p<0.00001).. Higher levels of fasting insulin or non-fasting/fasting C-peptide are not associated with breast cancer in women. HOMA-IR levels are slightly higher in women with breast cancer.

Topics: Breast Neoplasms; C-Peptide; Fasting; Female; Humans; Insulin; Insulin Resistance; Odds Ratio; Publication Bias

C-peptide is produced in equal amounts to insulin and is the best measure of endogenous insulin secretion in patients with diabetes. Measurement of insulin secretion using C-peptide can be helpful in clinical practice: differences in insulin secretion are fundamental to the different treatment requirements of Type 1 and Type 2 diabetes. This article reviews the use of C-peptide measurement in the clinical management of patients with diabetes, including the interpretation and choice of C-peptide test and its use to assist diabetes classification and choice of treatment. We provide recommendations for where C-peptide should be used, choice of test and interpretation of results. With the rising incidence of Type 2 diabetes in younger patients, the discovery of monogenic diabetes and development of new therapies aimed at preserving insulin secretion, the direct measurement of insulin secretion may be increasingly important. Advances in assays have made C-peptide measurement both more reliable and inexpensive. In addition, recent work has demonstrated that C-peptide is more stable in blood than previously suggested or can be reliably measured on a spot urine sample (urine C-peptide:creatinine ratio), facilitating measurement in routine clinical practice. The key current clinical role of C-peptide is to assist classification and management of insulin-treated patients. Utility is greatest after 3-5 years from diagnosis when persistence of substantial insulin secretion suggests Type 2 or monogenic diabetes. Absent C-peptide at any time confirms absolute insulin requirement and the appropriateness of Type 1 diabetes management strategies regardless of apparent aetiology.

Topics: C-Peptide; Diabetes Mellitus; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Humans; Insulin; Insulin Resistance; Insulin Secretion; Prognosis

Diabetes type 2 and insulin resistance are the risk factors for cardiovascular disease. It is already known that atherosclerosis is an inflammatory disease, and a lot of different factors are involved in its onset. C-peptide is a cleavage product of proinsulin, an active substance with a number of effects within different complications of diabetes. In this paper we discuss the role of C-peptide and its effects in the development of atherosclerosis in type 2 diabetic patients.

Topics: Animals; Atherosclerosis; C-Peptide; Diabetes Complications; Diabetes Mellitus; Humans; Inflammation; Insulin; Insulin Resistance; Models, Biological; Proinsulin; Signal Transduction

This review focuses on recent literature on insulin resistance in youth with type 2 diabetes mellitus (T2DM). Insulin resistance is associated with a variety of cardiometabolic problems leading to increased morbidity and mortality across the lifespan.. Functional pancreatic β-cell changes play a role in the transition from obesity to impaired glucose tolerance (IGT). Insulin resistance drives islet cell upregulation, manifested by elevated glucagon and c-peptide levels, early in the transition to IGT. Surrogate measurements of insulin resistance and insulin secretion exist but their accuracy compared to clamp data is imperfect. Recent large longitudinal studies provide detailed information on the progression from normoglycemia to T2DM and on the phenotype of T2DM youth. Defining prediabetes and T2DM remains a challenge in youth. Lifestyle interventions do not appear as effective in children as in adults. Metformin remains the only oral hypoglycemic agent approved for T2DM in youth.. New insights exist regarding the conversion from insulin resistance to T2DM, measurement of insulin resistance and phenotypes of insulin resistance youth, but more information is needed. Surrogate measurements of insulin resistance, additional treatment options for insulin resistance and individualization of treatment options for T2DM adolescents in particular require further investigation.

Topics: Adolescent; Body Mass Index; C-Peptide; Child; Diabetes Mellitus, Type 2; Exercise Tolerance; Female; Glucagon; Glucose Intolerance; Glucose Tolerance Test; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Male; Metformin; Obesity; Phenotype; Young Adult

This article emphasizes (1) the utility of routine measurement of pro-insulin to insulin ratio as a specific marker of insulin resistance and predictor of future T2DM, HT and CAD, (2) routine C-Peptide estimation to determine which T2DM needs insulin and to monitor the effect of newer drugs which promote beta cell regeneration, (3) routine estimation of adiponectin and TNF alpha and monitor response to thiozolidine drugs which increases adiponectin and decreases TNF alpha production by adipocytes, (4) crucial role of AMPK--Cellular energy sensor in mediating the beneficial effects of exercise as well as drugs (adiponectin, metformin) in T2DM, (5) Availability of glucogon suppressors will eliminate the need for giving insulin to T2 DM with normal C Pepetide levels which inevitably causes undesirable weight gain & hypoglycemia.

Topics: Adipocytes; Adiponectin; AMP-Activated Protein Kinases; Biomarkers; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Glucagon; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Tumor Necrosis Factor-alpha

Patients with insulin resistance and early type 2 diabetes exhibit an increased propensity to develop a diffuse and extensive pattern of arteriosclerosis. Various risk factors such as hypertension, dyslipidemia, and a proinflammatory and prothrombotic state contribute to atherogenesis in this high-risk population, but the pathophysiologic mechanisms leading to this characteristic pattern remain largely unexplored. Recent data suggest that the proinsulin cleavage product C-peptide could play a causal role in atherogenesis by promoting monocyte and CD4-positive lymphocyte recruitment in early arteriosclerotic lesions and by inducing the proliferation of vascular smooth muscle cells. The following review will summarize the effects of C-peptide in vascular cells and discuss the potential relevance of such C-peptide effects on atherogenesis in diabetic patients.

Topics: Atherosclerosis; C-Peptide; Diabetic Angiopathies; Humans; Insulin Resistance

The prevalence of latent autoimmune diabetes of the adult (LADA) varies according to the population studied, criteria used and antibodies analyzed. In a series of 256 patients > 25 years, we found that 26 (10.2%) were anti-GAD antibody (GADA) positive and 16 of them (6.3%) progressed without initial insulin requirement. Although controversy exists, the following diagnostic criteria for LADA are suggested: age between 25 and 65 years; absence of ketoacidosis or symptomatic hyperglycemia at diagnosis or immediately thereafter, without insulin requirement for 6-12 months; and presence of autoantibodies (especially GADA). Autoimmunity and insulin resistance coexist in LADA and the contribution of these factors seems to be reflected in GADA titers. A subgroup, which is phenotypically and in terms of insulin requirement similar to type 2 diabetic patients, seems to be better identified based on the presence of low GADA titers, especially when these antibodies are present alone. On the other hand, subjects with high GADA titers and multiple antibodies show a phenotype close to that of classical DM 1 and are at a higher risk of premature beta-cell failure. Compared to GADA-negative diabetics, patients with LADA present a higher prevalence of other autoantibodies (anti-TPO, anti-21-hydroxylase and antibodies associated with celiac disease) and a higher frequency of genotypes and haplotypes indicating a risk for DM 1. Patients with high GADA titers may benefit from early insulinization and avoiding the use of sulfonylureas, delaying beta-cell failure. In contrast, patients with low GADA titers do not seem to have any disadvantage when managed as type 2 diabetic patients (GADA negative).

Topics: Adult; Aged; Aged, 80 and over; Autoantibodies; Autoimmunity; Biomarkers; Brazil; C-Peptide; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diagnosis, Differential; Genetic Predisposition to Disease; Glutamate Decarboxylase; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Middle Aged; Prevalence; Young Adult

Topics: Atherosclerosis; C-Peptide; Cardiovascular Diseases; Cell Proliferation; Diabetic Angiopathies; Humans; Hyperinsulinism; Insulin Resistance; Mitogens; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle

Topics: Adolescent; Adult; Aged; C-Peptide; Child; Coronary Disease; Diabetes Complications; Glucose; Humans; Insulin; Insulin Resistance; Leptin; Middle Aged; Obesity; Potassium; Risk Factors; Vascular Resistance

Topics: Biomarkers; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Postprandial Period; Severity of Illness Index; Time Factors

Topics: Biomarkers; C-Peptide; Chromatography, Gel; Diabetes Mellitus, Type 2; Diagnostic Techniques, Endocrine; Factitious Disorders; Humans; Hypoglycemia; Immunoassay; Insulin Resistance; Insulin-Secreting Cells; Insulinoma; Kidney Diseases; Pancreatic Function Tests; Pancreatic Neoplasms; Proinsulin; Reference Values; Specimen Handling

Despite extensive and ongoing investigations of the immune mechanisms of autoimmune diabetes in humans and animal models, there is much less information about the natural history of insulin secretion before and after the clinical presentation of type 1 diabetes and the factors that may affect its course. Studies of insulin production previously published and from the Diabetes Prevention Trial (DPT)-1 suggest that there is progressive impairment in insulin secretory responses but the reserve in response to physiological stimuli may be significant at the time of diagnosis, although maximal responses are more significantly impaired. Other factors, including insulin resistance, may play a role in the timing of clinical presentation along this continuum. The factors that predict the occurrence and rapidity of decline in beta-cell function are still largely unknown, but most studies have identified islet cell autoantibodies as predictors of future decline and age as a determinant of residual insulin production at diagnosis. Historical as well as recent clinical experience has emphasized the importance of residual insulin production for glycemic control and prevention of end-organ complications. Understanding the modifiers and predictors of beta-cell function would allow targeting immunological approaches to those individuals most likely to benefit from therapy.

Topics: Adolescent; Adult; Aging; C-Peptide; Child; Diabetes Mellitus, Type 1; Humans; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Middle Aged

The incidence of type 2 diabetes mellitus (T2DM) in children and adolescents has substantially increased over the past decade. This is attributed to obesity, insulin resistance and deficient beta-cell function. In children a pubertal increase in insulin resistance and an inability to mount an adequate beta-cell insulin response results in hyperglycemia. Adults with T2DM have a diminished first phase response to intravenous glucose and a delayed early insulin response to oral glucose. Long-term studies show progressive loss of beta-cell function in T2DM in adults; however, such long-term studies are not available in children. To characterize beta- and alpha-cell function in African-American adolescents with established T2DM, we used mixed meal, intravenous glucagon and oral glucose tolerance testing and compared them to obese non-diabetic controls. T2DM was defined as fasting C-peptide >0.232 nmol/l and absent autoimmune markers. BETA-CELL FUNCTION: Meal testing in 24 children and adolescents with T2DM, mean age 14 years, BMI 30 kg/m2, Tanner stage II-V, HbA1c 8.9%, were compared with BMI- and age-matched controls. Forty percent presented with DKA. Half were treated with insulin and half with diet/oral anti-diabetic agents. Although absolute C-peptide response in both groups was similar, the incremental rise in C-peptide relative to plasma glucose in the patients with T2DM compared to controls was 40% and 35% lower 30 and 60 min after the meal, p <0.007 and p <0.026. Glucagon testing in 20 pediatric patients with T2DM compared with 15 matched controls showed significantly lower 6 min stimulated C-peptide relative to the ambient plasma glucose in patients with T2DM compared to controls (0.039 +/- 0.026 vs 0.062 +/- 0.033, p <0.05). The clinical utility is that 78% of patients with a 6 min C-peptide <1.4 nmol required insulin, while 81% of those >1.4 nmol required oral anti-diabetic agents, p <0.0001. Furthermore, the duration of T2DM up to 5 years after diagnosis was associated with lower fasting and glucagon-stimulated C-peptide levels, implying worsening beta-cell function over time, even in children and adolescents. ALPHA-CELL FUNCTION: During meal testing, children and adolescents with T2DM had less suppression of plasma glucagon than non-diabetic controls; this was more severe with longer duration of T2DM and poorer glycemic control. BETA-CELL RECOVERY: In African-American and Hispanic adults, intensive treatment of blood glucose may achieve beta-cell. T2DM in children, as in adults, is characterized by insulin deficiency relative to insulin resistance. Plasma C-peptide levels may be clinically useful in guiding therapeutic choices, since patients with lower levels required insulin treatment; beta-cell function is also diminished with longer duration of T2DM. The possibility exists that in children, as in adults, intensive glycemic regulation may allow for beta-cell recovery and preservation. Thus, optimum beta- and alpha-cell function are central to the prevention of DM and maintenance of good glycemic control in African-American and Hispanic children and adolescents with T2DM.

Topics: Adolescent; Adult; Black People; Body Mass Index; C-Peptide; Child; Diabetes Mellitus, Type 2; Food; Glucagon; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Puberty

Topics: Biomarkers; C-Peptide; Diabetes Mellitus; Humans; Insulin Resistance

The search for the genetic basis of NIDDM has magnified the need for an efficient representation of the pre-NIDDM phenotype. The overall goal is to relate specific mutations on the genome to specific changes in physiologic function which lead to NIDDM. Unfortunately, there is still not a clear understanding of the molecular cause of NIDDM in most individuals. Therefore, one must take an alternative approach: to express in quantitative terms the various tissue processes which determine the ability to regulate the blood glucose in fasting and after carbohydrate administration. A minimal list of such processes includes the provision of glucose by the liver, insulin sensitivity, insulin secretion, and glucose effectiveness. The latter function is the ability of glucose per se to enhance glucose disappearance from blood, independent of a dynamic insulin response. Approaches to measuring the list of functions which determine the glucose tolerance are reviewed: they include the minimal model method, which quantitates insulin sensitivity (Sl) and glucose effectiveness (SG), and a combined model approach, which measures insulin secretion. These methods are being developed for large populations. Such a development is important for elucidating the causes of reduced glucose tolerance in populations, and examining the relation between such causes and outcomes including diabetes and cardiovascular disease. Of particular importance for diabetes development is the characteristic hyperbolic relationship between insulin secretion and insulin action. This relationship, the "hyperbolic law of glucose tolerance' indicates that insulin secretion can only be assessed in terms of the ambient degree of insulin sensitivity. By applying this principle, it is clear that latent pancreatic islet-cell dysfunction has been underestimated, and may be significant even in subjects with impaired glucose tolerance. Finally, new explorations of insulin control of liver glucose output indicate that this process may be under the control of free fatty acids. The latter realization indicates that the insulin effect on lipolysis is what is critical for determination of glucose output in the fasting state, and that insulin resistance at the level of the adipocyte may determine the extent of fasting hyperglycaemia, and may be an important factor in the overall phenotype in prediabetic and NIDDM individuals.

Topics: Animals; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Glucose; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Hyperglycemia; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Liver; Models, Biological; Phenotype; Prediabetic State; Risk Factors; Tolbutamide

Topics: Adult; C-Peptide; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Infections; Insulin; Insulin Resistance; Myocardial Infarction

Diabetes mellitus is a heterogeneous disorder. About 80% of the patients with this disease are categorized as having non-insulin-dependent diabetes mellitus, a disorder resulting from varied degrees of insulin resistance and impaired insulin secretion; the causes for these abnormalities are unknown. The remaining 15 to 20% of patients have insulin-dependent diabetes mellitus, a disorder caused by the destruction of insulin-producing endocrine cells within the pancreas and currently considered to be the result of an autoimmune process. During the course of both types of diabetes mellitus, the so-called long-term complications of diabetes invariably occur to some extent in all patients. These complications include retinopathy, nephropathy, neuropathy, and premature atherosclerosis. The molecular basis for these complications is not completely understood, but recent evidence obtained from both experiments in animals and prospective clinical studies indicates that metabolic derangements associated with poor glycemic control are a major determinant of the frequency and severity of these complications. Such evidence is the rationale for current attempts to maintain near-normal glycemia in patients with diabetes mellitus.

Topics: Autoimmune Diseases; Blood Glucose; C-Peptide; Diabetes Mellitus; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Diabetic Nephropathies; Diabetic Neuropathies; Diabetic Retinopathy; Diagnosis, Differential; Glucagon; Humans; Insulin; Insulin Resistance

Topics: Adolescent; Adult; Animals; Blood Glucose; C-Peptide; Child; Diabetes Mellitus; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Time Factors

In normal and diabetic pregnancies, the placenta functions as a complex endocrine gland that modulates all classes of maternal nutrients to the fetus. The metabolic alterations of normal pregnancy are diabetogenic and associated with modest resistance to endogenous insulin. Pregnant women with carbohydrate intolerance represent three metabolically heterogeneous groups: type I (insulin-dependent), type II (non-insulin-dependent), and gestational diabetes. Patients with type I diabetes are at risk for ketosis and require replacement therapy because of a deficient production of insulin. They have decreased 24-hour, around-the-clock levels of C-peptide and glucagon, and lower nocturnal cortisol values and higher 24-hour prolactin levels than those of women with type II diabetes. Type II pregnant diabetic patients are not prone to ketosis and are more resistant to endogenous and exogenous insulin. They have higher fasting and meal-stimulated levels of C-peptide, accentuated fasting hypertriglyceridemia, and significantly lower high-density lipoprotein cholesterol levels than those of normal or type I women. In gestational diabetes, the metabolic stress of pregnancy evokes reversible hyperglycemia which may be associated with either a surfeit or a deficiency of insulin. These metabolic differences among diabetic pregnant women could have implications for placental structure and function that might influence fetal growth.

Topics: Blood Glucose; C-Peptide; Child; Circadian Rhythm; Female; Glucagon; Humans; Hydrocortisone; Insulin; Insulin Resistance; Lipoproteins, HDL; Maternal-Fetal Exchange; Placenta; Postpartum Period; Pregnancy; Pregnancy in Diabetics; Prolactin; Time Factors; Triglycerides; Uterus

Topics: C-Peptide; Diabetes Mellitus; Humans; Insulin; Insulin Antagonists; Insulin Antibodies; Insulin Resistance; Islets of Langerhans; Proinsulin; Receptor, Insulin

Topics: C-Peptide; Carbohydrate Metabolism; Glucose Tolerance Test; Hepatitis, Viral, Human; Humans; Hypoglycemia; Insulin; Insulin Resistance; Liver Cirrhosis; Liver Diseases

Topics: C-Peptide; Fatty Acids, Nonesterified; Glucagon; Glucose; Glycerol; Growth Hormone; Humans; Insulin Resistance; Liver; Prediabetic State; Tritium

Increased glucose level and insulin resistance are major factors in Type 2 diabetes mellitus (T2M), which is chronic and debilitating disease worldwide. Submerged culture medium of Ceriporia lacerata mycelium (CLM) is known to have glucose lowering effects and improving insulin resistance in a mouse model in our previous studies. The main purpose of this clinical trial was to evaluate the functional efficacy and safety of CLM in enrolled participants with impaired fasting blood sugar or mild T2D for 12 weeks.. A total of 72 participants with impaired fasting blood sugar or mild T2D were participated in a randomized, double-blind, placebo-controlled clinical trial. All participants were randomly assigned into the CLM group or placebo group. Fasting blood glucose (FBG), HbA1c, insulin, C-peptide, HOMA-IR, and HOMA-IR by C-peptide were used to assess the anti-diabetic efficacy of CLM for 12 weeks.. In this study, the effectiveness of CLM on lowering the anti-diabetic indicators (C-peptide levels, insulin, and FBG) was confirmed. CLM significantly elicited anti-diabetic effects after 12 weeks of ingestion without showing any side effects in both groups of participants. After the CLM treatment, FBG levels were effectively dropped by 63.9% (ITT), while HOMA-IR level in the CLM group with FBG > 110 mg/dL showed a marked decrease by 34% up to 12 weeks. Remarkably, the effect of improving insulin resistance was significantly increased in the subgroup of participants with insulin resistance, exhibiting effective reduction at 6 weeks (42.5%) and 12 weeks (61%), without observing a recurrence or hypoglycemia. HbA1c levels were also decreased by 50% in the participants with reduced indicators (FBG, insulin, C-peptide, HOMA-IR, and HOMA-IR). Additionally, it is noteworthy that the levels of insulin and C-peptide were significantly reduced despite the CLM group with FBG > 110 mg/dL. No significant differences were detected in the other parameters (lipids, blood tests, and blood pressure) after 12 weeks.. The submerged culture medium of CLM showed clinical efficacy in the improvement of FBG, insulin, C-peptide, HbAc1, and HOMA-index. The microbiome-based medium could benefit patients with T2D, FBG disorders, or pre-diabetes, which could guide a new therapeutic pathway in surging the global diabetes epidemic.

Topics: Blood Glucose; C-Peptide; Culture Media; Diabetes Mellitus, Type 2; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Polyporales

Empagliflozin reduces the risk of cardiovascular disease (CVD) in patients with type 2 diabetes (T2DM) and high cardiovascular risk via mechanisms which have not been fully explained. The mechanisms of such benefit have not been fully understood, and whether empagliflozin can be safely administered as first-line treatment in patients with CVD at the initial stages of glycaemic perturbations remains to be established. We investigated the effects of empagliflozin on insulin resistance, insulin sensitivity and β-cell function indexes in patients with a recent acute coronary event and newly detected dysglycaemia, i.e., impaired glucose tolerance (IGT) or T2DM.. Forty-two patients (mean age 67.5 years, 19% females) with a recent myocardial infarction (n = 36) or unstable angina (n = 6) and newly detected dysglycaemia were randomized to either empagliflozin 25 mg daily (n = 20) or placebo (n = 22). Patients were investigated with stress-perfusion cardiac magnetic resonance imaging before randomization, 7 months after the start of study drug and 3 months following its cessation. Indexes of insulin resistance, sensitivity and β-cell function were calculated based on glucose and insulin values from 2-hour oral glucose tolerance tests (OGTT) and fasting C-peptide. The differences in glucose, insulin, C-peptide, mannose levels and indexes between the two groups were computed by repeated measures ANOVA including an interaction term between the treatment allocation and the time of visit.. After 7 months, empagliflozin significantly decreased glucose and insulin values during the OGTT, whereas C-peptide, mannose and HbA1c did not differ. Empagliflozin significantly improved insulin sensitivity indexes but did not impact insulin resistance and β-cell function. After cessation of the drug, all indexes returned to initial levels. Insulin sensitivity indexes were inversely correlated with left ventricular mass at baseline.. Empagliflozin improved insulin sensitivity indexes in patients with a recent coronary event and drug naïve dysglycaemia. These findings support the safe use of empagliflozin as first-line glucose-lowering treatment in patients at very high cardiovascular risk with newly diagnosed dysglycaemia.. EudraCT number 2015-004571-73.

Topics: Acute Coronary Syndrome; Aged; Benzhydryl Compounds; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucose; Humans; Insulin; Insulin Resistance; Male; Mannose

Nutrition therapy for gestational diabetes mellitus (GDM) has conventionally focused on carbohydrate restriction. In a randomized controlled trial (RCT), we tested the hypothesis that a diet (all meals provided) with liberalized complex carbohydrate (60%) and lower fat (25%) (CHOICE diet) could improve maternal insulin resistance and 24-h glycemia, resulting in reduced newborn adiposity (NB%fat; powered outcome) versus a conventional lower-carbohydrate (40%) and higher-fat (45%) (LC/CONV) diet.. After diagnosis (at ∼28-30 weeks' gestation), 59 women with diet-controlled GDM (mean ± SEM; BMI 32 ± 1 kg/m2) were randomized to a provided LC/CONV or CHOICE diet (BMI-matched calories) through delivery. At 30-31 and 36-37 weeks of gestation, a 2-h, 75-g oral glucose tolerance test (OGTT) was performed and a continuous glucose monitor (CGM) was worn for 72 h. Cord blood samples were collected at delivery. NB%fat was measured by air displacement plethysmography (13.4 ± 0.4 days).. There were 23 women per group (LC/CONV [214 g/day carbohydrate] and CHOICE [316 g/day carbohydrate]). For LC/CONV and CHOICE, respectively (mean ± SEM), NB%fat (10.1 ± 1 vs. 10.5 ± 1), birth weight (3,303 ± 98 vs. 3,293 ± 81 g), and cord C-peptide levels were not different. Weight gain, physical activity, and gestational age at delivery were similar. At 36-37 weeks of gestation, CGM fasting (86 ± 3 vs. 90 ± 3 mg/dL), 1-h postprandial (119 ± 3 vs. 117 ± 3 mg/dL), 2-h postprandial (106 ± 3 vs. 108 ± 3 mg/dL), percent time in range (%TIR; 92 ± 1 vs. 91 ± 1), and 24-h glucose area under the curve values were similar between diets. The %time >120 mg/dL was statistically higher (8%) in CHOICE, as was the nocturnal glucose AUC; however, nocturnal %TIR (63-100 mg/dL) was not different. There were no between-group differences in OGTT glucose and insulin levels at 36-37 weeks of gestation.. A ∼100 g/day difference in carbohydrate intake did not result in between-group differences in NB%fat, cord C-peptide level, maternal 24-h glycemia, %TIR, or insulin resistance indices in diet-controlled GDM.

Topics: Adiposity; Blood Glucose; C-Peptide; Diabetes, Gestational; Diet, Fat-Restricted; Female; Glucose; Humans; Infant, Newborn; Insulin Resistance; Obesity; Pregnancy; Random Allocation

To examine the effects of d-tagatose or stevia preloads on carbohydrate metabolism markers after an oral glucose load, as well as subjective and objective appetite in women with insulin resistance (IR).. Randomized controlled crossover study. Women with IR without T2DM (n = 33; aged 23.4 ± 3.8; BMI 28.1 ± 3.4 kg × m. Our findings suggest that these NNS are not inert. Stevia intake produced an acute response on C-peptide release while increased serum glucose at earlier times. It is possible that NNS affects subjective but not objective appetite. This trial is registered at clinicaltrials.gov as NCT04327245.. NCT04327245.

Topics: Appetite; Blood Glucose; C-Peptide; Cross-Over Studies; Female; Glucose; Hexoses; Humans; Insulin; Insulin Resistance; Stevia; Water

Obesity-associated breast cancer recurrence is mechanistically linked with elevated insulin levels and insulin resistance. Exercise and weight loss are associated with decreased breast cancer recurrence, which may be mediated through reduced insulin levels and improved insulin sensitivity. This is a secondary analysis of the WISER Survivor clinical trial examining the relative effect of exercise, weight loss and combined exercise and weight loss interventions on insulin and insulin resistance. The weight loss and combined intervention groups showed significant reductions in levels of: insulin, C-peptide, homeostatic model assessment 2 (HOMA2) insulin resistance (IR), and HOMA2 beta-cell function (β) compared to the control group. Independent of intervention group, weight loss of ≥10% was associated with decreased levels of insulin, C-peptide, and HOMA2-IR compared to 0-5% weight loss. Further, the combination of exercise and weight loss was particularly important for breast cancer survivors with clinically abnormal levels of C-peptide.

Topics: Blood Glucose; Breast Neoplasms; C-Peptide; Cancer Survivors; Exercise Therapy; Female; Humans; Insulin; Insulin Resistance; Middle Aged; Neoplasm Recurrence, Local; Weight Reduction Programs

Maternal obesity in pregnancy is a pro-inflammatory condition exposing the fetus to an adverse environment. Here, we tested associations of maternal obesity (primary exposures: BMI, leptin) and metabolic parameters (secondary exposures: glucose, C-peptide, and insulin sensitivity) with total serum concentrations of fatty acids in the first trimester of human pregnancy. This cross-sectional study included 123 non-smoking women with singleton pregnancy. In maternal serum, cotinine, leptin, and C-peptide (ELISA), glucose (hexokinase-based test) and fatty acids (gas chromatography) were quantified, and the insulin sensitivity index (IS

Topics: Adult; Body Mass Index; C-Peptide; Cross-Sectional Studies; Fatty Acids, Omega-3; Female; Humans; Insulin Resistance; Obesity, Maternal; Pregnancy; Pregnancy Trimester, First

It was observed that type II diabetes mellitus associated with chronic liver failure improved after stem cell transplantation. However, there were no adequate studies regarding this issue. The aim of this study was to evaluate the effect of stem cell transplantation on associated type II diabetes mellitus and on the liver function tests.. This pilot study included 30 patients of post-hepatitis chronic liver failure who were classified into two groups: Group I included patients with chronic liver cell failure associated with type 2 diabetes. Group II included patients without type II diabetes. Autologous CD34+ and CD133+ stem cells were percutaneously infused into the portal vein. Responders (regarding the improvement of diabetes as well as improvement of liver condition) and non-responders were determined. Patients were followed up for one, three and six months after the intervention evaluating their three-hour glucose tolerance test, C- peptide (Fasting and postprandial), Child-Pugh score and performance score one month, three months, and six months after stem cell therapy.. Both synthetic and excretory functions of the liver were improved in 10 patients (66.66 %) of group I and in 12 patients (80 %) of group II. Significant improvement in the Oral Glucose Tolerance Test in the responders of both the groups was well defined from the 3rd month and this was comparable to changes in liver function tests and Child-Pugh score.. Successful stem cell therapy in chronic liver cell failure patients can improve but not cure the associating type 2 diabetes by improving insulin resistance.

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Egypt; End Stage Liver Disease; Fasting; Female; Follow-Up Studies; Glucose Tolerance Test; Hepatitis C; Humans; Insulin; Insulin Resistance; Liver Cirrhosis; Liver Function Tests; Male; Middle Aged; Pilot Projects; Stem Cell Transplantation; Treatment Outcome

Insulin resistance early after acute myocardial infarction is associated with increased heart failure and mortality. OMEGA-REMODEL was a prospective double-blind 1:1 randomized control trial of patients with AMI. We reported that 6-month treatment with omega-3 fatty acid (O-3FA) 4 g/day attenuated cardiac remodeling accompanied by reduction in inflammation. We hypothesized that insulin resistance modifies the therapeutic effect of O-3FA on post-MI cardiac remodeling. The OMEGA-REMODEL study group was dichotomized according to cohort- and gender-specific median cutoff value of leptin-to-adiponectin ratio (LAR) at baseline (LAR-Hi vs LAR-Lo). Mixed model regression analyses were used to evaluate effect modification of O-3FA on reduction of left ventricular end-systolic volume index (LVESVI) by LAR status. Baseline LAR was evaluated on 325 patients (59 ± 11 years, 81% male). A total of 168 patients were categorized in LAR-Lo, and 157 in LAR-Hi. O-3FA treatment resulted in significant LVESVI reduction in patients with LAR-Lo but not with LAR-Hi (p = 0.0002 vs 0.66, respectively). Mixed model regression analysis showed significant modification of LAR on O-3FA's treatment effect in attenuating LVESVI (p = 0.021). In conclusion, this post-hoc efficacy analysis suggests that LAR status significantly modified O-3FA's treatment effect in attenuating cardiac remodeling. During the convalescent phase of acute infarct healing, patients with lower insulin resistance estimated by LAR appear to derive more therapeutic response from O-3FA toward improvement of LVESVI.

Topics: Adiponectin; Aged; C-Peptide; Double-Blind Method; Fatty Acids, Omega-3; Female; Humans; Insulin Resistance; Leptin; Male; Middle Aged; Myocardial Infarction; Prognosis; Proinsulin; Stroke Volume; Treatment Outcome; Ventricular Remodeling

For those with type 2 diabetes mellitus (T2DM), impact of short-term high-dose glucocorticoid exposure on beta-cell function is unknown. This study aims to compare the impact on beta-cell function and insulin resistance of prednisone 40 mg between adults with newly diagnosed T2DM and healthy adults.. Five adults with T2DM and five healthy adults, all between 18-50 years, were enrolled. T2DM diagnosis was less than one year prior, HbA1c<75 mmol/mol (9.0%), with metformin treatment only. Pre- and post-therapy testing included 75-g oral glucose tolerance, plasma glucose, C-peptide, and insulin. Intervention therapy was prednisone 40mg daily for 3 days.. Upon therapy completion, HOMA-IR did not increase or differ between groups. Percentile difference for HOMA-%B and insulinogenic index in those with T2DM was significantly lower statistically (50.4% and 69.2% respectively) compared to healthy subjects (19% and 32.2%).. Contrary to the assumption that insulin resistance is the main driver of glucocorticoid-induced hyperglycemia, results indicate that decreased beta-cell insulin secretion is the more likely cause in those with T2DM. This is evidenced by significant drops in C-peptide AUC and HOMA-%B and increased glucose AUC in T2DM group only. These results may be caused by increased beta-cell fragility along with reduced recovery ability after glucocorticoid exposure. ClinicalTrials.gov NCT03661684.

Topics: Adult; Blood Glucose; C-Peptide; Case-Control Studies; Diabetes Mellitus, Type 2; Female; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Metformin; Middle Aged; Prednisone; Young Adult

Excess body weight and insulin resistance lead to type 2 diabetes and other major health problems. There is an urgent need for dietary interventions to address these conditions.. To measure the effects of a low-fat vegan diet on body weight, insulin resistance, postprandial metabolism, and intramyocellular and hepatocellular lipid levels in overweight adults.. This 16-week randomized clinical trial was conducted between January 2017 and February 2019 in Washington, DC. Of 3115 people who responded to flyers in medical offices and newspaper and radio advertisements, 244 met the participation criteria (age 25 to 75 years; body mass index of 28 to 40) after having been screened by telephone.. Participants were randomized in a 1:1 ratio. The intervention group (n = 122) was asked to follow a low-fat vegan diet and the control group (n = 122) to make no diet changes for 16 weeks.. At weeks 0 and 16, body weight was assessed using a calibrated scale. Body composition and visceral fat were measured by dual x-ray absorptiometry. Insulin resistance was assessed with the homeostasis model assessment index and the predicted insulin sensitivity index (PREDIM). Thermic effect of food was measured by indirect calorimetry over 3 hours after a standard liquid breakfast (720 kcal). In a subset of participants (n = 44), hepatocellular and intramyocellular lipids were quantified by proton magnetic resonance spectroscopy. Repeated measure analysis of variance was used for statistical analysis.. Among the 244 participants in the study, 211 (87%) were female, 117 (48%) were White, and the mean (SD) age was 54.4 (11.6) years. Over the 16 weeks, body weight decreased in the intervention group by 5.9 kg (95% CI, 5.0-6.7 kg; P < .001). Thermic effect of food increased in the intervention group by 14.1% (95% CI, 6.5-20.4; P < .001). The homeostasis model assessment index decreased (-1.3; 95% CI, -2.2 to -0.3; P < .001) and PREDIM increased (0.9; 95% CI, 0.5-1.2; P < .001) in the intervention group. Hepatocellular lipid levels decreased in the intervention group by 34.4%, from a mean (SD) of 3.2% (2.9%) to 2.4% (2.2%) (P = .002), and intramyocellular lipid levels decreased by 10.4%, from a mean (SD) of 1.6 (1.1) to 1.5 (1.0) (P = .03). None of these variables changed significantly in the control group over the 16 weeks. The change in PREDIM correlated negatively with the change in body weight (r = -0.43; P < .001). Changes in hepatocellular and intramyocellular lipid levels correlated with changes in insulin resistance (both r = 0.51; P = .01).. A low-fat plant-based dietary intervention reduces body weight by reducing energy intake and increasing postprandial metabolism. The changes are associated with reductions in hepatocellular and intramyocellular fat and increased insulin sensitivity.. ClinicalTrials.gov Identifier: NCT02939638.

Topics: Absorptiometry, Photon; Adult; Aged; Blood Glucose; Body Composition; Body Weight; C-Peptide; Cholesterol; Cholesterol, HDL; Cholesterol, LDL; Diet, Fat-Restricted; Diet, Vegan; Energy Intake; Energy Metabolism; Female; Glycated Hemoglobin; Hepatocytes; Humans; Insulin; Insulin Resistance; Intra-Abdominal Fat; Lipid Metabolism; Liver; Male; Middle Aged; Muscle Fibers, Skeletal; Muscle, Skeletal; Obesity; Overweight; Postprandial Period; Proton Magnetic Resonance Spectroscopy; Triglycerides

Sedentary lifestyle increases the risk of type 2 diabetes. The aim of this study was to investigate the impact of different levels of energy turnover (ET; low, medium, and high level of physical activity and the corresponding energy intake) on glucose metabolism at zero energy balance, caloric restriction, and overfeeding.. Daylong glycemia and insulin secretion did not increase with higher ET at all conditions of energy balance (EB, CR, and OF), despite a correspondingly higher CHO intake (Δ low vs. high ET: +86 to 135 g of CHO/d). At CR, daylong glycemia (p = 0.02) and insulin secretion (p = 0.04) were even reduced with high compared with low ET. HOMA-IR was impaired with OF and improved with CR, whereas ET had no effect on fasting insulin sensitivity. A higher ET led to lower postprandial glucose and insulin levels under conditions of CR and OF.. Low-intensity physical activity can significantly improve postprandial glycemic response of healthy individuals, independent of energy balance.

Topics: Adult; Blood Glucose; C-Peptide; Caloric Restriction; Cross-Over Studies; Energy Intake; Energy Metabolism; Exercise; Female; Healthy Volunteers; Homeostasis; Humans; Insulin Resistance; Male; Postprandial Period; Young Adult

Postoperative hyperglycemia is associated with increased rate of surgical site infection, renal failure, and cardiovascular events. The study of insulin sensitivity state before surgery could help in treating postoperative hyperglycemia and preventing iatrogenic hypoglycemia. We studied the postoperative insulin secretion in patients who have a low insulin sensitivity (IR) before surgery compared to patients with normal preoperative insulin sensitivity (IS).. Forty-two consecutive patients, undergoing abdominal surgery, underwent preoperative sequential hyperglycemic-euglycemic clamp (SHEC) in order to measure insulin secretion and to screen patients with low insulin sensitivity (IR) or with normal insulin sensitivity (IS). Patients had been randomized to receive either general anesthesia with epidural or PCA.. Postoperative insulin secretion in IR patients is decreased compared to IS (P = 0.059) and to IR before surgery regardless to the type of analgesia (P < 0.001). In the IS group, postoperative insulin secretion depends on type of analgesia. It is increased when using PCA and decreased when using epidural (P < 0.05). Blood glucose increased after surgery in both IS an IR (P < 0.001). Patients with preoperative insulin resistance had a higher glycemia before and after surgery (P < 0.001). Blood glucose levels were comparable between PCA and epidural patients (P = 0.450).. Insulin secretion is reduced in IR regardless the type of anesthesia. PCA increases insulin secretion, whereas epidural decreases it in patients with normal insulin sensitivity. These findings implicate that after surgery insulin administration is advisable in patients with preoperative insulin resistance while it should be given cautiously in those with normal preoperative insulin sensitivity.

Topics: Abdomen; Aged; Analgesia, Patient-Controlled; Anesthesia, Epidural; Anesthesia, General; Blood Glucose; C-Peptide; Female; Glucose Clamp Technique; Humans; Insulin Resistance; Insulin Secretion; Male; Mass Screening; Middle Aged; Postoperative Period; Preoperative Period

Simvastatin is a cholesterol-lowering drug that is prescribed to lower the risk of cardiovascular disease following high levels of blood cholesterol. There is a possible risk of new-onset diabetes mellitus with statin treatment but the mechanisms behind are unknown. Coenzyme Q10 (CoQ10) supplementation has been found to improve glucose homeostasis in various patient populations and may increase muscle glucose transporter type 4 content. Our aim was to investigate if 8 weeks of CoQ10 supplementation can improve glucose homeostasis in simvastatin-treated subjects. Thirty-five men and women in treatment with a minimum of 40 mg of simvastatin daily were randomized to receive either 2 × 200 mg/day of CoQ10 supplementation or placebo for 8 weeks. Glucose homeostasis was investigated with fasting blood samples, oral glucose tolerance test (OGTT) and intravenous glucose tolerance test. Insulin sensitivity was assessed with the hyperinsulinemic-euglycemic clamp. Different indices were calculated from fasting samples and OGTT as secondary measures of insulin sensitivity. A muscle biopsy was obtained from the vastus lateralis muscle for muscle protein analyzes. There were no changes in body composition, fasting plasma insulin, fasting plasma glucose, or 3-h glucose with intervention, but glycated hemoglobin decreased with time. Glucose homeostasis measured as the area under the curve for glucose, insulin, and C-peptide during OGTT was unchanged after intervention. Insulin secretory capacity was also unaltered after CoQ10 supplementation. Insulin sensitivity was unchanged but hepatic insulin sensitivity increased. No changes in muscle GLUT4 content was observed after intervention. CoQ10 supplementation does not change muscle GLUT4 content, insulin sensitivity, or secretory capacity, but hepatic insulin sensitivity may improve.

Topics: Aged; Blood Glucose; C-Peptide; Female; Glucose Tolerance Test; Glucose Transporter Type 4; Glycated Hemoglobin; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Insulin; Insulin Resistance; Male; Middle Aged; Simvastatin; Ubiquinone

This study aimed to determine whether L-arginine supplementation lasting for 18 months maintained long-lasting effects on diabetes incidence, insulin secretion and sensitivity, oxidative stress, and endothelial function during 108 months among subjects at high risk of developing type 2 diabetes.. One hundred and forty-four middle-aged subjects with impaired glucose tolerance and metabolic syndrome were randomized in 2006 to an L-arginine supplementation (6.4 g orally/day) or placebo therapy lasting 18 months. This period was followed by a 90-month follow-up. The primary outcome was a diagnosis of diabetes during the 108 month study period. Secondary outcomes included changes in insulin secretion (proinsulin/c-peptide ratio), insulin sensitivity (IGI/HOMA-IR), oxidative stress (AOPPs), and vascular function. After the 18 month participation, subjects that were still free of diabetes and willing to continue their participation (104 subjects) were further followed until diabetes diagnosis, with a time span of about 9 years from baseline.. Although results derived from the 18 month of the intervention study demonstrated no differences in the probability of becoming diabetics, at the end of the study, the cumulative incidence of diabetes was of 40.6% in the L-arginine group and of 57.4% in the placebo group. The adjusted HR for diabetes (L-arginine vs. placebo) was 0.66; 95% CI 0.48, 0.91; p < 0.02). Proinsulin/c-peptide ratio (p < 0.001), IGI/HOMA-IR (p < 0.01), and AOPP (p < 0.05) levels were ameliorated in L-arginine compared to placebo.. These results may suggest that the administration of L-arginine could delay the development of T2DM for a long period. This effect could be mediated, in some extent, by L-arginine-induced reduction in oxidative stress.

Topics: Administration, Oral; Arginine; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Diet; Endothelial Cells; Exercise; Follow-Up Studies; Glucose Intolerance; Humans; Insulin; Insulin Resistance; Metabolic Syndrome; Middle Aged; Oxidative Stress; Sample Size; Surveys and Questionnaires; Treatment Outcome

To examine whether lowering plasma glucose concentration with the sodium-glucose transporter-2 inhibitor empagliflozin improves β-cell function in patients with type 2 diabetes mellitus (T2DM).. Patients with T2DM (N = 15) received empagliflozin (25 mg/d) for 2 weeks. β-Cell function was measured with a nine-step hyperglycemic clamp (each step, 40 mg/dL) before and at 48 hours and at 14 days after initiating empagliflozin.. Glucosuria was recorded on days 1 and 14 [mean ± standard error of the mean (SEM), 101 ± 10 g and 117 ± 11 g, respectively] after initiating empagliflozin, as were reductions in fasting plasma glucose levels (25 ± 6 mg/dL and 38 ± 8 mg/dL, respectively; both P < 0.05). After initiating empagliflozin and during the stepped hyperglycemic clamp, the incremental area under the plasma C-peptide concentration curve increased by 48% ± 12% at 48 hours and 61% ± 10% at 14 days (both P < 0.01); glucose infusion rate increased by 15% on day 3 and 16% on day 14, compared with baseline (both P < 0.05); and β-cell function, measured with the insulin secretion/insulin resistance index, increased by 73% ± 21% at 48 hours and 112% ± 20% at 14 days (both P < 0.01). β-cell glucose sensitivity during the hyperglycemic clamp was enhanced by 42% at 14 hours and 54% at 14 days after initiating empagliflozin (both P < 0.01).. Lowering the plasma glucose concentration with empagliflozin in patients with T2DM augmented β-cell glucose sensitivity and improved β-cell function.

Topics: Adult; Benzhydryl Compounds; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucose Clamp Technique; Glucosides; Glycosuria; Humans; Hypoglycemic Agents; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged

Glucagon-like peptide-1 receptor agonists lower blood glucose in type 2 diabetes (T2D) partially through glucose-dependent stimulation of insulin secretion. The aim of this study was to investigate whether beta-cell function (as measured by HOMA2-%B) at baseline affects the glycaemic response to dulaglutide. Dulaglutide-treated patients from AWARD-1, AWARD-3 and AWARD-6 clinical studies were categorised based on their homeostatic model assessment of beta-cell function (HOMA2-%B) tertiles. Changes in glycaemic measures in response to treatment with once-weekly dulaglutide were evaluated in each HOMA2-%B tertile. Patients with low HOMA2-%B had higher baseline glycated haemoglobin (HbA1c), fasting and postprandial blood glucose, and longer duration of diabetes (P < .001, all) (mean low, middle and high tertiles with dulaglutide 1.5 mg: HOMAB-2%B, 31%, 58%, 109%; HbA1c, 8.7%, 7.7%, 7.3%, respectively). At 26 weeks, the low tertile experienced larger reductions in HbA1c compared to the high tertile with dulaglutide 1.5 mg (mean; -1.55% vs. -0.98% [-16.94 vs. -10.71 mmol/mol]). Differences between low and high tertiles disappeared when adjusted for baseline HbA1c (LSM; -1.00 vs. -1.18% [-10.93 vs. -12.90 mmol/mol]). Greater decreases in fasting blood glucose and greater increases in fasting C-peptide were observed in the low tertile. Similar increases in HOMA2-%B were observed in all tertiles. Dulaglutide demonstrated clinically relevant HbA1c reduction irrespective of estimated baseline beta-cell function.

Topics: Aged; Biomarkers; C-Peptide; Cohort Studies; Diabetes Mellitus, Type 2; Disease Progression; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Therapy, Combination; Female; Glucagon-Like Peptide-1 Receptor; Glucagon-Like Peptides; Glycated Hemoglobin; Humans; Hyperglycemia; Hypoglycemia; Hypoglycemic Agents; Immunoglobulin Fc Fragments; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Middle Aged; Recombinant Fusion Proteins

To evaluate the effect of a single preoperative dose of 125 mg methylprednisolone (MP) on glycemic homeostasis early after fast-track total hip and knee arthroplasty.. One-hundred thirty-four patients undergoing elective unilateral total hip arthroplasty and total knee arthroplasty were randomized (1:1) to preoperative intravenous MP 125 mg (group MP) or isotonic saline intravenous (group C). All procedures were performed under spinal anesthesia, using a standardized multimodal analgesic regime. The primary outcome was the change in plasma glucose 2 hours postoperatively, and secondary outcomes included plasma C-peptide concentrations, homeostatic model assessment (HOMA), HOMA-IR (insulin resistance), and HOMA-B (β-cell function). Fasting blood samples were collected at baseline and 2, 6 (nonfasting), 24, and 48 hours after surgery with complete samples from 122 patients (group MP = 62, group C = 60) for analyses.. MP patients had increased plasma glucose levels at 2 hours (adjusted mean [95% CI], 7.4 mmol·L [7.2-7.5] vs 6.0 mmol·L [5.9-6.2]; P = .023) and 6 hours (13.9 mmol·L [13.3-14.5] vs 8.4 mmol·L [7.8-9.0]; P < .001), and in plasma C-peptide 24 hours postoperatively (1675 pmol·L [1573-1778] vs 1248 pmol·L [1145-1351]; P < .001). An impaired insulin response was also observed in group MP as reflected by HOMA-B (P < .001). Additionally, HOMA-IR increased 24 hours postoperatively in group MP compared to group C (P < .001). Parameters were normalized 48 hours postoperatively.. Preoperative administration of MP 125 mg resulted in a transient postoperative increase in plasma glucose and insulin resistance and impaired insulin secretion in response to hyperglycemia.

Topics: Aged; Arthroplasty, Replacement, Hip; Arthroplasty, Replacement, Knee; Biomarkers; Blood Glucose; C-Peptide; Denmark; Double-Blind Method; Drug Administration Schedule; Female; Glucocorticoids; Humans; Hyperglycemia; Insulin Resistance; Male; Methylprednisolone; Middle Aged; Preoperative Care; Risk Factors; Time Factors; Treatment Outcome

Sedentary children have greater risk of developing abnormalities in glucose homeostasis. We investigated whether interrupting sedentary behavior (sitting) with very short periods of walking would improve glucose metabolism without affecting dietary intake in children with overweight or obesity. We hypothesized that interrupting sitting with short bouts of moderate-intensity walking would decrease insulin area under the curve (AUC) during an oral glucose tolerance test (OGTT) compared with uninterrupted sitting.. Overweight/obese (BMI ≥85th percentile) children 7-11 years of age underwent two experimental conditions in random order: prolonged sitting (3 h of continuous sitting) and interrupted sitting (3 min of moderate-intensity walking at 80% of ventilatory threshold every 30 min for 3 h). Insulin, C-peptide, and glucose were measured every 30 min for 3 h during an OGTT. Each session was followed by a buffet meal. Primary outcomes were differences in OGTT hormones and substrates and in buffet meal intake by condition.. Among 35 children with complete data, mixed-model results identified lower insulin and C-peptide in the interrupted condition (. Interrupting sitting with brief moderate-intensity walking improved glucose metabolism without significantly increasing energy intake in children with overweight or obesity. Interrupting sedentary behavior may be a promising intervention strategy for reducing metabolic risk in such children.

Topics: Blood Glucose; C-Peptide; Child; Cross-Over Studies; Energy Intake; Female; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Male; Obesity; Overweight; Risk Reduction Behavior; Sedentary Behavior; Sitting Position; Time Factors; Walking

Type-1 diabetes mellitus (T1DM) is caused by autoimmune insulitis. There are evidences that pregnancy and n-3 fatty acids exhibit suppressive effect on human inflammatory system.. Ninety pregnant women with T1DM were included in the prospective randomized placebo controlled clinical trial. Forty-seven of them were put on standard diabetic diet enriched with EPA and DHA twice a day (EPA 120 mg and DHA 616 mg; Study group) and 43 pregnant diabetic women were on standard diabetic diet with placebo (Control group). Duration of T1DM in all participants was between 5 to 30 years. Blood samples were analyzed from all pregnant women for fasting C-peptide (FC-peptide), fasting plasma glucose (FPG) and HbA1c in each trimester throughout pregnancy and after delivery. Umbilical vein blood was analyzed for fetal C-peptide level, glucose concentration and insulin resistance.. In the Study group FC-peptide concentration raised from 59.6±103.9 pmol/l in first trimester, to 67.7±101.3 pmol/l in the second trimester and to 95.1±152.7 pmol/l in the third trimester. Comparing the FC-peptide values during first and third trimester a statistically significant increase in third trimester was found (P<0.001). In the Control group FC-peptide concentration ranged from 41.7±91.6 pmol/l in the first trimester to 41.2±70.9 mmol/l in the second trimester while in the third trimester it reached 52.4±95.3 pmol/l. Comparing the FC-peptide values during first and third trimester the statistical difference was not significant.. Combining of LC n-3 PUFAs and pregnancy yields immunological tolerance and stimulates the production of endogenous insulin in women with T1DM.

Topics: Adult; Biomarkers; C-Peptide; Combined Modality Therapy; Diabetes Mellitus, Type 1; Diet, Diabetic; Dietary Supplements; Docosahexaenoic Acids; Eicosapentaenoic Acid; Female; Fetal Blood; Glycated Hemoglobin; Humans; Hyperglycemia; Hypoglycemia; Hypoglycemic Agents; Insulin; Insulin Resistance; Maternal Nutritional Physiological Phenomena; Pregnancy; Pregnancy in Diabetics; Young Adult

The role of glucose effectiveness (S. Fourteen participants with type 2 diabetes underwent three trials (IWT, CWT and no training) in a crossover study. Exclusion criteria were exogenous insulin treatment, smoking, pregnancy, contraindications to structured physical activity and participation in recurrent training (>90 min/week). The trials were performed in a randomised order (computerised-generated randomisation). IWT and CWT consisted of ten supervised treadmill walking sessions, each lasting 60 min, over 2 weeks. IWT was performed as repeated cycles of 3 min slow walking and 3 min fast walking (aiming for 54% and 89% of [Formula: see text], respectively, which was measured during the last minute of each interval), and CWT was performed aiming for a moderate walking speed (73% of [Formula: see text]). A two-step (pancreatic and hyperinsulinaemic) hyperglycaemic clamp was implemented before and after each trial. All data were collected in a hospitalised setting. Neither participants nor assessors were blinded to the trial interventions.. Thirteen individuals completed all procedures and were included in the analyses. IWT improved S. Two weeks of IWT, but not CWT, improves S. ClinicalTrials.gov NCT02320526 FUNDING: CFAS is supported by a grant from TrygFonden. During the study period, the Centre of Inflammation and Metabolism (CIM) was supported by a grant from the Danish National Research Foundation (DNRF55). The study was further supported by grants from Diabetesforeningen, Augustinusfonden and Krista og Viggo Petersens Fond. CIM/CFAS is a member of DD2-the Danish Center for Strategic Research in Type 2 Diabetes (the Danish Council for Strategic Research, grant no. 09-067009 and 09-075724).

Topics: Aged; Blood Glucose; Body Composition; C-Peptide; Cross-Over Studies; Diabetes Mellitus, Type 2; Energy Metabolism; Exercise; Female; Humans; Insulin; Insulin Resistance; Kinetics; Male; Middle Aged; Walking

Pancreatic β-cell dysfunction is an important factor in the development of type 2 diabetes mellitus. This study aimed to estimate the association between β-cell dysfunction and prognosis of nondiabetic patients with ischemic stroke.. Patients with ischemic stroke without a history of diabetes mellitus in the ACROSS-China (Abnormal Glucose Regulation in Patients with Acute Stroke across China) registry were included. Disposition index was estimated as computer-based model of homeostatic model assessment 2-β%/homeostatic model assessment 2-insulin resistance based on fasting C-peptide level. Outcomes included stroke recurrence, all-cause death, and dependency (modified Rankin Scale, 3-5) at 12 months after onset.. Among 1171 patients, 37.2% were women with a mean age of 62.4 years. At 12 months, 167 (14.8%) patients had recurrent stroke, 110 (9.4%) died, and 184 (16.0%) had a dependency. The first quartile of the disposition index was associated with an increased risk of stroke recurrence (adjusted hazard ratio, 3.57; 95% confidence interval, 2.13-5.99) and dependency (adjusted hazard ratio, 2.30; 95% confidence interval, 1.21-4.38); both the first and second quartiles of the disposition index were associated with an increased risk of death (adjusted hazard ratio, 5.09; 95% confidence interval, 2.51-10.33; adjusted hazard ratio, 2.42; 95% confidence interval, 1.17-5.03) compared with the fourth quartile. Using a multivariable regression model with restricted cubic spline, we observed an L-shaped association between the disposition index and the risk of each end point.. In this large-scale registry, β-cell dysfunction was associated with an increased risk of 12-month poor prognosis in nondiabetic patients with ischemic stroke.

Topics: Adult; Aged; Aged, 80 and over; Brain Ischemia; C-Peptide; Fasting; Female; Follow-Up Studies; Humans; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Models, Cardiovascular; Prognosis; Registries; Stroke

Previous work has shown that potentiation of insulin release is impaired in non-diabetic insulin resistance; we tested the hypothesis that this defect may be related to altered glucagon-like peptide-1 (GLP-1) release. On consecutive days, 82 non-diabetic individuals, classified as insulin sensitive (IS,

Topics: Adult; Biomarkers; Blood Glucose; C-Peptide; Dietary Carbohydrates; Fatty Acids, Nonesterified; Female; Glucagon-Like Peptide 1; Humans; Insulin; Insulin Resistance; Male; Meals; Postprandial Period; Time Factors

Glucagon-like peptide-1 (GLP-1), an incretin hormone, is released in response to food intake. It is unclear how meals high in protein (HP) and monounsaturated fat (HMF) affect GLP-1 response.. To examine the effect of a HP versus a HMF meal on GLP-1 response.. Twenty-four overweight/obese participants consumed two meals (HP: 31.9 % energy from protein; HMF: 35.2 % fat and 20.7 % monounsaturated fat) in a random order. Both meals contained the same energy and carbohydrate content. GLP-1, insulin, glucagon, C-peptide, and glucose were assessed from blood drawn in the fasting and postprandial states. The effect of meal condition on hormone and glucose responses and appetite ratings were assessed by repeated measures analysis.. Statistically significant (p < 0.01) time by meal condition effect was observed on active GLP-1, total GLP-1, insulin, C-peptide, and glucagon, but not glucose (p = 0.83). Area under the curve was significantly higher during the HP versus the HMF meal conditions for active GLP-1 (23.7 %; p = 0.0007), total GLP-1 (12.2 %; p < 0.0001), insulin (54.4 %; p < 0.0001), C-peptide (14.8 %; p < 0.0001), and glucagon (40.7 %; p < 0.0001). Blood glucose was not different between the HP versus HMF conditions (-4.8 %; p = 0.11). Insulin sensitivity was higher during the HMF versus HP conditions (Matsuda index mean difference: 16.3 %; p = 0.007). Appetite ratings were not different by meal condition.. GLP-1 and insulin responses were higher during the HP condition. However, no difference was found in blood glucose between conditions, and insulin sensitivity was higher during the HMF condition, indicating that a HMF meal may be optimal at regulating blood glucose in overweight/obese individuals without type 2 diabetes.

Topics: Adolescent; Adult; Aged; Appetite; Blood Glucose; Body Mass Index; C-Peptide; Cross-Over Studies; Exercise; Female; Glucagon; Glucagon-Like Peptide 1; Humans; Insulin; Insulin Resistance; Male; Meals; Mental Recall; Middle Aged; Obesity; Overweight; Postprandial Period; Young Adult

A bidirectional relationship exists between diabetes and periodontitis. In the present clinical trial, we evaluated the effects of non-surgical periodontal therapy (NSPT) on insulin resistance in patients with type II diabetes mellitus (DM) and chronic periodontitis.. Forty chronic periodontitis patients with type II DM were selected and equally allocated to case and control groups. All patients were assessed for periodontal parameters and systemic parameters. The case group received NSPT, and both groups were re-evaluated after 3 months.. All periodontal parameters were found to be significantly improved in the case group compared to the control group 3 months after NSPT. The mean differences in systemic parameters, such as fasting serum C-peptide, Homeostasis Assessment (HOMA) Index-insulin resistance, and HOMA-insulin sensitivity, from baseline to 3 months for the case group were 0.544 ± 0.73, 0.54 ± 0.63, and -25.44 ± 36.81, respectively; for the control group, they were significant at -1.66 ± 1.89, -1.48 ± 1.86, and 31.42 ± 38.82 respectively (P < 0.05). There was a significant decrease in fasting blood glucose and glycosylated hemoglobin A1c from baseline to 3 months in the case group (P < 0.05).. The present study showed that periodontal inflammation could affect glycemic control and insulin resistance. Effective periodontal therapy reduced insulin resistance and improved periodontal health status and insulin sensitivity in patients with type II DM and chronic periodontitis.

Topics: C-Peptide; Chronic Periodontitis; Diabetes Mellitus, Type 2; Homeostasis; Humans; Insulin Resistance

To examine the lipid and glycaemic effects of 52 weeks of treatment with evolocumab.. The Durable Effect of PCSK9 Antibody Compared with Placebo Study (DESCARTES) was a 52-week placebo-controlled trial of evolocumab that randomized 905 patients from 88 study centres in 9 countries, with 901 receiving at least one dose of study drug. For this post-hoc analysis, DESCARTES patients were categorized by baseline glycaemic status: type 2 diabetes, impaired fasting glucose (IFG), metabolic syndrome (MetS) or none of these. Monthly subcutaneous evolocumab (420 mg) or placebo was administered. The main outcomes measured were percentage change in LDL-cholesterol (LDL-C) at week 52 and safety.. A total of 413 patients had dysglycaemia (120, type 2 diabetes; 293, IFG), 289 had MetS (194 also had IFG) and 393 had none of these conditions. At week 52, evolocumab reduced LDL-C by >50% in all subgroups, with favourable effects on other lipids. No significant differences in fasting plasma glucose, HbA1c, insulin, C-peptide or HOMA indices were seen in any subgroup between evolocumab and placebo at week 52. The overall incidence of new-onset diabetes mellitus did not differ between placebo (6.6%) and evolocumab (5.6%); in those with baseline normoglycaemia, the incidences were 1.9% and 2.7%, respectively. Incidences of AEs were similar in evolocumab- and placebo-treated patients.. Evolocumab showed encouraging safety and efficacy at 52 weeks in patients with or without dysglycaemia or MetS. Changes in glycaemic parameters did not differ between evolocumab- and placebo-treated patients within the glycaemic subgroups examined.

Topics: Adult; Aged; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Anticholesteremic Agents; Blood Glucose; C-Peptide; Case-Control Studies; Cholesterol, HDL; Cholesterol, LDL; Diabetes Mellitus, Type 2; Female; Glucose Intolerance; Glycated Hemoglobin; Humans; Hypercholesterolemia; Insulin; Insulin Resistance; Male; Metabolic Syndrome; Middle Aged; Treatment Outcome; Triglycerides

Sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) cause weight loss and metabolic improvement, but results of published studies are contradictory.. The aim of this study was to compare the effects of SG and RYGB on ghrelin, leptin, and glucose homeostasis in a randomized controlled trial.. University hospital, Poland.. Seventy-two morbidly obese patients were randomly selected to undergo either SG (n = 36) or RYGB (n = 36). Fasting ghrelin, leptin, glucose, insulin, C-peptide, glucagon, glycated hemoglobin, and homeostasis model assessment of insulin resistance were assessed preoperatively and at 1, 6, and 12 months postoperatively. No differences were found in anthropometric and biochemical parameters between the study groups at baseline.. Sixty-nine (95.8%) patients completed the study. Percentage of excess weight loss at 12 months was 67.6±19.3% after SG and 64.2±18.5% after RYGB (P>.05). Fasting ghrelin levels decreased 1 month after SG (from 76.8 pmol/L to 35.3 pmol/L; P<.05) and remained reduced until 12 months (41.6 pmol/L; P<.05) but increased 12 months after RYGB from 74.6 pmol/L to 130.2 pmol/L (P<.05). Leptin, glucose, insulin, and C-peptide concentrations and glycated hemoglobin and homeostasis model assessment of insulin resistance values decreased significantly in both groups during 12 months.. RYGB and SG induce comparable weight loss and improvement in metabolism of glucose. Ghrelin levels decrease after SG and increase after RYGB, but this difference does not affect similar outcomes of these procedures during 1-year follow-up. The contribution of ghrelin to weight loss or metabolic benefits after bariatric surgery is not straightforward, but rather influenced by multiple factors.

Topics: Adolescent; Adult; Blood Glucose; C-Peptide; Female; Gastrectomy; Gastric Bypass; Ghrelin; Glucagon; Glycated Hemoglobin; Homeostasis; Humans; Insulin Resistance; Laparoscopy; Leptin; Male; Middle Aged; Obesity, Morbid; Operative Time; Prospective Studies; Weight Loss; Young Adult

Plant-derived foods rich in polyphenols are associated with several cardiometabolic health benefits, such as reduced postprandial hyperglycaemia. However, their impact on whole-body insulin sensitivity using the hyperinsulinaemic-euglycaemic clamp technique remains under-studied. We aimed to determine the effects of strawberry and cranberry polyphenols (SCP) on insulin sensitivity, glucose tolerance, insulin secretion, lipid profile, inflammation and oxidative stress markers in free-living insulin-resistant overweight or obese human subjects (n 41) in a parallel, double-blind, controlled and randomised clinical trial. The experimental group consumed an SCP beverage (333 mg SCP) daily for 6 weeks, whereas the Control group received a flavour-matched Control beverage that contained 0 mg SCP. At the beginning and at the end of the experimental period, insulin sensitivity was assessed by a hyperinsulinaemic-euglycaemic clamp, and glucose tolerance and insulin secretion by a 2-h oral glucose tolerance test (OGTT). Insulin sensitivity increased in the SCP group as compared with the Control group (+0·9 (sem 0·5)×10-3 v. -0·5 (sem 0·5)×10-3 mg/kg per min per pmol, respectively, P=0·03). Compared with the Control group, the SCP group had a lower first-phase insulin secretion response as measured by C-peptide levels during the first 30 min of the OGTT (P=0·002). No differences were detected between the two groups for lipids and markers of inflammation and oxidative stress. A 6-week dietary intervention with 333 mg of polyphenols from strawberries and cranberries improved insulin sensitivity in overweight and obese non-diabetic, insulin-resistant human subjects but was not effective in improving other cardiometabolic risk factors.

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus; Double-Blind Method; Female; Fragaria; Fruit; Glucose Tolerance Test; Humans; Inflammation; Insulin; Insulin Resistance; Lipids; Male; Middle Aged; Obesity; Oxidative Stress; Plant Extracts; Polyphenols; Vaccinium macrocarpon

While simultaneous pancreas kidney transplant (SPKTx) is a therapeutic option for patients with type 1 diabetes (T1DM) and renal failure, few centers offer SPKTx to "select" non-T1DM patients. To address concerns that existing insulin resistance may limit the benefits of the pancreas allograft among non-T1DM, we compared several indices of glucose homeostasis, in "select" non-T1DM and T1DM patients who received SPKTx.. Criteria for "select" non-T1DM included the following: positive C-peptide, BMI <30 kg/m(2) , treatment with oral agents before insulin initiation, and insulin at <1 unit/kg/d. We compared several indices of glucose homeostasis within 1 yr post-SPKTx among seven "select" patients with non-T1DM and nine patients with T1DM with similar age, BMI, and immunosuppression. Measurements of insulin resistance included the following: homeostatic model, insulin sensitivity index, and insulin-glucose ratio; insulin secretion measures included the following: corrected insulin response.. Non-T1DM had similar pre-transplant metabolic (fasting glucose, HbA1c, blood pressure, and lipid) parameters to the T1DM cohort. There were no significant differences in the various measures of insulin resistance and secretion between T1DM and "select" non-T1DM patients.. Our results suggest SPKTx should be considered in the therapeutic armamentarium among carefully select non-T1DM with features of minimal insulin resistance; however, a larger cohort with longer follow-up is needed to confirm our results.

Topics: Adolescent; Adult; Aged; Blood Glucose; C-Peptide; Child; Diabetes Mellitus, Type 1; Female; Follow-Up Studies; Homeostasis; Humans; Insulin Resistance; Kidney Transplantation; Male; Middle Aged; Pancreas Transplantation; Prognosis; Prospective Studies; Risk Factors; Young Adult

Children whose parents have diabetes are at increased risk for developing type 2 diabetes. This report assessed relationships between parental diabetes status and baseline demographics, anthropometrics, metabolic measurements, insulin sensitivity, and β-cell function in children recently diagnosed with type 2 diabetes.. The sample included 632 youth (aged 10-17 years) diagnosed with type 2 diabetes for <2 years who participated in the TODAY clinical trial. Medical history data were collected at baseline by self-report from parents and family members. Youth baseline measurements included an oral glucose tolerance test and other measures collected by trained study staff.. Youth exposed to maternal diabetes during pregnancy (whether the mother was diagnosed with diabetes prior to pregnancy or had gestational diabetes mellitus) were diagnosed at younger ages (by 0.6 years on average), had greater dysglycemia at baseline (HbA1c increased by 0.3% [3.4 mmol/mol]), and had reduced β-cell function compared with those not exposed (C-peptide index 0.063 vs. 0.092). The effect of maternal diabetes on β-cell function was observed in non-Hispanic blacks and Hispanics but not whites. Relationships with paternal diabetes status were minimal.. Maternal diabetes prior to or during pregnancy was associated with poorer glycemic control and β-cell function overall but particularly in non-Hispanic black and Hispanic youth, supporting the hypothesis that fetal exposure to aberrant metabolism may have long-term effects. More targeted research is needed to understand whether the impact of maternal diabetes is modified by racial/ethnic factors or whether the pathway to youth-onset type 2 diabetes differs by race/ethnicity.

Topics: Adolescent; Black or African American; Blood Glucose; C-Peptide; Child; Diabetes Mellitus, Type 2; Diabetes, Gestational; Ethnicity; Family Health; Female; Glucose Tolerance Test; Hispanic or Latino; Humans; Hyperglycemia; Insulin Resistance; Insulin-Secreting Cells; Linear Models; Male; Parents; Pregnancy; Risk Factors; White People

PlanHab is a planetary habitat simulation study. The atmosphere within future space habitats is anticipated to have reduced Po2, but information is scarce as to how physiological systems may respond to combined exposure to moderate hypoxia and reduced gravity. This study investigated, using a randomized-crossover design, how insulin sensitivity, glucose tolerance, and circulating lipids were affected by 16 days of horizontal bed rest in normobaric normoxia [NBR: FiO2 = 0.209; PiO2 = 133.1 (0.3) mmHg], horizontal bed rest in normobaric hypoxia [HBR: FiO2 = 0.141 (0.004); PiO2 = 90.0 (0.4) mmHg], and confinement in normobaric hypoxia combined with daily moderate intensity exercise (HAMB). A mixed-meal tolerance test, with arterialized-venous blood sampling, was performed in 11 healthy, nonobese men (25-45 yr) before (V1) and on the morning ofday 17of each intervention (V2). Postprandial glucose and c-peptide response were increased at V2 of both bed rest interventions (P< 0.05 in each case), with c-peptide:insulin ratio higher at V2 in HAMB and HBR, both in the fed and fasted state (P< 0.005 in each case). Fasting total cholesterol was reduced at V2 in HAMB [-0.47 (0.36) mmol/l;P< 0.005] and HBR [-0.55 (0.41) mmol/l;P< 0.005]. Fasting HDL was lower at V2 in all interventions, with the reduction observed in HBR [-0.30 (0.21) mmol/l] greater than that measured in HAMB [-0.13 (0.14) mmol/l;P< 0.005] and NBR [-0.17 (0.15) mmol/l;P< 0.05]. Hypoxia did not alter the adverse effects of bed rest on insulin sensitivity and glucose tolerance but appeared to increase insulin clearance. The negative effect of bed rest on HDL was compounded in hypoxia, which may have implications for long-term health of those living in future space habitats.

Topics: Adult; Bed Rest; C-Peptide; Cholesterol; Cross-Over Studies; Fasting; Glucose; Glucose Tolerance Test; Humans; Hypogravity; Hypoxia; Insulin; Insulin Resistance; Lipids; Male

Preclinical studies in endometrial cancer (EC) show that metformin reduces cellular proliferation by PI3K-AKT-mTOR inhibition. We tested the hypothesis that short-term presurgical metformin reduces cellular proliferation in atypical endometrial hyperplasia (AEH) and endometrioid EC, and assessed the feasibility of using phosphorylated PI3K-AKT-mTOR proteins as tissue end points.. Women with AEH or EC received metformin 850 mg twice a day or no drug in the presurgical window between diagnosis and hysterectomy. Before and after the window, tissue samples were obtained; serum markers of insulin resistance (e.g. homeostasis model of assessment of insulin resistance index) were determined; and anthropometrics measured (e.g. BMI). Cell proliferation (Ki-67) and PI3K-AKT-mTOR phosphostatus were assessed by immunohistochemistry and scored blinded to treatment.. Twenty-eight metformin-treated and 12 untreated patients, well matched for age and BMI, completed the study. Metformin treatment (median 20 days, range 7-34) was associated with a 17.2% reduction in tumour Ki-67 (95% CI -27.4, -7.0, P=0.002), in a dose-dependent manner. Tumour PI3K-AKT-mTOR protein phosphostatus varied but the effects were not significant after adjusting for changes in controls.. Short-term metformin was associated with reduced Ki-67 expression in EC. Changes in tumour PI3K-AKT-mTOR protein phosphostatus were seen in both groups. Future studies should address the variability attributed to different sampling techniques including devascularisation of the uterus at hysterectomy.

Topics: Aged; Aged, 80 and over; Blood Glucose; C-Peptide; Carcinoma, Endometrioid; Endometrial Hyperplasia; Endometrial Neoplasms; Enzyme-Linked Immunosorbent Assay; Female; Humans; Hypoglycemic Agents; Hysterectomy; Immunohistochemistry; Insulin; Insulin Resistance; Ki-67 Antigen; Metformin; Middle Aged; Myometrium; Neoadjuvant Therapy; Neoplasm Grading; Neoplasm Invasiveness; Phosphatidylinositol 3-Kinases; Phosphorylation; Preoperative Care; Proto-Oncogene Proteins c-akt; TOR Serine-Threonine Kinases; Treatment Outcome

The changes in blood glucose concentrations that result from an oral glucose challenge are dependent on the rate of gastric emptying, the rate of glucose absorption and the rate of insulin-driven metabolism that include the incretins, glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1). The rate of insulin-driven metabolism is clearly altered in obese subjects, but it is controversial which of these factors is predominant. We aimed to quantify gastric emptying, plasma insulin, C-peptide, glucagon and glucose responses, as well as incretin hormone secretions in obese subjects and healthy controls during increasing glucose loads.. The study was conducted as a randomized, double-blind, parallel-group trial in a hospital research unit. A total of 12 normal weight (6 men and 6 women) and 12 non-diabetic obese (BMI > 30, 6 men and 6 women) participants took part in the study. Subjects received intragastric loads of 10 g, 25 g and 75 g glucose dissolved in 300 ml tap water.. Main outcome measures were plasma GLP-1 and GIP, plasma glucagon, glucose, insulin, C-peptide and gastric emptying. The primary findings are: i) insulin resistance (P < 0.001) and hyperinsulinemia (P < 0.001); ii) decreased insulin disposal (P < 0.001); iii) trend for reduced GLP-1 responses at 75 g glucose; and iv) increased fasting glucagon levels (P < 0.001) in obese subjects.. It seems that, rather than changes in incretin secretion, fasting hyperglucagonemia and consequent hyperglycemia play a role in reduced disposal of insulin, contributing to hyperinsulinemia and insulin resistance.. ClinicalTrials.gov NCT01875575.

Topics: Adult; Blood Glucose; Body Mass Index; Body Weight; C-Peptide; Case-Control Studies; Diabetes Mellitus; Double-Blind Method; Female; Gastric Emptying; Gastric Inhibitory Polypeptide; Glucagon; Glucagon-Like Peptide 1; Glucose; Humans; Incretins; Insulin; Insulin Resistance; Male; Middle Aged; Obesity; Young Adult

In the IMMEDIATE Trial, intravenous glucose-insulin-potassium (GIK) was started as early as possible for patients with suspected acute coronary syndrome by ambulance paramedics in communities. In the IMMEDIATE Biological Mechanism Cohort substudy, reported here, we investigated potential modes of GIK action on specific circulating metabolic components. Specific attention was given to suppression of circulating oxygen-wasting free fatty acids (FFAs) that had been posed as part of the early GIK action related to averting cardiac arrest.. We analyzed the changes in plasma levels of FFA, glucose, C-peptide, and the homeostasis model assessment (HOMA) index.. With GIK, there was rapid suppression of FFA levels with estimated levels for GIK and placebo groups after 2 hours of treatment of 480 and 781 μmol/L (P<.0001), even while patterns of FFA saturation remained unchanged. There were no significant changes in the HOMA index in the GIK or placebo groups (HOMA index: placebo 10.93, GIK 12.99; P = .07), suggesting that GIK infusions were not countered by insulin resistance. Also, neither placebo nor GIK altered endogenous insulin secretion as reflected by unchanging C-peptide levels.. These mechanistic observations support the potential role of FFA suppression in very early cardioprotection by GIK. They also suggest that the IMMEDIATE Trial GIK formula is balanced with respect to its insulin and glucose composition, as it induced no endogenous insulin secretion.

Topics: Acute Coronary Syndrome; Aged; Angina Pectoris; Blood Glucose; C-Peptide; Early Medical Intervention; Electrocardiography; Emergency Medical Services; Fatty Acids, Nonesterified; Female; Glucose; Heart Arrest; Humans; Hypoglycemic Agents; Infusions, Intravenous; Insulin; Insulin Resistance; Male; Middle Aged; Non-ST Elevated Myocardial Infarction; Potassium; ST Elevation Myocardial Infarction

To compare pharmacokinetics (PK) and pharmacodynamics (PD) of insulin glargine in type 2 diabetes mellitus (T2DM) after evening versus morning administration.. Ten T2DM insulin-treated persons were studied during 24-h euglycemic glucose clamp, after glargine injection (0.4 units/kg s.c.), either in the evening (2200 h) or the morning (1000 h).. The 24-h glucose infusion rate area under the curve (AUC0-24h) was similar in the evening and morning studies (1,058 ± 571 and 995 ± 691 mg/kg × 24 h, P = 0.503), but the first 12 h (AUC0-12h) was lower with evening versus morning glargine (357 ± 244 vs. 593 ± 374 mg/kg × 12 h, P = 0.004), whereas the opposite occurred for the second 12 h (AUC12-24h 700 ± 396 vs. 403 ± 343 mg/kg × 24 h, P = 0.002). The glucose infusion rate differences were totally accounted for by different rates of endogenous glucose production, not utilization. Plasma insulin and C-peptide levels did not differ in evening versus morning studies. Plasma glucagon levels (AUC0-24h 1,533 ± 656 vs. 1,120 ± 344 ng/L/h, P = 0.027) and lipolysis (free fatty acid AUC0-24h 7.5 ± 1.6 vs. 8.9 ± 1.9 mmol/L/h, P = 0.005; β-OH-butyrate AUC0-24h 6.8 ± 4.7 vs. 17.0 ± 11.9 mmol/L/h, P = 0.005; glycerol, P < 0.020) were overall more suppressed after evening versus morning glargine administration.. The PD of insulin glargine differs depending on time of administration. With morning administration insulin activity is greater in the first 0-12 h, while with evening administration the activity is greater in the 12-24 h period following dosing. However, glargine PK and plasma C-peptide levels were similar, as well as glargine PD when analyzed by 24-h clock time independent of the time of administration. Thus, the results reflect the impact of circadian changes in insulin sensitivity in T2DM (lower in the night-early morning vs. afternoon hours) rather than glargine per se.

Topics: Aged; Blood Glucose; C-Peptide; Circadian Rhythm; Cross-Over Studies; Diabetes Mellitus, Type 2; Drug Administration Schedule; Fatty Acids, Nonesterified; Female; Glucose; Glucose Clamp Technique; Humans; Hypoglycemic Agents; Injections; Insulin Glargine; Insulin Resistance; Insulin, Long-Acting; Male; Middle Aged

The effects of 12 weeks of supplementation with a dieckol-rich extract (AG-dieckol) from brown algae, Ecklonia cava, on glycemic parameters, serum biochemistry, and hematology were investigated in this study. Eighty pre-diabetic male and female adults were enrolled in a randomized, double-blind, placebo-controlled trial with parallel-group design. Subjects were randomly allocated into two groups designated as placebo and AG-dieckol (1500 mg per day). Compared with the placebo group, the AG-dieckol group showed a significant decrease in postprandial glucose levels after 12 weeks. The AG-dieckol group also showed a significant decrease in insulin and C-peptide levels after 12 weeks, but there was no significant difference between the AG-dieckol and placebo groups. There were no significant adverse events related to the consumption of AG-dieckol, and biochemical and hematological parameters were maintained within the normal range during the intervention period. In conclusion, these results demonstrate that AG-dieckol supplementation significantly contributes to lowering postprandial hyperglycemia and in reducing insulin resistance. Furthermore, we believe that based on these results the consumption of phlorotannin-rich foods such as marine algae may be useful for the treatment of diabetes.

Topics: Benzofurans; Biological Products; C-Peptide; Diabetes Mellitus, Type 2; Dietary Supplements; Double-Blind Method; Female; Humans; Hyperglycemia; Hyperinsulinism; Hypoglycemic Agents; Insulin; Insulin Resistance; Male; Middle Aged; Pacific Ocean; Phaeophyceae; Prediabetic State; Republic of Korea; Seaweed

To assess the glucose-stimulated insulin secretion effect of imeglimin in patients with type 2 diabetes.. We conducted a double-blind, randomized, placebo-controlled study in 33 patients with type 2 diabetes [glycated haemoglobin 6.8 ± 0.1% (51 mmol/mol)], who were drug-naïve or withdrawn from their previous metformin monotherapy for 2 weeks and received imeglimin 1500 mg twice daily or placebo for 1 week. Glucose-stimulated insulin secretion was assessed using a hyperglycaemic clamp. The primary endpoint was insulin secretion as defined by total insulin response [incremental area under the curve (iAUC)0-45 min ] and insulin secretion rate (ISR) calculated from C-peptide deconvolution. β-cell glucose sensitivity at steady state (second phase: 25-45 min), hepatic insulin extraction and insulin clearance were also calculated.. Imeglimin treatment for 7 days raised the insulin secretory response to glucose by +112% (iAUC0-45 , p = 0.035), first-phase ISR by +110% (p = 0.034) and second-phase ISR by +29% (p = 0.031). Imeglimin improved β-cell glucose sensitivity by +36% (p = 0.034) and tended to decrease hepatic insulin extraction (-13%; p = 0.056). Imeglimin did not affect glucagon secretion.. In patients with type 2 diabetes, imeglimin improves β-cell function, which may contribute to the glucose-lowering effect observed with imeglimin in clinical trials.

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Double-Blind Method; Female; Glucagon; Glucose Clamp Technique; Hepatobiliary Elimination; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Middle Aged; Triazines

Oxidative stress plays an important role in pathogenesis of diabetes mellitus and its complications. Our previous study has shown glucose lowering effect produced by 3 months supplementation of Nigella sativa (NS) in combination with oral hypoglycemic drugs among type 2 diabetics. This study explored the long term glucose lowering effect (over one year) of NS in patients with type 2 diabetes mellitus on oral hypoglycemic drugs and to study its effect on redox status of such patients.. 114 type 2 diabetic patients on standard oral hypoglycemic drugs were assigned into 2 groups by convenience. The control group (n = 57) received activated charcoal as placebo and NS group (n = 57) received 2g NS, daily, for one year in addition to their standard medications. Fasting blood glucose (FBG), glycosylated hemoglobin (HbA1c), C- peptide, total antioxidant capacity (TAC), superoxide dismutase (SOD), catalase (CAT), glutathione and thiobarbituric acid reactive substances (TBARS) at the baseline, and every 3 months thereafter were determined. Insulin resistance and β-cell activity were calculated using HOMA 2 calculator.. Comparison between the two groups showed a significant drop in FBG (from 180 ± 5.75 to 180 ± 5.59 in control Vs from 195 ± 6.57 to 172 ± 5.83 in NS group), HbA1c (from 8.2 ± 0.12 to 8.5 ± 0.14 in control VS from 8.6 ± 0.13 to 8.2 ± 0.14 in NS group), and TBARS (from 48.3 ± 6.89 to 52.9 ± 5.82 in control VS from 54.1 ± 4.64 to 41.9 ± 3.16 in NS group), in addition to a significant elevation in TAC, SOD and glutathione in NS patients compared to controls. In NS group, insulin resistance was significantly lower, while β-cell activity was significantly higher than the baseline values during the whole treatment period.. Long term supplementation with Nigella sativa improves glucose homeostasis and enhances antioxidant defense system in type 2 diabetic patients treated with oral hypoglycemic drugs.. Clinical Trials Registry-India (CTRI) CTRI/2013/06/003781.

Topics: Adult; Antioxidants; Blood Glucose; C-Peptide; Catalase; Diabetes Mellitus; Female; Glutathione; Humans; Hypoglycemic Agents; Insulin Resistance; Male; Middle Aged; Nigella sativa; Oxidative Stress; Plant Extracts; Superoxide Dismutase; Thiobarbituric Acid Reactive Substances

Parameter reproducibility is necessary to perform longitudinal studies where parameters are assessed to monitor disease progression or effect of therapy but are also useful in powering the study, i.e., to define how many subjects should be studied to observe a given effect. The assessment of parameter reproducibility is usually accomplished by methods that do not take into account the fact that these parameters are estimated with uncertainty. This is particularly relevant in physiological and clinical studies where usually reproducibility cannot be assessed by multiple testing and is usually assessed from a single replication of the test. Working in a suitable stochastic framework, here we propose a new index (S) to measure reproducibility that takes into account parameter uncertainty and is particularly suited to handle the normal testing conditions of physiological and clinical investigations. Simulation results prove that S, by properly taking into account parameter uncertainty, is more accurate and robust than the methods available in the literature. The new metric is applied to assess reproducibility of insulin sensitivity and β-cell responsivity of a mixed-meal tolerance test from data obtained in the same subjects retested 1 wk apart. Results show that the indices of insulin sensitivity and β-cell responsivity to glucose are well reproducible. We conclude that the oral minimal models provide useful indices that can be used safely in prospective studies or to assess the efficacy of a given therapy.

Topics: Adult; Blood Glucose; C-Peptide; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Meals; Middle Aged; Models, Biological; Reproducibility of Results; Uncertainty

It is not known whether calorie restriction (CR) has additive benefits to those from exercise (EX)-induced weight loss. We hypothesized that weight loss from CR and EX (CREX) improves insulin sensitivity more than matched weight loss induced by EX or CR alone and that the incretin system may be involved in adaptations to CR.. Sedentary, overweight men and women (n = 52, 45-65 years of age) were randomized to undergo 6-8% weight loss by using CR, EX, or CREX. Glucose, insulin, C-peptide, insulin sensitivity, and incretin hormones (glucagon-like peptide 1 [GLP-1] and glucose-dependent insulinotropic polypeptide [GIP]) were measured during frequently sampled oral glucose tolerance tests (FSOGTTs). Incretin effects on insulin secretion were measured by comparing insulin secretion rates from the FSOGTTs to those from a glycemia-matched glucose infusion.. Despite similar weight losses in all groups, insulin sensitivity index values increased twofold more in the CREX group (2.09 ± 0.35 μM/kg/pM × 100) than in the CR (0.89 ± 0.39 μM/kg/pM × 100) and EX (1.04 ± 0.39 μM/kg/pM × 100) groups. Postprandial GLP-1 concentrations decreased only in the CR group (P = 0.04); GIP concentrations decreased in all groups. Incretin effects on insulin secretion were unchanged.. CR and EX have additive beneficial effects on glucoregulation. Furthermore, the adaptations to CR may involve reductions in postprandial GLP-1 concentrations. These findings underscore the importance of promoting both CR and EX for optimal health. However, because data from participants who withdrew from the study and from those who did not adhere to the intervention were excluded, the results may be limited to individuals who are capable of adhering to a healthy lifestyle intervention.

Topics: Adaptation, Physiological; Aged; Blood Glucose; C-Peptide; Caloric Restriction; Energy Intake; Energy Metabolism; Exercise Therapy; Female; Gastric Inhibitory Polypeptide; Glucagon-Like Peptide 1; Glucose; Glucose Tolerance Test; Humans; Incretins; Insulin; Insulin Resistance; Insulin Secretion; Life Style; Male; Middle Aged; Overweight; Postprandial Period; Weight Loss

Improvement in type 2 diabetes after Roux-en-Y gastric bypass (RYGB) has been attributed partly to weight loss, but mechanisms beyond weight loss remain unclear. We performed an ancillary study to the Diabetes Surgery Study to assess changes in incretins, insulin sensitivity, and secretion 1 year after randomization to lifestyle modification and intensive medical management (LS/IMM) alone (n = 34) or in conjunction with RYGB (n = 34). The RYGB group lost more weight and had greater improvement in HbA1c. Fasting glucose was lower after RYGB than after LS/IMM, although the glucose area under the curve decreased comparably for both groups. Insulin sensitivity increased in both groups. Insulin secretion was unchanged after LS/IMM but decreased after RYGB, except for a rapid increase during the first 30 min after meal ingestion. Glucagon-like peptide 1 (GLP-1) was substantially increased after RYGB, while gastric inhibitory polypeptide and glucagon decreased. Lower HbA1c was most strongly correlated with the percentage of weight loss for both groups. At baseline, a greater C-peptide index and 90-min postprandial C-peptide level were predictive of lower HbA1c at 1 year after RYGB. β-Cell glucose sensitivity, which improved only after RYGB, and improved disposition index were associated with lower HbA1c in both groups, independent of weight loss. Weight loss and preserved β-cell function both predominantly determine the greatest glycemic benefit after RYGB.

Topics: Adiponectin; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Gastric Bypass; Gastric Inhibitory Polypeptide; Glucagon; Glucagon-Like Peptide 1; Glucagon-Like Peptide 2; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Middle Aged; Obesity; Treatment Outcome; Weight Loss

Ingestion of probiotics can modify gut microbiota and alter insulin resistance and diabetes development in rodents. We hypothesized that daily intake of Lactobacillus reuteri increases insulin sensitivity by changing cytokine release and insulin secretion via modulation of the release of glucagon-like peptides (GLP)-1 and -2.. A prospective, double-blind, randomized trial was performed in 21 glucose-tolerant humans (11 lean: age 49 ± 7 years, BMI 23.6 ± 1.7 kg/m(2); 10 obese: age 51 ± 7 years, BMI 35.5 ± 4.9 kg/m(2)). Participants ingested 10(10) b.i.d. L. reuteri SD5865 or placebo over 4 weeks. Oral glucose tolerance and isoglycemic glucose infusion tests were used to assess incretin effect and GLP-1 and GLP-2 secretion, and euglycemic-hyperinsulinemic clamps with [6,6-(2)H2]glucose were used to measure peripheral insulin sensitivity and endogenous glucose production. Muscle and hepatic lipid contents were assessed by (1)H-magnetic resonance spectroscopy, and immune status, cytokines, and endotoxin were measured with specific assays.. In glucose-tolerant volunteers, daily administration of L. reuteri SD5865 increased glucose-stimulated GLP-1 and GLP-2 release by 76% (P < 0.01) and 43% (P < 0.01), respectively, compared with placebo, along with 49% higher insulin (P < 0.05) and 55% higher C-peptide secretion (P < 0.05). However, the intervention did not alter peripheral and hepatic insulin sensitivity, body mass, ectopic fat content, or circulating cytokines.. Enrichment of gut microbiota with L. reuteri increases insulin secretion, possibly due to augmented incretin release, but does not directly affect insulin sensitivity or body fat distribution. This suggests that oral ingestion of one specific strain may serve as a novel therapeutic approach to improve glucose-dependent insulin release.

Topics: Adult; Aged; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Double-Blind Method; Female; Glucagon; Glucagon-Like Peptide 1; Glucagon-Like Peptide 2; Glucose; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Incretins; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Limosilactobacillus reuteri; Male; Middle Aged; Obesity; Oxidative Stress; Pilot Projects; Probiotics; Prospective Studies; Protein Precursors

The gut microbiota has been implicated in obesity and its progression towards metabolic disease. Dietary interventions that target the gut microbiota have been suggested to improve metabolic health. The aim of the present study was to investigate the effect of interventions with Lactobacillus paracasei F19 or flaxseed mucilage on the gut microbiota and metabolic risk markers in obesity. A total of fifty-eight obese postmenopausal women were randomised to a single-blinded, parallel-group intervention of 6-week duration, with a daily intake of either L. paracasei F19 (9.4 × 1010 colony-forming units), flaxseed mucilage (10 g) or placebo. Quantitative metagenomic analysis of faecal DNA was performed to identify the changes in the gut microbiota. Diet-induced changes in metabolic markers were explored using adjusted linear regression models. The intake of flaxseed mucilage over 6 weeks led to a reduction in serum C-peptide and insulin release during an oral glucose tolerance test (P< 0.05) and improved insulin sensitivity measured by Matsuda index (P< 0.05). Comparison of gut microbiota composition at baseline and after 6 weeks of intervention with flaxseed mucilage showed alterations in abundance of thirty-three metagenomic species (P< 0.01), including decreased relative abundance of eight Faecalibacterium species. These changes in the microbiota could not explain the effect of flaxseed mucilage on insulin sensitivity. The intake of L. paracasei F19 did not modulate metabolic markers compared with placebo. In conclusion, flaxseed mucilage improves insulin sensitivity and alters the gut microbiota; however, the improvement in insulin sensitivity was not mediated by the observed changes in relative abundance of bacterial species.

Topics: Aged; C-Peptide; Diet; Feces; Female; Flax; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Intestines; Lactobacillus; Middle Aged; Obesity; Plant Mucilage; Postmenopause; Prebiotics; Probiotics; Single-Blind Method

Limited data suggest that interrupting sedentary behaviors with activity improves metabolic parameters in adults.. We tested whether interrupting sitting with short, moderate-intensity walking bouts improved glucose tolerance in children.. Participants underwent two experimental conditions in random order on different days: continuous sitting for 3 hours or sitting interrupted by walking (3 min of moderate-intensity walking every 30 min). Insulin, C-peptide, glucose, and free fatty acids were measured every 30 minutes for 3 hours during an oral glucose tolerance test. Area under the curve (AUC) was calculated from hormone and substrate measurements. Children were given a buffet meal after each condition.. The study was conducted at the National Institutes of Health Hatfield Clinical Research Center.. Twenty-eight normal-weight 7-11 year olds participated.. Patterns of substrate/hormone secretion and AUC, as well as energy intake, were examined by experimental condition.. Interrupting sitting resulted in a 32% lower insulin AUC (P < .001), 17% lower C-peptide AUC (P < .001), and 7% lower glucose AUC (P = .018) vs continuous sitting. Mixed model results indicated that insulin (P = .036) and free fatty acid concentrations (P = .009) were significantly lower in the interrupted vs the continuous sitting condition. Lunchtime buffet meal energy intake did not significantly differ between the conditions (975 ± 387 vs 963 ± 309 kcal; P = .85).. Interrupting sedentary time with brief moderate-intensity walking improved short-term metabolic function in non-overweight children without increasing subsequent energy intake. These findings suggest that interrupting sedentary behavior may be a promising prevention strategy for reducing cardiometabolic risk in children.

Topics: Blood Glucose; C-Peptide; Child; Child Behavior; Exercise; Fatty Acids, Nonesterified; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Male; Sedentary Behavior; Walking

Gender plays a role in the development of a number of cardiovascular and metabolic diseases and it has been suggested that females may be more insulin resistant in utero. We sought to assess the relationship between infant gender and insulin resistance in a large pregnancy cohort.. This is a secondary analysis of a cohort from the ROLO randomized control trial of low GI diet in pregnancy. Serum insulin, glucose and leptin were measured in early pregnancy and at 28 weeks. At delivery cord blood C-peptide and leptin were measured. A comparison of maternal factors, fetal biometry, insulin resistance and leptin was made between male and female offspring. A multivariate regression model was built to account for the possible effects of maternal BMI, birthweight and original study group assignment on findings.. A total of 582 women were included in this secondary analysis, of whom 304 (52.2%) gave birth to male and 278 (47.8%) gave birth to female infants. Compared to male infants at birth, female infants were significantly lighter, (3945 ± 436 vs. 4081± 549g, p<0.001), shorter in length (52.36 ± 2.3 vs. 53.05 ± 2.4cm, p<0.001) and with smaller head circumferences (35.36 ± 1.5 vs. 36.10 ± 1.1cm, p<0.001) than males. On multiple regression analysis, women pregnant with female fetuses were less insulin resistant in early pregnancy, i.e. had lower HOMA indices (B = -0.19, p = 0.01). Additionally female fetuses had higher concentrations of both cord blood leptin and C-peptide at birth when compared to male offspring (B = 0.38, p<0.001 and B = 0.31, p = 0.03 respectively).. These findings suggest gender is a risk factor for insulin resistance in-utero. Additionally, carrying a female fetus decreases the risk of insulin resistance in the mother, from as early as the first trimester.

Topics: Birth Weight; Body Mass Index; C-Peptide; Female; Fetal Blood; Fetal Development; Humans; Infant; Insulin Resistance; Leptin; Male; Pregnancy; Risk Factors; Sex Factors

To examine associations of baseline insulin dynamics with changes in body composition and resting energy expenditure (REE) following weight loss.. Twenty-one participants with overweight or obesity achieved 10-15% weight loss and then received 3 weight loss maintenance diets (high-carbohydrate, moderate-carbohydrate, and low-carbohydrate) in random order, each for 4 weeks. Body composition was measured at baseline and after weight loss. Insulin 30 min after glucose consumption (insulin-30; insulin response), C-peptide deconvolution analysis, HOMA, hepatic insulin sensitivity (IS), and REE were assessed at baseline and after each maintenance diet.. Insulin-30, but not maximal insulin secretion, hepatic IS, or HOMA, predicted changes in fat mass (standardized β = 0.385, 1.7 kg difference between 10th and 90th centile of insulin-30, P = 0.04) after weight loss. Insulin-30 (β = -0.341, -312 kcal day(-1) , P = 0.008), maximal insulin secretion (β = -0.216, -95 kcal day(-1) , P = 0.0002), HOMA (β = -0.394, -350 kcal day(-1) , P = 0.002), and hepatic IS (β = 0.217, 225 kcal day(-1) , P = 0.0003) predicted change in REE during weight loss maintenance, independent of changes in body composition. The inverse relationship between insulin-30 and REE was substantially attenuated when the low-carbohydrate diet was consumed first.. These findings distinguish a novel phenotype, characterized by high insulin response, at risk for weight regain, and identify a dietary approach to ameliorate this risk.

Topics: Adult; Body Composition; Body Weight; C-Peptide; Diet, Carbohydrate-Restricted; Diet, Reducing; Energy Metabolism; Female; Humans; Insulin; Insulin Resistance; Male; Obesity; Overweight; Rest; Weight Loss; Young Adult

The effects of twice-daily GLP-1 analogue injections added on continuous subcutaneous insulin infusion (CSII) in patients with poorly controlled type 2 diabetes (T2DM) were unknown. After optimization of blood glucose in the first 3 days by CSII during hospitalization, patients with poorly controlled T2DM were randomized to receive CSII combined with injections of exenatide or placebo for another 3 days. A total of 51 patients (30 in exenatide and 21 in placebo groups) with mean A1C 11% were studied. There was no difference in mean glucose but a significant higher standard deviation of plasma glucose (SDPG) was found in the exenatide group (50.51 ± 2.43 vs. 41.49 ± 3.00 mg/dl, p = 0.027). The improvement of incremental area under the curve (AUC) of glucose and insulinogenic index (Insulin 0-peak/ Glucose 0-peak) in 75 g oral glucose tolerance test was prominent in the exenatide group (p < 0.01). The adiponectin level was significantly increased with exenatide added on (0.39 ± 0.32 vs. -1.62 ± 0.97 μg/mL, in exenatide and placebo groups, respectively, p = 0.045). In conclusion, the add-on of GLP-1 analogue to CSII increased glucose variability and the β - cell response in patients with poorly controlled T2DM.

Topics: Adiponectin; Biomarkers; Blood Glucose; C-Peptide; Cardiovascular Diseases; Diabetes Mellitus, Type 2; Endpoint Determination; Exenatide; Female; Glucagon-Like Peptide 1; Glucose Tolerance Test; Humans; Injections, Subcutaneous; Insulin; Insulin Infusion Systems; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Peptides; Risk Factors; Venoms

Surgical stress response, results in elevated levels of anti-insulin hormones and reduced insulin secretion. This hormonal state may be detrimental for surgical patients due to the presence of insulin resistance and hyperglycemia. Additionally, pre-operative fasting favors this conditions. The aim of this study is to analyze the impact of pre-operative caloric load, with 440kJ from amino acid infusions on the levels of glucose, cortisol and insulin resistance in surgical patients.. The study included 20 female patients scheduled for mastectomy, aged 30-60 years without diabetes and BMI < 30 m(2), divided into two groups. The study group A, the evening before the surgery, received 1000 ml amino acid infusions, while the control group B didn't receive any infusion. In both groups glucose, C-peptide and cortisol levels were determinate preoperatively and postoperatively. From the obtained C-peptide and glucose values, with the help of computer model (HOMA2*), the insulin resistance (IR), functionality of beta cells (BETA) and insulin sensitivity (IS) were calculated.. Postoperative values of insulin resistance (0.94 ± 0.12 vs 1.13 ± 0.2; p = 0.02) and glucose (4.79 ± 0.5 vs 5.77 ± 0.6; p = 0.002) were lower in the study group compared to control group. Postoperative cortisol levels in both groups were higher than the preoperative, but no significant difference was found. The study group showed higher values for BETA and IS. Percentage changes between the groups were significant for all parameters.. Pre-operative caloric load (amino acids) reduces the level of insulin resistance and glucose in the presence of elevated cortisol levels.

Topics: Adult; Amino Acids; Biomarkers; Blood Glucose; C-Peptide; Energy Intake; Female; Humans; Hydrocortisone; Hyperglycemia; Infusions, Parenteral; Insulin Resistance; Mastectomy; Middle Aged; Pilot Projects; Preoperative Care; Prospective Studies; Republic of North Macedonia; Time Factors; Treatment Outcome

The Restoring Insulin Secretion (RISE) Consortium is testing interventions designed to preserve or improve β-cell function in prediabetes or early type 2 diabetes.. β-Cell function is measured using hyperglycemic clamps and oral glucose tolerance tests (OGTTs). The adult medication protocol randomizes participants to 12 months of placebo, metformin alone, liraglutide plus metformin, or insulin (3 months) followed by metformin (9 months). The pediatric medication protocol randomizes participants to metformin or insulin followed by metformin. The adult surgical protocol randomizes participants to gastric banding or metformin (24 months). Adult medication protocol inclusion criteria include fasting plasma glucose 95-125 mg/dL (5.3-6.9 mmol/L), OGTT 2-h glucose ≥140 mg/dL (≥7.8 mmol/L), HbA1c 5.8-7.0% (40-53 mmol/mol), and BMI 25-40 kg/m(2). Adult surgical protocol criteria are similar, except for fasting plasma glucose ≥90 mg/dL (≥5.0 mmol/L), BMI 30-40 kg/m(2), HbA1c <7.0% (<53 mmol/mol), and diabetes duration <12 months. Pediatric inclusion criteria include fasting plasma glucose ≥90 mg/dL (≥5.0 mmol/L), 2-h glucose ≥140 mg/dL (≥7.8 mmol/L), HbA1c ≤8.0% (≤64 mmol/mol), BMI >85th percentile and ≤50 kg/m(2), 10-19 years of age, and diabetes <6 months.. Primary outcomes are clamp-derived glucose-stimulated C-peptide secretion and maximal C-peptide response to arginine during hyperglycemia. Measurements are made at baseline, after 12 months on treatment, and 3 months after treatment withdrawal (medication protocols) or 24 months postintervention (surgery protocol). OGTT-derived measures are also obtained at these time points.. RISE is determining whether medication or surgical intervention strategies can mitigate progressive β-cell dysfunction in adults and youth with prediabetes or early type 2 diabetes.

Topics: Adolescent; Adult; Aged; Arginine; Blood Glucose; C-Peptide; Child; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Female; Gastroplasty; Glucagon-Like Peptide 1; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Hyperglycemia; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Liraglutide; Male; Metformin; Middle Aged; Prediabetic State; Young Adult

This randomized, double-blind, placebo-controlled parallel-group study assessed the effects of sodium glucose cotransporter 2 inhibition by dapagliflozin on insulin sensitivity and secretion in subjects with type 2 diabetes mellitus (T2DM), who had inadequate glycemic control with metformin (with or without an insulin secretagogue).. Forty-four subjects were randomized to receive dapagliflozin 5 mg or matching placebo once daily for 12 weeks. Subjects continued stable doses of background antidiabetes medication throughout the study. Insulin sensitivity was assessed by measuring the glucose disappearance rate (GDR) during the last 40 min of a 5-h hyperinsulinemic, euglycemic clamp. Insulin secretion was determined as the acute insulin response to glucose (AIRg) during the first 10 min of a frequently sampled intravenous glucose tolerance test. Where noted, data were adjusted for baseline values and background antidiabetes medication.. An adjusted mean increase from baseline in GDR (last observation carried forward), at Week 12, was observed with dapagliflozin (7.98%) versus a decrease with placebo (-9.99%). The 19.97% (95% confidence interval 5.75-36.10) difference in GDR versus placebo was statistically significant (P=0.0059). A change from baseline in adjusted mean AIRg of 15.39 mU/L min was observed with dapagliflozin at Week 12, versus -12.73 mU/L min with placebo (P=0.0598). Over 12 weeks, numerical reductions from baseline in glycosylated hemoglobin (HbA1c), fasting plasma glucose, and body weight were observed with dapagliflozin (-0.38%, -0.39 mmol/L, and -1.58%, respectively) versus slight numerical increases with placebo (0.03%, 0.26 mmol/L, and 0.62%, respectively).. In patients with T2DM and inadequate glycemic control, dapagliflozin treatment improved insulin sensitivity in the setting of reductions in HbA1c and weight.

Topics: Adult; Aged; Benzhydryl Compounds; Blood Glucose; C-Peptide; Creatinine; Diabetes Mellitus, Type 2; Double-Blind Method; Drug Therapy, Combination; Female; Glucose Tolerance Test; Glucosides; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Male; Metformin; Middle Aged; Sodium-Glucose Transporter 2 Inhibitors; Treatment Outcome

This is a secondary analysis of 621 women in ROLO study, a randomized control trial of low glycemic index (GI) diet in pregnancy to prevent the recurrence of macrosomia, which aims to assess the effect of the diet on maternal and fetal insulin resistance, leptin, and markers of inflammation. In early pregnancy and at 28 weeks, serum was analyzed for insulin, leptin, tumor necrosis factor α (TNF-α), and interleukin 6 (IL-6). At delivery, cord blood concentrations of leptin, TNF-α, IL-6, and C-peptide were recorded. We found no difference between those who did or did not receive low GI advice with respect to the concentrations of any marker in early pregnancy, at 28 weeks or in cord blood. Women in the intervention arm of the study did have a lower overall rise in insulin concentrations from early pregnancy to 28 weeks gestation, P = .04. Of the women in the intervention arm, 20% were in the highest quartile for insulin change (28-week insulin - insulin at booking) compared to 29% of controls (P = .02). In conclusion, a low GI diet in pregnancy has little effect on leptin and markers of inflammation although an attenuated response to the typical increase in insulin resistance seen in pregnancy with advancing gestation was seen in those who received the low GI advice.

Topics: Biomarkers; C-Peptide; Diet, Carbohydrate-Restricted; Female; Fetal Blood; Fetal Macrosomia; Gestational Age; Glycemic Index; Humans; Inflammation Mediators; Insulin Resistance; Interleukin-6; Leptin; Maternal Nutritional Physiological Phenomena; Nutritional Status; Pregnancy; Tumor Necrosis Factor-alpha

To evaluate whether clinically relevant concentrations of stimulated C-peptide in response to a mixed-meal tolerance test can be detected after almost 30 years of diabetes in people included in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications cohort.. Mixed-meal tolerance tests were performed in a sample of 58 people. C-peptide levels were measured using a chemiluminescent immunoassay. This sample size assured a high probability of detecting C-peptide response if the true prevalence was at least 5%, a level that would justify the subsequent assessment of C-peptide in the entire cohort.. Of the 58 participants, 17% showed a definite response, defined as one or more post-stimulus concentrations of C-peptide > 0.03 nmol/l, and measurable concentrations were found in all participants.. These results show that a stimulated C-peptide response can be measured in some people with long-term Type 1 diabetes. Further investigation of all participants in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications study will help relate long-term residual C-peptide response to glycaemia over time and provide insight into the relevance of this response in terms of insulin dose, severe hypoglycaemia, retinopathy, nephropathy and macrovascular disease. Establishing the clinical relevance of long-term C-peptide responses is important in understanding the impact that therapy to preserve or improve β-cell function may have in patients with long-term Type 1 diabetes.

Topics: C-Peptide; Canada; Cohort Studies; Diabetes Complications; Diabetes Mellitus, Type 1; Disease Progression; Female; Follow-Up Studies; Glycated Hemoglobin; Humans; Hyperglycemia; Hypoglycemic Agents; Incidence; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Middle Aged; Pilot Projects; Postprandial Period; United States

The pathogenesis of type 2 diabetes is characterized by insulin resistance and insulin secretory dysfunction. Few existing metabolic tests measure both characteristics, and no such tests are inexpensive enough to enable widespread use. A hierarchical approach uses 2 down-sampled tests in the dynamic insulin sensitivity and secretion test (DISST) family to first determine insulin sensitivity (SI) using 4 glucose measurements. Second the insulin secretion is determined for only participants with reduced SI using 3 C-peptide measurements from the original test. The hierarchical approach is assessed via its ability to classify 214 individual test responses of 71 females with an elevated risk of type 2 diabetes into 5 bins with equivalence to the fully sampled DISST. Using an arbitrary SI cut-off, 102 test responses were reassayed for C-peptide and unique insulin secretion characteristics estimated. The hierarchical approach correctly classified 84.5% of the test responses and 94.4% of the responses of individuals with increased fasting glucose. The hierarchical approach is a low-cost methodology for measuring key characteristics of type 2 diabetes. Thus the approach could provide an economical approach to studying the pathogenesis of type 2 diabetes, or in early risk screening. As the higher cost test uses the same clinical protocol as the low-cost test, the cost of the additional information is limited to the assay cost of C-peptide, and no additional procedures or callbacks are required.

Topics: Algorithms; C-Peptide; Cohort Studies; Diabetes Mellitus, Type 2; Female; Humans; Insulin; Insulin Resistance; Reference Values; Reproducibility of Results; Risk Assessment

The effects of marked weight loss, induced by Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) surgeries, on insulin sensitivity, β-cell function and the metabolic response to a mixed meal were evaluated.. Fourteen nondiabetic insulin-resistant patients who were scheduled to undergo SG (n = 7) or RYGB (n = 7) procedures completed a hyperinsulinemic-euglycemic clamp procedure and a mixed-meal tolerance test before surgery and after losing ∼20% of their initial body weight.. Insulin sensitivity (insulin-stimulated glucose disposal during a clamp procedure), oral glucose tolerance (postprandial plasma glucose area under the curve), and β-cell function (insulin secretion in relationship to insulin sensitivity) improved after weight loss, and were not different between surgical groups. The metabolic response to meal ingestion was similar after RYGB or SG, manifested by rapid delivery of ingested glucose into the systemic circulation and a large early postprandial increase in plasma glucose, insulin, and C-peptide concentrations in both groups.. When matched on weight loss, RYGB and SG surgeries result in similar improvements in the two major factors involved in regulating plasma glucose homeostasis, insulin sensitivity and β-cell function in obese people without diabetes.

Topics: Adult; Blood Glucose; C-Peptide; Case-Control Studies; Female; Gastrectomy; Gastric Bypass; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Obesity, Morbid; Postprandial Period; Weight Loss

Saxagliptin reduced glycated hemoglobin (HbA1c), fasting plasma glucose (FPG), and postprandial glucose (PPG) in Asian patients with type 2 diabetes mellitus (T2DM). To understand the physiology of this effect, indices of α- and β-cell function were measured in a subpopulation of Chinese patients following a noodle mixed-meal tolerance test.. Data from Chinese patients were pooled from two phase 3, 24-week studies of saxagliptin 5mg/d as monotherapy in drug-naive patients and as add-on to metformin in patients inadequately controlled with metformin alone. The end points for β- and α-cell function were change from baseline in C-peptide, insulin, and glucagon areas under the curve from 0 to 180 min (AUC0-180), insulinogenic index, and insulin sensitivity from Matsuda index after a mixed meal. Also glycemic variables, HbA1c, FPG, and PPG (AUC0-180), and homeostasis model assessment (HOMA) 2β were measured.. At 24 weeks, greater improvements in adjusted mean change from baseline HbA1c (difference vs placebo [95% CI], -0.33% [-0.50%, -0.17%], [-4 (-5.5, -1.9) mmol/mol], P<0.0001), FPG (-0.41 [-0.78, -0.03] mmol/L, P=0.03), PPG AUC0-180 (-168 [-245, -91.8] mmol min/L, P<0.0001), C-peptide AUC0-180 (19.7 [5.2, 34.2] nmol min/L, P=0.008), insulinogenic index (0.06% [0.02%, 0.09%], P=0.002), and greater suppression of glucagon secretion (glucagon AUC0-180, -322 [-493.6, -150.7] pmol min/L, P=0.0003) were observed with saxagliptin versus placebo.. In Chinese patients with T2DM, saxagliptin as monotherapy or as add-on to metformin improved glycemic control by modulating α- and β-cell function.

Topics: Adamantane; Asian People; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Dipeptides; Dipeptidyl-Peptidase IV Inhibitors; Double-Blind Method; Drug Therapy, Combination; Fasting; Female; Glucagon; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Metformin; Middle Aged; Postprandial Period

Low-dose GH (LGH) therapy has been reported to improve insulin sensitivity in GH-deficient adults; however, the mechanism is unclear.. Effects of LGH therapy on insulin sensitivity are mediated through changes in cortisol metabolism and ectopic fat accumulation.. This was a double-blind, placebo-controlled, parallel, 3-month study.. Seventeen GH-deficient adults were randomized to receive either daily LGH or placebo injections. Fasting blood samples were collected at baseline, and months 1 and 3, whereas hyperinsulinemic-euglycemic clamps, magnetic resonance spectroscopy scans, 24-hour cortisol production rates (CPRs), and sc abdominal fat biopsies were performed at baseline and month 3.. Clamp glucose infusion rate, intramyocellular, extramyocellular, and intrahepatic lipid content, 24-hour CPRs, adipocyte size, and adipocyte 11β-hydroxysteroid dehydrogenase activity in adults with GH deficiency were evaluated.. At month 1, LGH did not alter fasting levels of glucose, insulin, C-peptide, free fatty acid, adiponectin, total IGF-1, IGF-1 bioactivity, IGF-2, IGF binding protein (IGFBP)-2, or IGF-1 to IGFBP-3 molar ratio. At month 3, LGH increased clamp glucose infusion rates (P < .01) and IGF-1 to IGFBP-3 molar ratio (P < .05), but fasting glucose, insulin, C-peptide, free fatty acid, adiponectin, IGF-1 bioactivity, IGF-2, IGFBP-2, 24-hour CPRs, adipocyte size, adipocyte 11β-hydroxysteroid dehydrogenase activity, intrahepatic lipid, extramyocellular, or intramyocellular were unchanged. In the placebo group, all within-group parameters from months 1 and 3 compared with baseline were unchanged.. Short-term LGH therapy improves insulin sensitivity without inducing basal lipolysis and had no effect on cortisol metabolism and ectopic fat accumulation in GH-deficient adults. This may reflect an LGH-induced increase in IGF-1 to IGFBP-3 molar ratio exerting insulin-like effects through the abundant muscle IGF-1 receptors, but this hypothesis requires confirmation with further studies.

Topics: 11-beta-Hydroxysteroid Dehydrogenase Type 1; Adipocytes; Adipose Tissue; Adult; Anthropometry; Blood Glucose; C-Peptide; Double-Blind Method; Female; Glucose Clamp Technique; Growth Disorders; Human Growth Hormone; Humans; Hydrocortisone; Insulin Resistance; Insulin-Like Growth Factor Binding Protein 3; Insulin-Like Growth Factor I; Insulin-Like Growth Factor II; Male

Vitamin D insufficiency is common in subjects with type 2 diabetes. Observational studies suggest that vitamin D plays a role in the pathogenesis of type 2 diabetes. However, results of intervention studies have been inconsistent. We investigated the effects of improving vitamin D status on insulin sensitivity, insulin secretion, and inflammatory markers in patients with type 2 diabetes.. A double blind, randomized, placebo controlled trial was conducted. Sixteen patients with type 2 diabetes and hypovitaminosis D were recruited. Eight patients received colecalciferol and (280 μg daily for 2 weeks, 140 μg daily for 10 weeks) and 8 patients received identical placebo tablets for 12 weeks. Before and after intervention, patients underwent IVGTT, hyperinsulinemic euglycemic clamp, assessment of baseline high-frequency insulin pulsatility, glucose-entrained insulin pulsatility, DXA scans, 24-hour-ambulatory blood pressure monitorings, and fasting blood samples.. Serum-25(OH) vitamin D and serum-1,25(OH)₂ vitamin D increased significantly after 12 weeks in the intervention group (p=0.01, p=0.004). Serum-25(OH) vitamin D was also significantly higher in the vitamin D group compared to the placebo group (p=0.02) after intervention. Although no significant changes in insulin sensitivity, inflammation, blood pressure, lipid profile, or HbA1c were found, we observed borderline (p between 0.05 and 0.10) improvements of insulin secretion, in terms of c-peptide levels, first phase incremental AUC insulin and insulin secretory burst mass.. Improvement in vitamin D status does not improve insulin resistance, blood pressure, inflammation or HbA1c, but might increase insulin secretion in patients with established type 2 diabetes.

Topics: Aged; Biomarkers; C-Peptide; Calcifediol; Calcitriol; Cholecalciferol; Denmark; Diabetes Mellitus, Type 2; Dietary Supplements; Double-Blind Method; Female; Humans; Inflammation Mediators; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Kinetics; Male; Middle Aged; Seasons; Severity of Illness Index; Vitamin D Deficiency

To examine counterregulatory glucose kinetics and test the hypothesis that β-adrenergic blockade impairs these in patients with type 2 diabetes mellitus (T2DM) and advanced β-failure.. Nine insulin-requiring T2DM subjects and six matched nondiabetic control subjects were studied. β-Cell function was assessed by the C-peptide response to arginine stimulation. Counterregulatory hormonal responses and glucose kinetics were assessed by hyperinsulinemic euglycemic-hypoglycemic clamps with [3-(3)H]glucose infusion. T2DM subjects underwent two clamp experiments in a randomized crossover fashion: once with infusion of the β-adrenergic antagonist propranolol and once with infusion of normal saline.. Compared with the control subjects, T2DM subjects had threefold reduced C-peptide responses to arginine stimulation. During the hypoglycemic clamp, glucagon responses were markedly diminished (16.0 ± 4.2 vs. 48.6 ± 6.0 ng/L, P < 0.05), but other hormonal responses and the decrement in the required exogenous glucose infusion rate (GIR) from the euglycemic clamp were normal (-10.4 ± 1.1 vs. -7.8 ± 1.9 µmol · kg(-1) · min(-1) in control subjects); however, endogenous glucose production (EGP) did not increase (-0.8 ± 1.0 vs. 2.2 ± 0.7 µmol · kg(-1) · min(-1) in control subjects, P < 0.05), whereas systemic glucose disposal decreased normally. β-Adrenergic blockade in the T2DM subjects increased GIR ∼20% during the euglycemic clamp (P < 0.01), but neither increased GIR during the hypoglycemic clamp or decreased its decrement from the euglycemic clamp to the hypoglycemic clamp.. Overall glucose counterregulation is preserved in advanced T2DM, but the contribution of EGP is diminished. β-Adrenergic blockade may increase insulin sensitivity at normoglycemia but does not impair glucose counterregulation in T2DM patients, even those with advanced β-cell failure.

Topics: Adrenergic beta-Antagonists; C-Peptide; Case-Control Studies; Cross-Over Studies; Diabetes Mellitus, Type 2; Female; Glucagon; Glucose; Glucose Clamp Technique; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Single-Blind Method

To examine whether combined vitamin D and calcium supplementation improves insulin sensitivity, insulin secretion, β-cell function, inflammation and metabolic markers.. 6-month randomized, placebo-controlled trial.. Ninety-five adults with serum 25-hydroxyvitamin D [25(OH)D] ≤55 nmol/L at risk of type 2 diabetes (with prediabetes or an AUSDRISK score ≥15) were randomized. Analyses included participants who completed the baseline and final visits (treatment n = 35; placebo n = 45).. Daily calcium carbonate (1,200 mg) and cholecalciferol [2,000-6,000 IU to target 25(OH)D >75 nmol/L] or matching placebos for 6 months.. Insulin sensitivity (HOMA2%S, Matsuda index), insulin secretion (insulinogenic index, area under the curve (AUC) for C-peptide) and β-cell function (Matsuda index x AUC for C-peptide) derived from a 75 g 2-h OGTT; anthropometry; blood pressure; lipid profile; hs-CRP; TNF-α; IL-6; adiponectin; total and undercarboxylated osteocalcin.. Participants were middle-aged adults (mean age 54 years; 69% Europid) at risk of type 2 diabetes (48% with prediabetes). Compliance was >80% for calcium and vitamin D. Mean serum 25(OH)D concentration increased from 48 to 95 nmol/L in the treatment group (91% achieved >75 nmol/L), but remained unchanged in controls. There were no significant changes in insulin sensitivity, insulin secretion and β-cell function, or in inflammatory and metabolic markers between or within the groups, before or after adjustment for potential confounders including waist circumference and season of recruitment. In a post hoc analysis restricted to participants with prediabetes, a significant beneficial effect of vitamin D and calcium supplementation on insulin sensitivity (HOMA%S and Matsuda) was observed.. Daily vitamin D and calcium supplementation for 6 months may not change OGTT-derived measures of insulin sensitivity, insulin secretion and β-cell function in multi-ethnic adults with low vitamin D status at risk of type 2 diabetes. However, in participants with prediabetes, supplementation with vitamin D and calcium may improve insulin sensitivity.. Australian New Zealand Clinical Trials Registry ACTRN12609000043235.

Topics: Adiponectin; Adult; Aged; Blood Glucose; C-Peptide; C-Reactive Protein; Calcium, Dietary; Cholecalciferol; Diabetes Mellitus, Type 2; Dietary Supplements; Female; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Interleukin-6; Male; Middle Aged; Osteocalcin; Pilot Projects; Prediabetic State; Tumor Necrosis Factor-alpha; Vitamin D Deficiency

Plasma calprotectin is a potential biomarker of cardiovascular disease (CVD), insulin resistance (IR), and obesity. We examined the relationship between plasma calprotectin concentrations, CVD manifestations and the metabolic syndrome (MetS) in patients with type 2 diabetes mellitus (T2DM) in order to evaluate plasma calprotectin as a risk assessor of CVD in diabetic patients without known CVD.. An automated immunoassay for determination of plasma calprotectin was developed based on a fecal Calprotectin ELIA, and a reference range was established from 120 healthy adults. Plasma calprotectin concentrations were measured in 305 T2DM patients without known CVD. They were screened for carotid arterial disease, peripheral arterial disease (PAD), and myocardial ischemia (MI) by means of carotid artery ultrasonography, peripheral ankle and toe systolic blood pressure measurements, and myocardial perfusion scintigraphy.. The reference population had a median plasma calprotectin concentration of 2437 ng/mL (2.5-97.5% reference range: 1040-4262 ng/mL). The T2DM patients had significantly higher concentrations (3754 ng/mL, p < 0.0001), and within this group plasma calprotectin was significantly higher in patients with MetS (p < 0.0001) and also in patients with autonomic neuropathy, PAD, and MI compared with patients without (p < 0.001, p = 0.021 and p = 0.043, respectively). Plasma calprotectin was by linear regression analysis found independently associated with BMI, C-reactive protein, and HDL cholesterol. However, plasma calprotectin did not predict autonomic neuropathy, PAD, MI or CVD when these variables entered the multivariable regression analysis as separate outcome variables.. T2DM patients had higher concentrations of plasma calprotectin, which were associated with obesity, MetS status, autonomic neuropathy, PAD, and MI. However, plasma calprotectin was not an independent predictor of CVD, MI, autonomic neuropathy or PAD.. NCT00298844.

Topics: Adult; Aged; Biomarkers; Body Mass Index; C-Peptide; Cardiovascular Diseases; Cholesterol, HDL; Diabetes Mellitus, Type 2; Diabetic Neuropathies; Female; Homeostasis; Humans; Insulin; Insulin Resistance; Leukocyte L1 Antigen Complex; Male; Metabolic Syndrome; Middle Aged; Obesity; Reference Values; Young Adult

The glucose tolerance test demonstrates that content of unesterified fatty acids in blood plasma decreases up to three times and the content of oleic and linoleic acids is more decreased in the pool of fatty acids lipids. Out of resistance to insulin, hormone secretion increases up to three times. The decreasing of level of individual fatty acids occurs in a larger extent. Under resistance to insulin secretion of insulin is increasing up to eight times. The decreasing of level of each fatty acid is less expressed. The effect of insulin reflects decreasing of content of double bonds in blood plasma. The number of double bonds characterizes the degree of unsaturation of fatty acids in lipids of blood plasma. The higher number of double bonds is in the pool of unesterified fatty acids the more active is the effect of insulin. The hyper-secretion of insulin is directly proportional to content of palmitic fatty acid in lipids of blood plasma on fasting. According the phylogenetic theory of general pathology, the effect of insulin on metabolism of glucose is mediated by fatty acids. The insulin is blocking lipolysis in insulin-depended subcutaneous adipocytes and decreases content of unesterified fatty acids in blood plasma. The insulin is depriving all cells of possibility to absorb unesterified fatty acids and "forces" them to absorb glucose increasing hereby number of GLUT4 on cell membrane. The resistance to insulin is manifested in high concentration of unesterfied fatty acids, hyperinsulinemia, hyperalbuminemia and increasing of concentration of C-reactive protein-monomer. The resistance to insulin is groundlessly referred to as a symptom of diabetes mellitus type II. The resistance to insulin is only a functional disorder lasting for years. It can be successfully arrested. The diabetes mellitus is developed against the background of resistance to insulin only after long-term hyper-secretion of insulin and under emaciation and death of β-cells. The diabetes mellitus type I and not type II is an undesirable outcome of resistance to insulin.

Topics: C-Peptide; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Fatty Acids, Unsaturated; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Male

The effects of alkaloid caffeine on insulin sensitivity have been investigated primarily in men, and with a single caffeine dose most commonly of 5-6 mg·kg(-1) of body weight (BW). It is unknown if the effects of caffeine on glucose homeostasis are sex-specific and (or) dose-dependent. This study examined whether caffeine ingestion would disrupt glucose homeostasis in a dose-dependent or threshold manner. It also examined whether sex-specific responses to caffeine exist. It was hypothesized that women would have an exaggerated response to caffeine, and that caffeine would only impair glucose metabolism once a threshold was reached. Twenty-four healthy volunteers (12 males, 12 females) participated in 4 trials, in a crossover, randomized, and double-blind fashion. They ingested caffeine (1, 3, or 5 mg·kg(-1) of BW) or placebo followed, 1 h later, by a 2-h oral glucose tolerance test. Glucose, insulin, C-peptide area under the curve (AUC), and insulin sensitivity index data were fitted to a segmented linear model to determine dose-responses. There were no differences between sexes for any endpoints. Regression slopes were significantly different from zero (p < 0.05) for glucose, insulin, and C-peptide AUCs, with thresholds being no different from zero. Increasing caffeine consumption by 1 mg·kg(-1) of BW increased insulin and C-peptide AUCs by 5.8% and 8.7%, respectively. Despite this exaggerated insulin response, glucose AUC increased by 11.2 mmol per 120 min·L(-1) for each mg·kg(-1) BW consumed. These results showed that caffeine ingestion disrupted insulin sensitivity in a dose-dependent fashion beginning at very low doses (0-1 mg·kg(-1) BW) in both healthy men and women.

Topics: Adult; Blood Glucose; C-Peptide; Caffeine; Cross-Over Studies; Dose-Response Relationship, Drug; Double-Blind Method; Female; Glucose; Humans; Insulin; Insulin Resistance; Male; Sex Factors; Young Adult

We conducted a randomized, open, placebo-controlled crossover trial to investigate the effects of the pregnane X receptor (PXR) agonist rifampin on an oral glucose tolerance test (OGTT) in 12 healthy volunteers. The subjects were administered 600 mg rifampin or placebo once daily for 7 days, and OGTT was performed on the eighth day. The mean incremental glucose and insulin areas under the plasma concentration-time curves (AUC(incr)) increased by 192% (P = 0.008) and 45% (P = 0.031), respectively. The fasting glucose, insulin, and C-peptide, and the homeostasis model assessment for insulin resistance, were not affected. The glucose AUC(incr) during OGTT was significantly increased in rats after 4-day treatment with pregnenolone 16α-carbonitrile (PCN), an agonist of the rat PXR. The hepatic level of glucose transporter 2 (Glut2) mRNA was downregulated by PCN. In conclusion, both human and rat PXR agonists elicited postprandial hyperglycemia, suggesting a detrimental role of PXR activation on glucose tolerance.

Topics: Adult; Animals; C-Peptide; Cross-Over Studies; Down-Regulation; Female; Glucose Tolerance Test; Glucose Transporter Type 2; Humans; Insulin; Insulin Resistance; Liver; Male; Mice; Mice, Inbred C57BL; Postprandial Period; Pregnane X Receptor; Pregnenolone Carbonitrile; Primary Cell Culture; Rats; Rats, Sprague-Dawley; Receptors, Steroid; Rifampin

Animal studies indicate that osteocalcin (OC), particularly the undercarboxylated isoform (unOC), affects insulin sensitivity and secretion, but definitive data from humans are lacking.. The objectives of the study were to determine whether total OC and unOC are independently associated with insulin sensitivity and β-cell response in overweight/obese adults; whether glucose tolerance status affects these associations; and whether the associations are independent of bone formation, as reflected in procollagen type 1 amino propeptide (P1NP).. This was a cross-sectional study conducted at a university research center involving 63 overweight/obese adults with normal (n = 39) or impaired fasting glucose (IFG; n = 24).. Serum concentrations of total/undercarboxylated OC and P1NP were assessed by RIA; insulin sensitivity was determined by iv glucose tolerance test (S(I)-IVGTT), liquid meal test (S(I) meal), and homeostasis model assessment of insulin resistance; β-cell response to glucose [basal β-cell response to glucose; dynamic β-cell response to glucose; static β-cell response to glucose; and total β-cell response to glucose] was derived using C-peptide modeling of meal test data; and intraabdominal adipose tissue was measured using computed tomography scanning.. Multiple linear regression, adjusting for intraabdominal adipose tissue and P1NP, revealed that total OC was positively associated with S(I)-iv glucose tolerance test (P < .01) in the total sample. OC was not associated with S(I) meal or homeostasis model assessment of insulin resistance. In participants with IFG, unOC was positively associated with static β-cell response to glucose and total β-cell response to glucose (P < .05), independent of insulin sensitivity.. In overweight/obese individuals, total OC may be associated with skeletal muscle but not hepatic insulin sensitivity. unOC is uniquely associated with β-cell function only in individuals with IFG. Further research is needed to probe the causal inference of these relationships and to determine whether indirect nutrient sensing pathways underlie these associations.

Topics: Adult; Biomarkers; Body Mass Index; C-Peptide; Cohort Studies; Cross-Sectional Studies; Female; Glucose Intolerance; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Intra-Abdominal Fat; Liver; Male; Middle Aged; Models, Biological; Muscle, Skeletal; Osteocalcin; Overweight; Peptide Fragments; Procollagen; Protein Processing, Post-Translational; Young Adult

This clinical trial assessed whether a potent, selective GPR109A agonist, GSK256073, could, through inhibition of lipolysis, acutely improve glucose homeostasis in subjects with type 2 diabetes mellitus.. Thirty-nine diabetic subjects were enrolled in the randomized, single-blind, placebo-controlled, three-period crossover trial. Each subject received placebo and two of four regimens of GSK256073 for 2 days. GSK256073 was dosed 5 mg every 12 h before breakfast and supper (BID), 10 mg every 24 h before breakfast (QD), 25 mg BID and 50 mg QD.. The change from baseline weighted mean glucose concentration for an interval from 24 to 48 h after the initial drug dose was significantly reduced for all GSK256073 regimens, reaching a maximum of -0.87 mmol/l (-1.20, -0.52) with the 25 mg BID dose. Sustained suppression of non-esterified fatty acid (NEFA) and glycerol concentrations was observed with all GSK256073 doses throughout the 48-h dosing period. Serum insulin and C-peptide concentrations fell in concert with glucose concentrations and calculated HOMA-IR scores decreased 27-47%, consistent with insulin sensitization. No marked differences were evident between either 10 and 50 mg total daily doses or QD versus BID dosing.. Administration of a GPR109A agonist for 2 days significantly decreased serum NEFA and glucose concentrations in diabetic subjects. Glucose improvements were associated with decreased insulin concentrations and measures of enhanced insulin sensitivity. Improved glucose control occurred with GSK256073 doses that were generally safe and not associated with events of flushing or gastrointestinal disturbances.

Topics: C-Peptide; Cross-Over Studies; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Drug Administration Schedule; Drugs, Investigational; Fatty Acids, Nonesterified; Female; Follow-Up Studies; Glycerol; Humans; Hyperglycemia; Hyperinsulinism; Hypoglycemic Agents; Hypolipidemic Agents; Insulin Resistance; Male; Middle Aged; Receptors, G-Protein-Coupled; Receptors, Nicotinic; Single-Blind Method

To evaluate the effects of exenatide on some inflammatory markers and to quantify the effect of exenatide on β-cell function.. A randomized, double-blind, placebo-controlled trial.. Seven hospitals in Italy.. A total of 174 white treatment-naive adults with type 2 diabetes and a glycated hemoglobin (HbA(1c)) level higher than 7.5%.. After an open-label run-in period of 8 ± 2 months with metformin, patients were randomized to take exenatide (5 μg twice/day for the first 4 weeks, 10 μg twice/day thereafter) or a placebo volume equivalent for 12 months.. Body mass index, HbA(1c), fasting plasma glucose, postprandial plasma glucose, fasting plasma insulin (FPI), homeostasis model assessment insulin resistance index, homeostasis model assessment β-cell function index (HOMA-β), fasting plasma proinsulin (FPPr), proinsulin-to-fasting plasma insulin ratio (Pr:FPI ratio), C-peptide, glucagon, vaspin, chemerin, and resistin were evaluated at baseline, at randomization, and at 3, 6, 9, and 12 months. Patients also underwent a combined euglycemic, hyperinsulinemic, and hyperglycemic clamp with subsequent arginine stimulation to assess insulin sensitivity and insulin secretion. HbA(1c) was significantly improved with exenatide plus metformin compared with placebo plus metformin. Exenatide plus metformin was also significantly more effective than placebo plus metformin in increasing HOMA-β C-peptide, and all measures of β-cell function after the euglycemic hyperinsulinemic and hyperglycemic clamp. We observed that exenatide plus metformin also reduced resistin compared with placebo plus metformin. No variations in vaspin and chemerin were noted in group-to-group comparisons. We observed a significant correlation between M value increase, an index of insulin sensitivity, and a decrease in inflammatory parameters in the exenatide plus metformin group.. The combination of exenatide plus metformin was more effective than metformin alone in improving glycemic control, β-cell function, and inflammatory parameters.

Topics: Aged; Arginine; Biomarkers; Blood Glucose; Body Mass Index; Body Weight; C-Peptide; Chimerin Proteins; Diabetes Mellitus, Type 2; Diet; Double-Blind Method; Drug Therapy, Combination; Endpoint Determination; Exenatide; Female; Glucose Clamp Technique; Humans; Hypoglycemic Agents; Inflammation; Insulin Resistance; Male; Metformin; Middle Aged; Peptides; Resistin; Risk Factors; Serpins; Venoms

This study investigated if additional non-starch polysaccharide (NSP) or resistant starch (RS), above that currently recommended, leads to better improvement in insulin sensitivity (IS) than observed with modest weight loss (WL). Obese male volunteers (n = 14) were given an energy-maintenance (M) diet containing 27 g NSP and 5 g RS daily for one week. They then received, in a cross-over design, energy-maintenance intakes of either an NSP-enriched diet (42 g NSP, 2.5 g RS) or an RS-enriched diet (16 g NSP, 25 g RS), each for three weeks. Finally, a high protein (30% calories) WL diet was provided at 8 MJ/day for three weeks. During each dietary intervention, endogenous glucose production (EGP) and IS were assessed. Fasting glycaemia was unaltered by diet, but plasma insulin and C-peptide both decreased with the WL diet (p < 0.001), as did EGP (-11%, p = 0.006). Homeostatis model assessment of insulin resistance improved following both WL (p < 0.001) and RS (p < 0.05) diets. Peripheral tissue IS improved only with WL (57%-83%, p < 0.005). Inclusion of additional RS or NSP above amounts currently recommended resulted in little or no improvement in glycaemic control, whereas moderate WL (approximately 3 kg fat) improved IS.

Topics: Blood Glucose; C-Peptide; Carbohydrate Metabolism; Cross-Over Studies; Diet, Reducing; Dietary Proteins; Energy Intake; Energy Metabolism; Fasting; Homeostasis; Humans; Insulin; Insulin Resistance; Leucine; Male; Metabolic Syndrome; Models, Biological; Obesity; Polysaccharides; Starch; Weight Loss

Type 2 diabetes mellitus (T2DM) is associated with peripheral insulin resistance, impaired incretin effect, and increased plasma levels of tumour necrosis factor-alpha (TNF-α). Although TNF-α infusion at a dose that induces systemic inflammation in healthy volunteers has been demonstrated to induce peripheral insulin resistance, the influence of this cytokine on the incretin effect is unknown.. We investigated whether systemic inflammation induced by TNF-α infusion in healthy volunteers alters the incretin hormone response to oral and intravenous glucose loads in a crossover study design with ten healthy male volunteers (mean age 24 years, mean body mass index 23.7 kg/m(2) ). The study consisted of four study days: days 1 and 2, 6-h infusion of saline; days 3 and 4, 6-h infusion of TNF-α; days 1 and 3, 4-h oral glucose tolerance test; and days 2 and 4, 4-h corresponding intravenous isoglycaemic glucose tolerance test. Glucose tolerance tests were initiated after 2 h of saline/TNF-α infusion. Plasma concentrations of TNF-α, interleukin 6, glucose, incretin hormones, and cortisol, and serum concentrations of C-peptide and insulin were measured throughout the study days. Insulin sensitivity was estimated by the Matsuda index and homeostasis model assessment of insulin resistance (HOMA-IR). Prehepatic insulin secretion rates were calculated.. TNF-α infusion induced symptoms of systemic inflammation; increased plasma levels of cortisol, TNF-α, and interleukin 6; and increased the HOMA-IR. The secretion of incretin hormones as well as the incretin effect remained unchanged.. In healthy young male volunteers, acute systemic inflammation induced by infusion of TNF-α is associated with insulin resistance with no change in the incretin effect.

Topics: Adolescent; Adult; Blood Glucose; C-Peptide; Cross-Over Studies; Cytokines; Glucose Tolerance Test; Healthy Volunteers; Humans; Hydrocortisone; Incretins; Inflammation; Insulin; Insulin Resistance; Male; Tumor Necrosis Factor-alpha; Young Adult

To determine the effects of tibolone or oestradiol (E(2) )/norethisterone acetate (NETA) hormone replacement therapy on glucose and insulin metabolism in postmenopausal women.. Single-centre double-blind placebo-controlled randomized clinical trial.. We randomized 105 healthy postmenopausal women to tibolone 2·5 mg daily, continuous combined oral E(2) 2 mg/NETA 1 mg daily or placebo over a 2-year study. We performed intravenous glucose tolerance tests (IVGTT) with measurements of plasma glucose, insulin and C-peptide concentrations and the IVGTT glucose elimination rate, k. Mathematical modelling was performed to determine measures of insulin sensitivity, S(i) , pancreatic insulin secretion and hepatic and plasma insulin elimination.. Tibolone decreased S(i) to 53-63% and k to 72-79% of baseline values but increased IVGTT phase 2 C-peptide concentrations 1·6-1·8-fold and pancreatic insulin secretion 2·2-2·4-fold, so overall IVGTT glucose concentrations were unaffected. Similar, but for k, significantly smaller changes in insulin and C-peptide secretion were seen with E(2) /NETA, also with no effect on overall IVGTT glucose concentrations.. Tibolone reduces insulin sensitivity. Healthy postmenopausal women seem able to compensate for this and maintain normal postload glucose concentrations, but it may not be advisable to prescribe tibolone to women with, or at increased risk for, diabetes.

Topics: Aged; Blood Glucose; C-Peptide; Contraceptives, Oral, Synthetic; Estradiol; Estrogen Receptor Modulators; Estrogens; Female; Glucose; Humans; Insulin; Insulin Resistance; Middle Aged; Norethindrone; Norpregnenes

Given that the repetitive loss and regain of body weight, termed weight cycling, is a prevalent phenomenon that has been associated with negative physiological and psychological outcomes, the purpose of this study was to investigate weight change and physiological outcomes in women with a lifetime history of weight cycling enrolled in a 12-month diet and/or exercise intervention.. 439 overweight, inactive, postmenopausal women were randomized to: i) dietary weight loss with a 10% weight loss goal (N=118); ii) moderate-to-vigorous intensity aerobic exercise for 45 min/day, 5 days/week (n=117); ii) both dietary weight loss and exercise (n=117); or iv) control (n=87). Women were categorized as non-, moderate- (≥3 losses of ≥4.5 kg), or severe-cyclers (≥3 losses of ≥9.1 kg). Trend tests and linear regression were used to compare adherence and changes in weight, body composition, blood pressure, insulin, C-peptide, glucose, insulin resistance (HOMA-IR), C-reactive protein, leptin, adiponectin, and interleukin-6 between cyclers and non-cyclers.. Moderate (n=103) and severe (n=77) cyclers were heavier and had less favorable metabolic profiles than non-cyclers at baseline. There were, however, no significant differences in adherence to the lifestyle interventions. Weight-cyclers (combined) had a greater improvement in HOMA-IR compared to non-cyclers participating in the exercise only intervention (P=.03), but no differences were apparent in the other groups.. A history of weight cycling does not impede successful participation in lifestyle interventions or alter the benefits of diet and/or exercise on body composition and metabolic outcomes.

Topics: Adiponectin; Blood Glucose; Blood Pressure; Body Composition; C-Peptide; C-Reactive Protein; Diet, Reducing; Exercise; Female; Humans; Insulin; Insulin Resistance; Interleukin-6; Leptin; Linear Models; Middle Aged; Overweight; Postmenopause; Weight Gain; Weight Loss

Adverse effects of hypercaloric, high-fructose diets on insulin sensitivity and lipids in human subjects have been shown repeatedly. The implications of fructose in amounts close to usual daily consumption, however, have not been well studied. This study assessed the effect of moderate amounts of fructose and sucrose compared with glucose on glucose and lipid metabolism.. Nine healthy, normal-weight male volunteers (aged 21-25 years) were studied in this double-blind, randomized, cross-over trial. All subjects consumed four different sweetened beverages (600 mL/day) for 3 weeks each: medium fructose (MF) at 40 g/day, and high fructose (HF), high glucose (HG), and high sucrose (HS) each at 80 g/day. Euglycemic-hyperinsulinemic clamps with [6,6]-(2)H(2) glucose labeling were used to measure endogenous glucose production. Lipid profile, glucose, and insulin were measured in fasting samples.. Hepatic suppression of glucose production during the clamp was significantly lower after HF (59.4 ± 11.0%) than HG (70.3 ± 10.5%, P < 0.05), whereas fasting glucose, insulin, and C-peptide did not differ between the interventions. Compared with HG, LDL cholesterol and total cholesterol were significantly higher after MF, HF, and HS, and free fatty acids were significantly increased after MF, but not after the two other interventions (P < 0.05). Subjects' energy intake during the interventions did not differ significantly from baseline intake.. This study clearly shows that moderate amounts of fructose and sucrose significantly alter hepatic insulin sensitivity and lipid metabolism compared with similar amounts of glucose.

Topics: Adult; Blood Glucose; C-Peptide; Cholesterol, LDL; Cross-Over Studies; Double-Blind Method; Fatty Acids, Nonesterified; Fructose; Glucose; Glucose Clamp Technique; Humans; Insulin Resistance; Lipid Metabolism; Liver; Sweetening Agents; Triglycerides; Young Adult

We designed an experiment to examine the effect of bile acid sequestration with Colesevelam on fasting and postprandial glucose metabolism in type 2 diabetes. To do so, we tested the hypothesis that Colesevelam increases the disposition index (DI), and this increase is associated with increased glucagon-like peptide-1 (GLP-1) concentrations. Thirty-eight subjects on metformin monotherapy were studied using a double-blind, placebo-controlled, parallel-group design. Subjects were studied before and after 12 weeks of Colesevelam or placebo using a labeled triple-tracer mixed meal to measure the rate of meal appearance (Meal Ra), endogenous glucose production (EGP), and glucose disappearance (Rd). Insulin sensitivity and β-cell responsivity indices were estimated using the oral minimal model and then used to calculate DI. Therapy with Colesevelam was associated with a decrease in fasting (7.0 ± 0.2 vs. 6.6 ± 0.2 mmol/L; P = 0.004) and postprandial glucose concentrations (3,145 ± 138 vs. 2,896 ± 127 mmol/6 h; P = 0.01) in the absence of a change in insulin concentrations. Minimal model-derived indices of insulin secretion and action were unchanged. Postprandial GLP-1 concentrations were not altered by Colesevelam. Although EGP and Rd were unchanged, integrated Meal Ra was decreased by Colesevelam (5,191 ± 204 vs. 5,817 ± 204 μmol/kg/6 h; P = 0.04), suggesting increased splanchnic sequestration of meal-derived glucose.

Topics: Allylamine; Anticholesteremic Agents; Blood Glucose; C-Peptide; Colesevelam Hydrochloride; Diabetes Mellitus, Type 2; Double-Blind Method; Fasting; Female; Glucagon; Glucagon-Like Peptide 1; Glucose; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Postprandial Period

To evaluate the effects the administration of myo-inositol (MYO) on hormonal parameters in a group of polycystic ovary syndrome (PCOS) patients.. Controlled clinical study.. PCOS patients in a clinical research environment.. 50 overweight PCOS patients were enrolled after informed consent.. All patients underwent hormonal evaluations and an oral glucose tolerance test (OGTT) before and after 12 weeks of therapy (Group A (n¼10): MYO 2 g plus folic acid 200 mg every day; Group B (n¼10): folic acid 200 mg every day). Ultrasound examinations and Ferriman-Gallwey score were also performed.. Plasma LH, FSH, PRL, E2, 17OHP, A, T, glucose, insulin, C peptide concentrations, BMI, HOMA index and glucose-to-insulin ratio.. After 12 weeks of MYO administration plasma LH, PRL, T, insulin levels and LH/FSH resulted significantly reduced. Insulin sensitivity, expressed as glucose-to-insulin ratio and HOMA index resulted significantly improved after 12 weeks of treatment. Menstrual cyclicity was restored in all amenorrheic and oligomenorrheic subjects. No changes occurred in the patients treated with folic acid.. MYO administration improves reproductive axis functioning in PCOS patients reducing the hyperinsulinemic state that affects LH secretion.

Topics: Blood Glucose; Body Mass Index; C-Peptide; Drug Therapy, Combination; Estradiol; Female; Folic Acid; Follicle Stimulating Hormone; Glucose Tolerance Test; Humans; Inositol; Insulin; Insulin Resistance; Luteinizing Hormone; Polycystic Ovary Syndrome; Prolactin; Testosterone; Treatment Outcome

Chronic sub-acute inflammation contributes to the pathogenesis of type 2 diabetes mellitus and cardiovascular disease. High doses of salicylate reduce inflammation, glucose and triacylglycerols, and may improve insulin sensitivity, suggesting therapeutic potential in impaired fasting glucose and/or impaired glucose tolerance. This trial aimed to evaluate the effect of salsalate vs placebo on insulin resistance and glycaemia in impaired fasting glucose and/or impaired glucose tolerance.. We conducted a 12 week, two-centre, randomised, placebo-controlled study to evaluate the effect of salsalate (up to 4 g/day) vs placebo on systemic glucose disposal. Secondary objectives included treatment effects on glycaemia, inflammation and cardiovascular risk factors. Seventy-eight participants with impaired fasting glucose and/or impaired glucose tolerance from two VA healthcare systems were enrolled. Randomisation assignment was provided by the coordinating center directly to site pharmacists, and participants and research staff were blinded to treatment assignment.. Seventy-one individuals were randomised to placebo (n = 36) or salsalate (n = 35). Glucose disposal did not change in either group (salsalate 1% [95% CI -39%, 56%]; placebo 6% [95% CI -20%, 61%], p = 0.3 for placebo vs salsalate). Fasting glucose was reduced by 6% during the study by salsalate (p = 0.006) but did not change with placebo. Declines in glucose were accompanied by declines in fasting C-peptide with salsalate. Insulin clearance was reduced with salsalate. In the salsalate group, triacylglycerol levels were lower by 25% (p = 0.01) and adiponectin increased by 53% (p = 0.02) at the end of the study. Blood pressure, endothelial function and other inflammation markers did not differ between groups. Adipose tissue nuclear factor κB (NF-κB) activity declined in the salsalate group compared with placebo (-16% vs 42%, p = 0.005), but was not correlated with metabolic improvements. The frequency of tinnitus was low but tended to be higher with salsalate therapy (n = 4 vs n = 2).. In summary, salsalate therapy was well tolerated, lowered fasting glucose, increased adiponectin and reduced adipose tissue NF-κB activity. These changes were not related to changes in peripheral insulin sensitivity, suggesting additional mechanisms for metabolic improvement.. ClinicalTrials.gov NCT00330733.. Office of Research and Development, Medical Research Service, Department of Veterans Affairs and NIH K24 DK63214.

Topics: Adiponectin; Adipose Tissue; Aged; Anti-Inflammatory Agents, Non-Steroidal; Blood Glucose; C-Peptide; Cardiovascular Diseases; Female; Glucose Tolerance Test; Humans; Inflammation; Insulin; Insulin Resistance; Male; Middle Aged; NF-kappa B; Risk Factors; Salicylates; Triglycerides

To investigate the dose-related effects of glucocorticoid treatment on glucose tolerance, beta cell function, and insulin sensitivity in patients with early active rheumatoid arthritis (RA).. A randomized, controlled, single-blind trial was conducted in 41 patients with early active RA. At the beginning of the trial patients had not been treated for their RA, and were randomized to begin treatment with prednisolone at 60 mg/day or 30 mg/day. Before and at the end of 1 week of treatment, a frequently sampled oral glucose tolerance test was performed. The glucose area under the curve (AUC(G) ) was calculated. In addition, beta cell function and insulin sensitivity parameters were computed.. Patients (mean ± SD age 55.5 ± 14.8 years and 54.2 ± 12.6 years in the prednisone 60 mg/day and prednisone 30 mg/day groups, respectively; body mass index 24.5 ± 4.1 kg/m(2) and 25.4 ± 4.2 kg/m(2) , respectively) had active disease at baseline (mean ± SD Disease Activity Score in 44 joints 4.1 ± 0.7 and 4.0 ± 0.8, respectively; median C-reactive protein [CRP] level 14 mg/liter [interquartile range 6-34] and 19 mg/liter [interquartile range 3-39], respectively). In addition, 56% of the patients had impaired glucose tolerance at baseline, and 7% were found to have previously unrecognized type 2 diabetes mellitus (DM). Associations of the AUC(G) with erythrocyte sedimentation rate (β = 2.430 [95% confidence interval 0.179-4.681], P = 0.04) and with CRP level (β = 2.358 [95% confidence interval 0.210-4.506], P = 0.03) were demonstrated. Treatment with prednisolone at both dosages reduced CRP levels significantly. The incidence of type 2 DM increased to 24% (P < 0.001) (evenly distributed across the groups). The mean AUC(G) did not change in either treatment arm. Beta cell function improved during prednisone treatment at 60 mg/day (P = 0.02) and at 30 mg/day (P = 0.04). Disease duration was associated with changes in the AUC(G) (β = 3.626 [95% confidence interval 1.077-6.174], P = 0.007) and with deterioration of the glucose state (odds ratio 1.068 [95% confidence interval 1.017-1.122], P = 0.009).. In this study, short-term treatment with prednisolone 60 mg or 30 mg per day improved disease activity without deterioration of glucose tolerance in patients with active RA. However, due to individual differences, monitoring is recommended.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Antirheumatic Agents; Arthritis, Rheumatoid; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Drug Therapy, Combination; Early Diagnosis; Female; Glucocorticoids; Glucose Tolerance Test; Health Status; Humans; Inflammation; Insulin Resistance; Joints; Male; Middle Aged; Prednisolone; Severity of Illness Index

This study was performed to determine the effect of a single, large, intramuscular injection of vitamin D post-partum on glucose tolerance and insulin resistance in women with gestational diabetes.. Forty-five participants in a randomized controlled trial on gestational diabetes mellitus were divided into an intervention group and a control group. Only subjects in the intervention group received one intramuscular injection of 300,000 IU of vitamin D3. HbA(1c), serum 25-hydroxyvitamin D3, fasting insulin and blood glucose, C-peptide, homeostasis model assessment insulin resistance index (HOMA-IR), β-cell function, insulin sensitivity and the Quantitative Insulin Sensitivity Check Index (QUICKI) were measured at baseline and after 3 months of intervention.. Approximately 80% of the mothers had a degree of vitamin D deficiency. Post-intervention, this was found in 4.2 and 71.4% in the intervention and control groups, respectively. The medians of HOMA-IR indices before and after intervention were 0.6 and 0.5 (P = 0.7), respectively, in subjects in the intervention group, and 0.5 and 0.9 (P = 0.01) in subjects in the control group. The mean of the QUICKI fell only in the control group (P = 0.008). In the control group, β-cell function increased by ~8% (P = 0.01) and insulin sensitivity decreased after 3 months (P = 0.002). Post-intervention, the median C-peptide decreased in the intervention group and increased in the control group, but the change was significant only in the control group (P = 0.03).. A single injection of 300,000 IU of vitamin D3 achieves a 3-month serum 25-hydroxyvitamin D range of 50-80 nmol/l and is an efficient, effective and safe procedure for improving the vitamin status and indices of insulin resistance in mothers with gestational diabetes after delivery.

Topics: Adult; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Diabetes, Gestational; Fasting; Female; Follow-Up Studies; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Injections, Intramuscular; Insulin Resistance; Postpartum Period; Pregnancy; Treatment Outcome; Vitamin D

Pinitol is thought to mediate insulin action and improve insulin resistance. We evaluated the effects of pinitol on glycemic control, insulin resistance and adipocytokine levels in type 2 diabetic patients.. A total of 66 patients with type 2 diabetes who had been taking oral hypoglycemic agents for at least 3 months were enrolled and randomized to receive pinitol (n = 33) or matching placebo (n = 33). All subjects took 1,200 mg pinitol or placebo and maintained their current oral hypoglycemic agents throughout the study.. Mean HbA1c, fasting plasma glucose, and HOMA-IR were significantly lowered more in patients taking pinitol than in those given a placebo. Patients who had an HbA1c over 8.0% showed a greater reduction (p < 0.01) than those who had an HbA1c below 8.0% (p =0.16). In addition, in the group of patients with a HOMA-IR over 2.5, there was a significant decrease in HbA1c compared to that in the group of patients with a HOMA-IR below 2.5. There were no differences in the changes in adiponectin, FFA and CRP between the two groups.. Pinitol can mediate insulin action to improve glycemic control and insulin sensitivity in patients with type 2 diabetes mellitus, especially in patients with insulin resistance.

Topics: Adipokines; Adiponectin; Adult; Aged; Blood Glucose; C-Peptide; C-Reactive Protein; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Fatty Acids, Nonesterified; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Inositol; Insulin Resistance; Male; Middle Aged; Milk Proteins; Treatment Outcome; Whey Proteins

The insulinotropic effect of the incretin hormones, glucose-dependent insulinotropic polypeptide (GIP), and glucagon-like peptide-1 (GLP-1) is impaired in patients with type 2 diabetes. It remains unclear whether this impairment is a primary pathophysiological trait or a consequence of developing diabetes. Therefore, we aimed to investigate the insulinotropic effect of GIP and GLP-1 compared with placebo before and after 12 d of glucose homeostatic dysregulation in healthy subjects.. The insulinotropic effect was measured using hyperglycemic clamps and infusion of physiological doses of GIP, GLP-1, or saline in 10 healthy Caucasian males before and after intervention using a high-calorie diet, sedentary lifestyle, and administration of prednisolone (37.5 mg once daily) for 12 d.. The intervention resulted in increased insulin resistance according to the homeostatic model assessment (1.2 ± 0.2 vs. 2.6 ± 0.5, P = 0.01), and glucose tolerance deteriorated as assessed by the area under curve for plasma glucose during a 75-g oral glucose tolerance test (730 ± 30 vs. 846 ± 57 mm for 2 h, P = 0.021). The subjects compensated for the change in insulin resistance by significantly increasing their postintervention insulin responses during saline infusion by 2.9 ± 0.5-fold (P = 0.001) but were unable to do so in response to incretin hormones (which caused insignificant increases of only 1.78 ± 0.3 and 1.38 ± 0.3-fold, P value not significant).. These data show that impairment of the insulinotropic effect of both GIP and GLP-1 can be induced in healthy male subjects without risk factors for type 2 diabetes, indicating that the reduced insulinotropic effect of the incretin hormones observed in type 2 diabetes most likely is a consequence of insulin resistance and glucose intolerance rather than a primary event causing the disease.

Topics: Adult; Blood Glucose; C-Peptide; Gastric Inhibitory Polypeptide; Glucagon; Glucagon-Like Peptide 1; Glucose Clamp Technique; Glucose Intolerance; Glucose Tolerance Test; Humans; Incretins; Infusions, Intravenous; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Kinetics; Male; Severity of Illness Index; Young Adult

Postoperative insulin resistance and the consequent hyperglycemia affects clinical outcome. Insulin sensitivity may be modulated by preoperative nutrition, adequate pain management and minimal invasive surgery. This study aims to disclose the impact of perioperative glucose control on postoperative insulin resistance.. Twenty patients scheduled for elective open hepatectomy were enrolled in this prospective, randomized study. In the treatment group (n = 9) insulin was administered intravenously to keep blood glucose between 6 and 8 mmol/l during surgery. The control group (n = 8) received insulin if blood glucose >14 mmol/l. Insulin sensitivity was measured by a hyperinsulinemic normoglycemic clamp (0.8 mU/kg/min), performed on all patients both on the day before surgery and immediately postoperatively. Plasma cortisol, insulin and C-peptide were measured.. There was a significant difference in mean glucose value during surgery. In the control group 8.8 mmol/l (SD 1.5) vs. 6.9 mmol/l (SD 0.4) in the treated group, p = 0.003. In the control group insulin sensitivity decreased to 21.9% ± 16.2% of the preoperative value and in the insulin treated group to 46.8 ± 15.5%, p < 0.005. Insulin levels were significantly higher in the treatment group as well as consequently lower C-peptide levels.. This trial revealed a significant difference in postoperative insulin resistance in the group treated with insulin during surgery.

Topics: Administration, Intravenous; Aged; Blood Glucose; C-Peptide; Female; Glucose Clamp Technique; Hepatectomy; Humans; Hydrocortisone; Hyperglycemia; Insulin; Insulin Resistance; Male; Middle Aged; Perioperative Care; Postoperative Period; Prospective Studies

Increased risks of weight gain and diabetes mellitus have been reported for schizophrenic patients under long-term treatment with several atypical antipsychotic drugs including olanzapine. Among other antipsychotic drugs, treatment with the selective dopamine D2 and D3 receptor antagonist amisulpride has been implicated with a lower risk for metabolic complications.. In this study we compared the acute, non-adiposity related effects of a single dose of olanzapine, amisulpride and placebo on insulin sensitivity and secretion in 10 healthy subjects in a randomised, double blind cross-over design. Subjects underwent euglycemic-hyperinsulinemic and hyperglycemic clamp tests using an automated clamp device. C-peptide and pro-insulin levels were determined using highly specific immuno-assays.. Insulin sensitivity was not significantly different between both verum medications and placebo. However, C-peptide secretion during hyperglycemic clamp was significantly higher after administration of amisulpride than after olanzapine or placebo. This was true both for the early phase and for the second phase of insulin secretion (C-peptide at 0, 5,10 and 30 min: amisulpride 1.49±0.49; 4.22±1.45; 3.19±1.22; 5.33±1.85; olanzapine 1.35±0.47; 3.84±1.37; 2.72±0.91; 4.28±1.96; placebo 1.72±0.82; 3.59±1.19; 2.71±1.02; 4.54±1.42 ng/mL, mean±SD; ANOVA p=0.043). Pro-insulin levels did not differ significantly between groups.. A low dose of the D2/D3 antagonist amisulpride, but not olanzapine appears to acutely increase pancreatic insulin secretion in healthy controls. Stimulation of β-cells could be a protective factor against the development of diabetes mellitus.

Topics: Adult; Amisulpride; Antipsychotic Agents; Benzodiazepines; C-Peptide; Cross-Over Studies; Double-Blind Method; Glucose Clamp Technique; Humans; Insulin; Insulin Resistance; Insulin Secretion; Male; Olanzapine; Proinsulin; Sulpiride

This study evaluated the effect of vildagliptin + metformin on glycemic control and β-cell function in type 2 diabetes patients.. One hundred seventy-one type 2 diabetes patients, naive to antidiabetes therapy and with poor glycemic control, were instructed to take metformin for 8±2 months up to a mean dosage of 2,500±500 mg/day; then they were randomly assigned to add vildaglipin 50 mg twice a day or placebo for 12 months. We evaluated at 3, 6, 9, and 12 months: body mass index, glycemic control, fasting plasma insulin, homeostasis model assessment insulin resistance index (HOMA-IR), homeostasis model assessment β-cell function index (HOMA-β), fasting plasma proinsulin, proinsulin/fasting plasma insulin ratio, C-peptide, glucagon, adiponectin, and high-sensitivity C-reactive protein. Before and at 12 months after the addition of vildagliptin, patients underwent a combined euglycemic hyperinsulinemic and hyperglycemic clamp, with subsequent arginine stimulation, to assess insulin sensitivity and insulin secretion.. After 12 months of treatment, vildagliptin + metformin gave a better decrease of body weight, glycemic control, HOMA-IR, and glucagon and a better increase of HOMA-β compared with placebo + metformin. Regarding the measures of β-cell function, treatment-induced changes in M-value, first- and second-phase C-peptide response to glucose, and C-peptide response to arginine were significantly higher in the vildagliptin + metformin group compared with the placebo + metformin group.. The addition of vildagliptin to metformin gave a better improvement of glycemic control, insulin resistance, and β-cell function compared with metformin alone.

Topics: Adamantane; Blood Glucose; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Fasting; Female; Glucose Clamp Technique; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Metformin; Middle Aged; Nitriles; Pyrrolidines; Vildagliptin; Weight Loss

Our aim was to study the potential mechanisms responsible for the improvement in glucose control in Type 2 diabetes (T2D) within days after Roux-en-Y gastric bypass (RYGB). Thirteen obese subjects with T2D and twelve matched subjects with normal glucose tolerance (NGT) were examined during a liquid meal before (Pre), 1 wk, 3 mo, and 1 yr after RYGB. Glucose, insulin, C-peptide, glucagon-like peptide-1 (GLP-1), glucose-dependent-insulinotropic polypeptide (GIP), and glucagon concentrations were measured. Insulin resistance (HOMA-IR), β-cell glucose sensitivity (β-GS), and disposition index (D(β-GS): β-GS × 1/HOMA-IR) were calculated. Within the first week after RYGB, fasting glucose [T2D Pre: 8.8 ± 2.3, 1 wk: 7.0 ± 1.2 (P < 0.001)], and insulin concentrations decreased significantly in both groups. At 129 min, glucose concentrations decreased in T2D [Pre: 11.4 ± 3, 1 wk: 8.2 ± 2 (P = 0.003)] but not in NGT. HOMA-IR decreased by 50% in both groups. β-GS increased in T2D [Pre: 1.03 ± 0.49, 1 wk: 1.70 ± 1.2, (P = 0.012)] but did not change in NGT. The increase in DI(β-GS) was 3-fold in T2D and 1.5-fold in NGT. After RYGB, glucagon secretion was increased in response to the meal. GIP secretion was unchanged, while GLP-1 secretion increased more than 10-fold in both groups. The changes induced by RYGB were sustained or further enhanced 3 mo and 1 yr after surgery. Improvement in glycemic control in T2D after RYGB occurs within days after surgery and is associated with increased insulin sensitivity and improved β-cell function, the latter of which may be explained by dramatic increases in GLP-1 secretion.

Topics: Adult; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Female; Follow-Up Studies; Gastric Bypass; Glucagon; Glucagon-Like Peptide 1; Glucose; Humans; Hyperglycemia; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Obesity; Obesity, Morbid; Postprandial Period; Time Factors

Fibroblast growth factor 21 (FGF21), an endocrine factor predominantly secreted from liver, possesses multiple beneficial effect on energy metabolism and insulin sensitivity in animals. This study aimed to investigate the acute change of serum FGF21 in response to glucose challenge in humans.. A 75-g oral glucose tolerance test was performed among 20 healthy subjects, 18 with impaired glucose tolerance (IGT) and 21 with type 2 diabetes mellitus (T2DM). Blood samples were collected for measurement of FGF21 and other biochemical parameters. The associations of FGF21 with insulin and other metabolic parameters were analyzed.. Fasting serum FGF21 levels increased progressively from healthy, IGT to T2DM subjects (P < 0.05 for global trend). After oral glucose administration, the serum FGF21 level showed a similar biphasic change in all three groups. It declined to a nadir level at 60 min and then increased gradually to its peak level at 180 min. FGF21 levels at different time points of oral glucose tolerance test negatively correlated with glucose levels in all subjects, and the fold change of serum FGF21 at different time points (compared with the basal level) were inversely associated with fold changes of insulin (P = 0.012) and C-peptide (P = 0.043) levels in healthy subjects but not in IGT and T2DM patients.. The dynamic change of circulating FGF21 was associated with alterations in insulin levels in response to glucose challenge in humans. These findings support the role of FGF21 as a potential regulator of insulin secretion and glucose metabolism in humans.

Topics: Adult; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Fibroblast Growth Factors; Glucose; Glucose Intolerance; Glucose Tolerance Test; Health; Humans; Insulin; Insulin Resistance; Male; Matched-Pair Analysis

To evaluate the impact on glycemic control, insulin resistance, and insulin secretion of sitagliptin+metformin compared to metformin in type 2 diabetic patients.. Patients were instructed to take metformin for 8 ± 2 months, then they were randomly assigned to sitaglipin 100 mg or placebo for 12 months. We evaluated at 3, 6, 9, and 12 months: body mass index (BMI), glycemic control, fasting plasma insulin (FPI), HOMA-IR, HOMA-β, fasting plasma proinsulin (FPPr), proinsulin/fasting plasma insulin ratio (Pr/FPI ratio), C-peptide, glucagon, adiponectin (ADN), and high sensitivity-C reactive protein (Hs-CRP). Before, and after 12 months since the addition of sitagliptin, patients underwent a combined euglycemic hyperinsulinemic and hyperglycemic clamp, with subsequent arginine stimulation.. Both treatments similarly decreased body weight, and BMI; on the other hand, they both improved glycemic control, glucagon and HOMA-IR, but sitagliptin+metformin were more effective in reducing these parameters. Sitagliptin+metformin, but not placebo+metformin, decreased FPPr, FPPR/FPI ratio, and increased C-peptide values, even if no differences between the groups were recorded. Sitaglitin+metformin gave also a greater increase of HOMA-β, M value, C-peptide response to arginine and disposition index compared to placebo+metformin group.. Other than improving glycemic control, sitagliptin+metformin also improved β-cell function better than metformin alone.

Topics: Blood Glucose; C-Peptide; C-Reactive Protein; Diabetes Mellitus, Type 2; Double-Blind Method; Drug Therapy, Combination; Exercise; Fasting; Female; Glucagon; Glucose Clamp Technique; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin Resistance; Insulin-Secreting Cells; Italy; Male; Metformin; Middle Aged; Pyrazines; Sitagliptin Phosphate; Treatment Outcome; Triazoles

What is the effect of alternative administration routes of combined contraceptives (CCs) on androgen secretion, chronic inflammation, glucose tolerance and lipid profile?. The use of oral, transdermal and vaginal CCs impairs glucose tolerance and induces chronic inflammation.. Oral CCs worsen insulin sensitivity and are associated with increased levels of circulating inflammatory markers, whereas the metabolic effects of transdermal and vaginal CCs have been reported to be minimal. This is the first study comparing three different administration routes of CCs on metabolic variables.. This randomized (computer-generated) open-label 9-week follow-up study was conducted at the Oulu University Hospital, Finland. Fasting blood samples were collected at baseline and thereafter at 5 and 9 weeks of treatment, and serum levels of 17-hydroxyprogesterone, androstenedione, testosterone, C-reactive protein (CRP), sex hormone-binding globulin (SHBG), glucose, insulin, C-peptide, total, low-density lipoprotein and high-density lipoprotein cholesterol and triglycerides were measured. Oral glucose tolerance tests were performed and plasma levels of pentraxin 3 (PTX-3) were measured at 0 and 9 weeks. The randomization list, with an allocation ratio of 1:1:1 and block size of six, was computer generated and constructed by a pharmacist at the Oulu University Hospital. The research nurse controlled the randomization list and assigned participants to their groups at the first visit.. Forty-two of 54 healthy women who entered the study used oral contraceptive pills (n = 13), transdermal contraceptive patches (n = 15) or contraceptive vaginal rings (n = 14) continuously for 9 weeks. Inclusion criteria were regular menstrual cycles, at least a 2-month washout as regards hormonal contraceptives and no medication.. Serum levels of SHBG increased and consequently the free androgen index (FAI) decreased in all study groups from baseline to 9 weeks of treatment [FAI, oral: 1.3 (95% confidence interval, CI: 0.94; 1.62) to 0.40 (0.25; 0.54); transdermal: 1.2 (0.96; 1.4) to 0.36 (0.30; 0.43); vaginal: 1.6 (1.1; 2.1) to 0.43 (0.29; 0.58), P < 0.001 in all groups]. Insulin sensitivity was reduced at 9 weeks in all three groups according to the Matsuda index [oral: 7.3 (5.5; 9.0) to 5.6 (3.9; 7.3); transdermal: 9.1 (6.7; 11.4) to 6.6 (4.5; 8.8); vaginal: 7.7 (5.9; 9.5) to 5.4 (3.9; 7.0), P= 0.004-0.024]. Levels of HDL cholesterol, triglycerides and CRP rose in all three groups [CRP, oral: 0.70 (0.38; 1.0) to 5.4 (1.0; 9.9) mg/l; transdermal: 0.77 (0.45; 1.1) to 2.9 (1.4;4.4) mg/l; vaginal: 0.98 (0.52; 1.4) to 3.7 (-0.25; 7.7, a negative value due to skewed distribution to right) mg/l, P≤ 0.002 in all groups] and PTX-3 levels increased in the oral and transdermal study groups (P = 0.007 and P = 0.002).. Although the long-term consequences of the present results remain undetermined, these findings emphasize the importance of monitoring glucose metabolism during the use of CCs, especially in women with known risks of type 2 diabetes or cardiovascular diseases. BIAS, LIMITATIONS, GENERALIZABILITY: The number of subjects was relatively low. Moreover, the 9-week exposure to CCs is too short to draw conclusions about the long-term health consequences. However, as the subjects were healthy, normal-weight young women, the possible alterations in the glucose and inflammatory profiles among women with known metabolic risks might be even greater.. This work was supported by grants from the Academy of Finland, the Sigrid Jusélius Foundation, the Finnish Medical Foundation, the Research Foundation of Obstetrics and Gynecology, Oulu University Scholarship Foundation, the North Ostrobothnia Regional Fund of the Finnish Cultural Foundation, the Tyyni Tani Foundation of the University of Oulu and the Finnish-Norwegian Medical Foundation. No competing interests.. NCT01087879.

Topics: 17-alpha-Hydroxyprogesterone; Administration, Cutaneous; Administration, Intravaginal; Adult; Androgens; Androstenedione; Biomarkers; Blood Glucose; C-Peptide; C-Reactive Protein; Contraceptive Agents, Female; Contraceptives, Oral, Combined; Female; Glucose; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Lipoproteins; Sex Hormone-Binding Globulin; Testosterone

Elevated thyroid-stimulating hormone (TSH) concentrations in association with normal/slightly elevated free triiodothyronine (fT(3)) and/or free thyroxine (fT(4)) have been consistently found in obese children. To examine relationships between adiposity, insulin sensitivity, and TSH, fT(3) and fT(4).. 240 overweight/obese prepubertal children were studied. Fasting TSH, fT(3), fT(4), glucose, insulin, C-peptide, lipids, leptin and adiponectin were evaluated. Insulin sensitivity and resistance were estimated [quantitative insulin check index (QUICKI), insulin sensitivity index (ISI), and hepatic insulin resistance index]. Body fat was measured by dual-energy X-ray absorptiometry. The central obesity index was calculated as the ratio of fat tissue in the trunk region to fat tissue in the leg region.. The multiple regression analysis with age, gender and measures of fatness as covariates showed that QUICKI was the only significant negative predictor of TSH and central obesity index the strongest positive predictor of fT(3), in association with either age or hepatic insulin resistance index, and that the only positive determinant of fT(4) was hepatic insulin resistance index.. Reduced insulin sensitivity is associated with augmented TSH and fT(4), while progressive central fat accumulation is strictly related to a parallel increase in fT(3) levels, independently from total body fat. Further studies are needed to understand mechanisms linking thyroid function to insulin sensitivity and body composition in obese children.

Topics: Adiponectin; Adiposity; Blood Glucose; C-Peptide; Child; Female; Humans; Insulin; Insulin Resistance; Leptin; Lipids; Male; Obesity; Thyroid Function Tests; Thyroxine; Triiodothyronine

In adults, dietary protein seems to induce weight loss and dairy proteins may be insulinotropic. However, the effect of milk proteins in adolescents is unclear. The objective was to test whether milk and milk proteins reduce body weight, waist circumference, homeostatic model assessment, plasma insulin, and insulin secretion estimated as the plasma C-peptide concentration in overweight adolescents. Overweight adolescents (n = 203) aged 12-15 y with a BMI of 25.4 ± 2.3 kg/m(2) (mean ± SD) were randomized to 1 L/d of skim milk, whey, casein, or water for 12 wk. All milk drinks contained 35 g protein/L. Before randomization, a subgroup of adolescents (n = 32) was studied for 12 wk before the intervention began as a pretest control group. The effects of the milk-based test drinks were compared with baseline (wk 0), the water group, and the pretest control group. Diet and physical activity were registered. Outcomes were BMI-for-age Z-scores (BAZs), waist circumference, plasma insulin, homeostatic model assessment, and plasma C-peptide. We found no change in BAZ in the pretest control and water groups, whereas it was greater at 12 wk in the skim milk, whey, and casein groups compared with baseline and with the water and pretest control groups. The plasma C-peptide concentration increased from baseline to wk 12 in the whey and casein groups and increments were greater than in the pretest control (P < 0.02). There were no significant changes in plasma C-peptide in the skim milk or water group. These data suggest that high intakes of skim milk, whey, and casein increase BAZs in overweight adolescents and that whey and casein increase insulin secretion. Whether the effect on body weight is primary or secondary to the increased insulin secretion remains to be elucidated.

Topics: Adolescent; Animals; Body Mass Index; C-Peptide; Caseins; Cattle; Child; Humans; Insulin; Insulin Resistance; Milk; Milk Proteins; Overweight; Waist Circumference; Weight Gain; Whey Proteins

Posttransplantation diabetes mellitus (PTDM) is a frequent complication after allogeneic stem cell transplantation (allo-SCT), important for its negative impact on cardiovascular health. Risk factors for PTDM are not well defined. We conducted a prospective study to investigate the risk factors and incidence for PTDM in the first 100 days after allo-SCT. A total of 84 patients completed the study, 60% of whom developed PTDM. In a multivariate logistic regression model, pretransplantation c-peptide level (>3.6 ng/mL; odds ratio [OR], 5.9; 95% confidence interval [CI], 1.77-20.22; P = .004), unrelated donor allo-SCT (OR, 4.3; 95% CI, 1.34-14.2; P = .014), and peak steroid dose >1 mg/kg/day (OR, 5.09; 95% CI, 1.19-23.2; P = .035) were identified as independent predictors of PTDM. In addition, overall survival (OS) was inferior in patients with PTDM compared with those without PTDM (mean survival, 2.26 years vs 2.7 years; P = .021). Pretransplantation c-peptide level greater than the cohort median (>3.6 ng/mL) also was associated with inferior OS (mean, 1.7 years vs 2.9 years; P = .012). In a multivariate Cox proportional hazards model, high-risk disease (hazard ratio [HR], 2.34; 95% CI, 1.09-5.28; P = .029) and pretransplantation c-peptide level >3.6 ng/mL (HR, 1.05; 95% CI, 1.01-1.09; P = .013) were independent predictors of OS when adjusted for systemic steroids and regimen intensity. We suspect that diabetes mellitus in the immediate posttransplantation period may be mediated via an inflammatory pathway that contributes to insulin resistance in the host adipose tissue. Our study is the first to report the risk factors of early PTDM in patients undergoing allo-SCT and identifies pretransplantation c-peptide as an independent predictor of diabetes and survival.

Topics: Adult; C-Peptide; Diabetes Mellitus; Female; Hematopoietic Stem Cell Transplantation; Humans; Inflammation; Insulin Resistance; Male; Middle Aged; Predictive Value of Tests; Prospective Studies; Risk Factors; Survival Rate; Time Factors; Transplantation, Homologous

Glucocorticoids (GCs) are regarded as diabetogenic because they impair insulin sensitivity and islet-cell function. This study assessed whether treatment with the glucagon-like peptide receptor agonist (GLP-1 RA) exenatide (EXE) could prevent GC-induced glucose intolerance.. A randomized, placebo-controlled, double-blind, crossover study in eight healthy men (age: 23.5 [20.0-28.3] years; BMI: 26.4 [24.3-28.0] kg/m(2)) was conducted. Participants received three therapeutic regimens for 2 consecutive days: 1) 80 mg of oral prednisolone (PRED) every day (q.d.) and intravenous (IV) EXE infusion (PRED+EXE); 2) 80 mg of oral PRED q.d. and IV saline infusion (PRED+SAL); and 3) oral placebo-PRED q.d. and intravenous saline infusion (PLB+SAL). On day 1, glucose tolerance was assessed during a meal challenge test. On day 2, participants underwent a clamp procedure to measure insulin secretion and insulin sensitivity.. PRED+SAL treatment increased postprandial glucose levels (vs. PLB+SAL, P = 0.012), which was prevented by concomitant EXE (vs. PLB+SAL, P = NS). EXE reduced PRED-induced hyperglucagonemia during the meal challenge (P = 0.018) and decreased gastric emptying (vs. PRED+SAL, P = 0.028; vs. PLB+SAL, P = 0.046). PRED+SAL decreased first-phase glucose- and arginine-stimulated C-peptide secretion (vs. PLB+SAL, P = 0.017 and P = 0.05, respectively), whereas PRED+EXE improved first- and second-phase glucose- and arginine-stimulated C-peptide secretion (vs. PLB+SAL; P = 0.017, 0.012, and 0.093, respectively).. The GLP-1 RA EXE prevented PRED-induced glucose intolerance and islet-cell dysfunction in healthy humans. Incretin-based therapies should be explored as a potential strategy to prevent steroid diabetes.

Topics: Adolescent; Adult; Blood Glucose; C-Peptide; Cross-Over Studies; Exenatide; Glucagon-Like Peptide 1; Glucocorticoids; Glucose Clamp Technique; Glucose Intolerance; Humans; Hyperglycemia; Hyperinsulinism; Hypoglycemic Agents; Insulin Resistance; Islets of Langerhans; Male; Peptides; Prednisone; Venoms; Young Adult

Glucose is the major stimulus for insulin release. Time course and amount of insulin secreted after glycemic stimulus are different between type 2 diabetes mellitus (T2DM) patients and healthy subjects. In rodents, it was demonstrated that insulin can modulate its own release. Previous studies in humans yielded contrasting results: Insulin was shown to have an enhancing effect, no effect, or a suppressive effect on its own secretion. Thus, we aimed to evaluate short-term effects of human insulin infusion on insulin secretion during normoglycemia in healthy humans and T2DM subjects of both sex.. Hyperinsulinemic-isoglycemic clamps with whole-body insulin-sensitivity (M) and C-peptide measurements for insulin secretion modeling were performed in 65 insulin-sensitive (IS) subjects (45 ± 1 year, BMI: 24.8 ± 0.5 kg/m(2)), 17 insulin-resistant (IR) subjects (46 ± 2 years, 28.1 ± 1.3 kg/m(2)), and 20 T2DM patients (56 ± 2 years, 28.0 ± 0.8 kg/m(2); HbA(1c) = 6.7 ± 0.1%).. IS subjects (M = 8.8 ± 0.3 mg · min(-1) · kg(-1)) had higher (P < 0.00001) whole-body insulin sensitivity than IR subjects (M = 4.0 ± 0.2) and T2DM patients (M = 4.3 ± 0.5). Insulin secretion profiles during clamp were different (P < 0.00001) among the groups, increasing in IS subjects (slope: 0.56 ± 0.11 pmol/min(2)) but declining in IR (-0.41 ± 0.14) and T2DM (-0.87 ± 0.12, P < 0.00002 IR and T2DM vs. IS) subjects. Insulin secretion changes during clamp directly correlated with M (r = 0.6, P < 0.00001).. Insulin release during normoglycemia can be modulated by exogenous insulin infusion and directly depends on whole-body insulin sensitivity. Thus, in highly sensitive subjects, insulin increases its own secretion. On the other hand, a suppressive effect of insulin on its own secretion occurs in IR and T2DM subjects.

Topics: Adult; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucose Clamp Technique; Humans; Hyperinsulinism; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Male; Middle Aged; Predictive Value of Tests

Intake of industrially produced trans-fatty acids (TFA) has been linked to increased risk of type 2 diabetes mellitus in observational studies. We investigated the causality of this association by examining if a high intake of TFA impairs measures of glucose homeostasis and induces intramuscular lipid deposition in abdominally obese women. In a double-blind, parallel dietary intervention study, 52 healthy but overweight postmenopausal women were randomized to receive either partially hydrogenated soybean oil (15 g/d TFA) or a control oil (mainly oleic and palmitic acid) for 16 weeks. Three markers of glucose homeostasis and 4 markers of lipolysis were derived from glucose, insulin, C-peptide, nonesterified fatty acid, and glycerol concentrations during a 3-hour frequent sampling oral glucose tolerance test. Intramuscular lipids were assessed by magnetic resonance spectroscopy. Forty-nine women completed the study. Insulin sensitivity (assessed by ISI(composite)), β-cell function (the disposition index), and the metabolic clearance rate of insulin were not significantly affected by the dietary intervention. Neither was the ability of insulin to suppress plasma nonesterified fatty acid and glycerol during oral glucose ingestion nor the intramuscular lipid deposition. In conclusion, high TFA intake did not affect glucose metabolism over 16 weeks in postmenopausal overweight women. A study population with a stronger predisposition to insulin resistance and/or a longer duration of exposure may be required for insulin sensitivity to be affected by intake of industrial TFA.

Topics: Aged; Blood Glucose; C-Peptide; Dietary Fats, Unsaturated; Fatty Acids, Nonesterified; Female; Glycerol; Homeostasis; Humans; Insulin; Insulin Resistance; Lipids; Middle Aged; Muscle, Skeletal; Oleic Acid; Overweight; Palmitic Acid; Postmenopause; Soybean Oil; Trans Fatty Acids

It is clinically relevant and of physiological interest to investigate whether GH-induced insulin resistance depends on the timing of GH exposure relative to when insulin sensitivity is assessed.. GH-induced insulin resistance is rapidly reversible.. Eight male GH-deficient patients underwent a 6-h euglycemic-hyperinsulinemic glucose clamp thrice in a randomized crossover design receiving either no GH (study 0), a 7-h GH infusion (0.2-0.3 mg in total) that terminated 5 h before the clamp (study 1), or a similar GH infusion timed to continue during the first hour of the clamp (study 2). A muscle biopsy was obtained 30 min into the clamp. The patients were compared with eight healthy untreated control subjects (study c).. The glucose infusion rate, indirect calorimetry, and free fatty acid metabolism were assessed. In muscle biopsies, protein phosphorylation of signal transducer and activator of transcription 5, Akt, and Akt substrate 160 (phospho-Akt substrate signal) and gene expression of IGF-I and SOCS1-3 were assessed.. Insulin sensitivity differed significantly between the GH-deficiency studies (P = 0.005) with distinct insulin resistance in study 2 and increased insulin sensitivity in study 0 [area under the glucose infusion rate curve (mg/kg · min): 1663 ± 151 (study 0) vs. 1482 ± 166 (study 1) vs. 1123 ± 136 (study 2) vs. 1492 ± 229 (control group)]. Free fatty acid levels and lipid oxidation were elevated in response to GH exposure but became suppressed during the clamp. IGF-I and SOCS3 gene expression was increased in study 2.. Very-low-dose GH exposure evokes acute insulin resistance that subsides after 5 h. This time-dependent reversibility should be considered when assessing the impact of GH on glucose homeostasis.

Topics: Acute Disease; Adult; Aged; Biopsy; Blood Glucose; C-Peptide; Calorimetry, Indirect; Cross-Over Studies; Fatty Acids, Nonesterified; Gene Expression; Glucose Clamp Technique; Glucose Intolerance; Human Growth Hormone; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Insulin-Like Growth Factor I; Male; Middle Aged; Muscle, Skeletal; Signal Transduction; Suppressor of Cytokine Signaling Proteins

Evidence suggests that somatostatin not only inhibits the secretion of GH but also suppresses GH action in peripheral tissues.. We tested the hypothesis that somatostatin suppresses GH activity in human skeletal muscle in vivo.. Eight healthy young men (25.3 ± 2.8 yr) were studied on a single occasion after an overnight fast for 4 h [including a basal period (0-2 h) and a hyperinsulinemic euglycemic clamp (2-4 h)] during an iv GH infusion (50 ng/kg⁻¹ · min⁻¹). Each subject received an intraarterial somatostatin infusion (150 μg/h⁻¹) into one femoral artery and an intraarterial saline infusion into the contra lateral artery. The simultaneous blood samples were drawn from both femoral veins. Muscle biopsies were obtained from one leg at t = 0 and from both legs during the basal period and during the clamp.. Muscle glucose uptake, signaling proteins for GH (phosphorylated signal transducer and activator of transcription-5) and insulin (phosphorylation of AS160), and expression of GH-regulated genes (IGF-I and suppressor of cytokine signaling 1-3) were measured.. Somatostatin significantly increased glucose uptake measured by arteriovenous glucose difference during the basal period (P = 0.03) but not during the clamp. There was a tendency for the phosphorylation of AS160 to be higher in the somatostatin-infused leg compared with the saline leg (P = 0.055). The expression of suppressor of cytokine signaling-1 mRNA was significantly elevated in the clamp-biopsy from the saline-infused leg (P = 0.024).. We concluded the following: 1) in the presence of systemic GH exposure, somatostatin increases basal glucose uptake and reduces the expression of GH-regulated genes directly in skeletal muscle; 2) this supports the concept that somatostatin suppresses GH activity in peripheral tissues, and 3) this may add to the therapeutic effects of somataostatin analogs.

Topics: Adult; Biopsy; Blood Glucose; C-Peptide; Gene Expression; Glucagon; Glucose Clamp Technique; GTPase-Activating Proteins; Human Growth Hormone; Humans; Hyperinsulinism; Infusions, Intra-Arterial; Insulin Resistance; Insulin-Like Growth Factor I; Leg; Lipids; Male; Muscle, Skeletal; Somatostatin; STAT5 Transcription Factor; Suppressor of Cytokine Signaling Proteins; Young Adult

Comprehensive lifestyle interventions are effective in preventing diabetes and restoring glucose regulation; however, the key stimulus for change has not been identified and effects in older individuals are not established. The aim of the study was to investigate the independent and combined effects of dietary weight loss and exercise on insulin sensitivity and restoration of normal fasting glucose in middle-aged and older women.. Four-arm RCT, conducted between 2005 and 2009 and data analyzed in 2010.. 439 inactive, overweight/obese postmenopausal women.. Women were assigned to: dietary weight loss (n=118); exercise (n=117); exercise+diet (n=117); or control (n=87). The diet intervention was a group-based reduced-calorie program with a 10% weight-loss goal. The exercise intervention was 45 min/day, 5 days/week of moderate-to-vigorous intensity aerobic activity.. 12-month change in serum insulin, C-peptide, fasting glucose, and whole body insulin resistance (HOMA-IR).. A significant improvement in HOMA-IR was detected in the diet (-24%, p<0.001) and exercise+ diet (-26%, p<0.001) groups but not in the exercise (-9%, p=0.22) group compared with controls (-2%); these effects were similar in middle-aged (50-60 years) and older women (aged 60-75 years). Among those with impaired fasting glucose (5.6-6.9 mmol/L) at baseline (n=143; 33%), the odds (95% CI) of regressing to normal fasting glucose after adjusting for weight loss and baseline levels were 2.5 (0.8, 8.4); 2.76 (0.8, 10.0); and 3.1 (1.0, 9.9) in the diet, exercise+diet, and exercise group, respectively, compared with controls.. Dietary weight loss, with or without exercise, significantly improved insulin resistance. Older women derived as much benefit as did the younger postmenopausal women.. This study is registered at Clinicaltrials.govNCT00470119.

Topics: Age Factors; Aged; Blood Glucose; Body Mass Index; C-Peptide; Diet, Reducing; Exercise; Female; Follow-Up Studies; Humans; Insulin; Insulin Resistance; Life Style; Middle Aged; Postmenopause; Weight Loss

Cirrhosis of the liver is characterised by insulin resistance and low levels of insulin-like growth factor I (IGF-I). Lack of IGF-I may contribute to this insulin resistance, as IGF-I increases insulin sensitivity. This study aimed to determine the effects of normalisation of IGF-I on insulin action in cirrhosis.. This article is a randomised sequence-crossover placebo controlled study. Eight patients with cirrhosis and eight controls were studied following treatment with IGF-I (50 μg/kg twice daily) or saline. Insulin action, glucose utilisation and endogenous glucose production were measured during the euglycaemic hyperinsulinaemic clamp.. The patients with cirrhosis had normal fasting glucose level, but increased levels of insulin (P < 0.05) and C-peptide (P < 0.05). Insulin resistance resulted from a defect in glycogen synthesis, whereas insulin-mediated suppression of glucose production was unaltered. In cirrhosis, IGF-I treatment normalised free (from 0.07 ± 0.01 to 0.26 ± 0.05 μg/L) and total IGF-I (from 73 ± 6 to 250 ± 39 μg/L), whereas in controls, the IGF-I level increased into the upper physiological range (free IGF-I from 0.23 ± 0.02 to 0.61 ± 0.06 μg/L; total IGF-I from 200 ± 19 to 500 ± 50 μg/L) (all P-values < 0.05). In cirrhosis, IGF-I treatment did not change fasting glucose, insulin or C-peptide levels (P > 0.05). In the controls, insulin and C-peptide levels decreased (P < 0.05). IGF-I treatment did not improve insulin sensitivity in cirrhosis.. Because normalisation of IGF-I levels did not affect insulin sensitivity lack of IGF-I is unlikely to result in insulin resistance in cirrhosis. IGF-I supplementation is therefore unlikely to improve insulin action in patients with cirrhosis.

Topics: Blood Glucose; C-Peptide; Cross-Over Studies; Fatty Acids, Nonesterified; Fluoroimmunoassay; Glucose Clamp Technique; Humans; Insulin; Insulin Resistance; Insulin-Like Growth Factor I; Liver Cirrhosis; Male; Middle Aged; Radioimmunoassay; Statistics, Nonparametric

The intake of wholemeal foods is consistently associated with reduced risk of type 2 diabetes and cardiovascular diseases in epidemiological studies, although the mechanisms of this association are unclear. Here we aim to compare in healthy subjects the metabolic effects of a diet rich in wholemeal wheat foods versus one based on the same products in refined form.. Fifteen healthy individuals (12 M/3 F), mean age 54.5+/-7.6 years, BMI 27.4+/-3.0 kg/m(2) (mean+/-SD), participated in a randomized sequential crossover study. After 2 weeks run-in, participants were randomly assigned to two isoenergetic diets with similar macronutrient composition, one rich in wholemeal wheat foods and the other with the same foods but in refined form (cereal fibre 23.1 vs. 9.8 g/day). After the two treatment periods (each lasting 3 weeks) plasma glucose and lipid metabolism, antioxidant activity, acetic acid, magnesium, adipokines, incretins and high-sensitivity C-reactive protein (hs-CRP) were measured at fasting and for 4h after a standard test meal (kcal 1103, protein 12%, CHO 53%, fat 35%) based on wholemeal or refined wheat foods, respectively. After the two diets there were no differences in fasting nor in postprandial plasma parameter responses; only glucose was slightly but significantly lower at 240 min after the refined wheat food meal compared to the wholemeal wheat food meal. Conversely, after the wholemeal diet both total (-4.3%; p<0.03) and LDL (-4.9%; p<0.04) cholesterol levels were lower than after the refined wheat diet at fasting.. Consumption of wholemeal wheat foods for 3 weeks reduces significantly fasting plasma cholesterol as well as LDL cholesterol levels in healthy individuals without major effects on glucose and insulin metabolism, antioxidant status and sub-clinical inflammation markers.

Topics: Blood Glucose; Blood Pressure; Body Weight; C-Peptide; Cardiovascular Diseases; Cholesterol; Cholesterol, LDL; Cross-Over Studies; Diet; Fasting; Female; Food Handling; Gastric Inhibitory Polypeptide; Ghrelin; Humans; Insulin; Insulin Resistance; Leptin; Male; Middle Aged; Risk Factors; Triticum

To examine the effects of acute altitude-induced hypoxia on the hormonal and metabolic response to ingested glucose, 8 young, healthy subjects (5 men and 3 women; age, 26 +/- 2 years; body mass index, 23.1 +/- 1.0 kg/m(2)) performed 2 randomized trials in a hypobaric chamber where a 75-g glucose solution was ingested under simulated altitude (ALT, 4300 m) or ambient (AMB, 362 m) conditions. Plasma glucose, insulin, C-peptide, epinephrine, leptin, and lactate concentrations were measured at baseline and 30, 60, 90, and 120 minutes after glucose ingestion during both trials. Compared with AMB, the plasma glucose response to glucose ingestion was reduced during the ALT trial (P = .04). There were no differences in the insulin and C-peptide responses between trials or in insulin sensitivity based on the homeostasis model assessment of insulin resistance. Epinephrine and lactate were both elevated during the ALT trial (P < .05), whereas the plasma leptin response was reduced compared with AMB (P < .05). The data suggest that the plasma glucose response is suppressed at ALT, but this is not due to insulin per se because insulin and C-peptide levels were similar for both trials. Elevated plasma epinephrine and lactate during ALT are indicative of increased glycogenolysis, which may have masked the magnitude of the reduced glucose response. We conclude that, during acute altitude exposure, there is a rapid metabolic response that is accompanied by a shift in the hormonal milieu that appears to favor increased glucose utilization.

Topics: Adult; Altitude; Blood Glucose; C-Peptide; Epinephrine; Female; Glucose; Humans; Hypoxia; Insulin; Insulin Resistance; Lactic Acid; Leptin; Male; Solutions

Resistant starch (RS), a non-viscous dietary fibre, may have postprandial effects on appetite regulation and metabolism, although the exact effects and mechanisms are unknown. An acute randomised, single-blind crossover study, aimed to determine the effects of consumption of 48 g RS on appetite compared to energy and available carbohydrate-matched placebo. Twenty young healthy adult males consumed either 48 g RS or the placebo divided equally between two mixed meals on two separate occasions. Effects on appetite were assessed, using an ad libitum test meal and 24-h diet diaries for energy intake, and using visual analogue scales for subjective measures. Changes to postprandial glucose, insulin and C-peptide were also assessed. There was a significantly lower energy intake following the RS supplement compared to the placebo supplement at both the ad libitum test meal (5241 (sem 313) v. 5606 (sem 345) kJ, P = 0.033) and over the 24 h (12 603 (sem 519) v. 13 949 (sem 755) kJ, P = 0.044). However, there was no associated effect on subjective appetite measures. Postprandial plasma glucose concentrations were not significantly different between supplements, but there was a significantly lower postprandial insulin response following the RS supplement (P = 0.029). The corresponding C-peptide concentrations were not significantly different, although the ratio of C-peptide to insulin was higher following the RS supplement compared to placebo (P = 0.059). These results suggest that consumption of 48 g RS, over a 24-h period, may be useful in the management of the metabolic syndrome and appetite. Further studies are required to determine the exact mechanisms.

Topics: Adult; Appetite; Blood Glucose; Body Mass Index; C-Peptide; Cross-Over Studies; Dietary Carbohydrates; Dietary Fiber; Digestion; Eating; Energy Intake; Humans; Insulin; Insulin Resistance; Male; Placebos; Starch

Caffeine and caffeinated coffee (CC) elicit acute insulin insensitivity when ingested before a carbohydrate load. The effects of CC on glucose tolerance and insulin sensitivity when co-ingested with a high carbohydrate meal and on postprandial metabolism of a subsequent (second) carbohydrate load have not been studied. In a randomised, crossover design, ten healthy males ingested either CC (5 mg caffeine/kg body weight), decaffeinated coffee (DC) or water (W; equal volume) co-ingested with a high glycaemic index cereal followed 3 h later by a 75 g oral glucose tolerance test. After the initial meal, insulin area under the curve (AUC) and insulin sensitivity index did not differ between treatments, although glucose AUC for CC (107 (sem 18) mmol/l x 3 h) and DC (74 (sem 15) mmol/l x 3 h) was greater than W ( - 0.2 (sem 29) mmol/l x 3 h, P < 0.05). After the second carbohydrate load, insulin AUC for CC was 49 % and 57 % greater (P < 0.01) than for DC and W, respectively. Despite the greater insulin response, glucose AUC for CC (217 (sem 24) mmol/l x 2 h) was greater than both DC (126 (sem 11) mmol/l x 2 h, P = 0.01) and W (55 (sem 34) mmol/l x 2 h, P < 0.001). Insulin sensitivity index after the second meal was lower after CC (8.2 (sem 0.9)) compared with both DC (12.4 (sem 1.2), P < 0.01) and W (13.4 (sem 1.4), P < 0.001). Co-ingestion of CC with one meal resulted in insulin insensitivity during the postprandial phase of a second meal in the absence of further CC ingestion. Thus, CC may play a role in daily glycaemic management.

Topics: Adult; Blood Glucose; C-Peptide; Caffeine; Coffee; Cross-Over Studies; Dietary Carbohydrates; Fasting; Fatty Acids, Nonesterified; Food; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Kinetics; Male

OBJECTIVE To determine if glucose and C-peptide values obtained as part of the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study could be used to estimate insulin sensitivity during late pregnancy. RESEARCH DESIGN AND METHODS A total of 78 women enrolled in the HAPO study were recruited for this ancillary study. Venous plasma samples were drawn after an 8- to 10-h fast (time 0) and at 30, 60, 90, and 120 min after a 75-g glucose challenge, which was performed at 24-32 weeks' gestation. Samples were analyzed for plasma glucose, insulin, and C-peptide. Insulin sensitivity was estimated using the established Matsuda and DeFronzo insulin sensitivity index for oral glucose tolerance tests (IS(OGTT)). Insulin sensitivity was also calculated from two other commonly used indexes of insulin sensitivity (that for homeostasis model assessment [IS(HOMA)] and that for quantitative insulin sensitivity check index [IS(QUICKI)]). A new insulin sensitivity index was calculated using the glucose and C-peptide concentrations at 0 and 60 min to derive IS(HOMA C-pep), IS(QUICKI C-pep), and IS(OGTT C-pep). These indexes were then correlated with insulin sensitivity estimated from the IS(OGTT). RESULTS The strongest correlation with the IS(OGTT) was obtained for IS(OGTT C-pep) (r = 0.792, P < 0.001). Further, the correlations of IS(HOMA) (C-pep) and IS(QUICKI C-pep) with IS(OGTT) were also significant (r = 0.676, P < 0.001 and r = 0.707, P < 0.001, respectively). CONCLUSIONS These data suggest that calculated IS(OGTT C-pep) is an excellent predictor of insulin sensitivity in pregnancy and can be used to estimate insulin sensitivity in over 25,000 women participating in the HAPO study.

Topics: Adult; Blood Glucose; C-Peptide; Diabetes, Gestational; Female; Glucose Tolerance Test; Health Status Indicators; Humans; Hyperglycemia; Insulin; Insulin Resistance; Pregnancy; Pregnancy Outcome; Young Adult

Glucocorticoids (GCs), such as prednisolone, are associated with adverse metabolic effects, including glucose intolerance and diabetes. In contrast to the well known GC-induced insulin resistance, the effects of GCs on beta-cell function are less well established. We assessed the acute and short-term effects of prednisolone treatment on beta-cell function in healthy men.. A randomised, double-blind, placebo-controlled trial consisting of two protocols was conducted. In protocol 1 (n=6), placebo and a single dose of 75 mg of prednisolone were administered. In protocol 2 (n=23), participants received 30 mg of prednisolone daily or placebo for 15 days. Both empirical and model-based parameters of beta-cell function were calculated from glucose, insulin and C-peptide concentrations obtained during standardised meal tests before and during prednisolone treatment (protocols 1 and 2), and 1 day after cessation of treatment (protocol 2).. Seventy-five milligrams of prednisolone acutely increased the area under the postprandial glucose curve (AUC(gluc); P=0.005), and inhibited several parameters of beta-cell function, including AUC(c-pep)/AUC(gluc) ratio (P=0.004), insulinogenic index (P=0.007), glucose sensitivity (P=0.02) and potentiation factor ratio (PFR; P=0.04). A 15-day treatment with prednisolone increased AUC(gluc) (P<0.001), despite augmented C-peptide secretion (P=0.05). beta-cell function parameters were impaired, including the fasting insulin secretory tone (P=0.02) and PFR (P=0.007).. Acute and short-term exposure to prednisolone impairs different aspects of beta-cell function, which contribute to its diabetogenic effects.

Topics: Adult; Blood Glucose; C-Peptide; Double-Blind Method; Drug Administration Schedule; Glucocorticoids; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Postprandial Period; Prednisolone; Young Adult

Hyperinsulinemia and obesity-related metabolic disturbances are common and have been associated with increased cancer risk and poor prognosis. To investigate this issue in relation to prostate cancer, we conducted a nested case-control study within the Prostate Cancer Prevention Trial (PCPT), a randomized, placebo-controlled trial testing finasteride versus placebo for primary prevention of prostate cancer. Cases (n = 1,803) and controls (n = 1,797) were matched on age, PCPT treatment arm, and family history of prostate cancer; controls included all eligible non-whites. Baseline bloods were assayed for serum C-peptide (marker of insulin secretion) and leptin (an adipokine) using ELISA. All outcomes were biopsy determined. Logistic regression calculated odds ratios (OR) for total prostate cancer and polytomous logistic regression calculated ORs for low-grade (Gleason <7) and high-grade (Gleason >7) disease. Results were stratified by PCPT treatment arm for C-peptide. For men on placebo, higher versus lower serum C-peptide was associated with a nearly 2-fold increased risk of high-grade prostate cancer (Gleason >7; multivariate-adjusted OR, 1.88; 95% confidence interval, 1.19-2.97; P(trend) = 0.004). When C-peptide was modeled as a continuous variable, every unit increase in log(C-peptide) resulted in a 39% increased risk of high-grade disease (P = 0.01). In contrast, there was no significant relationship between C-peptide and high-grade prostate cancer among men receiving finasteride. Leptin was not independently associated with high-grade prostate cancer. In conclusion, these results support findings from other observational studies that high serum C-peptide and insulin resistance, but not leptin, are associated with increased risk of high-grade prostate cancer. Our novel finding is that the C-peptide-associated risk was attenuated by use of finasteride.

Topics: C-Peptide; Case-Control Studies; Enzyme Inhibitors; Enzyme-Linked Immunosorbent Assay; Finasteride; Humans; Insulin Resistance; Leptin; Male; Middle Aged; Prostatic Neoplasms; Risk Factors

The effects of extended regimens of combined oral contraceptives (COCs) on carbohydrate metabolism are largely unknown. The present study compared the effects of a COC containing 30 microg ethinylestradiol and 2 mg dienogest (EE/DNG) in conventional and extended-cycle regimen over 1 year. Parameters of carbohydrate metabolism were measured in 59 women treated with EE/DNG either conventionally (13 cycles of 21+7 days) or in extended-cycle regimen (4 cycles of 84+7 days). Blood samples were taken in a control cycle, and at 3 and 12 months of treatment. The mean levels of HbA1c and fasting glucose levels remained stable in both conventional and extended-regimen of EE/DNG. The mean levels of fasting insulin and C-peptide underwent comparable increases in both regimens, suggesting a similar readjustment of glucose metabolism via slightly increased insulin secretion. For both regimens, the response to the oral glucose tolerance test (OGTT) showed a slightly impaired glucose tolerance and insulin resistance at 3 months. These changes improved or returned to baseline at 12 months. Accordingly, the mean index for insulin resistance (homeostasis model assessment of insulin resistance, HOMA-IR) increased and the mean insulin sensitivity index [ISI (composite)] decreased modestly in both groups. The present study demonstrates that there are no statistically significant differences between the effects of conventional and extended-cycle treatment on carbohydrate metabolism over 1 year of treatment. In general, the effects of both regimens were moderate and mostly transient.

Topics: Adolescent; Adult; Blood Glucose; C-Peptide; Carbohydrate Metabolism; Contraceptives, Oral, Hormonal; Ethinyl Estradiol; Female; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Menstruation; Nandrolone; Prospective Studies; Young Adult

Growth hormone-deficient patients show deterioration of insulin sensitivity and beta cell function. High-dose growth hormone treatment often induces further impairment of insulin sensitivity, leading to an increase in insulin and glucose levels or even, in cases of preexisting beta cell defect, to overt diabetes. However, low-dose treatment may improve insulin sensitivity, although data in humans with detailed metabolic phenotyping are as yet not available. We postulated that long-term low-dose growth hormone replacement, restoring IGF-1 to the low-normal range, might beneficially affect glucose metabolism.. We studied prospectively the metabolic responses to 24 and 48 weeks of growth hormone treatment in a small group of six adults with severe growth hormone deficiency (four men, two women; age 40-59 years; BMI 30.2 +/- 1 kg/m(2); mean growth hormone dose 0.3 +/- 0.04 mg/day). All participants underwent an oral glucose tolerance test, euglycaemic-hyperinsulinaemic clamp and hyperglycaemic-hyperinsulinaemic clamp plus i.v. L: -arginine on three occasions. Insulin sensitivity was measured by calculating the M value during the steady state of the euglycaemic-hyperinsulinaemic clamp. Insulin secretion and clearance were estimated from AUC(C-peptide), AUC(insulin) and their ratio at each phase of the hyperglycaemic-hyperinsulinaemic clamp.. Growth hormone significantly improved insulin sensitivity (M value 13.8 +/- 2.6 [baseline] vs 19.6 +/- 2.6 [24 weeks] and 23.7 +/- 1.9 [48 weeks] micromol kg(-1) min(-1); p < 0.01). Although the insulin response to glucose and arginine decreased slightly, the disposition index, integrating insulin sensitivity and secretion, significantly increased (p < 0.01), indicating an improvement in whole-body glucose metabolism. Insulin clearance was not affected during treatment (p > 0.05).. Our data indicate that long-term low-dose growth hormone treatment may improve insulin sensitivity and whole-body glucose metabolism in adults with severe growth hormone-deficiency.

Topics: Adult; C-Peptide; Female; Glucose; Glucose Tolerance Test; Hormone Replacement Therapy; Human Growth Hormone; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged

The purpose of the study was to test prospectively whether healthy individuals with a family history of type 2 diabetes are more susceptible to adverse metabolic effects during experimental overfeeding.. We studied the effects of 3 and 28 days of overfeeding by 5,200 kJ/day in 41 sedentary individuals with and without a family history of type 2 diabetes (FH+ and FH- respectively). Measures included body weight, fat distribution (computed tomography) and insulin sensitivity (hyperinsulinaemic-euglycaemic clamp).. Body weight was increased compared with baseline at 3 and 28 days in both groups (p < 0.001), FH+ individuals having gained significantly more weight than FH- individuals at 28 days (3.4 +/- 1.6 vs 2.2 +/- 1.4 kg, p < 0.05). Fasting serum insulin and C-peptide were increased at 3 and 28 days compared with baseline in both groups, with greater increases in FH+ than in FH- for insulin at +3 and +28 days (p < 0.01) and C-peptide at +28 days (p < 0.05). Fasting glucose also increased at both time points, but without a significant group effect (p = 0.1). Peripheral insulin sensitivity decreased in the whole cohort at +28 days (54.8 +/- 17.7 to 50.3 +/- 15.6 micromol min(-1) [kg fat-free mass](-1), p = 0.03), and insulin sensitivity by HOMA-IR decreased at both time points (p < 0.001) and to a greater extent in FH+ than in FH- (p = 0.008). Liver fat, subcutaneous and visceral fat increased similarly in the two groups (p < 0.001).. Overfeeding induced weight and fat gain, insulin resistance and hepatic fat deposition in healthy individuals. However, individuals with a family history of type 2 diabetes gained more weight and greater insulin resistance by HOMA-IR. The results of this study suggest that healthy individuals with a family history of type 2 diabetes are predisposed to adverse effects of overfeeding.. ClinicalTrials.gov NCT00562393. The study was funded by the National Health and Medical Research Council (NHMRC), Australia (no. #427639).

Topics: Adult; Analysis of Variance; Australia; Body Composition; C-Peptide; Diabetes Mellitus, Type 2; Feeding Behavior; Female; Genetic Predisposition to Disease; Glucose; Humans; Insulin; Insulin Resistance; Leptin; Male; Middle Aged; Overnutrition; Risk Factors; Sedentary Behavior; Weight Gain

To determine whether altered GLP-1 activity contributes to the abnormal endogenous glucose production (EGP) and insulin secretion characteristic of people with impaired fasting glucose (IFG).. People with IFG (n=10) and normal glucose tolerance (NGT; n=13) underwent assessment of EGP (via [6,6-(2)H(2)]-glucose infusion). Parameters of whole body insulin action and secretion were estimated by IVGTT and OGTT. Measures of EGP and insulin secretion were made before and after sitagliptin administration.. EGP was not different at baseline (glucose R(a); 1.47+/-0.08 vs. 1.46+/-0.05mg/kg/min, IFG vs. NGT, p=0.93). However, when differences in circulating insulin were accounted for (EGPXSSPI; 20.2+/-2.1 vs. 14.4+/-1.0AU, vs. NGT, p=0.03) the hepatic insulin resistance index was significantly higher in IFG. Baseline insulin action (S(i); 2.3+/-0.1x10(-4)/microU/ml vs. 3.5+/-0.4x10(-4)/microU/ml, p=0.01, IFG vs. NGT) and secretion (DI; 587+/-81x10(-4)/min vs. 1171+/-226x10(-4)/min, p=0.04, IFG vs. NGT) were impaired in IFG when evaluated by the IVGTT, but not by OGTT (insulin sensitivity 4.52+/-1.08x10(-4)dl/kg/min vs. 6.73+/-1.16x10(-4)dl/kg/min, IFG vs. NGT, p=0.16; indices of basal (Phi(b)), static (Phi(s)), dynamic (Phi(d)), and total (Phi(t)) insulin secretion, p>0.07). Sitagliptin did not change EGP or insulin secretion in either group.. Incretin action maintained insulin secretion, but not hepatic insulin action, in people with IFG.

Topics: Aged; Blood Glucose; Body Mass Index; C-Peptide; Dipeptidyl-Peptidase IV Inhibitors; Female; Glucagon-Like Peptide 1; Glucose; Glucose Tolerance Test; Humans; Hyperglycemia; Incretins; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Liver; Male; Middle Aged; Pyrazines; Severity of Illness Index; Sitagliptin Phosphate; Triazoles

Insulin resistance is a significant risk factor in the pathogenesis of type 2 diabetes. This article presents pilot study results of the dynamic insulin sensitivity and secretion test (DISST), a high-resolution, low-intensity test to diagnose insulin sensitivity (IS) and characterize pancreatic insulin secretion in response to a (small) glucose challenge. This pilot study examines the effect of glucose and insulin dose on the DISST, and tests its repeatability.. DISST tests were performed on 16 subjects randomly allocated to low (5 g glucose, 0.5 U insulin), medium (10 g glucose, 1 U insulin) and high dose (20 g glucose, 2 U insulin) protocols. Two or three tests were performed on each subject a few days apart.. Average variability in IS between low and medium dose was 10.3% (p=.50) and between medium and high dose 6.0% (p=.87). Geometric mean variability between tests was 6.0% (multiplicative standard deviation (MSD) 4.9%). Geometric mean variability in first phase endogenous insulin response was 6.8% (MSD 2.2%). Results were most consistent in subjects with low IS.. These findings suggest that DISST may be an easily performed dynamic test to quantify IS with high resolution, especially among those with reduced IS.

Topics: Adult; Biomarkers; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Feasibility Studies; Female; Glucose; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Male; Middle Aged; New Zealand; Pancreas; Pilot Projects; Predictive Value of Tests; Reproducibility of Results; Research Design; Time Factors; Young Adult

Second-generation and third-generation oral contraceptives containing 30 mcg or more of ethinylestradiol (EE) decrease insulin sensitivity (SI). In this study, we investigated whether SI is decreased by contraceptives containing lower doses EE or by progestins with antiandrogenic properties.. Twenty-eight young healthy women were randomly allocated to receive 20 mcg of EE and 150 mcg of desogestrel (DSG) (n=14) or 30 mcg of EE and 2 mg of chlormadinone acetate (CMA) (n=14) for 6 months. SI and glucose utilization independent of insulin (Sg) were investigated by the minimal model method. Lipid modifications were also analyzed.. SI decreased with EE/DSG (7.09+/-1.4 vs. 4.30+/-0.91; p=.04; n=12), but not with EE/CMA (5.79+/-0.93 vs. 6.79+/-1.1; p=.48; n=12). SI modifications observed in the two groups were significantly different (-2.79+/-1.15 vs. 1.0+/-1.38; p=.05). Sg did not vary with either treatment. The response of C-peptide to glucose increased, but significantly so only with EE/CMA (p=.01). The C-peptide/insulin response increased with both EE/DSG (p=.05) and EE/CMA (p=.04). High-density lipoprotein (HDL) cholesterol (p=.02) and triglycerides (p=.02 and p=.01) increased in both groups, but HDL/low-density lipoprotein cholesterol (p=.02), apoprotein A1 (Apo-A1) (p=.04) and Apo-A1/apoprotein B (p=.048) increased significantly only with EE/CMA.. The present study confirms that DSG, even when associated with low EE dose, decreases SI. By contrast, EE/CMA does not deteriorate SI and induces a favorable lipid profile.

Topics: Adolescent; Adult; Blood Glucose; C-Peptide; Chlormadinone Acetate; Contraceptives, Oral, Combined; Desogestrel; Ethinyl Estradiol; Female; Follicle Stimulating Hormone; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Lipid Metabolism; Liver Function Tests; Luteinizing Hormone; Young Adult

A high-fat, high-calorie diet is associated with obesity and type 2 diabetes. However, the relative contribution of metabolic defects to the development of hyperglycaemia and type 2 diabetes is controversial. Accumulation of excess fat in muscle and adipose tissue in insulin resistance and type 2 diabetes may be linked with defective mitochondrial oxidative phosphorylation. The aim of the current study was to investigate acute effects of short-term fat overfeeding on glucose and insulin metabolism in young men. We studied the effects of 5 days' high-fat (60% energy) overfeeding (+50%) versus a control diet on hepatic and peripheral insulin action by a hyperinsulinaemic euglycaemic clamp, muscle mitochondrial function by (31)P magnetic resonance spectroscopy, and gene expression by qrt-PCR and microarray in 26 young men. Hepatic glucose production and fasting glucose levels increased significantly in response to overfeeding. However, peripheral insulin action, muscle mitochondrial function, and general and specific oxidative phosphorylation gene expression were unaffected by high-fat feeding. Insulin secretion increased appropriately to compensate for hepatic, and not for peripheral, insulin resistance. High-fat feeding increased fasting levels of plasma adiponectin, leptin and gastric inhibitory peptide (GIP). High-fat overfeeding increases fasting glucose levels due to increased hepatic glucose production. The increased insulin secretion may compensate for hepatic insulin resistance possibly mediated by elevated GIP secretion. Increased insulin secretion precedes the development of peripheral insulin resistance, mitochondrial dysfunction and obesity in response to overfeeding, suggesting a role for insulin per se as well GIP, in the development of peripheral insulin resistance and obesity.

Topics: Adipokines; Administration, Oral; Adult; Blood Glucose; Body Composition; Body Weight; C-Peptide; Cross-Over Studies; Dietary Fats; Gastric Inhibitory Polypeptide; Gene Expression; Glucose; Glucose Clamp Technique; Glycolysis; Heat-Shock Proteins; Humans; Insulin; Insulin Resistance; Lipids; Liver; Male; Muscle, Skeletal; Oxidative Phosphorylation; Pancreatic Polypeptide; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Phosphates; Phosphocreatine; Transcription Factors

The aim of this study was to study the effects of pioglitazone on several diabetic parameters with subjects possessing distinct levels of insulin. Treatment naive patients with type 2 diabetes received 15-30 mg/day pioglitazone monotherapy. At 3 months, levels of insulin, C-peptide, HbA1c, HOMA-R, HOMA-B and BMI were compared with those at baseline between the low (below 5.9 microU/ml, n = 48), medium (11.9-6 microU/ml n = 39) and high (above 12 microU/ml, n = 33) insulin groups. At baseline, differences existed in the levels of HbA1c, insulin, C-peptide, HOMA-R, HOMA-B, and BMI between these groups. In the high-insulin group significant reductions of insulin/C-peptide levels were observed, while in the low-insulin group significant increases of insulin/C-peptide were observed. In the medium-insulin group, no significant changes were observed. In contrast, the HbA1c levels significantly and similarly decreased in all the groups. Significant correlations between the changes of insulin/C-peptide levels with pioglitazone and the baseline insulin/C-peptide levels were observed. HOMA-R showed greater reductions in the high-insulin group, while HOMA-B showed greater increases in the low-insulin group in comparison to other groups. Multiple regression analysis revealed that the baseline insulin level is the predominant determinant of the changes of insulin levels with pioglitazone. These results suggest that pioglitazone appears to have two effects: to reduce insulin resistance (and lower insulin) and to improve beta-cell function (and increase insulin). The predominance of these effects appears to be determined by the insulin levels. Based on these data, a novel physiological model showing that pioglitazone may shift the natural history of diabetes toward an earlier stage (rejuvenation of beta-cell function) will be presented.

Topics: Adult; Aged; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Models, Biological; Pioglitazone; Thiazolidinediones

To provide an initial evaluation of insulin sensitivity and secretion indices derived from a standard liquid meal tolerance test protocol in subjects with normal (NFG), impaired fasting glucose (IFG) or type 2 diabetes mellitus.. Areas under the curve (AUC) for glucose, insulin and C-peptide from pre-meal to 120 min after consumption of a liquid meal were calculated, as were homeostasis model assessments of insulin resistance (HOMA2-IR) and the Matsuda index of insulin sensitivity.. Subjects with NFG (n = 19), IFG (n = 19), and diabetes (n = 35) had mean +/- SEM HOMA2-IR values of 1.0 +/- 0.1, 1.6 +/- 0.2 and 2.5 +/- 0.3 and Matsuda insulin sensitivity index values of 15.6 +/- 2.0, 8.8 +/- 1.2 and 6.0 +/- 0.6, respectively. The log-transformed values for these variables were highly correlated overall and within each fasting glucose category (r = -0.91 to -0.94, all p < 0.001). Values for the product of the insulin/glucose AUC ratio and the Matsuda index, an indicator of the ability of the pancreas to match insulin secretion to the degree of insulin resistance, were 995.6 +/- 80.7 (NFG), 684.0 +/- 57.3 (IFG) and 188.3 +/- 16.1 (diabetes) and discriminated significantly between fasting glucose categories (p < 0.001 for each comparison).. These results provide initial evidence to support the usefulness of a standard liquid meal tolerance test for evaluation of insulin secretion and sensitivity in clinical and population studies.

Topics: Area Under Curve; Blood Glucose; C-Peptide; Cross-Over Studies; Diabetes Mellitus, Type 2; Female; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Male; Middle Aged

This study assessed the efficacy of add-on pioglitazone vs. placebo in patients with type 2 diabetes uncontrolled by metformin and a sulphonylurea or a glinide.. This multicentre, double-blind, parallel-group study randomized 299 patients with type 2 diabetes to receive 30 mg/day pioglitazone or placebo for 3 months. After this time, patients continued with pioglitazone, either 30 mg [if glycated haemoglobin A1c (HbA(1c)) 6.5%), or placebo for a further 4 months. The primary efficacy end-point was improvement in HbA(1c) (per cent change). Secondary end-points included changes in fasting plasma glucose (FPG), insulin, C-peptide, proinsulin and lipids. The proinsulin/insulin ratio and homeostasis model assessment of insulin resistance (HOMA-IR) and homeostasis model assessment of beta-cell function (HOMA-B) were calculated.. Pioglitazone add-on therapy to failing metformin and sulphonylurea or glinide combination therapy showed statistically more significant glycaemic control than placebo addition. The between-group difference after 7 months of triple therapy was 1.18% in HbA(1c) and -2.56 mmol/l for FPG (p < 0.001). Almost half (44.4%) of the patients in the pioglitazone group who had a baseline HbA(1c) level of <8.5% achieved the HbA(1c) target of < 7.0% by final visit compared with 4.9% in the placebo group. When the baseline HbA(1c) level was >or= 8.5%, 13% achieved the HbA(1c) target of < 7.0% in the pioglitazone group and none in the placebo group. HOMA-IR, insulin, proinsulin and C-peptide decreased and HOMA-B increased in the pioglitazone group relative to the placebo group.. In patients who were not well controlled with dual combination therapy, the early addition of pioglitazone improved HbA(1c), FPG and surrogate measures of beta-cell function. Patients were more likely to reach target HbA(1c) levels (< 7.0%) with pioglitazone treatment if their baseline HbA(1c) levels were < 8.5%, highlighting the importance of early triple therapy.

Topics: Aged; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Double-Blind Method; Drug Therapy, Combination; Female; Glycated Hemoglobin; Homeostasis; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Lipids; Male; Metformin; Middle Aged; Pioglitazone; Proinsulin; Sulfonylurea Compounds; Thiazolidinediones

Fatty acids (FA) can impair glucose metabolism to a varying degree depending on time of exposure and also of type of FA. Here we tested for acute effects of marine n-3 FA on insulin sensitivity, insulin secretion, energy metabolism, and oxidative stress. This was a randomized, double-blind, crossover study in 11 subjects with type 2 diabetes mellitus. A 4-hour lipid infusion (Intralipid [Fresenius Kabi, Halden, Norway], total of 384 mL) was compared with a similar lipid infusion partly replaced by Omegaven (Fresenius Kabi) that contributed a median of 0.1 g fish oil per kilogram body weight, amounting to 0.04 g/kg of marine n-3 FA. Insulin sensitivity was assessed by isoglycemic hyperinsulinemic clamps; insulin secretion (measured after the clamps), by C-peptide glucagon tests; and energy metabolism, by indirect calorimetry. Infusion of Omegaven increased the proportion of n-3 FA in plasma nonesterified fatty acids (NEFA) compared with Intralipid alone (20:5n-3: median, 1.5% [interquartile range, 0.6%] vs -0.2% [0.2%], P = .001; 22:6n-3: 0.8% [0.4%] vs -0.7% [0.2%], P = .001). However, glucose utilization was not affected; neither was insulin secretion or total energy production (P = .966, .210, and .423, respectively, for the differences between the lipid clamps). Omegaven tended to lower oxidation of fat (P = .062) compared with Intralipid only, correlating with the rise in individual n-3 NEFA (r = 0.627, P = .039). The effects of clamping on phospholipid FA composition, leptin, adiponectin, or F(2)-isoprostane concentrations were not affected by Omegaven. Enrichment of NEFA with n-3 FA during a 4-hour infusion of Intralipid failed to affect insulin sensitivity, insulin secretion, or markers of oxidative stress in subjects with type 2 diabetes mellitus.

Topics: Adult; Aged; Biomarkers; Body Composition; C-Peptide; Calorimetry, Indirect; Cross-Over Studies; Diabetes Mellitus, Type 2; Diet; Dinoprost; Double-Blind Method; Fat Emulsions, Intravenous; Fatty Acids, Nonesterified; Fatty Acids, Omega-3; Female; Glucagon; Glucose Clamp Technique; Humans; Infusions, Intravenous; Insulin; Insulin Resistance; Isoprostanes; Male; Middle Aged; Oxidative Stress

Prolonged elevation of plasma nonesterified fatty acids (NEFA) induces insulin resistance and impairs pancreatic β-cell adaptation to insulin resistance. Studies in rodents suggest that inflammation may play a role in this "lipotoxicity." We studied the effects of sodium salicylate, an anti-inflammatory agent, on lipid-induced alterations in β-cell function and insulin sensitivity in six overweight and obese nondiabetic men. Each subject underwent four separate studies, 4-6 wk apart, in random order: 1) SAL, 1-wk placebo followed by intravenous (iv) infusion of saline for 48 h; 2) IH, 1-wk placebo followed by iv infusion of intralipid plus heparin for 48 h to raise plasma NEFA approximately twofold; 3) IH + SS, 1-wk sodium salicylate (4.5 g/day) followed by 48-h IH infusion; and 4) SS, 1-wk oral sodium salicylate followed by 48-h saline infusion. After 48-h saline or lipid infusion, insulin secretion and sensitivity were assessed by hyperglycemic clamp and euglycemic hyperinsulinemic clamp, respectively, in sequential order. Insulin sensitivity was reduced by lipid infusion (IH = 67% of SAL) and was not improved by salicylate (IH + SS = 56% of SAL). Lipid infusion also reduced the disposition index (P < 0.05), which was not prevented by sodium salicylate. Salicylate reduced insulin clearance. These data suggest that oral sodium salicylate at this dose impairs insulin clearance but does not ameliorate lipid-induced insulin resistance and β-cell dysfunction in overweight and obese nondiabetic men.

Topics: Adult; Anti-Inflammatory Agents, Non-Steroidal; Anticoagulants; Area Under Curve; C-Peptide; Emulsions; Fatty Acids, Nonesterified; Female; Glucose; Glucose Clamp Technique; Heparin; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Obesity; Overweight; Phospholipids; Sodium Salicylate; Soybean Oil; Triglycerides

Nuts appear to have a marked effect in cohort studies in reducing the risk of coronary heart disease (CHD), but their demonstrated ability to lower cholesterol can only explain a proportion of the reduction in risk. Our aim was to assess whether improvement in carbohydrate metabolism provides a further explanation for the effect of nuts in reducing CHD. The effects of whole almonds, taken as snacks, were compared with the effects of low saturated fat (<5% energy) whole-wheat muffins (control) in the therapeutic diets of hyperlipidemic subjects. In a randomized crossover study, 27 hyperlipidemic men and women consumed 3 isoenergetic (mean, 423 kcal/d) supplements each for 1 month. Supplements provided 22.2% of energy and consisted of full-dose almonds (73 +/- 3 g/d), half-dose almonds plus half-dose muffins, and full-dose muffins. Subjects were assessed at weeks 0, 2, and 4 and fasting blood samples were obtained. Twenty-four-hour urinary output was collected at the end of week 4 on each treatment. Mean body weights differed by less than 300 g between treatments. No differences were seen in baseline or treatment values for fasting glucose, insulin, C-peptide, or insulin resistance as measured by homeostasis model assessment of insulin resistance. However, 24-hour urinary C-peptide output as a marker of 24-hour insulin secretion was significantly reduced on the half-and full-dose almonds by comparison to the control after adjustment for urinary creatinine output (P = .002 and P = .004, respectively). We conclude that reductions in 24-hour insulin secretion appear to be a further metabolic advantage of nuts that in the longer term may help to explain the association of nut consumption with reduced CHD risk.

Topics: Aged; Aged, 80 and over; Blood Glucose; C-Peptide; Carbohydrate Metabolism; Cholesterol, LDL; Cross-Over Studies; Diet; Dose-Response Relationship, Drug; Female; Humans; Hyperlipidemias; Insulin; Insulin Resistance; Male; Middle Aged; Prunus

To investigate the effect of raloxifene on insulin sensitivity, beta-cell function, hepatic insulin clearance, and glucose tolerance in postmenopausal women.. Prospective study.. University of Texas Medical Branch at Galveston, Texas.. Twenty normal postmenopausal women.. An oral glucose tolerance test (OGTT) was performed on all study participants before and after treatment with 60 mg of raloxifene daily for 3 months. Blood samples were obtained at baseline and 1, 2, and 3 hours after 75-g oral glucose administration for measurement of glucose, insulin, proinsulin, and c-peptide levels. Insulin tolerance test (ITT) and euglycemic clamp studies were also performed before and after treatment.. Glucose and insulin area under curve (AUC) were calculated. The c-peptide to insulin ratio was determined to assess hepatic clearance of insulin. The homeostasis model assessment (HOMA) was used to calculate the index of insulin resistance (HOMA-IR) and beta-cell function (HOMA-%beta). Insulin sensitivity was assessed by insulin tolerance test and glucose infusion rate (GIR) during euglycemic clamp studies.. There was no change in fasting or AUC glucose levels. Fasting insulin levels were not statistically significantly different, but the insulin levels at 2 hours and insulin AUC were higher after treatment compared with before treatment. Proinsulin, c-peptide levels, and HOMA-%beta did not change. The c-peptide to insulin molar ratio was statistically significantly decreased after treatment. There was no change in insulin sensitivity.. These results indicate that raloxifene has no adverse effect on insulin sensitivity or glucose tolerance, and it does not affect beta-cell function. After glucose load, raloxifene decreases hepatic insulin extraction and thus conserves insulin, which may be beneficial to patients with decreased beta-cell reserve or those predisposed to type 2 diabetes.

Topics: Blood Glucose; C-Peptide; Fasting; Female; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Lipids; Liver; Middle Aged; Postmenopause; Prospective Studies; Raloxifene Hydrochloride; Reference Values; Selective Estrogen Receptor Modulators; Time Factors

Women with former gestational diabetes mellitus (fGDM) often show defects in both insulin sensitivity and beta-cell function but it is not clear which defect plays the major role or which appears first. This might be because fGDM women are often studied as a unique group and not divided according to their glucose tolerance. Different findings might also be the result of using different tests. Our aim was to study insulin sensitivity and beta-cell function with two independent glucose tolerance tests in fGDM women divided according to their glucose tolerance.. A total of 108 fGDM women divided into normal glucose tolerance (IGT; N = 82), impaired glucose metabolism (IGM; N = 20) and overt type 2 diabetes (T2DM; N = 6) groups, and 38 healthy control women (CNT) underwent intravenous (IVGTT) and oral glucose tolerance tests (OGTT). Measurements Insulin sensitivity and beta-cell function were assessed by both the IVGTT and the OGTT.. Both tests revealed impaired insulin sensitivity in the normotolerant group compared to controls (IVGTT: 4.2 +/- 0.3 vs. 5.4 +/- 0.4 10(-4) min(-1) (microU/ml)(-1); OGTT: 440 +/- 7 vs. 472 +/- 9 ml min(-1) m(-2)). Conversely, no difference was found in beta-cell function from the IVGTT. However, some parameters of beta-cell function by OGTT modelling analysis were found to be impaired: glucose sensitivity (106 +/- 5 vs. 124 +/- 7 pmol min(-1) m(-2) mm(-1), P = 0.0407) and insulin secretion at 5 mm glucose (168 +/- 9 vs. 206 +/- 10 pmol min(-1) m(-2), P = 0.003).. Both insulin sensitivity and beta-cell function are impaired in normotolerant fGDM but the subtle defect in beta-cell function is disclosed only by OGTT modelling analysis.

Topics: Adult; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Diabetes, Gestational; Female; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Pregnancy; Prognosis; Recovery of Function; Sensitivity and Specificity

To assess the effect of liraglutide, a once-daily human glucagon-like peptide-1 analogue on pancreatic B-cell function. methods: Patients with Type 2 diabetes (n = 39) were randomized to treatment with 0.65, 1.25 or 1.9 mg/day liraglutide or placebo for 14 weeks. First- and second-phase insulin release were measured by means of the insulin-modified frequently sampled intravenous glucose tolerance test. Arginine-stimulated insulin secretion was measured during a hyperglycaemic clamp (20 mmol/l). Glucose effectiveness and insulin sensitivity were estimated by means of the insulin-modified frequently sampled intravenous glucose tolerance test.. The two highest doses of liraglutide (1.25 and 1.9 mg/day) significantly increased first-phase insulin secretion by 118 and 103%, respectively (P < 0.05). Second-phase insulin secretion was significantly increased only in the 1.25 mg/day group vs. placebo. Arginine-stimulated insulin secretion increased significantly at the two highest dose levels vs. placebo by 114 and 94%, respectively (P < 0.05). There was no significant treatment effect on glucose effectiveness or insulin sensitivity.. Fourteen weeks of treatment with liraglutide showed improvements in first- and second-phase insulin secretion, together with improvements in arginine-stimulated insulin secretion during hyperglycaemia.

Topics: C-Peptide; Diabetes Mellitus, Type 2; Drug Administration Schedule; Female; Glucagon-Like Peptide 1; Humans; Hypoglycemic Agents; Incretins; Insulin Resistance; Islets of Langerhans; Liraglutide; Male; Middle Aged; Receptors, Glucagon; Treatment Outcome

Obesity and aging increase the risk of type 2 diabetes (T2D). We evaluated whether weight loss therapy improves pancreatic endocrine function and insulin sensitivity in obese older adults.. Twenty-four obese (BMI: 38 +/- 2 kg/m(2)) older (age: 70 +/- 2 years) adults completed a 6-month randomized, controlled trial. Participants were randomized to diet and exercise (treatment group) or no therapy (control group). beta-Cell function (assessed using the C-peptide minimal model), alpha-cell function (assessed by the glucagon response to an oral glucose load), insulin sensitivity (assessed using the glucose minimal model), and insulin clearance rate were evaluated using a 5-h modified oral glucose tolerance test.. Body weight decreased in the treatment group, but did not change in the control group (-9 +/- 1% vs. 0 +/- 1%; P < 0.001). Insulin sensitivity doubled in the treatment group and did not change in the control group (116 +/- 49% vs. -11 +/- 13%; P < 0.05). Even though indices of beta-cell responsivity to glucose did not change (P > 0.05), the disposition index (DI), which adjusts beta-cell insulin response to changes in insulin sensitivity, improved in the treatment group compared with the control group (100 +/- 47% vs. -22 +/- 9%; P < 0.05). The glucagon response decreased in the treatment but not in the control group (-5 +/- 2% vs. 4 +/- 4%; P < 0.05). Insulin secretion rate did not change (P > 0.05), but insulin clearance rate increased (51 +/- 25%; P < 0.05), resulting in lower plasma insulin concentrations.. Weight loss therapy concomitantly improves beta-cell function, lowers plasma glucagon concentrations, and improves insulin action in obese older adults. These metabolic effects are likely to reduce the risk of developing T2D in this population.

Topics: Aged; Aging; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Diet, Reducing; Exercise; Female; Glucagon; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Islets of Langerhans; Male; Obesity; Risk Factors; Weight Loss

To evaluate clinically useful measures of beta-cell function derived from the oral glucose tolerance test (OGTT) or mixed-meal (ie, Boost) tolerance test to assess insulin secretion in comparison with the gold standard, the hyperglycemic clamp (Hyper-C) test.. We hypothesized that OGTT/Boost-derived measures are useful estimates of beta-cell function and correlate well with insulin secretion measured by the Hyper-C test. This study was designed to assess the correlation between the ratio of the early incremental insulin/glucose responses at 15 and 30 minutes (DeltaI(15)/DeltaG(15) and DeltaI(30)/DeltaG(30)) of the OGTT and the Boost test with insulin secretion measured during the Hyper-C test (225 mg/dL). The same indices were evaluated using C-peptide. A total of 26 children (14 males, 12 females; mean age, 9.9 +/- 0.2 years; mean body mass index = 22.1 +/- 1.2 kg/m(2)) underwent a 2-hour Hyper-C test (225 mg/dL) and 3-hour OGTT and Boost tests with measurements of glucose, insulin, and C-peptide.. Correlations between Hyper-C- and OGTT-derived measures of insulin secretion were stronger for the 15-minute index than for the 30-minute index of insulin secretion and stronger for C-peptide levels than for insulin levels (r = .7, P < .001 for first-phase C-peptide vs both OGTT and Boost, DeltaC(15)/DeltaG(15)).. In children with normal glucose tolerance, C-peptide rather than insulin level measured after 15 minutes of the OGTT or Boost test provides a reliable estimate of beta-cell function that correlates well with Hyper-C-derived insulin secretion.

Topics: C-Peptide; Child; Female; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Overweight; Reproducibility of Results

We have previously demonstrated that type 2 diabetes resolves after bariatric surgery. To study the role of NEFA in the prompt normalisation of beta cell glucose sensitivity, insulin secretion and beta cell glucose and lipid metabolism were investigated by a model of nutrient-stimulated insulin secretion using a multiple-meal test.. Hourly glucose, C-peptide and NEFA were measured in nine morbidly obese, type 2 diabetic patients before and 1 week after bariatric surgery and in six matched healthy volunteers over 24 h. A mathematical model of glucose-NEFA comodulation of insulin secretion rate (ISR) was used to compute ISR and beta-oxidation. Insulin sensitivity was measured by an OGTT minimal model.. Beta cell sensitivity to glucose and NEFA was doubled after surgery, while the 24 h insulin secretion decreased from 277.1 +/- 144.4 to 198.0 +/- 107.6 nmol/m(2) (p < 0.02). Insulin sensitivity was restored. The beta-oxidation rate of beta cells was completely normalised (from 0.032 +/- 0.012 x 10(-12) to 0.103 +/- 0.031 x 10(-12) mmol/min per cell, p < 0.005). The best predictor of beta cell function improvement was the duration of diabetes.. Bariatric surgery in type 2 diabetes restores beta-oxidation in beta cells, doubles glucose-NEFA sensitivity and reverses diabetes. It is likely that ISR is reduced to match insulin-sensitivity normalisation, in spite of no significant reduction in NEFA levels. We hypothesise that insulin sensitivity normalisation might appear as a consequence of nutrient exclusion from proximal intestinal transit, and that secondarily the need for insulin secretion diminishes. The insulin sensitivity increase is much higher than usually obtained by insulin-sensitising agents and is independent of weight changes.

Topics: Bariatric Surgery; Blood Glucose; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Fatty Acids, Nonesterified; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Models, Biological; Obesity, Morbid; Oxidation-Reduction; Postoperative Care; Preoperative Care

A growing body of evidence supports the concept that treatment with the newer angiotensin type-1 receptor blockers (ARBs) improves glucose homeostasis under conditions wherein it is impaired. Controversy exists, however, regarding the ability of losartan, an older ARB, to exert comparable improvement. The present study was undertaken to evaluate the effects of losartan on glucose homeostasis in subjects with type 2 diabetes and nephropathy.. Twenty-seven subjects with type 2 diabetic nephropathy were enrolled in this prospective, randomized, controlled study. Losartan (100 mg daily) or the calcium channel blocker amlodipine (10 mg daily) was administered for a period of 3 months. Fasting blood glucose, serum insulin and C-peptide concentrations were measured at baseline and at the end of the study. Oral glucose tolerance tests were performed to evaluate insulin sensitivity and beta-cell responsiveness. Insulin resistance was measured using the homeostasis model assessment of insulin resistance (HOMA-IR).. Fasting blood glucose, HbA1c, AUC glucose, and urinary protein values were significantly decreased in the losartan group as compared with the amlodipine group (P<0.05). Furthermore, C-peptide concentrations, the insulin sensitivity index, and the insulin-to-glucose ratio were significantly increased after 3 months of therapy with losartan as compared to amlodipine (P<0.05). Reductions of fasting insulin concentrations and HOMA-IR were also observed for the losartan group; however, reductions were not significant when compared with the amlodipine group.. In addition to reducing urinary protein excretion, losartan at 100 mg daily increases insulin sensitivity and improves glucose homeostasis in subjects with type 2 diabetic nephropathy.

Topics: Adult; Aged; Amlodipine; Angiotensin II Type 1 Receptor Blockers; Blood Glucose; C-Peptide; Calcium Channel Blockers; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Fasting; Female; Glycated Hemoglobin; Homeostasis; Humans; Insulin; Insulin Resistance; Losartan; Male; Middle Aged; Proteinuria; Time Factors; Treatment Outcome

Hyperglycemia and hyperinsulinemia are common in intensive care unit (ICU) patients and relate to illness severity. Intensive insulin therapy (IIT) to maintain normoglycemia reduces morbidity and mortality. Blood glucose control explains this benefit because a high insulin dose is associated with adverse outcome. Mitogenic insulin effects could theoretically explain this link.. To investigate further the association between insulin dose and adverse outcome, we studied the effect of IIT on circulating insulin levels, markers of insulin sensitivity, and the metabolic and mitogenic insulin signaling molecules in key tissues.. This is a subanalysis of a large randomized, controlled study.. The study was performed in a university hospital surgical ICU.. A total of 339 critically ill patients, treated in ICU for at least a week, were included in this subanalysis.. Strict normoglycemia with IIT compared with conventional insulin therapy was performed.. Severalfold higher insulin doses than with conventional insulin therapy were required to maintain normoglycemia with IIT. However, serum insulin levels were only transiently higher with IIT, despite the much lower blood glucose levels. IIT normalized the elevated serum C-peptide levels and increased circulating adiponectin levels. The metabolic insulin signal was increased by IIT in muscle, but not in liver. The mitogenic insulin signal in either tissue was not affected by IIT.. Normoglycemia can be maintained in ICU patients without a sustained further elevation of insulinemia. Together with the increased adiponectin levels, this finding suggests that IIT may improve insulin sensitivity. Skeletal muscle, but not liver, revealed an increased metabolic insulin signal. The therapy did not impose mitogenic risk in these tissues.

Topics: Adiponectin; Aged; Blood Glucose; C-Peptide; Critical Illness; Female; Humans; Hyperglycemia; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin-Like Growth Factor Binding Protein 1; Liver; Male; Middle Aged; Muscle, Skeletal; Receptors, Adiponectin; Signal Transduction

Ghrelin is a major hormone, regulating the energy balance of the body. Weight gain is a significant side effect of valproic acid, which has not been clearly identified pathogenetically. The aim of this study was to investigate the effect of valproic acid on ghrelin and its potential effects on weight gain and growth. Each patient and control group consisted of 35 children aged 3 to 15 years. Fasting serum glucose, insulin, C-peptide, leptin, ghrelin, insulin-like growth factor-1, and insulin-like growth factor binding protein-3 levels were measured in patients treated with valproic acid before and at month 6 of treatment. A significant increase in body weight, body mass index, height, and height standard deviation scores was observed in all patients after 6 months of treatment. Significant increases in growth velocity and weight gain were observed in the patient group compared with controls at 6 months of therapy. A significant increase in serum ghrelin levels (P < .01) was detected at the same time in the study group. A negative correlation of ghrelin with insulin-like growth factor-1 and insulin-like growth factor binding protein-3 was detected. Serum ghrelin levels were significantly increased (P < .05), and insulin-like growth factor-1 and insulin-like growth factor binding protein-3 levels were significantly decreased (P < .01 and P < .05, respectively) in the prepubertal group at 6 months of treatment, but no significant change was observed in the pubertal group. Consequently, ghrelin levels significantly increase in the prepubertal children treated with valproic acid. The weight gain in using valproic acid may be associated with the increase in ghrelin level in the early treatment period.

Topics: Adolescent; Anticonvulsants; Blood Glucose; Body Height; Body Mass Index; Body Weight; C-Peptide; Child; Child, Preschool; Epilepsy; Female; Ghrelin; Humans; Insulin; Insulin Resistance; Insulin-Like Growth Factor Binding Protein 3; Insulin-Like Growth Factor I; Leptin; Male; Puberty; Valproic Acid; Weight Gain

To investigate the pathogenesis of distal pancreatectomy (d-Px)-induced diabetes in Korean patients, we investigated insulin secretory and sensitivity indexes obtained by oral glucose tolerance testing in 20 patients that had received d-Px (10 with d-Px-induced diabetes and 10 with normal glucose tolerance with d-Px [NGT d-Px]) and in 164 control subjects (77 with type 2 diabetes mellitus and 87 with NGT) that did not receive d-Px. The pancreatectomized subjects had lower fasting serum insulin, homeostasis model assessment of pancreatic beta-cell function (HOMA-beta) levels, and insulinogenic indices than the NGT controls. The HOMA-beta values of nonobese NGT d-Px- and d-Px-induced diabetic subjects were 73.7% and 38.7% of those for nonobese NGT controls, respectively, and HOMA-beta was significantly lower only for d-Px-induced diabetic subjects (P < .01). In obese subjects, the HOMA-beta values of obese d-Px-induced diabetic subjects were significantly lower than those of obese NGT controls (P < .05). The insulin sensitivity was significantly lower in nonobese type 2 diabetes mellitus controls than in nonobese NGT d-Px or in nonobese d-Px-induced diabetic subjects (P < .001 and .05, respectively). These results show that a reduced insulin secretory function is a typical feature of glucose homeostasis in distal pancreatectomized patients and that insulin secretory defect plays a major role in the development of diabetes in these patients. In addition, the study suggests that pancreatic resections of 60% or less and body mass index are not the main causes of diabetes onset after d-Px in this study.

Topics: Adult; Blood Glucose; Blood Pressure; Body Mass Index; C-Peptide; Diabetes Mellitus; Female; Humans; Insulin; Insulin Resistance; Insulin Secretion; Lipids; Male; Middle Aged; Pancreatectomy

First-degree relatives of type 2 diabetic patients (offspring) are often characterized by insulin resistance and reduced physical fitness (VO2 max). We determined the response of healthy first-degree relatives to a standardized 10-wk exercise program compared with an age-, sex-, and body mass index-matched control group. Improvements in VO2 max (14.1 +/- 11.3 and 16.1 +/- 14.2%; both P < 0.001) and insulin sensitivity (0.6 +/- 1.4 and 1.0 +/- 2.1 mg x kg(-1) x min(-1); both P < 0.05) were comparable in offspring and control subjects. However, VO2 max and insulin sensitivity in offspring were not related at baseline as in the controls (r = 0.009, P = 0.96 vs. r = 0.67, P = 0.002). Likewise, in offspring, exercise-induced changes in VO2 max did not correlate with changes in insulin sensitivity as opposed to controls (r = 0.06, P = 0.76 vs. r = 0.57, P = 0.01). Skeletal muscle oxidative capacity tended to be lower in offspring at baseline but improved equally in both offspring and controls in response to exercise training (delta citrate synthase enzyme activity 26 vs. 20%, and delta cyclooxygenase enzyme activity 25 vs. 23%. Skeletal muscle fiber morphology and capillary density were comparable between groups at baseline and did not change significantly with exercise training. In conclusion, this study shows that first-degree relatives of type 2 diabetic patients respond normally to endurance exercise in terms of changes in VO2 max and insulin sensitivity. However, the lack of a correlation between the VO2 max and insulin sensitivity in the first-degree relatives of type 2 diabetic patients indicates that skeletal muscle adaptations are dissociated from the improvement in VO2 max. This could indicate that, in first-degree relatives, improvement of insulin sensitivity is dissociated from muscle mitochondrial functions.

Topics: Adult; Blood Glucose; Body Mass Index; C-Peptide; Citrate (si)-Synthase; Diabetes Mellitus, Type 2; Electron Transport Complex IV; Exercise; Exercise Test; Family Health; Female; Humans; Insulin; Insulin Resistance; Lipid Metabolism; Male; Muscle, Skeletal; Oxidation-Reduction; Oxygen; Physical Fitness; Regression Analysis

Hyperproinsulinemia in type 2 diabetic subjects has recently been accepted as an independent cardiovascular risk factor. Moreover, it has been confirmed that high proinsulin concentrations stimulate amylin secretion by pancreatic beta-cells and amyloid accumulation within pancreatic islets leading to impairment of pancreatic islets secretory function. The association between sulfonylureas administration and secretory function of pancreatic beta-cells, especially concerning insulin precursor peptides, is not sufficiently elucidated. Preliminary studies by our research group revealed that the fasting proinsulin serum concentration is significantly higher in type 2 diabetic patients treated with sulfonylureas than in a well-matched group treated with insulin only.. A total of 101 subjects with type 2 diabetes were treated either with sulfonylureas (n = 32), with insulin (n = 40), with sulfonylureas + insulin (n = 17) or with diet alone (n = 12).. The basal secretory function in the four groups were comparable (C-peptide fasting serum level > 0.5 ng/l). An effect of fasting glycemia, long-term metabolic control (HbA1c), postprandial hyperglycemia (1,5-anhydro-D-glucitol), insulin resistance (HOMA(IR)score) and diabetes duration on the fasting proinsulin serum level in the subjects treated could be excluded.. The disproportionately high proinsulin levels are due to sulfonylureas therapy. The effect is independent of fasting glycemia, long-term metabolic control, postprandial hyperglycemia, diabetes duration and peripheral insulin resistance.

Topics: Aged; Blood Glucose; Body Mass Index; C-Peptide; Caloric Restriction; Deoxyglucose; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Fasting; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Multivariate Analysis; Patient Selection; Proinsulin; Sulfonylurea Compounds

We have previously demonstrated abnormalities in insulin secretion in adolescents with type 2 diabetes mellitus (DM2) in response to the mixed meal test and to glucagon. In order to further assess beta-cell function in DM2, we measured insulin and C-peptide responses to oral glucose in adolescents with DM2 in comparison to non-diabetic obese and lean adolescents. We studied 20 patients with DM2, 25 obese adolescents with matching body mass index (BMI) (33.8 +/- 1.4 vs 34.3 +/- 1.0 kg/m2), and 12 non-obese control adolescents (BMI 22.6 +/- 0.6 kg/m2). Mean age, sex and sexual maturation did not differ between the three groups. All adolescents with DM2 had negative islet cell antibodies (ICA); five patients were on diet and 15 on insulin treatment. Fasting lipid profiles were determined in all participants. Plasma glucose and serum C-peptide and insulin levels were measured at 0, 30, 60, 90, and 120 min after an oral glucose load. The C-peptide increment (deltaCP) was calculated as peak minus fasting C-peptide. Area under the curve (AUC) was estimated using the trapezoid method. Insulin resistance was estimated using the HOMA model (HOMA-IR). The first phase of insulin secretion (PH1) was computed using a previously published formula. Serum triglyceride levels were significantly higher in the patients with DM2 compared to the non-obese controls (1.4 +/- 0.1 vs 0.9 +/- 0.1 mmol/l; p = 0.02). Plasma glucose AUC was greater in the patients with DM2 compared to the obese and non-obese control groups (1,660 +/- 130 vs 717 +/- 17 vs 647 +/- 14 mmol/l x min; p < 0.0001). ACP was lower in adolescents with DM2 than in obese and non-obese adolescents (761 +/- 132 vs 1,721 +/- 165 vs 1,225 +/- 165 pmol/l; p < 0.001). Insulin AUC was lower in the patients with DM2 compared to obese controls (888 +/- 206 vs 1,606 +/- 166 pmol/l x h; p = 0.009), but comparable to that of the non-obese controls (888 +/- 206 vs 852 +/- 222 pmol/l x h; p = 0.9). Insulin AUC was also higher in the obese than in the non-obese group (p = 0.05). PH1 was significantly higher in the obese group compared to the patients with DM2 as well as to the non-obese controls (2,614 +/- 2,47.9 vs 929.6 +/- 403.5 vs 1,946 +/- 300.6 pmol/l, respectively; p = 0.001). PH1 was also higher in the non-obese controls than in the patients with DM2 (p = 0.05). HOMA-IR was three-fold higher in the patients with DM2 than in the BMI-matched obese group, and five-fold higher than in the lean controls (14.3 +/- 1.2 vs 5.4

Topics: Adolescent; Black or African American; Blood Glucose; C-Peptide; Child; Cholesterol; Diabetes Mellitus, Type 2; Dyslipidemias; Female; Humans; Hyperglycemia; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Obesity; Reference Values; Triglycerides

Both carvedilol and metoprolol have cardioprotective effects and decrease infarct size in myocardium. We compared effects of carvedilol and metoprolol on insulin resistance and serum lipid levels after myocardial infarction.. Fifty-nine patients aged between 30 and 70 and BMI = 25-30 kg/m2, who were diagnosed with myocardial infarction with ST segment elevation, were considered to be eligible for the study. Patients were randomly allocated to two different therapy protocols. Metoprolol 100 mg bid or carvedilol 25 mg bid was added to their standardized therapy regimen. Baseline to week 4 and 12, fasting blood glucose, serum lipid profile, BMI, C-peptide, insulin and homeostasis model assessment of insulin resistance (HOMA-IR) were measured.. After 12 weeks of metoprolol therapy HOMA-IR, insulin and C-peptide levels were significantly higher (p < 0.05 for all) and total cholesterol and triglyceride levels decreased significantly (p < 0.05 for all) compared to baseline. After 12 weeks of carvedilol therapy HOMA-IR, insulin and C-peptide (p < 0.05 for all), total cholesterol and triglyceride (p = 0.001 for all) decreased significantly compared to baseline. Carvedilol provided more decrease in total cholesterol and LDL levels than metoprolol (p = 0.043 and p = 0.021, respectively).. In patients after myocardial infarction, carvedilol added to background therapy improved insulin resistance and lipid profile.

Topics: Adrenergic alpha-Antagonists; Adrenergic beta-Antagonists; Adult; Aged; C-Peptide; Carbazoles; Carvedilol; Cholesterol, LDL; Female; Glucose Clamp Technique; Humans; Insulin Resistance; Male; Metoprolol; Middle Aged; Myocardial Infarction; Propanolamines; Triglycerides

Glucose and lipid metabolism dysfunction is a significant side effect associated with antipsychotics. Although there are many studies about the linkages between drugs and metabolic dysfunction, most of these studies have compared the effects of two antipsychotics on only one metabolic measure: either glucose or lipid metabolism.. The present study aimed to investigate the effects of clozapine, olanzapine, risperidone, and sulpiride on glucose and lipid metabolism in first-episode schizophrenia.. One hundred twelve schizophrenics were assigned randomly to receive clozapine, olanzapine, risperidone, or sulpiride for 8 weeks. Planned assessments included body mass index (BMI), waist-to-hip ratio, fasting glucose, insulin, C-peptide, insulin resistance index (IRI), cholesterol, and triglyceride. All measures were collected at baseline and at the end of the 8-week treatment.. After treatment, insulin, C-peptide, and IRI were significantly increased in the four groups, but not fasting glucose levels. Cholesterol and triglyceride levels were significantly increased in the clozapine and olanzapine groups. Patients treated with clozapine and olanzapine had higher fasting insulin, C-peptide, and IRI levels than those treated with risperidone and sulpiride. Among the four antipsychotics, the increases of mean BMI from high to low were as follows: clozapine, olanzapine, sulpiride, and risperidone.. This study confirmed that the four antipsychotic drugs were associated with an increase of insulin, C-peptide, and IRI. It was found that clozapine and olanzapine were associated with an increase in cholesterol and triglyceride levels. The effects of clozapine and olanzapine on the glucose and lipid metabolism outweighed those of risperidone and sulpiride.

Topics: Adult; Antipsychotic Agents; Benzodiazepines; Blood Glucose; Body Mass Index; C-Peptide; Cholesterol; Clozapine; Female; Homeostasis; Humans; Insulin; Insulin Resistance; Lipid Metabolism; Male; Metabolic Syndrome; Olanzapine; Prospective Studies; Risperidone; Schizophrenia; Sulpiride; Triglycerides; Waist-Hip Ratio

Large interventional studies have shown that statins may reduce the incidence of type 2 diabetes mellitus. However, it is uncertain whether short-term statin therapy can affect insulin sensitivity in patients with the metabolic syndrome. We evaluated the effect of atorvastatin (10 mg/day) in 10 insulin-resistant subjects (age 40 +/- 12 years, body mass index 33.6 +/- 5.2 kg/m(2), triglycerides 2.84 +/- 1.99 mmol/L [249 +/- 175 mg/dl], glucose 6.06 +/- 0.67 mmol/L [109 +/- 12 mg/dl)] using the homeostasis model assessment (HOMA) index (parameter of insulin resistance derived from fasting glucose and fasting insulin concentrations; 5.7 +/- 2.6) in a randomized placebo-controlled, double-blind, crossover study. Subjects were randomized to receive placebo or atorvastatin, each given for 6 weeks separated by a 6-week wash-out period. At the beginning and end of each treatment phase, the patients underwent an oral glucose tolerance test, a 72-hour continuous glucose measurement, and a detailed lipid determination, including a standardized fat tolerance test. Compared with placebo, atorvastatin resulted in a significant (p = 0.05) reduction in the HOMA index (-21%), fasting C-peptides (-18%), glucose (area under the curve during the oral glucose tolerance test, -7%), and a borderline (p = 0.08) reduction of insulin (-18%). The parameters derived from the continuous 72-hour glucose monitoring did not change. A significant reduction also occurred in the total and low-density lipoprotein cholesterol concentrations, although the fasting and postprandial triglyceride concentrations did not change significantly. However, we found a significant correlation between atorvastatin-induced changes in the HOMA and baseline HOMA and between the atorvastatin-induced changes in triglycerides and insulin concentrations. The free-fatty acid, interleukin-6, and high sensitivity C-reactive protein concentrations did not change. Our data indicated that in insulin-resistant, nondiabetic subjects, 6 weeks of atorvastatin (10 mg/day) resulted in significant improvement in insulin sensitivity.

Topics: Adult; Atorvastatin; Blood Glucose; C-Peptide; Cross-Over Studies; Diabetes Mellitus, Type 2; Double-Blind Method; Female; Heptanoic Acids; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Insulin; Insulin Resistance; Male; Metabolic Syndrome; Pyrroles; Treatment Outcome

This study was designed to assess the usefulness of a model-based index of insulin sensitivity during an oral glucose tolerance test (OGTT) in the identification of possible changes in this metabolic parameter produced by pharmacological agents known to be potent insulin sensitizers, that is metformin (M) and thiazolidinedione (T). The association of these agents with several other factors related to glucose metabolism was also investigated, as well as the relation of insulin sensitivity and secretion with markers of endothelial function such as different adhesion molecules (cAMs), that is vascular cell adhesion molecule-1, intercellular adhesion molecule-1 and E-Selectin.. Twenty type 2 diabetic patients treated with diet only underwent a 3-h OGTT for measurement of plasma glucose, insulin, proinsulin, C-peptide and cAMs before and after administration of randomly given M (n = 9; 1700 mg/day) or T (n = 11; 600 mg/day). After 16 weeks of treatment, a second OGTT was performed. Insulin sensitivity was calculated with homeostasis model assessment and with oral glucose insulin sensitivity (OGIS), which quantifies dynamic glucose clearance per unit change of insulin. Insulin secretion was assessed by modelling technique. Differences in these parameters before and after treatment, as well as possible relationships with cAMs, were assessed.. Basal and stimulated plasma glucose decreased after therapy in both the groups by approximately 20%. Basal insulin resistance also decreased. Insulin sensitivity in dynamic conditions (OGIS: ml/min/m(2)) increased with M (289.3 +/- 18.8 vs. 234.7 +/- 18.1, p < 0.02) and tended to improve with T (323.5 +/- 18.1 vs. 286.8 +/- 22.1, p = 0.09). Total insulin secretion over the OGTT [TIS: nmol/l(3 h)] tended to decrease with M (17.1 +/- 2.5 vs. 27.3 +/- 0.3, p = 0.08) but not with T (23.6 +/- 3.5 vs. 22.5 +/- 2.7). Plasma concentrations of E-Selectin decreased in T (38.0 +/- 2.3 vs. 51.2 +/- 6.1 ng/ml, p < 0.05). No correlation was found between insulin sensitivity and cAMs.. Model-based indices of insulin sensitivity and secretion during an OGTT can be able to detect changes observed in patients under treatment with pharmacological agents such as M or T. Both the drugs improved glucose control similarly. Decreased plasma E-Selectin concentrations were seen in patients on T therapy only.

Topics: Blood Glucose; Body Weight; C-Peptide; Cell Adhesion Molecules; Chromans; Diabetes Mellitus, Type 2; Drug Monitoring; Female; Glucose Tolerance Test; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Male; Metformin; Middle Aged; Proinsulin; Thiazolidinediones; Troglitazone

Intervention studies have shown that angiotensin receptor blocker therapy may reduce the incidence of type 2 diabetes mellitus. It is unknown whether short-term angiotensin receptor blocker therapy can improve glucose and lipid metabolism in insulin-resistant subjects. We evaluated the effect of telmisartan (40 mg/d, 12 weeks) in 20 subjects with insulin resistance (body mass index, 31.8 +/- 3.31 kg/m(2); triglycerides, 179 +/- 98 mg/dL; glucose, 104 +/- 9 mg/dL; homeostasis model assessment index, 3.78 +/- 1.52) in a randomized, placebo-controlled, double-blind, cross-over study. At the end of each treatment phase, oral and intravenous glucose tolerance tests including C-peptide and insulin measurements were performed, and fasting and postprandial lipids were determined. Compared to placebo, telmisartan resulted in a reduction in homeostasis model assessment index (-11%, P = .06) and glucose area under the curve during intravenous glucose tolerance (-11%, P = .04). We observed an increase (+32%, P = .05) in the insulinogenic index indicating an improved beta-cell function. Fasting and postprandial lipid parameters did not change. We observed an increase in adiponectin (6%, P = .09), whereas IL-6, high-sensitivity C-reactive protein, fibrinogen, and free fatty acid concentrations did not change. This indicates that the improvement in glucose metabolism is rather mediated by direct effects, such as activation of PPARgamma. Our data indicate that in insulin-resistant persons 12 weeks of telmisartan result in a significant improvement in glucose metabolism with a predominant improvement in beta-cell function.

Topics: Adiponectin; Adult; Angiotensin Receptor Antagonists; Benzimidazoles; Benzoates; Blood Glucose; C-Peptide; Cross-Over Studies; Double-Blind Method; Glucose Tolerance Test; Homeostasis; Humans; Insulin; Insulin Resistance; Lipid Metabolism; Lipids; Middle Aged; Overweight; Telmisartan; Treatment Outcome

This study was designed to evaluate the effects of rosiglitazone (ROS) on insulin sensitivity, beta-cell function, and glycaemic response to glucose challenge and meal in subjects with impaired glucose tolerance (IGT).. Thirty patients with IGT (ages between 30 and 75 years and BMI (body mass index) < or = 27 kg/m2) were randomly assigned to receive either placebo (n = 15) or ROS (4 mg/day) (n = 15). All participants underwent a 75-g oral glucose tolerance test (OGTT), meal test, and frequently sampled intravenous glucose tolerance test (FSIGT) before and after the 12-week treatment.. After 12 weeks of ROS treatment, there were significant increases in total cholesterol (TC) (4.25 +/- 0.22 vs 4.80 +/- 0.17 mmol/l, P < 0.001), high-density lipoprotein cholesterol (HDL-C) (1.25 +/- 0.07 vs 1.43 +/- 0.06 mmol/l, P < 0.05), and low-density lipoprotein cholesterol (LDL-C) (2.70 +/- 0.15 vs 3.37 +/- 0.17 mmol/l, P < 0.05) without changes in triglyceride concentration, TC/HDL-C and LDL-C/HDL-C ratio. Although the acute insulin response (AIR) to intravenous glucose and disposition index (measured as the ability of pancreatic beta-cell compensation in the presence of insulin resistance) remained unchanged, the insulin sensitivity (SI) and glucose effectiveness (SG) were remarkably elevated (0.38 +/- 0.06 vs 0.54 +/- 0.09 x 10(-5) min(-1)/pmol, P < 0.05; 0.017 +/- 0.002 vs 0.021 +/- 0.001 min(-1), P < 0.05, respectively) in the ROS group. The glucose, insulin, and c-peptide areas under curve (AUC) in response to OGTT and the glucose and insulin AUC during meal were significantly ameliorated in the ROS group. Five out of 15 (33%) and two out of 15 (13%) subjects treated with ROS and placebo, respectively, reversed to normal response during OGTT (P < 0.05).. Rosiglitazone treatment significantly improved insulin resistance and reduced postchallenge glucose and insulin concentrations in patients with impaired glucose tolerance without remarkable effects on beta-cell secretory function.

Topics: Adult; Aged; Blood Glucose; C-Peptide; Chi-Square Distribution; Female; Glucose Tolerance Test; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Male; Middle Aged; Rosiglitazone; Sex Factors; Single-Blind Method; Thiazolidinediones; Treatment Outcome

In healthy, nondiabetic individuals with insulin resistance, fasting insulin is inversely correlated to the posthepatic insulin clearance rate (MCRi) and the hepatic insulin extraction (HEXi). We investigated whether similar early mechanisms to facilitate glucose homeostasis exist in nondiabetic, human immunodeficiency virus (HIV)-infected patients with and without lipodystrophy. We studied 18 HIV-infected patients with lipodystrophy (LIPO) on antiretroviral therapy and 25 HIV-infected patients without lipodystrophy (controls) of whom 18 were on antiretroviral therapy and 7 were not. Posthepatic insulin clearance rate was estimated as the ratio of posthepatic insulin appearance rate to steady-state plasma insulin concentration during a euglycemic hyperinsulinemic clamp (40 mU.m-2 .min-1). Posthepatic insulin appearance rate during the clamp was calculated, taking into account the remnant endogenous insulin secretion, which was estimated by deconvolution of C-peptide concentrations. Hepatic extraction of insulin was calculated as 1 minus the ratio of fasting posthepatic insulin delivery rate to fasting endogenous insulin secretion rate. Compared with controls, LIPO displayed increased fasting insulin (130%, P < .001), impaired insulin sensitivity index (M value, -29%, P < .001), and reduced MCRi (-17%, P < .01). Hepatic extraction of insulin was similar between groups (LIPO, 55%; controls, 57%; P > .8). In LIPO, HEXi and MCRi correlated inversely with fasting insulin (r = -0.56, P < .02 and r = -0.68, P < .002) and positively with M value (r = 0.63, P < .01 and r = 0.65, P < .004). In controls, MCRi correlated inversely with fasting insulin (r = -0.47, P < .02) and positively with M value (r = 0.57, P < .004); however, the correlations between HEXi and these parameters were insignificant (P > .1). Our data suggest that HEXi and MCRi are decreased in proportion to the degree of insulin resistance in nondiabetic HIV-infected patients with lipodystrophy.

Topics: Adipose Tissue; Adult; Algorithms; Antiretroviral Therapy, Highly Active; Body Composition; C-Peptide; Fatty Acids, Nonesterified; Female; Glucose Clamp Technique; HIV Infections; Humans; Insulin; Insulin Resistance; Kinetics; Lipodystrophy; Liver; Male

The purpose of this study was to evaluate intraoperative glucose control.. Prospective unblinded study.. Tertiary care center.. Diabetic (n = 17) and nondiabetic (n = 23) patients undergoing elective cardiac surgery.. Diabetics received a modified insulin regimen consisting of a fixed rate infusion of regular insulin, 10 U/m2/h, and a variable infusion of D10W, adjusted to maintain glucose between 101 to 140 mg/dL.. Baseline glucose was higher in diabetics versus nondiabetics (mean +/- standard error of the mean: 203 +/- 27 v 117 +/- 3 mg/dL, p < 0.005). After baseline, insulin levels were increased in diabetics to 410 to 568 microU/mL. Corresponding insulin levels in nondiabetics were 12 to 40 microU/mL. Compared with baseline, glucose was decreased by 10% +/- 29% in diabetics during hypothermic cardiopulmonary bypass and increased by 21% +/- 30% in nondiabetics (p < 0.005). After discontinuation of bypass, glucose was lower in diabetics (137 +/- 12 mg/dL) versus nondiabetics (162 +/- 8 mg/dL, p < 0.005). Nine diabetics had adequate intraoperative glycemic control during hypothermic bypass (glucose 123 +/- 8 mg/dL, insulin 550 +/- 68 microU/mL, glucose infusion rate 1.87 +/- 0.29 mg/kg/min), 6 approached adequate control near the end of surgery (glucose 147 +/- 8 mg/dL, insulin 483 +/- 86 microU/mL, glucose infusion rate 0.35 +/- 0.05 mg/kg/min), and 2 never achieved control. Diabetics with elevated initial glucose >300 mg/dL did not achieve adequate glycemic control. Four diabetics (3 with renal failure) required injection of 50% dextrose after bypass for hypoglycemia.. Adequate glycemic control can be achieved in most diabetics during cardiac surgery using a modified insulin clamp technique provided initial glucose is <300 mg/dL.

Topics: Aged; Aged, 80 and over; Biomarkers; Blood Glucose; C-Peptide; Cardiac Surgical Procedures; Cardiopulmonary Bypass; Diabetes Mellitus; Female; Human Growth Hormone; Humans; Hydrocortisone; Hypoglycemic Agents; Infusions, Intravenous; Insulin; Insulin Resistance; Intraoperative Complications; Lactic Acid; Male; Middle Aged; Prospective Studies; Tachycardia; Tumor Necrosis Factor-alpha

Adolescent obesity is a serious public health concern.. The aim of the study was to determine whether obese adolescents can adapt metabolically to changes in dietary macronutrient intake.. Using a random cross-over design, 13 healthy obese volunteers (six boys and seven girls; age, 14.7 +/- 0.3 yr; body mass index, 34 +/- 1 kg/m2; body fat, 42 +/- 1%) were studied twice after 7 d of isocaloric, isonitrogenous diets with 60% carbohydrate (CHO) and 25% fat (high CHO), or 30% CHO and 55% fat (low CHO).. Glucose metabolism, insulin sensitivity, and first- and second-phase insulin secretory indices were measured by stable isotope techniques and the stable labeled iv glucose tolerance test. The results were compared with those of previously studied lean adolescents.. Obese adolescents increased first- and second-phase insulin secretory indices by 18 (P = 0.05) and 36% (P = 0.05), respectively, to maintain normoglycemia during the high-CHO diet because they failed to increase insulin sensitivity as did the lean adolescents. Regardless of diet, in obese adolescents, insulin sensitivity was half (P < 0.05) and first- and second-phase insulin secretory indices twice (P < 0.01), compared with the the corresponding values in lean subjects. In obese adolescents, gluconeogenesis increased by 32% during the low-CHO (high-fat diet) (P < 0.01).. In obese adolescents, insulin secretory demands were increased regardless of diet. Failure to increase insulin sensitivity while receiving a high-CHO diet required a further increase in insulin secretion, which may lead to earlier beta-cell failure. A low-CHO/high-fat diet resulted in increased gluconeogenesis, which may be a prelude to the increased glucose production and hyperglycemia observed in type 2 diabetics.

Topics: Adolescent; Blood Glucose; C-Peptide; Cross-Over Studies; Dietary Carbohydrates; Dietary Fats; Energy Metabolism; Female; Gluconeogenesis; Glycolysis; Humans; Insulin; Insulin Resistance; Insulin Secretion; Kinetics; Lipids; Male; Obesity; Oxidation-Reduction

Highly informative yet simple protocols to assess insulin secretion and action would considerably enhance the quality of epidemiological and large-scale clinical trials. In an effort to develop such protocols, a 5-h, 11-sample oral glucose tolerance test (OGTT) was performed in 100 individuals and a 7-h, 21-sample meal in another 100. Plasma glucose, insulin, and C-peptide concentrations were measured. We show that virtually the same minimal model assessment of beta-cell responsivity (dynamic [Phi(d)] and static [Phi(s)]), insulin sensitivity (Si), and disposition index (DI) can be obtained with a reduced seven-sample 2-h protocol: Phi(d), reduced versus full: 871.50 vs. 873.32, r = 0.98 in OGTT and 494.88 vs. 477.99 10(-9), r = 0.91 in meal; Phi(s): 42.36 vs. 44.35, r = 0.88 in OGTT and 35.31 vs. 35.37 10(-9) min(-1), r = 0.90 in meal; Si: 24.33 vs. 22.77 10(-5) dl x kg(-1) x min(-1) per pmol/l, r = 0.89 in OGTT and 19.03 vs. 19.77 10(-5) dl x kg(-1) x min(-1) per pmol/l, r = 0.85 in meal; and DI: 1,282.26 vs. 1,273.23, r = 0.84 in OGTT and 726.92 vs. 776.97 10(-14) dl . kg(-1) x min(-2) per pmol/l, r = 0.84 in meal. This reduced protocol will facilitate the study of insulin secretion and action under physiological conditions in nondiabetic humans.

Topics: Adult; Aged, 80 and over; Blood Glucose; C-Peptide; Diet; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Middle Aged; Models, Biological; Time Factors

To evaluate the influence of two medical treatments for endometriosis on insulin sensitivity.. After surgery, 26 women with endometriosis were randomly allocated to a 6-month treatment with a GnRH agonist (Leuprorelin 3.75 mg/28 days) or a subdermal progestin implant (etonogestrel 68 mg). Insulin sensitivity (SI) and glucose utilization independent of insulin (Sg) were investigated at baseline and after 6 months by a frequently sampled intravenous glucose tolerance test (FSIGT) associated with the minimal model method.. Both therapies tended to decrease SI, but the effect did not reach statistical significance in the GnRH agonist group (5.43+/-1.29 vs. 3.99+/-0.8) and was significant in the etonogestrel group (5.74+/-1.12 vs. 3.95+/-0,78; p=.046). Sg, fasting glucose, insulin, C-peptide and C-peptide/insulin were not modified by either treatment.. The modifications of glucose-insulin metabolism induced by the GnRH agonist are of no relevance for the short-term use of this molecule. Even if the modification induced by the etonogestrel implant is subtle and of no major impact, it should be taken into consideration for the long-term treatment of individuals with abnormalities of glucose-insulin metabolism.

Topics: Blood Glucose; C-Peptide; Desogestrel; Drug Implants; Endometriosis; Fasting; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Leuprolide

Increased insulin resistance is the major pathogenic mechanism in the development of non-alcoholic steatohepatitis.. To investigate the therapeutic effect of metformin, a well-known insulin-sensitizing agent, in the treatment of non-alcoholic steatohepatitis.. Thirty-six patients with non-alcoholic steatohepatitis were randomized into two groups. The first group was given lipid and calorie-restricted dietary treatment alone, and the second group was given metformin 850 mg b.d. plus dietary treatment, for 6 months. The changes in biochemical, sonographic and histological parameters were compared.. The mean serum alanine/aspartate aminotransferase, insulin and C-peptide levels decreased and the index of insulin resistance improved significantly from baseline in the group given metformin. The mean changes in these parameters in the metformin group were significantly greater than those in the group given dietary treatment alone. Although more patients in the metformin group showed improvement in the necro-inflammatory activity, compared with the group given dietary treatment alone, no significant differences in necro-inflammatory activity or fibrosis were seen between the groups.. The data suggest that improvement of the insulin sensitivity with metformin may improve the liver disease in patients with non-alcoholic steatohepatitis.

Topics: Adult; Blood Glucose; C-Peptide; Female; Hepatitis; Humans; Hypoglycemic Agents; Insulin Resistance; Male; Metformin; Middle Aged; Steatorrhea; Treatment Outcome

The effect of short- (2 h) and long-term (24 h) low-grade Intralipid infusion on whole-body insulin action, cellular glucose metabolism, and proximal components of the insulin signal transduction cascade was studied in seven obese male glucose intolerant first degree relatives of type 2 diabetic patients [impaired glucose tolerance (IGT) relatives] and eight matched control subjects. Indirect calorimetry and excision of vastus lateralis skeletal muscle biopsies were performed before and during hyperinsulinemic euglycemic clamps combined with 3[(3)H]glucose. Clamps were performed after 0, 2, or 24 h Intralipid infusion (0.4 ml.kg(-1).min(-1)). Insulin-stimulated glucose disposal decreased approximately 25% after short- and long-term fat infusion in both IGT relatives and controls. Glucose oxidation decreased and lipid oxidation increased after both short- and long-term fat infusion in both groups. Insulin-stimulated glucose oxidation was higher after long-term as compared with short-term fat infusion in control subjects. Short- or long-term infusion did not affect the absolute values of basal or insulin-stimulated insulin receptor substrate-1 tyrosine phosphorylation, tyrosine-associated phosphoinositide 3-kinase (PI 3-kinase) activity, insulin receptor substrate-1-associated PI 3-kinase activity, or Akt serine phosphorylation in IGT relatives or matched controls. In fact, a paradoxical increase in both basal and insulin-stimulated PI 3-kinase activity was noted in the total study population after both short- and long-term fat infusion. Short- and long-term low-grade Intralipid infusion-induced (or enhanced) whole-body insulin resistance and impaired glucose metabolism in IGT relatives and matched control subjects. The fat-induced metabolic changes were not explained by impairment of the proximal insulin signaling transduction in skeletal muscle.

Topics: Blood Glucose; C-Peptide; Calorimetry, Indirect; Diabetes Mellitus, Type 2; Fat Emulsions, Intravenous; Fatty Acids, Nonesterified; Glucose Clamp Technique; Humans; Insulin; Insulin Receptor Substrate Proteins; Insulin Resistance; Middle Aged; Muscle, Skeletal; Oxidation-Reduction; Phosphatidylinositol 3-Kinases; Phosphoproteins; Phosphorylation; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-akt; Risk Factors; Signal Transduction; Triglycerides

To determine the effect of naltrexone (an opiate receptor blocker) on insulin metabolism in postmenopausal women with different insulinemic patterns.. Randomized placebo-controlled study.. Academic research environment.. Forty-one healthy normoinsulinemic or hyperinsulinemic postmenopausal women.. Oral glucose tolerance test (OGTT) before and after 5 weeks of the opioid antagonist (naltrexone, 50 mg/d orally) or the placebo administration; euglycemic-hyperinsulinemic glucose clamp.. Glucose, insulin, and C-peptide plasma levels assessed in fasting condition and during the OGTT. Insulin sensitivity was calculated as total body glucose utilization.. Naltrexone reduced fasting and stimulated insulin response to the glucose load while inducing a significant improvement of the hepatic extraction, only in the hyperinsulinemic patients. No differences were found in the C-peptide pancreatic secretion and in the peripheral insulin sensitivity. No net change in the glycoinsulinemic metabolism was observed in normoinsulinemic patients or in placebo-controlled normoinsulinemic and hyperinsulinemic subjects.. Similar to that reported in premenopausal women, endogenous opioid peptides are involved in the modulation of glycoinsulinemic metabolism in postmenopause. Through a prevalent action on liver insulin metabolism, without any clear improvement of insulin resistance and pancreatic beta-cell function, the chronic administration of naltrexone appears to reduce the hyperinsulinemia in those women with an exaggerated insulin response to the OGTT.

Topics: Blood Glucose; C-Peptide; Fasting; Female; Glucose; Glucose Tolerance Test; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Middle Aged; Naltrexone; Narcotic Antagonists; Pilot Projects; Postmenopause; Treatment Outcome

Modeling analysis of glucose, insulin, and C-peptide following a meal has been proposed as a means to estimate insulin sensitivity (S(i)) and beta-cell function from a single test. We compared the model-derived meal indexes with analogous indexes obtained from an intravenous glucose tolerance test (IVGTT) and hyperglycemic clamp (HGC) in 17 nondiabetic subjects (14 men, 3 women, aged 50 +/- 2 years [mean +/- SE], BMI 25.0 +/- 0.7 kg/m(2)). S(i) estimated from the meal was correlated with S(i) estimated from the IVGTT and the HGC (r = 0.59 and 0.76, respectively; P < 0.01 for both) but was approximately 2.3 and 1.4 times higher (P < 0.05 for both). The meal-derived estimate of the beta-cell's response to a steady-state change in glucose (static secretion index) was correlated with the HGC second-phase insulin response (r = 0.69; P = 0.002), but the estimated rate-of-change component (dynamic secretion index) was not correlated with first-phase insulin release from either the HGC or IVGTT. Indexes of beta-cell function obtained from the meal were significantly higher than those obtained from the HGC. In conclusion, insulin sensitivity and beta-cell indexes derived from a meal are not analogous to those from the clamp or IVGTT. Further work is needed before these indexes can be routinely used in clinical and epidemiological studies.

Topics: Blood Glucose; C-Peptide; Female; Glucose Clamp Technique; Glucose Tolerance Test; Homeostasis; Humans; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Male; Middle Aged; Models, Biological; Postprandial Period; Reference Values

We examined whether plasma concentrations of nonglucose insulin secretagogues are associated with prehepatic insulin secretion rates (ISR) in nondiabetic, insulin-resistant, human immunodeficiency virus (HIV)-infected, lipodystrophic patients (LIPO). Additionally, the negative feedback of insulin on ISR was evaluated. ISR were estimated by deconvolution of plasma C-peptide concentrations during fasting (basal) and during the last 30 min of a 120-min euglycemic insulin clamp (40 mU.m(-2).min(-1)). Eighteen normoglycemic LIPO were compared with 25 normoglycemic HIV-infected patients without lipodystrophy (controls). Thirty minutes before start of the clamp, a bolus of glucose was injected intravenously to stimulate endogenous insulin secretion. Insulin sensitivity index (SiRd) was estimated from glucose tracer analysis. LIPO displayed increased basal ISR (69%), clamp ISR (114%), basal insulin (130%), and clamp insulin (32%), all P < or = 0.001, whereas SiRd was decreased (57%, P < 0.001). In LIPO, ISRbasal correlated significantly with basal insulin, alanine, and glucagon (all r > 0.65, P < 0.01), but not with glucose. In control subjects, ISR(basal) correlated significantly with insulin, glucagon, and glucose (all r > 0.41, P < 0.05), but not with alanine. In LIPO, ISRclamp correlated significantly with clamp free fatty acids (FFA), alanine, triglyceride, and glucagon (all r > 0.51, P < 0.05). In control subjects, ISRclamp correlated with clamp triglyceride (r = 0.45, P < 0.05). Paradoxically, in LIPO, ISRclamp correlated positively with clamp insulin (r = 0.68, P < 0.01), which suggests an absent negative feedback of insulin on ISR. Our data support evidence that lipodystrophic, nondiabetic, HIV-infected patients exhibit increased ISR, which can be partially explained by an impaired negative feedback of insulin on beta-cells and an increased stimulation of ISR by FFA, alanine, triglyceride, and glucagon.

Topics: Adipose Tissue; Adult; Alanine; Anthropometry; Blood Glucose; Body Composition; Body Mass Index; C-Peptide; Feedback; Glucagon; HIV Infections; HIV-Associated Lipodystrophy Syndrome; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Male; Middle Aged; Triglycerides

Hyperproinsulinaemia reflects both beta cell dysfunction and insulin resistance in cross-sectional studies, but it is not known whether changes in proinsulin concentrations are related to insulin resistance over time. As trans10cis12 (t10c12)-conjugated linoleic acid (CLA) supplementation induces insulin resistance in obese men, we used this fatty acid to investigate the effects on plasma proinsulin, insulin, C-peptide and adiponectin concentrations, including their associations with change in insulin sensitivity.. We randomised (double-blind) 57 non-diabetic abdominally obese men to receive either 3.4 g t10c12CLA, CLA-isomer mixture or control oil for 12 weeks. Insulin sensitivity (hyperinsulinaemic-euglycaemic clamp), intact proinsulin, insulin, the proinsulin : insulin ratio, C-peptide, glucose and adiponectin were assessed before and after supplementation.. Supplementation with t10c12CLA increased proinsulin (p<0.01), the proinsulin : insulin ratio (p<0.05) and C-peptide concentrations (p<0.001) in comparison with control subjects. Adiponectin, however, did not change significantly. The change in proinsulin, but not the proinsulin : insulin ratio, was related to impaired insulin sensitivity (r= -0.58, p<0.0001), independently of changes in insulin, C-peptide, glucose, adiponectin and BMI. Conversely, the correlation between insulin sensitivity and specific insulin (r=-0.46, p<0.001) did not remain significant after adjustment for proinsulin. Induced hyperproinsulinaemia was also correlated to adiponectin concentrations ( r= -0.34, p<0.01).. In obese men, t10c12CLA induces hyperproinsulinaemia that is related to impaired insulin sensitivity, independently of changes in insulin concentrations. These results are of clinical interest, as hyperproinsulinaemia predicts diabetes and cardiovascular disease. The use of weight-loss supplements containing this fatty acid is worrying.

Topics: Abdomen; Adiponectin; Adipose Tissue; Analysis of Variance; Blood Glucose; C-Peptide; Dietary Supplements; Double-Blind Method; Drug Administration Schedule; Humans; Hyperinsulinism; Insulin Resistance; Intercellular Signaling Peptides and Proteins; Linoleic Acids, Conjugated; Male; Obesity; Time Factors

Caffeine ingestion decreases the insulin sensitivity index (ISI) for an oral-glucose-tolerance test (OGTT) and decreases insulin-induced glucose disposal in lean male subjects during a hyperinsulinemic clamp.. We examined the effects of caffeine ingestion on insulin and glucose homeostasis in obese men before and after a nutrition and exercise intervention.. Nine sedentary, obese [body mass index (in kg/m(2)): 34.0 +/- 1.0] men who had refrained from exercise and caffeine ingestion for 48 h underwent 2 oral-glucose-tolerance tests (OGTTs). The subjects randomly received caffeine (5 mg/kg) or placebo 1 h before each OGTT. After a 12-wk nutrition and exercise intervention, during which time the subjects avoided dietary caffeine, the OGTTs were repeated.. The intervention resulted in decreases (P < or = 0.05) in body weight (8.5 +/- 1.5 kg), percentage body fat (2.8 +/- 0.7%), and fasting glucose, insulin, and proinsulin concentrations and increases in the ISI for the placebo OGTT (P < or = 0.05). Caffeine caused a greater (P < or = 0.05) OGTT insulin response and a lower (P < or = 0.05) ISI both before and after weight loss. The proinsulin-insulin ratio indicated that neither weight loss nor caffeine affected the nature of the beta cell secretion of insulin.. A nutrition and exercise intervention improved, whereas caffeine ingestion impaired, insulin-glucose homeostasis in obese men. The results are consistent with previous findings that caffeine ingestion contributes to insulin resistance.

Topics: Administration, Oral; Adult; Area Under Curve; Blood Glucose; C-Peptide; Caffeine; Central Nervous System Stimulants; Diet, Reducing; Double-Blind Method; Exercise; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Lactic Acid; Male; Obesity; Proinsulin; Weight Loss; Xanthines

In spite of indisputable benefits, the use of antiretroviral therapy is associated with multiple metabolic complications. Switching to simpler regimens might maintain viral suppression, improve metabolic side effects, and provide insight into the pathogenesis of these complications. Our objective was to carefully characterize the virological and metabolic effects of switching from a successful protease inhibitor (PI)-based antiretroviral regimen to a nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimen with nevirapine (NVP). Forty patients, taking their first successful (less than 40 HIV RNA copies/ml) PI-based regimen, switched their PI to NVP. If patients did not tolerate NVP, substitution with efavirenz was allowed. The duration of the study was 48 weeks. At 12 weeks intervals subjects had multiple virological and metabolic parameters including glucose, insulin, C-peptide, glucagon, proinsulin, blood lipids, and lipoproteins. A subgroup of 18 patients also had body composition evaluations with DEXA scans and MRIs of the abdomen and the thighs as well as insulin tolerance tests. Ninety-five percent of the patients maintained viral suppression (95% CI 88-100%); only one patient failed and another developed hepatitis. There were improvements in glucose (decreased fasting glucose, insulin, and improved insulin tolerance) and lipid metabolism (decreased triglycerides and increased HDL), but no changes in body composition and bone mineral density. Our study supports a pathogenic role for PIs in the development of hypertriglyceridemia and insulin resistance, but a more limited role in the fat redistribution syndrome.

Topics: Alkynes; Anti-HIV Agents; Benzoxazines; Blood Glucose; Body Composition; Bone Density; C-Peptide; Cyclopropanes; Drug Therapy, Combination; Female; Glucagon; HIV; HIV Infections; HIV Protease Inhibitors; Humans; Insulin; Insulin Resistance; Lipids; Lipoproteins; Male; Nevirapine; Oxazines; Pilot Projects; RNA, Viral; Viral Load

Insulin resistance is present in nearly all patients with liver cirrhosis, but its etiology remains unclear. Recent studies have shown that tumor necrosis factor-alpha (TNF-alpha) system is involved in the insulin resistance of human obesity. Serum concentrations of TNF-alpha, and 2 soluble TNF receptors (sTNF-RI and sTNF-RII) are increased in cirrhotic patients. This study explored whether TNF-alpha system activity was associated with insulin resistance in liver cirrhosis. A total of 26 male nondiabetic patients with liver cirrhosis (mean age, 59 +/- 3 years; body mass index, 23.7 +/- 0.4 kg/m2) and 25 male control subjects (age, 65 +/- 2 years; body mass index, 24.4 +/- 0.5 kg/m2) were studied. Serum insulin, c-peptide, TNF-alpha, sTNF-RI, and sTNF-RII concentrations were determined by immunoassay. The insulin resistance was estimated by homeostasis assessment model (HOMA IR). In cirrhotic patients, serum levels of TNF-alpha, sTNF-RI, and sTNF-RII were all higher than those in the controls, and correlated with disease severity. Also, the serum c-peptide, insulin concentrations, and the HOMA IR were higher in liver cirrhosis with comparable blood glucose to control subjects, indicating a degree of insulin insensitivity. In the whole population, there was a moderate, but statistically significant, correlation between serum sTNF-RI or sTNF-RII, and HOMA IR. Also, body mass index was associated with HOMA IR, but not related to serum TNF-alpha, and sTNF-Rs levels. In multiple regression analysis, both sTNF-RII and body mass index jointly contributed to 30% variance of HOMA IR. Our study demonstrated that elevated sTNF-RII levels were associated with insulin resistance in liver cirrhosis. The data indicated that TNF-alpha system might play a role in modulating insulin action in patients with liver cirrhosis.

Topics: Aged; Aging; Body Mass Index; C-Peptide; Cytokines; Homeostasis; Humans; Immunoassay; Insulin; Insulin Resistance; Interleukin-6; Liver Cirrhosis; Male; Middle Aged; Receptors, Tumor Necrosis Factor; Regression Analysis

This study assessed whether glucose-dependent insulin secretion and overall counterregulatory response are preserved during hypoglycemia in the presence of exenatide. Twelve healthy fasted volunteers were randomized in a triple-blind crossover study to receive either intravenous exenatide (0.066 pmol. kg(-1). min(-1)) or placebo during a 270-min stepwise hyperinsulinemic-hypoglycemic clamp (insulin infusion 0.8 mU. kg(-1). min(-1)). Plasma glucose was clamped sequentially at 5.0 (0-120 min), 4.0 (120-180 min), 3.2 (180-240 min), and 2.7 mmol/l (240-270 min). At 270 min, insulin infusion was terminated and plasma glucose increased to approximately 3.2 mmol/l. The time to achieve plasma glucose >/=4 mmol/l thereafter was recorded. Insulin secretory rates (ISRs) and counterregulatory hormones were measured throughout. Glucose profiles were superimposable between the exenatide and placebo arms. In the presence of euglycemic hyperinsulinemia, ISRs in the exenatide arm were approximately 3.5-fold higher than in the placebo arm (353 +/- 29 vs. 100 +/- 29 pmol/min [least-square means +/- SE]). However, ISRs declined similarly and rapidly at all hypoglycemic steps (

Topics: Adult; Blood Glucose; C-Peptide; Cross-Over Studies; Exenatide; Fatty Acids, Nonesterified; Glucagon; Humans; Hydrocortisone; Hypoglycemia; Infusions, Intravenous; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Male; Peptides; Venoms

We investigated effects of weight loss from diet and exercise regimen in obese subjects with normal fasting plasma glucose or impaired glucose tolerance (IGT) on insulin release capacity and insulin sensitivity. Eight subjects were recruited among visceral obesity patients (4 men, 4 women; age range, 24 to 57 years; body mass index [BMI], 32.8 to 60.3 kg/m(2)). All were admitted to Chiba University Hospital for 2 weeks, were treated with a tapering 5,023 to 2,930 kJ diet, and were given exercise equivalent to 628 kJ/d. For assessments, we used a combination of C-peptide secretion rate determination and minimal model analysis as previously reported. BMI and visceral fat area (V) significantly decreased (BMI on initiation v after intervention, 43.0 +/- 3.2 v 40.3 +/- 3.1 kg/m(2), P <.05; V, 224 +/- 22 v 188 +/- 22 cm(2); P <.05). Fasting immunoreactive insulin (F-IRI) and leptin concentrations decreased significantly. Capacity for insulin release in response to glucose increased in all subjects (first-phase insulin secretion [CS1], 4.66 +/- 4.05 v 6.81 +/- 4.57 ng/mL/5 min, P <.05), but the insulin sensitivity index (S(i)) did not change significantly. These data suggest that weight reduction early in development of type 2 diabetes can oppose progression of diabetes by improving capacity for insulin release.

Topics: Adipose Tissue; Adult; Blood Glucose; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Exercise Therapy; Female; Glucose Intolerance; Humans; Insulin; Insulin Resistance; Lipids; Male; Middle Aged; Models, Biological; Obesity; Weight Loss

We examined the metabolic effects of rosiglitazone therapy on glucose control, insulin sensitivity, insulin secretion, and adiponectin in first-degree relatives of African Americans with type 2 diabetes (DM) with impaired glucose tolerance (IGT) and DM for 3 months. The study was comprised of 12 first-degree relatives with IGT, 17 newly diagnosed DM, and 19 healthy relatives with normal glucose tolerance (NGT). Oral glucose tolerance test (OGTT) was performed before and after 3 months of rosiglitazone therapy (4 to 8 mg/d) in patients with IGT and DM. Serum glucose, insulin, C-peptide, and adiponectin levels were measured before and 2 hours during OGTT in the NGT and patients with IGT and DM. Insulin resistance index (HOMA-IR) and beta-cell function (HOMA-%B) were calculated in each subject using homeostasis model assessment (HOMA). Rosglitazone improved the overall glycemic control in the IGT and DM groups. Following rosiglitazone, the beta-cell secretion remained unchanged, while HOMR-IR was reduced in DM by 30% (4.12 +/- 1.95 v 6.33 +/- 3.54, P < .05) and the IGT group (3.78 +/- 2.45 v 4.81 +/- 3.49, P = not significant [NS]). Mean plasma adiponectin levels were significantly (P < .05) lower in the DM (6.74 +/- 1.95 microg/mL) when compared with the NGT group(9.61 +/- 5.09). Rosiglitazone significantly (P < .001) increased adiponectin levels by 2-fold in patients with IGT (22.2 +/- 10.97 microg/mL) and 2.5-fold greater in DM (15.68 +/- 8.23 microg/mL) at 3 months when compared with the 0 month. We conclude that adiponectin could play a significant role (1) in the pathogenesis of IGT and DM and (2) the beneficial metabolic effects of thiazolidinediones (TZDs) in high-risk African American patients.

Topics: Adiponectin; Adult; Black or African American; Blood Glucose; Blood Pressure; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Glucose Tolerance Test; Homeostasis; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Intercellular Signaling Peptides and Proteins; Islets of Langerhans; Lipids; Longitudinal Studies; Middle Aged; Risk Factors; Rosiglitazone; Thiazolidinediones

A gut insulinotropic peptide, glucagon-like peptide-1 (GLP-1), when given continuously subcutaneously, has been shown to be an effective agent to treat type 2 diabetes. Because of inactivation by dipeptidyl peptidase IV (DPP IV), it has a very short half-life (90-120 s), hence the need for continuous administration. Exendin-4 is an agonist of the GLP-1 receptor. It is not a substrate for DPP IV, and we previously demonstrated that intravenous administration has potent insulinotropic properties in type 2 diabetic volunteers. We evaluated the efficacy of bolus subcutaneous exendin-4 in insulin-naive type 2 diabetic volunteers. Ten patients aged 44-72 yr with mean fasting glucose levels of 11.4 +/- 0.9 mmol/l were enrolled, and daily or twice-daily bolus subcutaneous exendin-4 was self-administered for 1 mo. Glycosylated hemoglobin, multiple daily capillary blood glucose, beta-cell sensitivity to glucose, and peripheral tissue sensitivity to insulin were compared before and after treatment. The greatest decline in capillary blood glucose was seen before bed, with a drop from 15.5 to 9.2 mmol/l (P < 0.0001). Glycosylated hemoglobin improved significantly with treatment, from 9.1 to 8.3% (P = 0.009). beta-Cell sensitivity to glucose was improved, as assessed by C-peptide levels during a hyperglycemic clamp. No significant adverse effects were noted or reported. Our data suggest that, even with this short duration of therapy, exendin-4 treatment had a significant effect on glucose homeostasis.

Topics: Aged; Blood Glucose; Body Composition; C-Peptide; Diabetes Mellitus, Type 2; Exenatide; Fatty Acids, Nonesterified; Female; Glucagon; Glucose; Glucose Clamp Technique; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Injections, Subcutaneous; Insulin; Insulin Resistance; Islets of Langerhans; Male; Middle Aged; Peptides; Venoms

We investigated the changes in the cardiovascular system [resting blood pressure (BP) and heart rate (HR), measured by means of a 24-h ambulatory BP and a holter-electrocardiogram (ECG)], glycemic parameters, and lipid metabolism of subjects suffering from metabolic syndrome during a 3-week sojourn at 1,700 m in the Austrian Alps. A total of 22 male subjects with metabolic syndrome were selected. Baseline investigations were performed at Innsbruck (500 m above sea level). During the 3-week altitude stay the participants simulated a holiday with moderate sports activities. Examinations were performed on days 1, 4, 9, and 19. After returning to Innsbruck, post-altitude examinations were conducted after 7-10 days and 6-7 weeks, respectively. The 24-h ambulatory BP and holter ECG revealed a decrease in average HR, BP, and rate pressure product (RPP: systolic blood pressure x HR) after 3 weeks of altitude exposure. In some patients, an increase in premature ventricular beats was observed at the end compared to the beginning of the exposure to moderate altitude. The ECG revealed no ischemic ST-segment changes. Maximal physical capacity as measured by symptom-limited maximal cycle ergometry tests remained unchanged during the study. Six weeks after the altitude exposure the blood pressure increased again and returned to pretest levels. The Homeostasis Model Assessment index, which is a measure of insulin resistance, decreased significantly and glucose concentrations obtained after an oral glucose tolerance test were significantly lower after the stay at altitude compared to the basal values. We conclude that after a 3-week exposure to moderate altitude, patients with metabolic syndrome (1) tolerated their sojourn without any physical problems, (2) exhibited short-term favorable effects on the cardiovascular system, and (3) had significant improvements in glycemic parameters that were paralleled by a significant increase in high-density-lipoprotein-cholesterol.

Topics: Adaptation, Physiological; Adult; Aged; Altitude; Austria; Blood Glucose; Blood Pressure; C-Peptide; Cardiovascular Physiological Phenomena; Diastole; Electrocardiography, Ambulatory; Exercise Test; Heart Rate; Hemoglobins, Abnormal; Homeostasis; Humans; Insulin; Insulin Resistance; Male; Metabolic Diseases; Middle Aged; Physical Exertion; Pilot Projects; Systole

Eight patients with end stage renal disease (ESRD) on chronic hemodialysis (CHD) treatment were supplemented with 1 g L-carnitine intravenously (i.v.) after each dialysis session for one month. A Tolbutamide test was done and blood sugar (BS), serum C-peptide (CP) were measured at 0, 20 and 60 minutes, as well as the plasma L-carnitine level before and after treatment. Delta CP and the area under CP curve were ascertained. After L-carnitine application delta CP was significantly increased (1.33 +/- 0.63 vs. 2.24 +/- 1.0 nmol/L; p<0.05) and also the area of the stimulated secretion under the CP curve (14.93 +/- 11.11 vs. 36.88 +/- 25.36 nmol/L x 60 min.; p<0.05). The fasting BS-level was significantly lower after the treatment--3.85 +/- 0.43 vs. 4.76 +/- 1.02 mmol/L; p<0.05 and plasma L-carnitine level significantly increased (72.8 +/- 43.2 vs. 35.2 +/- 18.3 mcmol/L; p<0.05) Improving the oxidative processes in peripheral tissues, L-carnitine increases the peripheral effectiveness of insulin and relieves the overstretched beta-cell apparatus.

Topics: Adult; Blood Glucose; C-Peptide; Carbohydrate Metabolism; Carnitine; Drug Administration Schedule; Drug Therapy, Combination; Female; Humans; Hypoglycemic Agents; Insulin Resistance; Islets of Langerhans; Kidney Failure, Chronic; Male; Middle Aged; Renal Dialysis; Time Factors; Tolbutamide

We examined the long-term metabolic effects of a potent sulfonylurea (SU), glipizide gastrointestinal therapeutic system (glipizide GITS) in normal glucose-tolerant (NGT), first-degree relatives of African American patients with type 2 diabetes in a randomized, placebo-controlled, double-blind manner for 24 months and 6 months after discontinuation of glipizide GITS. Fifty NGT African American first-degree relatives (n = 50)) were randomized to receive either glipizide GITS (GITS, 5 mg/d) or identical placebo (PLAC). The NGT consisted of NGT/GITS (n = 16; mean age, 43.1 +/- 8.7years; body mass index [BMI], 34.8 +/- 10) and NGT/PLAC (n = 34; 45.5 +/- 9.7 years; BMI, 31.3 +/- 3.1years). Each of the subjects underwent an oral glucose tolerance test (OGTT) and frequently sampled intravenous glucose tolerance test (FSIGT) at baseline and at yearly intervals for 2 years. Insulin sensitivity (Si) and glucose effectiveness (Sg) were determined by Bergman's minimal model method. Hepatic insulin extraction (HIE) was calculated as the molar ratio of C-peptide and insulin. The mean fasting serum glucose, insulin, and C-peptide levels in the NGT/GITS were not different from that of the NGT/PLAC. After oral glucose challenge, mean serum glucose responses slightly increased (P = not significant [NS]) at 12 and 24 months in the NGT/GITS group when compared with the baseline, 0 month, but remained unchanged in the NGT/PLAC group. In addition, serum insulin and C-peptide responses significantly increased in the NGT/GITS group, but were unchanged in the NGT/PLAC group at 12 and 24 months versus 0 month. The HIE, during OGTT, decreased by 30% from the baseline (0 month) values in the NGT/ GITS, but remained unchanged in the NGT/PLAC group at 12 and 24 months. Mean Si decreased by 30% from the baseline in the NGT/GITS group by 12 and 24 months, but remained unchanged in the NGT/PLAC group. However, the disposition index (DI) remained normal in the NGT/GITS and the NGT/PLAC groups. The DI data in the NGT/GITS group suggested that beta cells maintained the ability to compensate for the lower Si during the chronic GITS administration in our high risk African Americans. Chronic GITS was well tolerated without any symptoms of either hypoglycemia or weight gain in the NGT/IGTS group. After discontinuation of GITS, the altered metabolic parameters significantly improved, returning to baseline values in the NGT/IGTS group in 6 months. In summary, chronic glipizide GITS administration

Topics: Adult; Black People; Blood Glucose; C-Peptide; Delayed-Action Preparations; Diabetes Mellitus, Type 2; Double-Blind Method; Female; Follow-Up Studies; Glipizide; Glucose Tolerance Test; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Liver; Longitudinal Studies; Male; Middle Aged

It has been suggested that circulating free IGF-I participates in glucose homeostasis and that IGFBP-1 reflects changes in insulin sensitivity. To study this further, we examined 10 healthy, nonobese subjects under standardized conditions for 24 h with and without an intravenous infusion of glucose, the latter in order to augment insulin sensitivity. Serum was collected every 2 h for analysis of free and total IGFs, IGFBP-1, - 2 and - 3 and the acid labile subunit (ALS). Insulin sensitivity was estimated at the end of each 24-h study period by use of the hyperinsulinaemic euglycaemic clamp technique.. Glucose infusion resulted in mild hyperglycaemia (P < 0.0001), a reduction in IGFBP-1 by approximately 40% (P < 0.0003), and increased insulin and C-peptide levels (P < 0.0001). Glucose infusion also increased insulin sensitivity (P < 0.003). However, despite the reduction in IGFBP-1, glucose infusion did not increase free IGF-I over the control level, and free IGF-II was slightly reduced (P < 0.02). Irrespective of glucose infusion, free IGF-I and -II remained stable during daytime (i.e. they were unresponsive to meal-related changes in plasma glucose), but both free fractions decreased during the night, reaching nadir at 04.00 h. None of the other members of the IGF system showed any relationship with plasma glucose levels. Finally, we failed to observe any relationship between changes in insulin sensitivity and the circulating IGF system.. We found no evidence that the circulating IGF system is involved in meal-related blood glucose regulation or that it reflects short-term changes in insulin sensitivity in healthy, nonobese subjects. However, we cannot preclude that the observed changes in circulating IGFBP-1 may affect the glucose-lowering effect of IGF-I and -II at the local tissue level.

Topics: Adult; Area Under Curve; Blood Glucose; Blood Proteins; C-Peptide; Circadian Rhythm; Female; Glucose; Glucose Clamp Technique; Growth Hormone; Homeostasis; Humans; Infusions, Intravenous; Insulin; Insulin Resistance; Insulin-Like Growth Factor Binding Proteins; Insulin-Like Growth Factor I; Insulin-Like Growth Factor II; Male; Statistics, Nonparametric

We examined the simultaneous effects of a 24-h low-grade Intralipid infusion on peripheral glucose disposal, intracellular glucose partitioning and insulin secretion rates in twenty young men, by 2-step hyperinsulinemic euglycemic clamp [low insulin clamp (LI), 10 mU/m(2) x min; high insulin clamp (HI), 40 mU/m(2) x min], 3-(3)H-glucose, indirect calorimetry, and iv glucose tolerance test. Free fatty acid concentrations were similar during basal steady state but 3.7- to 13-fold higher during clamps. P-glucagon increased and the insulin/glucagon ratio decreased at both LI and HI during Intralipid infusion. At LI, glucose oxidation decreased by 10%, whereas glucose disposal, glycolytic flux, glucose storage, and glucose production were not significantly altered. At HI, glucose disposal, and glucose oxidation decreased by 12% and 24%, respectively, during Intralipid infusion. Glycolytic flux, glucose storage, and glucose production were unchanged. Insulin secretion rates increased in response to Intralipid infusion, but disposition indices (DI = insulin action.insulin secretion) were unchanged. In conclusion, a 24-h low-grade Intralipid infusion caused insulin resistance in the oxidative (but not in the nonoxidative) glucose metabolism in young healthy men. Moreover, insulin hypersecretion perfectly countered the free-fatty acid-induced insulin resistance. Future studies are needed to determine the role of a prolonged moderate lipid load in subjects at increased risk of developing diabetes.

Topics: Adult; Area Under Curve; Blood Glucose; C-Peptide; Fat Emulsions, Intravenous; Fatty Acids, Nonesterified; Glucagon; Glucose; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Male; Oxidation-Reduction

Insulin resistance decreases blood flow and volume in fat tissue. We hypothesised that fat tissue nutritive blood flow and volume, and thereby water content, would increase during weight loss and weight maintenance in obese persons.. Longitudinal clinical intervention with a 9-week very-low-calorie diet (VLCD) followed by one year of weight maintenance.. Obese men (n=13) and women (n=14) with the metabolic syndrome.. Water content of abdominal subcutaneous fat tissue as estimated by a sensor on the skin surface measuring the dielectric constant at 300 MHz. Anthropometric measures of fatness and fat distribution. Biochemical measures related to insulin resistance.. Subjects lost 14.5+/-3.4% of body weight during the VLCD, and generally sustained this weight loss during weight maintenance. Insulin sensitivity as estimated by an index (qualitative insulin sensitivity check index) increased during the VLCD, and remained increased throughout weight maintenance. The dielectric constant increased from 23.3+/-2.3 to 25.0+/-2.1 (P<0.001) during the VLCD, and further to 27.8+/-1.9 (P<0.001) during weight maintenance, indicating an increase in the water content of subcutaneous fat. The increase in subcutaneous fat water content did not correlate with weight loss and other measures of adiposity during the VLCD, but there was an inverse correlation that strengthened in significance from baseline to 6, 9 and 12 mo (r=-0.32 to -0.64, P=0.079-0.002). Increases in subcutaneous fat water content also correlated with improvements in insulin sensitivity at 6, 9 and 12 months of weight maintenance (r=0.34-0.54, P=0.094-0.006).. Water content of abdominal subcutaneous adipose tissue increases with weight loss in obese persons with the metabolic syndrome, and may reflect increased subcutaneous fat tissue nutritive blood flow. The increase in water content correlates with the increase in insulin sensitivity, suggesting that weight loss and consequent improved insulin sensitivity could mediate the increase in abdominal subcutaneous fat hydration.

Topics: Abdomen; Adipose Tissue; Adult; Blood Glucose; Body Composition; Body Water; C-Peptide; Cholesterol, HDL; Double-Blind Method; Energy Intake; Female; Humans; Insulin; Insulin Resistance; Lipoproteins, LDL; Longitudinal Studies; Male; Middle Aged; Obesity; Subcutaneous Tissue; Weight Loss

We have previously reported the beneficial effects of Caiapo, the extract of white-skinned sweet potato (ipomoea batatas), on fasting plasma glucose, as well as on total and low-density lipoprotein (LDL) cholesterol in type 2 diabetic patients. The present study aimed to describe the underlying mechanism responsible for the improvement in metabolic control following administration of Caiapo in those type 2 subjects. A total of 18 male patients (age=58+/-8 years, body mass index [BMI]=27.7+/-2.7 kg/m2, mean +/- SEM) treated only by diet were randomized into 3 groups (placebo, low-dose Caiapo, 2 g/d, and high-dose, 4 g/d). Parameters related to glucose tolerance, glucose disappearance, and insulin secretion were obtained by performing both frequently sampled intravenous glucose tolerance test (FSIGT) and oral glucose tolerance test (OGTT) before and after 6 weeks of treatment with Caiapo. Following treatment with high dose Caiapo, insulin sensitivity significantly ameliorated when assessed both with OGTT (from 308+/-13 mg/min/m2 to 334+/-10, P=.048) and FSIGT (from 1.21+/-0.32 10(4) min(-1)/(microU/mL) to 1.73+/-0.40, P=.021). Improvement of insulin sensitivity with the low dose was observed only with the FSIGT (from 2.02+/-0.70 10(4) min(-1)/(microU/mL) to 2.76+/-0.89, P<.05). Glucose effectiveness did not change. While no changes in glucose tolerance were observed in the placebo and low-dose groups, it increased from 0.85+/-0.13 %min(-1) to 1.46+/-0.13 (P<.02) in patients on high dose. No significant changes were seen in any of the parameters related to insulin dynamics: insulin secretion (from C-peptide), distribution, clearance, and hepatic extraction remained virtually the same after the treatment. In conclusion, short-term treatment with 4 g/d of the nutraceutical Caiapo consistently improved metabolic control in type 2 diabetic patients by decreasing insulin resistance without affecting body weight, glucose effectiveness, or insulin dynamics. No side effects related to the treatment were observed. Thus these results indicate that Caiapo could potentially play a role in the treatment of type 2 diabetes.

Topics: Blood Glucose; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Double-Blind Method; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Ipomoea batatas; Kinetics; Male; Middle Aged; Phytotherapy; Placebos; Plant Extracts; Prospective Studies

We studied the effect of a low-grade short- and long-term 20% Intralipid infusion (0.4 mL(-1) x kg(-1) x h(-1)) on insulin secretion and insulin action in 15 elderly obese men; 7 glucose intolerant first-degree relatives of type 2 diabetic patients (impaired glucose tolerance [IGT] relatives) and 8 healthy controls of similar age and body mass index (BMI). Intravenous glucose tolerance test (IVGTT) and a graded glucose infusion (dose-response test [DORE]) were performed to determine first phase insulin response and to explore the dose response relationship between glucose concentration and insulin secretion rates (ISR). ISR were calculated by deconvolution of plasma C-peptide concentrations. Insulin action was determined by performing a 120-minute hyperinsulinemic euglycemic clamp. All tests were performed 3 times, preceded by 0, 2, or 24 hours Intralipid infusion. Disposition indices (DI) were calculated for the IVGTT. Insulin action was reduced 25% after 2 and 24 hours Intralipid infusion in both groups. In IGT relatives, the beta-cell responsiveness to glucose (measured during DORE) decreased after 2 and 24 hours Intralipid infusion (P=.02), whereas first phase insulin response (measured during IVGTT) decreased after 24 hours Intralipid infusion. Insulin secretion measured during DORE and IVGTT was not affected by Intralipid infusion in controls. DI decreased after 2 and 24 hours Intralipid infusion in the total study population. In conclusion, insulin resistance induced by low-grade short- and long-term Intralipid infusion is not balanced by an adequate compensatory increase in insulin secretion in IGT relatives or in matched controls. IGT relatives appear to be more sensitive to the deleterious effects of low-grade fat infusion on insulin secretion than normal glucose tolerant control subjects.

Topics: Blood Glucose; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Fat Emulsions, Intravenous; Fatty Acids, Nonesterified; Glucose Clamp Technique; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Male; Middle Aged; Obesity; Triglycerides

The aim of the study was to evaluate the expression of tumor necrosis factor (TNF)-alpha protein in the subcutaneous and visceral adipose tIssue in correlation with adipocyte cell Volume, serum TNF-alpha, soluble TNF-receptor-2 (sTNFR-2) and indirect parameters of insulin resistance in overweight/obese and lean healthy persons.. A cross-sectional case-control study was used.. Twenty-eight overweight/obese probands with normal glucose tolerance (BMI>27 kg/m(2)) and 15 lean people (BMI<25 kg/m(2)), all of them undergoing planned surgical operation, participated in the study.. Two to four grams of subcutaneous and visceral adipose tIssue were removed and studied using semi-quantitative immunohistochemical staining of the TNF-alpha protein. Serum TNF-alpha, sTNFR-2 (ELISA) and fasting C-peptide (RIA) were measured.. TNF-alpha protein was expressed in adipocytes of both depots. The expression was evaluated visually and found to be greater in the obese patients. Significantly higher serum TNF-alpha (5.58+/-0.87 pg/ml vs 4.21+/-0.55, mean+/-s.d., P<0.01, Mann-Whitney) and sTNFR-2 levels (7.84+/-3.56 ng/ml vs 4.59+/-1.35, P=0.005) were found in the obese subgroup in correlation with the fasting C-peptide level (r=0.49, P=0.003; and r=0.74, P=0.001) and the C-peptide/ blood glucose ratio (r=0.47, Spearman, P=0.005; and r=0.70, P=0.001). The cell Volume of both adipocyte depots was found to have a significant positive correlation with serum TNF-alpha and sTNFR-2 levels in the total group of patients (subcutaneous: r=0.52, P=0.0003; r=0.69, P<0.0001; visceral: r=0.65, P<0.0001; r=0.63, P<0.0001) and in both subgroups.. Adipocyte cell Volume of both the subcutaneous and visceral fat depots may be determinants of TNF-alpha, sTNFR-2 production and obesity-linked insulin resistance.

Topics: Adipocytes; Adipose Tissue; Adult; C-Peptide; Cell Size; Female; Humans; Insulin Resistance; Linear Models; Male; Middle Aged; Receptors, Tumor Necrosis Factor; Tumor Necrosis Factor-alpha

Oral contraceptives slightly deteriorate insulin sensitivity. The present study investigated whether they may further unbalance the glucose metabolism of lean women with polycystic ovary syndrome (PCOS). Women with PCOS were assigned to receive for 6 months the biphasic association of 40/30 micro g ethinyl estradiol (EE) and 25/125 micro g desogestrel (DSG; n = 10) or the monophasic association of 35 micro g EE and 2 mg cyproterone acetate (CPA; n = 10). Glucose tolerance was investigated by an oral glucose tolerance test (OGTT). Glucose utilization dependent [insulin sensitivity (SI)] or independent (Sg) of insulin was investigated by the minimal model method applied to a frequently sampled iv glucose tolerance test. EE/DSG increased the response of C peptide to OGTT (1413 +/- 113 vs. 2053 +/- 213 area under the curve; P < 0.009) and the C peptide/insulin ratio (0.085 +/- 0.01 vs. 0.134 +/- 0.01 area under the curve; P < 0.003). It also increased the Sg (0.026 +/- 0.002 vs. 0.034 +/- 0.003; P < 0.04) and decreased the SI (2.40 +/- 0.26 vs. 1.68 +/- 0.27; P < 0.01). EE/CPA did not modify responses to OGTT of glucose, insulin, C peptide, or C peptide/insulin ratio. It did not modify Sg and significantly increased SI (1.47 +/- 0.38 vs. 3.27 +/- 0.48; P < 0.04). The present study indicates that EE/CPA improves SI, whereas EE/DSG impairs SI, but improves insulin clearance. The long-term metabolic effects of these two compounds on women with PCOS require further investigations.

Topics: Adult; Anthropometry; Blood Glucose; Body Weight; C-Peptide; Contraceptives, Oral, Hormonal; Cyproterone Acetate; Desogestrel; Ethinyl Estradiol; Female; Glucose; Glucose Tolerance Test; Hormones; Humans; Insulin; Insulin Resistance; Polycystic Ovary Syndrome

African Americans (AA) have greater prevalence of type 2 diabetes mellitus (DM), and nondiabetic AA have demonstrated increased insulin resistance when compared with Caucasian Americans (CA). The objective of this study was to examine the impact of chronic use of an insulin sensitizer on glucose metabolism in normal glucose tolerant AA at risk for DM (previous gestational diabetes mellitus [GDM] or first-degree relative with DM). Forty-nine high-risk AA received 200 mg/d troglitazone (TRO) versus 81 age-, weight-, and body mass index (BMI)-matched high-risk AA who received placebo (PLA) for 24 months. Yearly anthropometric measurements, oral glucose tolerance test (OGTT) and frequently sampled intravenous glucose tolerance test (FSIVGTT) were performed. Biochemical parameters were monitored quarterly. There was no significant change in anthropometric measurements over 24 months in TRO versus PLA. There were no significant differences in serum glucose, insulin, or C-peptide incremental area under the curve (AUC) in TRO versus PLA at baseline or 24 months for OGTT and FSIVGTT. The insulin sensitivity (S(I)) for TRO and PLA increased from baseline to 24 months by 17% and 16%, respectively. The TRO demonstrated a 26% increase in insulin/glucose ratio versus 1% increase in the PLA at 24 months. The disposition index (DI) increased 33% from baseline in TRO versus 21% increase in PLA. Modest improvement in glucose metabolism was seen in TRO when compared with PLA. TRO was well tolerated without significant reported adverse events. Based on our current data, the treatment of normal glucose tolerant high-risk AA with thiazolidinedione (TZD) may be beneficial to "reset" and protect glucose metabolism by improving insulin responses. Because of the potential drug-related risks associated with use of TZD and the proven positive impact of diet and exercise in prevention of DM, studies of longer duration with examination of other potentially beneficial parameters, such as cardiovascular indices and inflammatory markers will be necessary to justify the cost in the nondiabetic population.

Topics: Adult; Black People; Blood Glucose; Body Constitution; Body Mass Index; C-Peptide; Chromans; Diabetes Mellitus, Type 2; Double-Blind Method; Female; Genetic Predisposition to Disease; Glucose Intolerance; Homeostasis; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Lipids; Male; Placebos; Skinfold Thickness; Thiazoles; Thiazolidinediones; Troglitazone

The aim of this study was to evaluate the impact of a three-month continuous administration of oral E2, alone, or combined with 2 different dosages of dydrogesterone, on the glucose tolerance and insulin sensitivity in postmenopausal women. In a prospective placebo-controlled study, 43 normal weight and normoinsulinemic women were randomized to receive either 2 mg of oral 17beta E2 daily (group A), or 2 mg E2 daily plus 5 mg daily oral dydrogesterone, from day 14 to 28, in a sequentially combined regimen (group B), or 2 mg of E2 and 10 mg dydrogesterone in the same sequentially combined regimen (group C) or placebo for 12 weeks. An OGTT and a euglycemic hyperinsulinemic clamp were performed before and after treatment. Serum glucose and insulin concentrations were measured both in fasting conditions and after OGTT. C-peptide pancreatic secretion was tested only in fasting conditions. Total body glucose utilization (M), for insulin sensitivity evaluation, was determined in each subject. Postmenopausal women treated with unopposed 17beta E2 (group A) showed a slight but statistically significant decrease of insulin sensitivity (p<0.05). A more marked deterioration of the same parameter was observed in the 2 groups treated with E2 plus dydrogesterone (group B and group C: p<0.01). Post hoc testing for the percent change from baseline indicated that group A significantly differed from group C (p<0.05) and all treated groups significantly differed from the placebo group (p<0.01). Finally, after treatment in group C, a significant reduction of insulin and an increase of glucose responses to OGTT (p<0.01) were observed. These results indicate that, in a short-term period, the use of 17beta E2 and overall 17beta E2 plus dydrogesterone, even with the reduction of insulin plasma levels, might cause a decrease in insulin sensitivity in normal weight and normoinsulinemic post-menopausal women.

Topics: Blood Glucose; C-Peptide; Dydrogesterone; Estradiol; Estrogen Replacement Therapy; Female; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Middle Aged; Placebos; Postmenopause; Prospective Studies

Acarbose is an oral antidiabetic mainly acting on postprandial blood glucose, inhibiting alphaglucosidase. Through this mechanism, it could improve the peripheral insulin sensitivity and/or increase the insulin secretion. The aim of the present study is to assess the therapeutic efficacy of Acarbose in obese type 2 diabetic patients on both insulin resistance and insulin secretion.. 17 obese non insulin-dependent diabetic patients, well controlled with diet alone were randomized into 2 groups: acarbose (2 x 50 mg) or placebo during 16 weeks. A glucagon test allowed to evaluate insulin secretion before and after treatment as well as a triple test (glucose-insulin-somatostatin) with indirect calorimetry allowed to evaluate insulin sensitivity.. A significant improvement in post-prandial plasma glucose was detected only in the Acarbose group (8.0 +/- 0.5 mmol/l before vs 6.5 0.5 mmol/l after, p<0.05). Basal C-peptide secretion was similar between groups and remained unchanged after treatment. However, stimulated insulin secretion was significantly increased by 30%, p<0.05, in the Acarbose group while no change was detected in the placebo group. Interestingly, the group receiving Acarbose disclosed a 15% reduction in insulin resistance (15.0 +/- 1.8 mmol/l before vs 12.8 +/- 1.4 mmol/l after).. Our results show that a treatment with Acarbose is efficient even in diabetic patients presenting a good glucose control without any other associated treatment. By decreasing post-prandial blood glucose, acarbose improves both insulin sensitivity and secretion.

Topics: Acarbose; Blood Glucose; C-Peptide; Cholesterol; Diabetes Mellitus; Diabetes Mellitus, Type 2; Double-Blind Method; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Obesity; Placebos; Research Design

The insulinotropic hormone, glucagon-like peptide-1 (GLP-1), is being examined as a potential new agent for treatment in type 2 diabetic patients. Whereas the insulinotropic properties of this peptide are well established, another property of the hormone, an insulinomimetic effect per se, is controversial. In the normal glucose-tolerant lean state, it is difficult to demonstrate an insulinomimetic effect. The current study was conducted to examine whether GLP-1 has insulinomimetic effect in the obese state. Ten obese volunteers (body mass index, 34.6 +/- 0.8 kg/m(2)), whose ages were 32.5 +/- 3.0 yr, participated in two euglycemic clamp studies (n = 20 clamps) for 120 min. Five of the volunteers were females. The initial clamp was performed with a primed (0-10)-constant (10-60) infusion of GLP-1 at a final rate of 1.5 pmol x kg(-1) x min(-1). At 60 min, the GLP-1 infusion was terminated, and euglycemic was maintained from 60-120 min. After the GLP-1 study, each individual's plasma insulin level was measured. A second study was performed that was identical to the first, with the infusion of regular insulin in place of GLP-1. Insulin infusion rates were regulated in each individual to simulate plasma insulin levels produced during the GLP-1 infusion. The rate of disappearance of glucose was calculated for each subject. Fasting plasma insulin levels were similar between studies. In response to the GLP-1 infusion, with maintenance of plasma glucose level clamped at fasting level, significant increases in plasma insulin occurred in all subjects (P < 0.001). The insulin levels during the insulin infusion study were similar to that induced by GLP-1. The rate of disappearance of glucose (insulin-mediated glucose uptake) progressively increased in response to both the GLP-1 and insulin infusion. However, the rate of disappearance of glucose during the GLP-1 study was significantly higher (P = 0.033) than during the insulin study. We conclude that in insulin-resistant states, GLP-1 has insulinomimetic properties per se.

Topics: Adult; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Fatty Acids, Nonesterified; Female; Glucagon; Glucagon-Like Peptide 1; Glucose; Glucose Clamp Technique; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Male; Obesity; Peptide Fragments; Protein Precursors

The role of cortisol in the regulation of lipolysis is not clear. This study was undertaken to explore whether a standard dose of prednisolone for 1 week would influence lipolysis in abdominal and femoral tissue.. We used the microdialysis technique, the forearm technique, and indirect calorimetry, in the fasting state, after 1 week of treatment with prednisolone (30 mg daily) or placebo. Eight healthy young men (age: 25 +/- 3 years; height: 181 +/- 1 cm; body mass index [BMI]: 23.3 +/- 0.7 kg/m(2)) were studied.. Treatment with prednisolone induced insulin resistance (Homeostasis Model Assessment index: placebo vs. prednisolone: 7.15 +/- 1.63 vs. 17.00 +/- 14.26, p = 0.03), hyperinsulinemia (p = 0.01), and hyperglucagonemia (p = 0.001), whereas growth hormone concentrations were unaffected. Abdominal adipose tissue interstitial glycerol was increased during treatment with prednisolone in the face of significant hyperinsulinemia, although it barely reached statistical significance (p = 0.06). At the femoral adipose tissue depot, no difference in lipolysis was found. Arterial and venous free fatty acids (FFA) were comparable in the two situations, whereas the arteriovenous difference across the forearm was significantly decreased during treatment with prednisolone, indicating increased uptake, or decreased release of FFA. Energy expenditure (p = 0.3), respiratory quotient (p = 0.9), glucose oxidation (p = 0.9), lipid oxidation (p = 1.0), and protein oxidation (p = 0.1) were unaltered on the 2 study days.. Short-term treatment with a standard dose of corticosteroids induces increased abdominal adipose tissue lipolysis, as well as hyperinsulinemia, hyperglucagonemia, and insulin resistance.

Topics: Abdomen; Adipose Tissue; Adult; Blood Glucose; C-Peptide; Calorimetry, Indirect; Cross-Over Studies; Double-Blind Method; Energy Metabolism; Fasting; Fatty Acids, Nonesterified; Femur; Glucagon; Glycerol; Human Growth Hormone; Humans; Insulin; Insulin Resistance; Lipolysis; Male; Microdialysis; Placebos; Prednisolone

The purpose of this study was to assess the effect of glimepiride on insulin sensitivity and secretion in subjects with type 2 diabetes.. After a 2-week washout from prior sulfonylurea therapy, 11 obese subjects with type 2 diabetes underwent euglycemic and hyperglycemic clamp studies before and during glimepiride therapy.. Glimepiride resulted in a 2.4-mmol/l decrease in fasting plasma glucose (P = 0.04) that was correlated with reductions in postabsorptive endogenous glucose production (EGP) (16.4 +/- 0.6 vs. 13.5 +/- 0.5 micro mol. kg(-1). min(-1), P = 0.01) (r = 0.21, P = 0.01). Postabsorptive EGP on glimepiride was similar to that of control subjects (12.8 +/- 0.9 micro mol. kg(-1). min(-1), NS). Fasting plasma insulin (66 +/- 18 vs. 84 +/- 48 pmol/l, P = 0.05), and first-phase (19 +/- 8 vs. 32 +/- 11 pmol/l, P = 0.04) and second-phase incremental insulin responses to glucose (48 +/- 23 vs. 72 +/- 32 pmol/l, P = 0.02) improved with glimepiride therapy. Insulin sensitivity did not change with treatment (4.6 +/- 0.7 vs. 4.3 +/- 0.7 micro mol. kg(-1). min(-1). pmol(-1)) and remained below that of control subjects (8.1 +/- 1.8 micro mol. kg(-1). min(-1). pmol(-1), P = 0.04).. The current study demonstrates that glimepiride improves both first and second phases of insulin secretion, but not insulin sensitivity, in individuals with type 2 diabetes.

Topics: Aged; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Fasting; Female; Glucose Clamp Technique; Glycated Hemoglobin; Humans; Hyperglycemia; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Male; Middle Aged; Sulfonylurea Compounds

Topics: Adult; Area Under Curve; Blood Glucose; C-Peptide; Dietary Carbohydrates; Dietary Fiber; Glucose Intolerance; Humans; Hyperglycemia; Hyperinsulinism; Insulin; Insulin Resistance; Liver Cirrhosis; Male; Middle Aged; Pilot Projects; Postprandial Period

In patients with non-insulin dependent diabetes mellitus (T2DM) and associated chronic liver disease, plasma levels of glucose, insulin and triglycerides are high, lipid peroxidation is increased and natural antioxidant reserves are reduced. Thus, we hypothesised that the re-balancing of cell redox levels and amelioration of liver function could result in a better glucose and lipid metabolism. To study this, we assessed the effect of a new oral formulation of an antioxidant agent - silybin-beta-cyclodextrin (named IBI/S) - in patients with chronic alcoholic liver disease and concomitant T2DM.. Sixty outpatients were enrolled in a three-centre, double blind, randomised, IBI/S vs placebo study. Forty-two (21 in the group IBI/S - 135 mg/d silybin per os - and 21 in the placebo group) concluded the 6-month treatment period. The efficacy parameters included fasting and mean daily plasma glucose levels, glycosylated hemoglobin (HbA1c), basal, stimulated C-peptide and insulin levels, total-, HDL-cholesterol and triglycerides levels in addition to conventional liver function tests. Insulin sensitivity was estimated by HOMA-IR. Malondialdehyde (MDA) was also measured before and after treatment as an index of oxidative stress.. Fasting blood glucose levels, which were similar at baseline in IBI/S group and in the placebo group (173.9 mg/dl and 177.1 mg/dl, respectively), decreased to 148.4 mg/dl (-14.7% vs baseline; p = 0.03) in the IBI/S group while they were virtually unchanged in the placebo group. The comparison between the groups at mo 6 (T6) also showed a significant reduction of glucose levels in the IBI/S group (p = 0.03). The same trend was observed in mean daily blood glucose levels, HbA1c and HOMA-IR, although differences were not significant. Basal and stimulated C-peptide values showed that only a few changes had occured in both groups. Such results indicate that insulin secretion was virtually unaffected, as confirmed also by the insulinemia data. Plasma triglycerides concentrations dropped from a baseline value of 186 mg/dl to 111 mg/dl (T6) in the IBI/S group, with significant differences at all instances with respect to baseline values. By contrast, triglycerides increased from 159 mg/dl at entry to 185 mg/dl (T6) in the placebo group. The difference between the groups at T6 was highly significant (p < 0.01). Total and HDL cholesterol as well as liver function tests did not change significantly during the study in both groups. MDA decreased significantly only in the group receiving IBI/S. No clinically relevant side effects were observed in either group.. Oral administration silybin-beta-cyclodextrin in patients with T2DM and compensated chronic alcoholic liver disease causes a significant decrease in both glucose and triglyceride plasma levels. These effects may be due to the recovery of energy substrates, consistent with a reduced lipid peroxidation and an improved insulin activity.

Topics: Antioxidants; beta-Cyclodextrins; Blood Glucose; C-Peptide; Cholesterol, HDL; Cyclodextrins; Diabetes Mellitus, Type 2; Double-Blind Method; Female; gamma-Glutamyltransferase; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Liver Diseases, Alcoholic; Male; Malondialdehyde; Middle Aged; Oxidative Stress; Placebos; Silybin; Silymarin; Triglycerides

Type II (non-insulin-dependent) diabetes mellitus is characterized by abnormal insulin secretion, which involves a disrupted basal and glucose-entrained insulin pulsatility, and by insulin resistance. The aim of this study was to examine the influence of glucocorticoid-mediated insulin resistance on the regularity of high frequency insulin pulsatility.. Eight healthy men (means +/- SD; age 24.4 +/- 0.5 years, BMI 23.2 +/- 0.7 kg/m2) were examined after prednisolone treatment (30 mg/day) or placebo for 6 days in a double-blind, placebo controlled, cross-over study with a 6-week washout period. Blood was collected every minute for 60 min during baseline and glucose-entrainment. Time-series were assessed by spectral and autocorrelation analyses and a first-phase insulin secretion test was carried out.. Prednisolone treatment led to insulin resistance as expected (HOMA-S; prednisolone vs placebo; 1.85 +/- 0.26 vs 1.02 +/- 0.10; p < 0.01) with exaggerated first-phase insulin secretion (3016 +/- 468 pmol/l vs 1688 +/- 207 pmol/l; p < 0.01), suggesting a stable disposition index. During baseline, normalized spectral power of serum insulin concentration time-series was reduced during prednisolone exposure compared with placebo (8.40 +/- 0.95 vs 11.79 +/- 1.66; p < 0.05) indicating a disturbed high-frequency oscillatory insulin release. A similar trend was observed using autocorrelation analysis (0.23 +/- 0.04 vs 0.32 +/- 0.07; p = 0.12). During glucose entrainment no difference in normalized spectral power or in the autocorrelation coefficient between prednisolone and placebo (p > 0.1) was observed.. Six days of prednisolone treatment resulted in a pertubed high-frequency insulin release in the fasting state whereas the ability of glucose to entrain insulin secretion was preserved. This indicates a mechanism of pertubed glucose-insulin feedback mechanism which causes irregular oscillatory insulin release.

Topics: Adult; Area Under Curve; Blood Glucose; Body Mass Index; C-Peptide; Cross-Over Studies; Double-Blind Method; Glucocorticoids; Glucose Tolerance Test; Homeostasis; Humans; Insulin; Insulin Resistance; Insulin Secretion; Kinetics; Male; Placebos; Prednisolone; Time Factors

A weight-reducing effect of metformin has been demonstrated in obese subjects with and without diabetes. The mechanisms of this action are unclear, which may be partly due to the fact that in obese and diabetic patients the substance's effects result from a complex interaction with the distinct endocrine and metabolic disturbances in these patients. To dissociate primary from secondary action of metformin, we examined effects of the substance in normal-weight healthy subjects. Fifteen normal-weight men were treated with metformin (850 mg twice daily) or placebo for a 15-day period in a double-blind, placebo-controlled, cross-over study. Anthropometric, psychologic, cardiovascular, endocrine, and metabolic parameters were assessed before and at the end of the treatment period. Metformin did not affect body weight (P =.838) and body fat mass (P =.916). Yet, serum leptin concentration was distinctly reduced after metformin (P <.001). Also, metformin reduced the concentration of plasma glucose (P =.011), serum insulin (P=.044), and serum insulin-like growth factor -1 (IGF-1) (P=.013), while it increased serum glucagon concentration (P <.001). There were no effects of metformin on feelings of hunger, blood pressure, heart rate, resting energy expenditure, the respiratory quotient, free fatty acids, beta-hydroxybutyrate, glycerol, triglycerides, cholesterol, and uric acid (all P >.1). Data indicate that metformin decreases the serum leptin concentration even without affecting body weight and body composition in normal-weight men.

Topics: Adipose Tissue; Adult; Blood Pressure; Body Weight; C-Peptide; Diabetes Mellitus; Glucagon; Humans; Hydrocortisone; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin-Like Growth Factor Binding Protein 3; Insulin-Like Growth Factor I; Leptin; Male; Metformin; Obesity; Reference Values

The aim of this study was to evaluate the effects of sibutramine on plasma leptin levels, body weight and glucose metabolism in non-dieting women. Fourteen healthy, non-diabetic, obese women were studied before treatment, after 1 week of placebo administration, and after a 2-week course of sibutramine (10 mg/day). At each of these stages, we assessed body composition, measured the levels of plasma leptin, C-peptide and various biochemical parameters, and also recorded plasma insulin and glucose levels during oral glucose tolerance tests. After 1 week of placebo treatment, there were no significant changes in any of the parameters. However, two weeks of 10 mg/day sibutramine dropped plasma leptin levels from a mean (+/-SE) of 48.84+/-4.54 to 42.84+/-4.74 ng/ml (p<0.04), reduced BMI from 39.36+/-2.01 to 38.57+/-1.93 kg/m2 (p<0.002), and decreased insulin resistance (IR, as measured using the homeostasis model assessment of insulin resistance) from 5.59+/-0.85 to 3.66+/-0.43 (p<0.02). There was no correlation between the reduction in leptin concentration and the decrease in BMI, fat mass, percent body fat, IR, C-peptide, or the area under curve for glucose or insulin. There was also no correlation between the decrease in leptin levels and the increases that occurred in the insulin sensitivity index or the hepatic sensitivity index. The results showed that treatment with 10 mg/day sibutramine significantly reduces BMI, IR and leptin levels in non-dieting obese women.

Topics: Adult; Appetite Depressants; Blood Glucose; Body Mass Index; C-Peptide; Cyclobutanes; Female; Glucose Tolerance Test; Homeostasis; Humans; Insulin; Insulin Resistance; Leptin; Liver; Obesity; Placebos

Hyperinsulinaemia and reduced insulin sensitivity are common features in patients with cirrhosis. Octreotide, a long-acting somatostatin analogue, is used in cirrhotic patients in the treatment of bleeding oesophageal varices. Octreotide has potent effects on the growth hormone (GH)/insulin-like growth factor I (IGF-I) axis in healthy subjects. but the effects on the GH/IGF-I axis in patients with cirrhosis have been described only briefly. The effects of a 12 h infusion of octreotide (bolus 0.75 microg/kg followed by 0.75 microg/kg/h) in 25 subjects (normals n=9, compensated cirrhotics n=8, decompensated cirrhotics n=8) were compared with those in placebo-treated controls (n=19) during fasting conditions. IGF-I, free IGF-I, IGF binding proteins (IGFBPs), insulin, C-peptide, GH and glucose were measured. Insulin resistance was calculated using the HOMA method. Octreotide reduced levels of total IGF-I in patients with compensated cirrhosis (p=0.03) and free IGF-I in decompensated cirrhosis (p<0.01). Insulin resistance was significantly reduced in normal subjects. whereas the reduction in insulin resistance did not reach statistical significance in patients with cirrhosis. In normal subjects, octreotide increased the IGFBP-1 area under curve threefold (p<0.01) and decreased IGFBP-3 levels (p<0.01), but these effects were blunted in the cirrhotic patients. Similarly, the reduction of insulin and C-peptide was blunted in the cirrhotic patients, whereas a significant reduction in GH was demonstrated in all groups. The effects of octreotide on the GH/IGF-I axis are mitigated in patients with cirrhosis and this may be a reflection of relative hyperinsulinaemia during octreotide treatment in these patients.

Topics: Adult; Blotting, Western; C-Peptide; Female; Fluorescent Antibody Technique; Humans; Insulin; Insulin Resistance; Insulin-Like Growth Factor Binding Proteins; Insulin-Like Growth Factor I; Liver Cirrhosis; Male; Middle Aged; Octreotide; Placebos; Reproducibility of Results

To determine the efficacy of rosiglitazone compared with placebo in reducing hyperglycemia.. After a 4-week placebo run-in period, 959 patients were randomized to placebo or rosiglitazone (total daily dose 4 or 8 mg) for 26 weeks. The primary measure of efficacy was change in the HbA1c concentration.. Rosiglitazone produced dosage-dependent reductions in HbA1c of 0.8, 0.9, 1.1, and 1.5% in the 4 mg o.d., 2 mg b.i.d., 8 mg o.d., and 4 mg b.i.d. groups, respectively, compared with placebo. Clinically significant decreases from baseline in HbA1c were observed in drug-naive patients at all rosiglitazone doses and in patients previously treated with oral monotherapy at rosiglitazone 8 mg o.d. and 4 mg b.i.d. Clinically significant decreases from baseline in HbA1c were also observed with rosiglitazone 4 mg b.i.d. in patients previously treated with combination oral therapy. Approximately 33% of drug-naive patients treated with rosiglitazone achieved HbA1c < or =7% at study end. The proportions of patients with at least one adverse event were comparable among the rosiglitazone and placebo groups. There was no evidence of hepatotoxicity in any treatment group. There were statistically significant increases in weight and serum lipids in all rosiglitazone treatment groups compared with placebo. For LDL and HDL cholesterol, the observed increase appeared to be dose related.. Rosiglitazone at total daily doses of 4 and 8 mg significantly improved glycemic control in patients with type 2 diabetes and was well tolerated.

Topics: Aged; Blood Glucose; C-Peptide; Cholesterol, HDL; Cholesterol, LDL; Diabetes Mellitus, Type 2; Fasting; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin Resistance; Lipids; Male; Middle Aged; Placebos; Rosiglitazone; Thiazoles; Thiazolidinediones; Triglycerides

To evaluate the tolerability of insulin suppression test (IST) using octreotide instead of somatostatin, we compared the steady-state plasma glucose (SSPG) values and the safety during and after the test in 17 normal volunteers. The subject received IST twice (with somatostatin or with octreotide) in random order. During the test, all subjects were infused with regular insulin and glucose simultaneously for 180 min. In addition, either somatostatin or octreotide was infused intravenously over the same period of time. Plasma glucose, insulin and C-peptide were measured. The subject response to the test was recorded during and one day after the test by a structured questionnaire. The SSPG and the steady-state plasma insulin (SSPI) values reached during IST were similar, irrespective of the use of somatostatin or octreotide. There was a positive correlation between the SSPG values obtained from both methods (r = 0.67, P = 0.003). However, the mean intra-individual coefficient of variation is 17.9% for SSPG. The SSPG levels, no matter from which method, correlated positively with the 2-h insulin after oral glucose challenge. Most adverse events (especially gastrointestinal discomfort) occurred after the test, and increased much more after using octreotide than somatostatin (P = 0.002 by chi 2 test). In conclusion, the SSPG values measured by IST using octreotide or somatostatin are similar in normal healthy subjects. Yet, the octreotide method has more adverse events after the test.

Topics: Adult; Blood Glucose; C-Peptide; Female; Humans; Infusions, Intravenous; Insulin; Insulin Resistance; Insulin Secretion; Male; Octreotide; Reference Values; Regression Analysis; Reproducibility of Results; Somatostatin; Time Factors

The effect of melatonin on human carbohydrate metabolism is not yet clear. We investigated whether melatonin influences glucose tolerance and insulin sensitivity in aged women.. Twenty-two postmenopausal women of whom 14 were on hormone replacement therapy.. After an overnight fast, at 0800 hours on two nonconsecutive days, placebo or melatonin (1 mg) were administered randomly and in a double blind fashion. Forty-five minutes later, an oral glucose tolerance test (75 g; OGTT) was performed in 13 women. In another nine women insulin-dependent (Si) and -independent (Sg) glucose utilization was tested by a frequently sampled intravenous glucose tolerance test (FSIGT).. Areas under the response curve to OGTT (AUC) for glucose (1420 +/- 59 vs. 1250 +/- 55 mmol x min/l; P < 0.01), and C-peptide (42,0980 +/- 45,320 vs. 33,528 +/- 15,779 pmol x min/l; P < 0.02) were higher following melatonin than placebo, while Si values were lower (2.6 +/- 0.28 units vs. 3.49 +/- 0.4 units; P < 0.03). Si modifications induced by melatonin were inversely related to Si values of the placebo day (r(2) = 0.538; P < 0.025).. The present results indicate that in aged women administration of 1 mg of melatonin reduces glucose tolerance and insulin sensitivity. The present data may have both physiological and clinical implications.

Topics: Analysis of Variance; Area Under Curve; Blood Glucose; C-Peptide; Estradiol; Estrogen Replacement Therapy; Female; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Linear Models; Melatonin; Middle Aged; Postmenopause

The minimal model of Bergman et al has been used to yield estimates of insulin sensitivity (Si) and glucose effectiveness (Sg) in type 2 diabetes by incorporating exogenous insulin protocols into the regular intravenous glucose tolerance test (IVGTT). These estimates, however, are influenced by the degree to which the dose of exogenous insulin is greater than the physiologic response to a glucose load. Moreover, most studies have related to type 2 diabetes subjects whose diabetes was relatively mild in terms of therapeutic requirements. To develop a "minimal disturbance" approach in estimating Si and Sg in type 2 diabetes, we have used a reduced glucose load (200 mg/kg) and a "physiologic" insulin infusion throughout the IVGTT in a series of 8 patients, 5 of whom were insulin-requiring. Data from this approach were analyzed using the modelling program CONSAM to apply the Bergman model, either unmodified (BMM), or incorporating an additional delay element between the plasma and "remote" insulin compartments (MMD). Application of the MMD and extension of the IVGTT from 3 to 5 hours improved successful resolution of Si and Sg from 37.5% (BMM, 3-hour IVGTT) to 100% (MMD, 5-hour IVGTT). Si was reduced in these type 2 diabetes patients compared with normal subjects (1.86 +/- 0.60 v. 8.65 +/- 2.27 min(-1) x microU(-1) x mL x 10(4) P <.01). The results were validated in the type 2 diabetes group using a 2-stage euglycemic clamp ((Si)CLAMP = 2.02 +/- 0.42 min(-1) x microU(-1) x mL x 10(4) P >.4). Sg was not significantly reduced (2.00 +/- 0.25 type 2 diabetes v. 1.55 +/- 0.26 normal min(-1) x 10(2)). Data from a group of normal nondiabetic subjects was then analyzed using the MMD, but this approach did not enhance the fit of the model compared with the BMM. This result indicates that the delay in insulin action in type 2 diabetes represents an abnormality whereby the onset of insulin action cannot be described as a single phase in the transfer of insulin from plasma to the remote compartment. It is postulated that the physiologic basis for this delayed action may relate to transcapillary endothelial transfer of insulin, this process limiting the rate of onset of insulin action.

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Fatty Acids, Nonesterified; Female; Glucagon; Glucose; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Infusions, Intravenous; Insulin; Insulin Resistance; Kinetics; Male; Middle Aged; Models, Biological

The aim of this study was to examine the association between intact insulin, insulin propeptides, and femoral artery intima-media thickness. The design was a cross-sectional study and the study group (n = 391) consisted of randomly recruited clinically healthy 58-year-old Swedish men. The intima-media thickness of the common femoral artery was measured with ultrasound. Fasting plasma insulin; intact insulin; proinsulin; 32,33 split-proinsulin; and C-peptide concentrations were assessed. The results showed that the common femoral artery intima-media thickness correlated significantly and univariately with waist-hip ratio, systolic blood pressure, serum total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, ApoB, low-density lipoprotein peak particle size, and cigarette years. Furthermore, of intact insulin and insulin propeptides, only intact insulin and C-peptide were univariately associated with common femoral artery intima-media thickness (r= 0.14, p < 0.01; r= 0.18, p < 0.01; respectively). In a multiple regression analysis, common femoral artery intima-media thickness was independently associated with systolic blood pressure (beta-coefficient = 0.004, p = 0.002), ApoB (beta-coefficient = 0.338, p < 0.001 ) and cigarette years (beta-coefficient = 0.0004, p < 0.001), (R2= 25%, p

Topics: Apolipoproteins B; Arteriosclerosis; Biomarkers; Blood Pressure; C-Peptide; Cholesterol; Cross-Sectional Studies; Femoral Artery; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Proinsulin; Protein Precursors; Radioimmunoassay; Reference Values; Risk Factors; Triglycerides; Tunica Intima; Ultrasonography

To evaluate the glycemic control, lipid effects, and safety of pioglitazone in patients with type 2 diabetes mellitus.. Patients (n = 197) with type 2 diabetes mellitus, a hemoglobin A1c (HbA1c) > or = 8.0%, fasting plasma glucose (FPG) > 7.7 mmol/l (140 mg/dl), and C-peptide > 0.331 nmol/l (1 ng/ml) were enrolled in this 23-week multi-center (27 sites), double-blind clinical trial and randomized to receive either a placebo or pioglitazone HCl 30 mg (pioglitazone), administered once daily, as monotherapy. Patients were required to discontinue all anti-diabetic medications 6 weeks before receiving study treatment. Efficacy parameters included HbA1c fasting plasma glucose (FPG), serum C-peptide, insulin, triglycerides (Tg), and cholesterol (total cholesterol [TC], high-density lipoprotein-cholesterol [HDL-C], low-density lipoprotein-cholesterol [LDL-C]). Adverse event rates, serum chemistry, and physical examinations were recorded.. Compared with placebo, pioglitazone significantly (P= 0.0001) reduced HbA1c (-1.37% points), FPG (-3.19 mmol/l; -57.5 mg/dl), fasting C-peptide (-0.076+/-0.022 nmol/l), and fasting insulin (-11.88+/-4.70 pmol/l). Pioglitazone significantly (P < 0.001) decreased insulin resistance (HOMA-IR; -12.4+/-7.46%) and improved beta-cell function (Homeostasis Model Assessment (HOMA-BCF); +47.7+/-11.58%). Compared with placebo, fasting serum Tg concentrations decreased (-16.6%; P = 0.0178) and HDL-C concentrations increased (+12.6%; P= 0.0065) with pioglitazone as monotherapy. Total cholesterol and LDL-C changes were not different from placebo. The overall adverse event profile of pioglitazone was similar to that of placebo, with no evidence of drug-induced elevations of serum alanine transaminase (ALT) concentrations or hepatotoxicity.. Pioglitazone improved insulin resistance and glycemic control, as well as Tg and HDL-C - which suggests that pioglitazone may reduce cardiovascular risk for patients with type 2 diabetes.

Topics: Adult; Aged; Arteriosclerosis; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Double-Blind Method; Endpoint Determination; Female; Follow-Up Studies; Glycated Hemoglobin; Humans; Hyperlipidemias; Hypoglycemic Agents; Insulin; Insulin Resistance; Islets of Langerhans; Lipids; Lipoproteins; Male; Middle Aged; Pioglitazone; Single-Blind Method; Thiazoles; Thiazolidinediones; Treatment Outcome; United States

Twelve renal transplant recipients randomised to receive immunosuppression with either tacrolimus (FK506) or cyclosporin underwent oral glucose tolerance tests (OGTT) a median of 8 months (range 7-9) after transplantation. Six healthy subjects acted as controls. Compared with the controls, both transplant groups had significantly elevated fasting (p < 0.05 for both groups) and postprandial (p < 0.001 for tacrolimus and p < 0.05 for cyclosporin) blood glucose concentrations. Fasting hyperinsulinaemia was observed in both transplant groups (p < 0.05) relative to the control subjects. Glucose-stimulated plasma immunoreactive insulin concentrations in the tacrolimus-treatment group were significantly higher than in the cyclosporin group (p < 0.05) and the controls (p < 0.001). Postprandial blood alanine concentrations were also significantly elevated in the tacrolimus group compared with both the controls (p < 0.001) and cyclosporin-treated patients (p < 0.001). The raised insulin concentrations with normal or increased blood glucose concentrations after renal transplantation suggests that insulin resistance was more marked in patients receiving tacrolimus-based immunosuppression.

Topics: Alanine; Blood Glucose; C-Peptide; Cyclosporine; Fatty Acids, Nonesterified; Follow-Up Studies; Glucose Tolerance Test; Glycerol; Humans; Immunosuppressive Agents; Insulin; Insulin Resistance; Insulin Secretion; Ketone Bodies; Kidney Transplantation; Lactates; Postprandial Period; Pyruvates; Reference Values; Tacrolimus; Time Factors

To evaluate the effects of acute lowering of FFAs on glucose-induced insulin secretion and GH response to GHRH in polycystic ovary syndrome (PCOS), 27 PCOS subjects (11 lean and 16 obese) and 17 body mass index-matched controls (8 lean and 9 obese) were investigated. Patients underwent an oral glucose tolerance test and a GHRH test before and after administration of the antilipolytic drug acipimox (250 mg orally 3 h and 1 h before the starting of the tests). Blood samples were collected for 2 h after GHRH bolus and for 4 h after the oral glucose tolerance test. Serum concentrations of GH, insulin, glucose, and c-peptide were assayed in each sample, and the results were expressed as area under the curve (AUC). No significant differences were found as to glucose, insulin, and c-peptide AUC before and after acute FFA plasma reduction in any of the investigated groups. Basally, lower GH-AUC was found in lean PCOS compared with body mass index-matched controls and in obese vs. lean controls; no significant differences were found as to the same variable between the two obese groups. The acipimox induced FFA suppression elicited in the four groups a sustained increase in the GH response to its trophic hormone; indeed, the GH-AUC nearly doubled with respect to basal evaluation in all the studied groups. However, the antilipolytic drug was not able to abolish the differences found between lean groups in basal conditions. In conclusion, the presented data confirm that FFAs have a main role in regulating GH secretion at the pituitary level; however, it does not seem that they could explain the GH as well as insulin dysfunction of PCOS.

Topics: Adult; Area Under Curve; Body Mass Index; C-Peptide; Fatty Acids, Nonesterified; Female; Glucose Tolerance Test; Growth Hormone-Releasing Hormone; Hormones; Human Growth Hormone; Humans; Hypolipidemic Agents; Insulin; Insulin Resistance; Lipids; Obesity; Polycystic Ovary Syndrome; Pyrazines

Bedtime ingestion of slow-release carbohydrates leads to sustained nocturnal fatty acid suppression and improved glucose tolerance in type 2 diabetic patients.. This study assessed the effects of 2 different doses of bedtime carbohydrate supplement (BCS) on morning glycemic control and glycated hemoglobin (Hb A(1c)) in type 2 diabetic patients. In addition, the effects of the high-dose BCS on insulin sensitivity and postprandial glucose and triacylglycerol concentrations were assessed.. Two BCS doses were studied separately in 7-wk randomized, placebo-controlled, double-blind studies with either a parallel (low-dose BCS; n = 24 patients) or crossover (high-dose BCS; n = 14 patients) design. The effects of the low and high doses (0.30 and 0.55 g uncooked cornstarch/kg body wt, respectively) were compared with those of a starch-free placebo.. Compared with the starch-free placebo, the high-dose BCS ( approximately 45 g) produced enhanced nocturnal glucose (P < 0.01) and insulin (P < 0.01) concentrations as well as a 32% suppression of fatty acid concentrations (P < 0.01). Moreover, glucose tolerance (P < 0.05) and C-peptide response (P < 0.05) improved after breakfast the next morning. The low-dose BCS ( approximately 25 g) improved fasting blood glucose concentrations (P < 0.05). However, there were no improvements in insulin sensitivity, postprandial triacylglycerol concentrations, or Hb A(1c) after 7 wk.. Nocturnal fatty acid suppression by BCS improved fasting and postprandial blood glucose concentrations in type 2 diabetic patients the next morning. In contrast, no improvements in insulin sensitivity, postprandial triacylglycerol concentrations, or long-term glycemic control assessed by Hb A(1c) were seen after BCS supplementation.

Topics: Blood Glucose; Body Weight; C-Peptide; Circadian Rhythm; Cross-Over Studies; Diabetes Mellitus, Type 2; Double-Blind Method; Fatty Acids; Female; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Lactic Acid; Male; Middle Aged; Starch; Triglycerides

The role of the pattern, quantity and site of insulin secretion in the tolerance to a glucose challenge is not fully evaluated in humans because it is difficult to obtain appropriate clinical models.. To address this issue, we studied subjects with reduced pancreatic mass (hemipancreatectomized, HEMI), systemic insulin delivery (pancreas transplant recipients, PTX), and two control groups (healthy, CON; and with uveitis on the same immunosuppression as PTX, UVE), with an hyperglycaemic clamp (study 1, + 4.2 mmol L-1), using a repeat experiment (study 2) with a fixed glucose infusion, calculated to increase by 35% that in study 1.. In study 1, CON increased glucose uptake to 20 +/- 3 micromol kg-1 min-1 after a biphasic insulin response. In study 2, CON further increased the glucose uptake via an increment in prehepatic insulin secretion that stimulated insulin sensitivity without changes in peripheral insulin and glucose concentrations. HEMI and PTX had 35% less glucose uptake in study 1, compared to CON, and increased glucose concentrations (+ 1.6 mmol L-1) in study 2. UVE had an intermediate defect. The causes of intolerance were different: HEMI had a defective first-phase insulin secretion (50% peripheral insulin concentrations) but maintained insulin sensitivity; PTX had normal peripheral insulin but only one-third of the insulin sensitivity of CON.. Hemipancreatectomy and systemic insulin delivery impair first-phase insulin secretion; second-phase peripheral insulinization (HEMI); insulin sensitivity (PTX); and a mechanism evidentiated in study 2 of CON that increases insulin sensitivity in response to prehepatic insulin secretion (both groups). Failure of these mechanisms is largely compensated by hyperglycaemia.

Topics: Adult; Blood Glucose; C-Peptide; Fatty Acids, Nonesterified; Feedback; Female; Glucagon; Glucose; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Hydrocortisone; Hyperglycemia; Immunosuppression Therapy; Insulin; Insulin Resistance; Insulin Secretion; Male; Middle Aged; Pancreas Transplantation; Pancreatectomy

Characterization of beta-cell function in humans is essential for identifying genetic defects involved in abnormal insulin secretion and the pathogenesis of type 2 diabetes.. We designed a novel test assessing plasma insulin and C-peptide in response to 3 different secretagogues. Seven lean, healthy volunteers twice underwent a 200 min hyperglycaemic clamp (10 mmol L-1) with administration of GLP-1 (1.5 pmol. kg-1. min-1) starting at 120 min and an arginine bolus at 180 min. We determined glucose-induced first and second-phase insulin secretion, GLP-1-stimulated insulin secretion, arginine-stimulated insulin response (increase above prestimulus, DeltaIarg) and the maximal, i. e. highest absolute, insulin concentration (Imax). Insulin sensitivity was assessed during second-phase hyperglycaemia. On a third occasion 6 subjects additionally received an arginine bolus at > 25 mM blood glucose, a test hitherto claimed to provoke maximal insulin secretion.. Insulin levels increased from 46 +/- 11 pM to 566 +/- 202 pM at 120 min, to 5104 +/- 1179 pM at 180 min and to maximally 8361 +/- 1368 pM after arginine (all P < 0.001). The within subject coefficients of variation of the different secretion parameters ranged from 10 +/- 3% to 16 +/- 6%. Except for second-phase which failed to correlate significantly with DeltaIarg (r = 0.52, P = 0.23) and Imax (r = 0.75, P = 0.053) all phases of insulin secretion correlated with one another. The insulin concentration after the arginine bolus at > 25 mM glucose (n = 6) was 2773 +/- 855 pM vs. 7562 +/- 1168 pM for Imax (P = 0.003).. This novel insulin secretion test elicits a distinct pattern of plasma insulin concentrations in response to the secretagogues glucose, GLP-1 and arginine and is highly reproducible and can be used for differential characterization of islet function.

Topics: Adult; Arginine; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucagon; Glucagon-Like Peptide 1; Glucagon-Like Peptides; Glucose; Glucose Clamp Technique; Humans; Hyperglycemia; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Male; Peptide Fragments; Protein Precursors; Reproducibility of Results

The aim of the present study was to evaluate the long-term (30 months) metabolic effects of recombinant human GH (rhGH) given in a mean dose of 6.7 microg/kg x day (= 1.6 IU/day), in 11 patients with adult GH deficiency. Glucose metabolism was evaluated by an oral glucose tolerance test and an iv (frequently sampled iv glucose tolerance test) glucose tolerance test, and body composition was estimated by dual-energy x-ray absorptiometry. Treatment with rhGH induced persistent favorable changes in body composition, with a 10% increase in lean body mass (P < 0.001) and a 12% reduction of fat mass (P < 0.002); however, the glucose tolerance deteriorated significantly, and three patients developed impaired glucose tolerance. Fasting insulin level (P < 0.003) and the homeostasis model assessment insulin resistance score increased significantly, indicating a deterioration in insulin sensitivity; whereas the insulin sensitivity index, calculated from the frequently sampled iv glucose tolerance test, only decreased slightly. The clearance of C-peptide and insulin increased 100% and 60%, respectively, and the prehepatic insulin secretion was tripled during rhGH treatment; but related to the impairment in glucose tolerance, beta-cell response was still inappropriate. Our conclusion is that long-term rhGH-replacement therapy in GH deficiency adults induced a significant deterioration in glucose tolerance, profound changes in kinetics of C-peptide, and insulin and prehepatic insulin secretion, despite an increase in lean body mass and a reduction of fat mass. Therefore, rhGH treatment may precipitate diabetes in some patients already susceptible to the disorder.

Topics: Adult; Area Under Curve; Blood Glucose; Body Composition; Body Mass Index; Bone Density; C-Peptide; Double-Blind Method; Follow-Up Studies; Glucose Tolerance Test; Hormone Replacement Therapy; Human Growth Hormone; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Like Growth Factor I; Pituitary Diseases; Placebos; Time Factors

This study was initiated to test the hypothesis that metformin treatment leads to enhanced glucose disposal at ambient insulin concentrations.. Nineteen obese patients with impaired glucose tolerance (IGT) were treated with either metformin or placebo in a randomized, double-blind, placebo-controlled, cross-over study. Insulin secretion and insulin resistance were quantified using the homeostasis model assessment (HOMA) and insulin-stimulated glucose disposal were measured by determining the steady-state plasma glucose (SSPG).. The average benefit of metformin was 0.6 mmol/l for glucose (95% confidence interval (CI) 0.2-0.9 P = 0.002), 2.8 pmol/l for insulin (95% CI 0.2-5.4, P = 0.019). Insulin resistance, as quantified by HOMA, was improved by 1.1 (95% CI 0.2-2.0, P = 0.004), without any change in insulin secretion. Basal and insulin-stimulated glucose oxidation were comparable in the placebo and metformin-treated groups at the end of each treatment period, as was the SSPG concentration. However, both systolic and diastolic blood pressures fell significantly following metformin administration as compared to treatment with placebo.. These results indicate that metformin administration to patients with IGT is associated with enhanced glucose disposal at baseline insulin concentrations and a fall in blood pressure. In contrast, neither glucose oxidation nor glucose disposal were increased in association with metformin treatment under conditions of physiological hyperinsulinaemia.

Topics: Blood Glucose; C-Peptide; Double-Blind Method; Female; Fructosamine; Glucose Intolerance; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Male; Metformin; Obesity; Placebos

The fundamental role of insulin resistance for metabolic changes linked to cardiovascular disease and type 2 diabetes is increasingly recognized. Oral contraceptives (OC) may affect insulin sensitivity, and a detailed characterization hereof, as well as the secondary effects on related metabolic systems, are relevant in the evaluation of the risk of developing vascular disorders or diabetes in OC users. We studied insulin sensitivity index (S(I)), glucose effectiveness (S(g)), and insulin response in young, healthy women by frequently sampled intravenous glucose tolerance tests before and after randomization to 6 months of treatment with ethinyl estradiol in triphasic combination with norgestimate (n = 17) or gestodene (n = 20). Measurements of fasting triglycerides and antigen concentrations of tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor type 1 (PAI-1) were also included. Both compounds increased fasting plasma insulin and reduced S(i) but did not affect S(g). The relationships between S(i) and insulin response were unchanged. No consistent correlation between insulin sensitivity and triglycerides, t-PA, or PAI-1 were demonstrated before or during treatment. We conclude that the treatments were followed by a compensated decrease in insulin sensitivity that was unrelated to changes in triglycerides, t-PA, or PAI-1 antigen.

Topics: Adult; Antibodies, Monoclonal; Blood Glucose; C-Peptide; Cardiovascular Diseases; Contraceptives, Oral, Synthetic; Diabetes Mellitus, Type 2; Enzyme-Linked Immunosorbent Assay; Ethinyl Estradiol; Female; Fibrinolysis; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Norgestrel; Plasminogen Activator Inhibitor 1; Prospective Studies; Tissue Plasminogen Activator; Triglycerides

Troglitazone is a new insulin-sensitizing agent used to treat type 2 diabetes mellitus. The mechanism by which troglitazone exerts its effect on systemic glucose metabolism is unknown.. To determine the effects of 6 months of troglitazone monotherapy on glucose metabolism in patients with type 2 diabetes mellitus.. Randomized, double-blind, placebo-controlled trial.. Six general clinical research centers at university hospitals.. 93 patients (mean age, 52 years) with type 2 diabetes mellitus (mean fasting plasma glucose level, 11.2 mmol/L) who were being treated with diet alone or who had discontinued oral antidiabetic medication therapy.. Patients were randomly assigned to one of five treatment groups (100, 200, 400, or 600 mg of troglitazone daily or placebo) and had metabolic assessment before and after 6 months of treatment.. Plasma glucose and insulin profiles during a meal tolerance test; basal hepatic glucose production and insulin-stimulated glucose disposal rate during a hyperinsulinemic-euglycemic clamp procedure.. Troglitazone at 400 and 600 mg/d decreased both fasting (P < 0.001) and postprandial (P = 0.016) plasma glucose levels by approximately 20%. All four troglitazone dosages also decreased fasting (P = 0.012) and postprandial (P < 0.001) triglyceride levels; 600 mg of the drug per day decreased fasting free fatty acid levels (P = 0.018). Plasma insulin levels decreased in the 200-, 400-, and 600-mg/d groups (P < 0.001), and C-peptide levels decreased in all five study groups (P < 0.001). Basal hepatic glucose production was suppressed in the 600-mg/d group compared with the placebo group (P = 0.02). Troglitazone at 400 and 600 mg/d increased glucose disposal rate by approximately 45% above pretreatment levels (P = 0.003). Stepwise regression analysis showed that troglitazone therapy was the strongest predictor of a decrease in fasting (P < 0.001) or postprandial (P = 0.01) glucose levels. Fasting C-peptide level was the next strongest predictor (higher C-peptide level equaled greater glucose-lowering effect).. Troglitazone monotherapy decreased fasting and postprandial glucose levels in patients with type 2 diabetes, primarily by augmenting insulin-mediated glucose disposal.

Topics: Adult; Aged; Analysis of Variance; Blood Glucose; C-Peptide; Chromans; Diabetes Mellitus, Type 2; Double-Blind Method; Female; Glucose; Glucose Clamp Technique; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Liver; Male; Middle Aged; Placebos; Regression Analysis; Thiazoles; Thiazolidinediones; Troglitazone

To determine the effect of benfluorex on glycaemic control in obese insulin-requiring Type 2 diabetes, 76 patients (aged 53.8 +/- 12.8 years) receiving insulin (> or = 0.5 IU/kg) and an appropriate low-calorie diet were evaluated after a 1-month run-in followed by a 3-month double-blind treatment period (3 tablets daily) with benfluorex (B; n = 37) vs placebo (P; n = 39). At inclusion, the B and P groups respectively did not differ in body weight (80.9 +/- 10.3 vs 77.2 +/- 9.1 kg), body mass index (BMI) (30.1 +/- 4.6 vs 29.0 +/- 2.3 kg/m2) or fasting blood glucose (11.22 +/- 4.33 vs 10.35 +/- 4.42 mmol/l). However, daily insulin dose and HbA1c levels were higher in the B group (59.9 +/- 18.6 vs 50.4 +/- 12.8 IU, p = 0.012; and 7.72 +/- 1.60 vs 6.96 +/- 1.27%, p = 0.025, respectively). After 3 months of treatment, the decrease in daily insulin dose was greater in the B group (8.7 +/- 10.1 vs 2.7 +/- 8.1 IU; p = 0.032), with a decrease in HbA1c (-0.73 +/- 1.74%, p = 0.026), vs no change in the P group (+0.01 +/- 1.65%, NS) and a tendency towards a greater decrease in fasting blood glucose (-1.43 +/- 5.41 vs +0.42 +/- 3.78 mmol/l respectively). Body weight and BMI were also lower in the B group (1.77 ñ 2.27 vs 0.21 ñ 2.68 kg, p = 0.013; and 0.64 +/- 0.84 vs 0.07 +/- 1.07 kg/m2, p = 0.019, respectively) in parallel with the decrease in insulin dose. Triglycerides decreased in the B group vs an increase in the P group (-0.54 +/- 2.04 vs +0.21 +/- 0.70 mmol/l p = 0.06). Total cholesterol decreased within the B group (-0.47 +/- 1.01 mmol/l; p = 0.013) and vs the P group (intergroup p = 0.006). Adverse events were reported in 11 patients in the B group vs 5 in the P group (NS), causing dropout in only one case (intercurrent illness, P group). Addition of benfluorex in obese insulin-requiring Type 2 diabetes thus enhances glycaemic control and lowers both daily insulin requirement and body weight. Benfluorex + insulin is a valid alternative for obese patients who remain poorly controlled despite insulin or who require high doses of insulin.

Topics: Adolescent; Adult; Aged; Blood Glucose; Body Weight; C-Peptide; Diabetes Mellitus; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Female; Fenfluramine; Humans; Hypolipidemic Agents; Insulin; Insulin Resistance; Male; Middle Aged; Monitoring, Physiologic; Obesity; Postprandial Period

Insulin sensitivity is impaired in overweight subjects with IGT and is accompanied by hyperinsulinemia, a condition, that might promote early B-cell exhaustion. Twelve subjects were recruited for a double-blind trial using either 100 mg of acarbose or placebo for three months. Insulin sensitivity was measured by hyperglycemic clamp and with the minimal model. Baseline characteristics such as body weight, BMI, blood glucose, HB-A1c and serum lipids did not change throughout the study period. The steady state glucose infusion rate (SSGIR) improved significantly following acarbose. The insulin sensitivity as measured by clamp (MI) or minimal model, (SI), however, increased only descriptively (p = 0.08). The fasting proinsulin was raised in all subjects during pretreatment. Following acarbose, the proinsulin dropped from 20.3 +/- 12.9 to 13.6 +/- 7.1 ng/ml, but remained unchanged in the placebo group. Due to the high variability of values and the low number of subjects in this study, differences were only descriptive and did not reach significance (p = 0.08). The proinsulin/insulin ratio, however, significantly decreased after 3 months of acarbose treatment. Acarbose might therefore be considered recommendable for the protection of the B-cell function and for delaying the transition of IGT to overt NIDDM.

Topics: Acarbose; Adult; Analysis of Variance; Blood Glucose; Body Mass Index; Body Weight; C-Peptide; Double-Blind Method; Glucose; Glucose Clamp Technique; Glucose Intolerance; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Lipids; Male; Middle Aged; Obesity; Proinsulin; Trisaccharides

Glucosamine has a major influence on the impairment of some metabolic mechanisms in the human body. As shown in vitro experiments, it takes part in inducing mechanisms of insulin resistance. Therefore, the purpose of our study was to evaluate glucosamine levels in the serum of patients who suffered myocardial infarction (MI) and who either had or didn't have diagnosed type II diabetes in relation to healthy people. The levels of glucosamine, immunoreactive insulin, C-peptide, glucose and lipid indexes were measured in venous blood in investigated patients. In patients with MI without diabetes the highest concentrations of glucosamine, insulin and C-peptide were noted as compared to the results obtained from other groups of patients. In patients with diabetes, on the other hand, the highest glucose levels were noted as compared to the results of other patients. There were no statistically differences of lipid indexes between two groups of patients following MI. A negative correlation between glucosamine levels and glucose concentrations in patients without diabetes may suggest that glucose does not directly determine glucosamine levels. The returning of insulin levels to normal in patients with hyperinsulinemia (antidiabetic drugs) may play a role in the lowering of glucosamine induced peripheral insulin resistance.

Topics: Adult; C-Peptide; Cholesterol; Diabetes Mellitus, Type 2; Glucosamine; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Myocardial Infarction; Statistics, Nonparametric; Triglycerides

To compare and assess the single and joint effect of diet and exercise intervention for 1 year on insulin resistance and the development leading toward the insulin resistance syndrome.. An unmasked, randomized 2 x 2 factorial intervention trial was applied with a duration of 1 year for each participant. The trial comprised 219 men and women with diastolic blood pressure of 86-99 mmHg, HDL cholesterol < 1.20 mmol/l, triglycerides > 1.4 mmol/l, total cholesterol of 5.20-7.74 mmol/l, and BMI > 24 kg/m2. Participants were randomly allocated to diet group (n = 35), diet and exercise group (n = 67), exercise group (n = 54), and control group (n = 43). The diet included increased intake of fish and reduced total fat intake. The exercise program entailed supervised endurance exercise three times a week. Baseline cross-sectional changes and 1-year changes in insulin resistance, fasting serum levels of insulin, C-peptide, proinsulin, glucose, and lipids as well as weight, mean blood pressure, and plasminogen activator inhibitor 1 (PAI-1) values were recorded.. The cross-sectional results at baseline showed significant correlations between the calculated insulin resistance and BMI (r = 0.54) and correlations between the mean blood pressure (mBP) (r = 0.26) and PAI-1 (r = 0.40). The 1-year diet intervention gave a significant decrease in the calculated insulin resistance from 4.6 to 4.2 and a positive correlation between the changes in insulin resistance and changes in BMI (r = 0.40). The diet and exercise intervention also led to significantly decreased insulin resistance (from 5.0 to 4.0). The exercise intervention did not significantly change insulin resistance.. The cross-sectional and 1-year intervention results supported each other and underscored the important connection between increased BMI and the development leading toward the insulin resistance syndrome.

Topics: Blood Glucose; Blood Pressure; Body Mass Index; C-Peptide; Cholesterol, HDL; Cross-Sectional Studies; Data Interpretation, Statistical; Diet; Exercise; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Life Style; Linear Models; Male; Plasminogen Activator Inhibitor 1; Proinsulin; Statistics, Nonparametric; Syndrome; Triglycerides

Oestrogen replacement therapy is associated with a decreased risk of cardiovascular disease in postmenopausal women. Patients with non-insulin-dependent diabetes mellitus (NIDDM) have an increased cardiovascular risk. However, oestrogen replacement therapy is only reluctantly prescribed for patients with NIDDM. In a double blind randomized placebo controlled trial we assessed the effect of oral 17 beta-estradiol during 6 weeks in 40 postmenopausal women with NIDDM. Glycated haemoglobin (HbA1c), insulin sensitivity, suppressibility of hepatic glucose production, lipoprotein profile and parameters of fibrinolysis were determined. The oestrogen treated group demonstrated a significant decrease of HbA1c and in the normotriglyceridaemic group a significantly increased suppression of hepatic glucose production by insulin. Whole body glucose uptake and concentrations of non-esterified fatty acids did not change. LDL-cholesterol- and apolipoprotein B levels decreased, and HDL-cholesterol, its subfraction HDL2-cholesterol and apolipotrotein A1 increased. The plasma triglyceride level remained similar in both groups. Both the concentration of plasminogen activator inhibitor-1 antigen and its active subfraction decreased. Tissue type plasminogen activator activity increased significantly only in the normotriglyceridaemic group. Oestrogen replacement therapy improves insulin sensitivity in liver, glycaemic control, lipoprotein profile and fibrinolysis in postmenopausal women with NIDDM. For a definite answer as to whether oestrogens can be more liberally used in NIDDM patients, long term studies including the effect of progestogens are necessary.

Topics: C-Peptide; Cholesterol; Diabetes Mellitus, Type 2; Double-Blind Method; Estradiol; Estrogen Replacement Therapy; Fatty Acids, Nonesterified; Female; Fibrinolysis; Glycated Hemoglobin; Humans; Insulin Resistance; Lipids; Lipoproteins; Middle Aged; Plasminogen Activator Inhibitor 1; Postmenopause; Tissue Plasminogen Activator; Triglycerides

The liver plays a major role in regulating glucose metabolism, and since its function is influenced by sympathetic/ parasympathetic innervation, we used liver graft as a model of denervation to study the role of CNS in modulating hepatic glucose metabolism in humans. 22 liver transplant subjects were randomly studied by means of the hyperglycemic/ hyperinsulinemic (study 1), hyperglycemic/isoinsulinemic (study 2), euglycemic/hyperinsulinemic (study 3) as well as insulin-induced hypoglycemic (study 4) clamp, combined with bolus-continuous infusion of [3-3H]glucose and indirect calorimetry to determine the effect of different glycemic/insulinemic levels on endogenous glucose production and on peripheral glucose uptake. In addition, postabsorptive glucose homeostasis was cross-sectionally related to the transplant age (range = 40 d-35 mo) in 4 subgroups of patients 2, 6, 15, and 28 mo after transplantation. 22 subjects with chronic uveitis (CU) undergoing a similar immunosuppressive therapy and 35 normal healthy subjects served as controls. The results showed that successful transplantation was associated with fasting glucose concentration and endogenous glucose production in the lower physiological range within a few weeks after transplantation, and this pattern was maintained throughout the 28-mo follow-up period. Fasting glucose (4. 55+/-0.06 vs. 4.75+/-0.06 mM; P = 0.038) and endogenous glucose production (11.3+/-0.4 vs. 12.9+/-0.5 micromol/[kg.min]; P = 0.029) were lower when compared to CU and normal patients. At different combinations of glycemic/insulinemic levels, liver transplant (LTx) patients showed a comparable inhibition of endogenous glucose production. In contrast, in hypoglycemia, after a temporary fall endogenous glucose production rose to values comparable to those of the basal condition in CU and normal subjects (83+/-5 and 92+/-5% of basal), but it did not in LTx subjects (66+/-7%; P < 0.05 vs. CU and normal subjects). Fasting insulin and C-peptide levels were increased up to 6 mo after transplantation, indicating insulin resistance partially induced by prednisone. In addition, greater C-peptide but similar insulin levels during the hyperglycemic clamp (study 1) suggested an increased hepatic insulin clearance in LTx as compared to normal subjects. Fasting glucagon concentration was higher 6 mo after transplantation and thereafter. During euglycemia/hyperinsulinemia (study 3), the insulin-induced glucagon suppression detectable in CU and

Topics: Adult; Biomarkers; Blood Glucose; C-Peptide; Central Nervous System; Denervation; Glucagon; Glucose Clamp Technique; Growth Hormone; Homeostasis; Humans; Hydrocortisone; Hyperglycemia; Hyperinsulinism; Hypoglycemia; Insulin; Insulin Resistance; Liver; Liver Transplantation; Middle Aged; Models, Biological; Somatostatin; Time Factors

The present study was carried out to evaluate the effect of a low-dose intravenous supplementation of L-arginine on insulin-mediated vasodilatation and insulin sensitivity. The study was performed in healthy subjects (n = 7) and patients with obesity (n = 9) and non-insulin-dependent diabetes mellitus (NIDDM) (n = 9). Insulin-mediated vasodilatation was measured by venous occlusion plethysmography during the insulin suppression test, evaluating insulin sensitivity. Experiments were performed twice in each subject in the presence or absence of a concomitant infusion of L-arginine (0.52 mg kg-1 min-1). L-Arginine restored the imparied insulin-mediated vasodilatation observed in obesity (22.4 +/- 4.1%, P < 0.01 vs. without L-arginine) and NIDDM (20.3 +/- 3.2%, P < 0.01 vs. without L-arginine). In healthy subjects, no effect on insulin mediated-vasodilatation was observed (24.8 +/- 3.1% vs. 21.4 +/- 3.1%). Insulin sensitivity was improved significantly (P < 0.001) in all three groups by infusion of L-arginine. No effect of L-arginine was observed on insulin, insulin-like growth factor I (IGF-I), free fatty acids (FFAs) or C-peptide levels during the insulin suppression test. Our data indicate that defective insulin-mediated vasodilatation in obesity and NIDDM can be normalized by intravenous L-arginine. Furthermore, L-arginine improves insulin sensitivity in obese patients and NIDDM patients as well as in healthy subjects, indicating a possible mechanism that is different from the restoration of insulin-mediated vasodilatation.

Topics: Adult; Arginine; C-Peptide; Diabetes Mellitus, Type 2; Fatty Acids; Female; Humans; Insulin; Insulin Resistance; Insulin-Like Growth Factor I; Male; Middle Aged; Obesity; Vasodilation

It has previously been shown that in normal subjects, physiological elevation of norepinephrine (NE) impairs insulin sensitivity (Si) but does not influence insulin secretion. The aim of this study was to determine the effect of short-term physiological elevation of NE on insulin secretion, Si, and glucose-mediated glucose disposal, or the glucose effectiveness index (Sg), in non-insulin-dependent diabetes mellitus (NIDDM). Two intravenous glucose tolerance tests (IVGTTs) were performed in eight well-controlled NIDDM patients, using a supplemental exogenous insulin infusion to achieve an approximation of normal endogenous insulin secretion. The IVGTTs were performed in random order after 30 minutes of either the saline (SAL) or NE (25 ng/kg/min) infusions, which were continued throughout the 3-hour IVGTT. Sg and Si were estimated by minimal model analysis of the IVGTT data as previously described. Plasma C-peptide was used to estimate insulin secretion rate using the ISEC program. NE infusion produced approximately a threefold increase in plasma NE, associated with (1) a significant reduction in glucose disposal ([KG] SAL v NE, 0.73 +/- 0.06 v 0.61 +/- 0.06 x 10(-2).min-1, P < .05), (2) no reduction in Si (2.33 +/- 0.8 v 2.62 +/- 0.9 x 10(-4).min-1/mU/L, NS), (3) a reduced mean second-phase insulin secretion rate (1.21 +/- 0.19 v 1.01 +/- 0.16 x 10(-3) pmol/kg/min per mmol/L glucose, P < .05), (4) a significant increase in Sg (0.89 +/- 0.08 v 1.63 +/- 0.2 x 10(-2).min-1, P < .05), and (5) a corresponding increase in glucose effectiveness at zero insulin ([GEZI] 0.55 +/- 0.13 v 1.30 +/- 0.33 x 10(-2).min-1, P < .05). These results show that in contrast to normal subjects, physiological elevation of NE in NIDDM does not result in a reduction in Si, but causes a reduction in glucose disposal related to inhibition of insulin secretion that is only partially compensated for by increased Sg.

Topics: Adult; Aged; Blood Glucose; C-Peptide; Catecholamines; Computer Simulation; Diabetes Mellitus, Type 2; Fatty Acids, Nonesterified; Female; Glucagon; Glucose; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Male; Middle Aged; Models, Biological; Neurotransmitter Agents; Norepinephrine; Time Factors

To assess the effects of 16 weeks of heavy resistance exercise training (RE) on insulin sensitivity and secretion in healthy older men aged 64 to 75 years (N = 15), stable-label ([6,6,2H2]glucose) intravenous glucose tolerance tests (IVGTTs) were performed before and 7 days after the last bout of exercise. Glucose disappearance rate (Rd) and an index of insulin sensitivity (Si*) were derived using the minimal model of labeled glucose disappearance, and insulin secretion parameters were derived from C-peptide and glucose concentrations measured during the IVGTT, using a minimal model of C-peptide secretion and kinetics. Each subject trained at an intensity of 70% to 95% maximum strength 4 d/wk for 16 weeks on Nautilus (DeLand, FL) weight-training equipment. In conjunction with exercise, six men received daily injections of recombinant human growth hormone ([rhGH] 12.5 to 24 microg/kg/d) and the other nine received placebo injections. GH/placebo injections were administered in a double-blind randomized fashion. The RE program was supervised and progressive in nature, consisting of both upper-and lower-body exercises, and significantly increased muscle strength (P < .05) with no additional benefit from rhGH except for a tendency toward a greater increase in fat-free mass (FFM) in the RE + GH group (P = .06). Peak glucose Rd increased following RE (P < 01), and there was a trend for an improved Si* (ie, from 6.79 +/- 1.14 to 8.42 +/- 0.89 x 10(4) per min/[microU/mL], P = .06). Peak glucose Rd and Si* were unchanged in the RE + GH group following treatment. First- and second-phase insulin secretion were not affected by RE or RE + GH. Glucose tolerance, quantified as the glucose disappearance constant (Kg) between 10 and 32 minutes of the IVGTT, was unchanged by exercise or hormone treatment. These findings support those of a recent study that used the hyperinsulinemic-euglycemic clamp technique (Miller et al, J Appl Physiol 77:1122-1127, 1994), and suggest that when healthy older men engage in RE, whole-body glucose Rd and Si* are improved, and these beneficial effects are not only due to the acute effects of the last bout of exercise. Additionally, in six subjects who received GH, glucose Rd and Si* were not significantly improved following the RE program. Although this may suggest that GH can diminish improvements in glucose Rd and Si* that result from RE, further study is needed to confirm this observation.

Topics: Aged; Body Composition; C-Peptide; Double-Blind Method; Exercise; Glucose; Glucose Tolerance Test; Growth Hormone; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Like Growth Factor I; Male; Middle Aged; Muscle, Skeletal; Physical Education and Training

To investigate the relation between androgen excess and insulin resistance in nonobese Chinese women with polycystic ovary syndrome.. A prospective, controlled study.. School of Clinical Medicine, Nanjing University.. There were three groups: Group 1 (n = 15) comprised nonobese women with polycystic ovary syndrome; Group 2 comprised 12 of these 15 women in whom bilateral wedge resection had been performed six months to one year before enrolling in the study. Group 3 was a control group comprised of 15 normally menstruating women of similar age and body mass index.. An oral glucose (100 g) tolerance test was performed in all women in each group. The areas under the response curve of serum glucose, insulin, C-peptide (C-P), insulin/glucose (I/G) and C-P/insulin (C/I) were calculated by trapezoid rule.. When fasting the three groups had similar levels of glucose, insulin, C-P, I/G and C/I. During the oral glucose tolerance test women of Group 1 had a significantly higher mean serum area of the curve of glucose, insulin, C-P and I/G levels and lower C/I values, compared with the other two groups. Women of Group 2 and those in the control group showed similar levels of these indices during the oral glucose tolerance test.. Androgen excess in women with polycystic ovary syndrome may be responsible for a defect in peripheral insulin sensitivity and hepatic extraction which could be reversed by removing excessive androgens with wedge resection.

Topics: Adult; Analysis of Variance; Androgens; C-Peptide; Female; Follicle Stimulating Hormone; Glucose; Glucose Tolerance Test; Humans; Insulin Resistance; Luteinizing Hormone; Polycystic Ovary Syndrome; Prospective Studies

Most obese patients with noninsulin-dependent diabetes mellitus (NIDDM) are initially treated with diet, then with oral hypoglycemic agents, eventually with insulin. However several reports indicate that in these patients insulin therapy has little chance to control glucose metabolism, promotes weight gain and arterial hypertension, and is likely to aggravate insulin resistance. In this randomized, double-blind trial vs. placebo (P) we evaluated in 29 obese NIDDM patients poorly controlled by insulin (daily insulin doses 48.7 +/- 4.0 U/day, HbA1c 10 +/- 0.27%, mean daily blood glucose levels 12.3 +/- 0.3 mmol/L, fasting C-peptide 1.8 +/- 0.2, C-peptide after 1 mg iv glucagon 3.2 +/- 0.3 ng/mL, means +/- SE), the clinical and metabolic effects of benfluorex (B), a lipid-lowering drug able to improve insulin sensitivity. After a 2-3 week run-in period (1 tablet P at dinner and diet 800 cal/day to lose 5% of the initial body weight (BWi), patients received a 1000 kcal/day diet and were randomized to B, 150 mg/ tablet, or P (3 tablets/day); the time limit was set at a 10% decrease of BWi or at 90 days. At the end of run-in there was a significant reduction of BWi (P < 0.001), fasting (P = 0.002) and mean daily blood glucose levels (P < 0.001), triglycerides (P = 0.02), cholesterol (P < 0.001) and daily insulin doses (P < 0.001). At the end of the double-blind trial, weight-loss was greater (P < 0.05), faster (P = 0.018), and more frequent (P < 0.05) with B than with P, and systolic blood pressure (P < 0.05) decreased only with B. Considering only patients with a 10% decrease of BWi (B = 15, P = 10), HbA1c (P < 0.001) decreased only with B, while fasting insulin levels decreased with both B (P < 0.01) and with P (P < 0.05). Insulin sensitivity was evaluated by means of a double infusion test (LDIGIT, insulin 25 mU/Kg/h plus glucose 4 mg/kg/min, lasting 150 min) at the end of run-in and at the end of the double-blind trial; at the end of the double-blind trial steady state blood glucose (SSBG, P < 0.05), free fatty acids (FFA, P < 0.05) and blood beta-hydroxybutyrate (P < 0.05) decreased only with B, while blood glycerol decreased both with both P (P < 0.05) and B (P < 0.06). At the end of the double-blind trial, C-peptide release was unchanged with either P or B. In conclusion, benfluorex potentiates the effects of hypocaloric diet on weight loss and on glycemic control in obese NIDDM patients treated with insulin, and this effect seems to be the result of an

Topics: 3-Hydroxybutyric Acid; Appetite Depressants; Body Weight; C-Peptide; Diabetes Mellitus; Diabetes Mellitus, Type 2; Double-Blind Method; Fatty Acids, Nonesterified; Fenfluramine; Glucose; Glycerol; Humans; Hydroxybutyrates; Insulin; Insulin Resistance; Insulin Secretion; Middle Aged; Obesity; Placebos

Insulin sensitivity was measured by insulin tolerance test using KITT as an index of insulin mediated glucose metabolism in 9 non-obese healthy offspring of conjugal diabetic parents (OCDP) and 9 non-obese NIDDM patients. The mean KITT value in the offspring of conjugal diabetic parents was 3.85 +/- 1.64 min-1 x 100 which was lower (P < 0.05) than the value of 5.49 +/- 1.9 min-1 x 100 in the control subjects. While, the mean KITT value in NIDDM patients was 1.85 +/- 0.9 min-1 x 100 which was significantly lower (P < 0.001) than that in the control subjects. Estimation of plasma immunoreactive insulin (IRI) and C-peptide in these subjects and in subjects with impaired glucose tolerance (IGT) showed significantly higher levels of insulin than that in the control subjects but there was no corresponding increase in the C-peptide levels. The mean area under the insulin curve (IRI) was 242 +/- 69 microU/ml in the control subjects versus 527 +/- 206 microU/ml in IGT (P < 0.001), 648 +/- 215 microU/ml in NIDDM (P < 0.001) and 466 +/- 130 microU/ml in OCDP (P < 0.001). These results suggest that 1) healthy offspring of two type II diabetic parents have decreased insulin sensitivity and insulin resistance is present in all the NIDDM patients, 2) peripheral hyperinsulinism is a common feature in healthy offspring of conjugal diabetic parents, and in subjects with IGT and mild NIDDM and this hyperinsulinism is not due to increased B-Cell secretion but due to some metabolic alterations of insulin occurring at the extra pancreatic levels.

Topics: Adult; Blood Glucose; Body Weight; C-Peptide; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Female; Glucose Intolerance; Glucose Tolerance Test; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Male

Women with a history of gestational diabetes mellitus (GDM) tend to be insulin-resistant and hyperinsulinemic and are predisposed to the subsequent development of non-insulin-dependent diabetes mellitus (NIDDM). In the evolution of glucose intolerance, the first clinically detectable abnormality has not been defined and the relative importance of contributions of abnormal insulin secretion and insulin resistance is controversial. The present study was performed to evaluate the insulin secretory responses to oral and intravenous glucose and to mixed meals in women with a history of GDM, and to determine if the hyperinsulinemia present in these subjects is appropriate for the degree of insulin resistance. To address these questions, we studied the insulin secretory responses to oral glucose over a 3-hour period and to three mixed meals over a 24-hour period, and quantified the acute insulin response to glucose (AIRglucose) and insulin sensitivity (SI) during frequently sampled intravenous glucose tolerance tests (FSIVGTTs). Studies were performed in seven subjects with a history of GDM and in seven matched controls. Insulin secretion rates (ISRs) were derived by deconvolution of peripheral C-peptide values using a two-compartment model and standard C-peptide kinetic parameters.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Administration, Oral; Adult; Blood Glucose; C-Peptide; Causality; Diabetes Mellitus, Type 2; Diabetes, Gestational; Eating; Female; Glucose; Glucose Tolerance Test; Humans; Hyperinsulinism; Injections, Intravenous; Insulin; Insulin Resistance; Insulin Secretion; Pregnancy; Proinsulin; Time Factors

Insulin resistance that exists in patients with essential hypertension and in those with non-insulin-dependent diabetes mellitus (NIDDM) may be the common denominator for the impaired glucose homeostasis and elevated blood pressure (BP) levels in patients with NIDDM. Therefore, treatment that improves insulin action may also improve BP levels. Consequently, a four-phase (glipizide v insulin) cross-over design study was conducted to determine a better effect of glipizide treatment on insulin sensitivity and the effect this has on BP in 19 NIDDM patients. Patients were subjected to 1 month of diet only (phase I) followed by 3 months of glipizide treatment (phase II), then an additional 1 month of diet only (phase III), and finally 3 months of insulin treatment (phase IV). At the end of phases I, II, and IV oral glucose tolerance tests (OGTT) were performed and plasma glucose, insulin, and C-peptide levels were analyzed. Fasting plasma glucose, insulin, total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol and triglycerides, glycated hemoglobin, fructosamine, and 2-h postprandial plasma glucose were also analyzed at each phase. Supine and sitting BP levels and body weights were determined biweekly during the study. With the exception of higher plasma insulin and C-peptide levels during the OGTT (area under the curve) in phase IV (insulin) v phase II (glipizide) (both P < .05), and higher fasting plasma insulin levels (P < .06), there were no consistently significant metabolic differences between phases IV and II.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Aged; Blood Glucose; Blood Pressure; C-Peptide; Cholesterol; Cross-Over Studies; Diabetes Mellitus, Type 2; Diet, Diabetic; Female; Glipizide; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Lipids; Male; Middle Aged; Prospective Studies

Insulin resistance is a significant pathogenetic factor in the development of non-insulin-dependent diabetes mellitus (NIDDM). A new class of drugs, the thiazolidinediones, have been shown to lower blood glucose levels without stimulating insulin secretion. We report the metabolic effect of the thiazolidinedione, darglitazone, in obese NIDDM subjects. Nineteen subjects were enrolled in a double-blind placebo-controlled study in which 25 mg of darglitazone was given once a day for 14 days. Nine subjects received the active drug and ten subjects received placebo. Darglitazone-treated subjects showed; 1) a decrease in 24-h plasma glucose area under the curve from 292.8 +/- 31.2 to 235.2 +/- 21.6 mmol.h-1.l-1 p = 0.002; 2) a decrease in 24-h serum insulin area under the curve from 1027.2 +/- 254.4 to 765.6 +/- 170.4 microU.h-1.l-1 p = 0.045; 3) a decrease in 24-h non-esterified fatty acid area under the curve from 1900 +/- 236 to 947 +/- 63 g.h-1.l-1 p = 0.002; 4) a decrease in mean 24-h serum triglyceride by 25.9 +/- 6.2% as compared to -3.9 +/- 4.8% for the placebo-treated group, p = 0.012. Placebo-treated subjects showed no change in their metabolic parameters after treatment. Thus, darglitazone is effective in increasing insulin effectiveness in obese NIDDM subjects. The potential for this and similar drugs to treat or prevent NIDDM as well as the insulin-resistance syndrome needs to be explored.

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Double-Blind Method; Fatty Acids, Nonesterified; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Obesity; Thiazoles; Thiazolidinediones

Comparison of the effectiveness of combined therapy vs. an insulin regimen in NIDDM patients with secondary failure of oral hypoglycemic agents. RESEARCH DESIGN, PATIENTS AND METHODS: 27 NIDDM patients were randomly allocated to Group A (n = 14, insulin) and Group B (n = 13, insulin and sulfonylurea) with crossover after 3 months. After the next 3 months a decision was made about the further treatment according to the metabolic control. The patients were then treated for another year with the more successful regimen. Metabolic control, residual beta-cell secretory capacity, degree of peripheral insulin resistance (clamp) and insulin dose were followed during the whole study.. (median, interquartile range, in brackets; *, statistically significant difference at P < 0.05): the combined therapy was better than insulin alone in 2/3 of patients. Glycemic control was better (HbA1c at 3 months: Group A = 7.9(1.1)% vs. Group B = 7.0(0.5)%*; HbA1c at 6 months: Group A = 7.4(1.5)% vs. Group B = 8.1(1.5)%. Insulin dose was lower during the combined therapy in the first 3 months: Group A = 0.62(0.18) U/kg body weight vs. Group B = 0.39(0.16) U/kg body weight*. Combined treatment was associated with increased C-peptide excretion both fasting and postprandially. No significant differences in peripheral insulin resistance were noted between the two groups. The combined treatment remained successful even after one year. The two groups of patients with different effective treatment did not differ significantly in any of the observed parameters.. the combined therapy was more effective than insulin alone. Its favourable effect persisted after treatment for a year. It seems better to start the treatment of the oral failure with combined therapy compared with insulin first and later followed by combined therapy. On the basis of the observed parameters it is impossible to determine in advance which kind of treatment is more suitable for the individual patient.

Topics: Blood Glucose; Body Mass Index; C-Peptide; Cross-Over Studies; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Drug Therapy, Combination; Follow-Up Studies; Glucose Clamp Technique; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Middle Aged; Sulfonylurea Compounds; Time Factors; Treatment Failure

In spite of the high prevalence of diabetes mellitus (DM) in patients with liver cirrhosis (LC) few studies have focused on the clinical implications of this association. We investigated the clinical and pancreatic-endocrine features of 34 patients who developed DM after LC (Group I). Results were compared with 34 carefully matched patients with only Type II DM (Group II). A standard meal test was performed in 26 patients with normal renal function from each group to assess beta-cell function. Group I patients, less frequently had retinopathy (14.7% vs. 45.5%, P < 0.05) and a family history of diabetes (23.5% vs. 58.8%, P < 0.01). Group I patients also showed signs of enhanced insulin resistance, reflected by higher insulin dose requirements in insulin-treated patients (0.87 +/- 0.10 vs. 0.62 +/- 0.05 IU/kg/day, P < 0.01) and increased basal C-peptide values (0.88 +/- 0.06 vs. 0.68 +/- 0.07 pmol/l, P < 0.05, respectively) than those in Group II. These results suggest that several clinical features, probably related to the hepatopathy, define DM occurring in patients with LC.

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Humans; Insulin; Insulin Resistance; Islets of Langerhans; Liver Cirrhosis; Male; Middle Aged; Prevalence

Hyperinsulinaemia and abnormalities in hepatic insulin extraction commonly coexist in ethnic groups with severe insulin resistance. Therefore, we compared the effects of ethnicity on glucose/insulin/C-peptide dynamics, hepatic insulin extraction, and insulin sensitivity in healthy black (n = 32) and white (n = 30) Americans. Standard oral glucose tolerance test (OGTT) and tolbutamide-modified, frequently sampled, intravenous glucose tolerance (FSIVGT) tests were performed in each subject. Insulin sensitivity index (S1)) was calculated using the MINIMOD method described by Bergman et al. Basal and post-stimulation hepatic insulin extraction were calculated by the molar ratios of C-peptide and insulin concentrations during the basal steady state and areas under the post-stimulation hormone curves, respectively. Apart from a slightly greater mean serum glucose peak response after oral glucose in the whites, mean glucose levels were identical in the blacks and whites during both stimulations. In contrast, serum insulin levels at basal and during both stimulations were significantly greater (2-3 fold) in the blacks than whites. However, the corresponding C-peptide responses were identical in both groups. The basal and postprandial hepatic insulin extraction were 33% and 45% lower in the blacks when compared to whites, respectively. The mean S1 was significantly (p < 0.02) lower in the blacks (4.93 +/- 0.46) than the whites (7.17 +/- 0.88 x 10(-4).min-1 (mU l-1)-1). We conclude that ethnicity may be a major determinant of the mechanism of peripheral hyperinsulinaemia and insulin insensitivity in black and white Americans.

Topics: Administration, Oral; Adult; Black People; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucose; Glucose Tolerance Test; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Insulin Secretion; Liver; Male; United States; White People

Cirrhosis is characterized by paradoxical growth hormone secretion in response to glucose and insulin infusion. To ascertain whether this abnormality contributes to insulin resistance, euglycemic hyperinsulinemic glucose clamps were performed on six patients with cirrhosis and six normal control subjects. Each patient with cirrhosis underwent two clamps in random order, a clamp with somatostatin (250 micrograms/hr) together with insulin and glucagon replacement, and a control clamp without somatostatin. The normal subjects underwent the control clamp only. During the control clamp, growth hormone levels were considerably higher in the patients with cirrhosis (6.1 +/- 0.4 vs. 0.5 +/- 0.4 mU/L, p < 0.02), and glucose uptake was considerably lower (3.29 +/- 0.56 vs. 9.52 +/- 1.14 mg/kg/min, p < 0.001). Indirect calorimetry indicated that the defect was accounted for by lower nonoxidative glucose disposal (1.23 +/- 0.45 vs. 6.00 +/- 0.73, p < 0.001). Peripheral glucose uptake, exemplified by forearm glucose uptake (0.27 +/- 0.04 vs. 1.22 +/- 0.42 mg/100 ml/min, p < 0.02), and calculated insulin sensitivity (24 +/- 8 vs. 114 +/- 20 microliters/kg/min per mU/L) were particularly diminished. In the patients with cirrhosis somatostatin suppressed growth hormone levels (6.1 +/- 1.2 to 1.2 +/- 0.4 mU/L, p < 0.05). However, no significant changes occurred in whole-body glucose uptake (3.29 +/- 0.56 vs 3.01 +/- 0.54 mg/kg/min), forearm glucose uptake (0.27 +/- 0.04 vs 0.30 +/- 0.01 mg/100 ml/min) or insulin sensitivity (24 +/- 8 vs, 35 +/- 10 microliters/kg/min/mU/L, p = 0.42).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; C-Peptide; Calorimetry, Indirect; Fatty Acids, Nonesterified; Glucose; Glucose Clamp Technique; Growth Hormone; Humans; Insulin Resistance; Insulin-Like Growth Factor I; Liver; Liver Cirrhosis, Alcoholic; Male; Middle Aged; Somatostatin

To evaluate whether beta-cell hyperfunction characterizes glucose intolerant states per se independent of fasting glycemia, we conducted a case-control study among 430 subjects who were classified, by NDGG criteria, as having normal glucose tolerance (n = 230, 130M/130F), nondiagnostic tolerance (NDT, n = 100, 50M/50F) and impaired glucose tolerance (IGT, n = 100, 50M/50F). Thirty-four subjects (17M/17F) with normal glucose tolerance were matched by age, sex, body mass index (BMI), waist-to-hip ratio (WHR), fasting glucose and HbA1c with 30 NDT (15M/15F) and 30 IGT (15M/15F) subjects. The continuous and significant increase in insulin and C-peptide levels across categories of glucose tolerance (from normal to NDT to IGT) was no longer evident in the case-control study: at a fasting plasma glucose ranging from 5.2-5.5 mmol/L (HbA1c was 5%) the concentration of fasting C-peptide was 0.793 +/- 225 nmol/L (mean +/- SD) in subjects with normal glucose tolerance, 0.805 +/- 200 nmol/L in NDT and 0.807 +/- 231 nmol/L in IGT subjects (p = NS). Similarly, plasma concentrations of triglycerides and blood pressure values were similar when subjects of different categories were compared at the same level of glycemia. Sixteen normal subjects were rendered mildly hyperglycemic by a 24-h glucose infusion to match the fasting glucose level of NDT (1 mg/kg/min) and IGT (2 mg/kg/min) subjects. At the same fasting glucose level, normal subjects presented elevations of fasting C-peptide significantly (p < 0.01) higher than subjects belonging to the NDT and IGT categories.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Aged; Blood Glucose; Body Constitution; Body Mass Index; C-Peptide; Case-Control Studies; Female; Glucose Intolerance; Glycated Hemoglobin; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Male; Middle Aged; Triglycerides

We have evaluated the short-term effects of amiloride on insulin action in vivo, since amiloride is known to impair insulin action in vitro. Seven healthy subjects were treated according to a randomized, double-blind, cross-over protocol. The treatment periods were 3 days each with amiloride 15 mg daily and placebo. Insulin action on glucose turnover was assessed directly after each treatment period with the hyperinsulinaemic euglycaemic glucose clamp technique. At the two insulin concentrations studied (approximately 30 mU.l-1 and approximately 200 mU.l-1), the glucose infusion rate required to maintain constant euglycaemia did not differ after either amiloride or placebo. The rates of glucose production and utilization were also similar, whereas the so-called insulin sensitivity index at the lower insulin concentration was significantly reduced (by about 15%) after amiloride. Moreover, amiloride produced significantly higher fasting insulin and C-peptide concentrations, whereas fasting glucose and NEFA concentrations were unaltered. In conclusion, these data suggest that short-term amiloride slightly impairs insulin sensitivity with respect to glucose uptake. However, overall glucose homoeostasis does not appear to be affected, probably due to a compensatory rise in plasma insulin.

Topics: Adolescent; Adult; Amiloride; Blood Glucose; C-Peptide; Cross-Over Studies; Double-Blind Method; Fatty Acids, Nonesterified; Female; Glucose Clamp Technique; Humans; Insulin; Insulin Resistance; Male

Topics: Blood Pressure; C-Peptide; Dihydropyridines; Double-Blind Method; Female; Heart Rate; Humans; Hypertension; Insulin Resistance; Male; Middle Aged; Potassium

1. Twelve healthy male volunteers received lacidipine 4 mg and matching placebo, each for 2 weeks, in a randomised, double-blind crossover study, and attended on 4 study days to evaluate the effects of single and multiple dosing using the euglycaemic hyperinsulinaemic 'clamp'. 2. On each study day, a primed constant-rate infusion of soluble insulin (1.5 mu kg-1 min-1) was administered for 180 min with a variable-rate infusion of 20% dextrose to maintain euglycaemia (5.2 mmol l-1). Whole-body insulin sensitivity was calculated during the past 40 min of the 'clamp'. At frequent intervals, measurements of BP and HR were recorded and venous blood samples collected for serum insulin, C-peptide, potassium, triglyceride (TG) and plasma noradrenaline concentrations. 3. Lacidipine was generally well tolerated and there were no adverse biochemical events. Mean values for insulin sensitivity +/- s.d. were 8.9 +/- 1.6 and 9.1 +/- 2.0 mg kg-1 min-1 after single doses of lacidipine and placebo respectively (95% CI, -1.0, 1.3), and correspondingly 9.6 +/- 2.1 and 9.7 +/- 1.5 mg kg-1 min-1 after 2 weeks (95% CI, -1.0, 1.3). 4. There was a significant reduction in fasting serum TG concentrations after 2 weeks of lacidipine: 0.7 +/- 0.3 mmol l-1 vs 0.9 +/- 0.6 (P < 0.001). However, changes in serum TG and potassium concentrations during the 'clamp' were not significantly different between the 4 study days. 5. Thus, in 'insulin sensitive' volunteers, lacidipine reduces fasting serum TG concentrations but has no effect on insulin-stimulated uptake of glucose, potassium and TG under euglycaemic hyperinsulinaemic conditions.

Topics: Adolescent; Adult; Blood Glucose; Blood Pressure; C-Peptide; Calcium Channel Blockers; Dihydropyridines; Double-Blind Method; Heart Rate; Humans; Insulin; Insulin Resistance; Male; Potassium; Triglycerides

To evaluate the change in lipids and insulin sensitivity in 10 obese type II diabetic patients after treatment with benfluorex or placebo for 2 wk.. The study had a double-blind, cross-over design. Insulin sensitivity was measured with the euglycemic hyperinsulinemic glucose clamp technique at two different insulin infusion rates: 0.05 (clamp 1) and 0.10 U.kg-1.h-1 (clamp 2).. Subanalysis of the glucose infusion rate under steady-state conditions in the last 30 min of clamp 2 yielded a glucose infusion rate of 5.36 and 3.87 mmol.kg-1.min-1 after benfluorex and placebo, respectively (P = 0.018).. Benfluorex increases insulin sensitivity in obese type II diabetic patients.

Topics: Apolipoprotein A-I; Apolipoproteins B; Appetite Depressants; Blood Glucose; C-Peptide; Cholesterol; Diabetes Mellitus; Diabetes Mellitus, Type 2; Fenfluramine; Glucose Clamp Technique; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Lipids; Middle Aged; Multivariate Analysis; Obesity; Placebos; Triglycerides

To investigate the effects of metformin on glycemic control, insulin resistance, and risk factors for cardiovascular disease in NIDDM subjects from two ethnic groups (Caucasian and Asian) with different risks of cardiovascular disease.. A total of 27 subjects with NIDDM (17 Caucasian, 10 Asian) were given metformin and placebo each for a 12-wk period in a randomized, double-blind, placebo-controlled crossover study, and the dose was increased after 1 and 6 wk, up to a maximum of 850 mg three times a day. Insulin resistance, glycemic control, and cardiovascular risk factors were assessed before and after each treatment phase. The end of 12 wk of metformin treatment was compared with the end of 12 wk of placebo treatment.. Metformin treatment was associated with significant improvement in FPG at 6 and 12 wk (mean difference at 12 wk, -3.08 mM, 95% CI -4.12 to -2.04 mM, P < 0.0001) and MCR of glucose (median difference 0.40 ml.kg-1.min-1, interquartile range -0.10 to 1.30 ml.kg-1.min-1, P = 0.036). beta-cell function calculated by HOMA also improved significantly (median difference 14%, interquartile range 7 to 23%, P < 0.001). Total triglyceride (median difference -0.2 mM, interquartile range -0.6 to 0.1 mM, P = 0.034), total cholesterol (mean difference -0.52 mM, 95% CI -0.83 to -0.22 mM, P = 0.002), and LDL cholesterol (mean difference -0.40 mM, 95% CI -0.64 to -0.16 mM, P = 0.002) fell significantly on metformin treatment, whereas no significant changes were observed in HDL cholesterol. PAI-1 activity fell significantly (mean difference -5.3 AU/ml, 95% CI -8.2 to -2.4 AU/ml, P = 0.001), but plasma fibrinogen concentrations and platelet function, spontaneous or agonist induced, were unaffected. UAE was lower on metformin treatment (median difference -2.4 micrograms/min, interquartile range -4.4 to -0.2 micrograms/min, P = 0.004), but metformin had no significant effect on BP. The effects of metformin on glycemic control and cardiovascular risk factors were generally similar in the two ethnic groups.. These findings indicate that metformin treatment improves glycemic control, and lowers insulin resistance and risk factors for cardiovascular disease, including PAI-1, and may therefore be useful in the long-term management of NIDDM subjects who have a high risk of cardiovascular disease.

Topics: Albuminuria; Asia; Biomarkers; Blood Glucose; C-Peptide; Cardiovascular Diseases; Cholesterol; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Double-Blind Method; Ethnicity; Fructosamine; Hexosamines; Humans; Insulin; Insulin Resistance; Islets of Langerhans; Metabolic Clearance Rate; Metformin; Plasminogen Activator Inhibitor 1; Platelet Aggregation; Risk Factors; Triglycerides; United Kingdom; White People

Using carefully selected relatively non-obese non insulin dependent diabetic patients, we were not able to show differences in standard measures of insulin production or insulin action between patients treated with a long acting crystalline zinc insulin, with glibenclamide, or with metformin for a six week period. All three drugs were hypoglycaemic, but a fall in basal hepatic glucose output measured by the 3H3 glucose technique was only seen in those patients who had an initial fasting plasma glucose above 12.0 mmol/l, irrespective of treatment.

Topics: Blood Glucose; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Glucose Clamp Technique; Glyburide; Glycated Hemoglobin; Glycosuria; Humans; Insulin; Insulin Resistance; Insulin Secretion; Metabolic Clearance Rate; Metformin; Middle Aged; Radioisotope Dilution Technique; Tritium

1. Danazol elevates plasma insulin, plasma glucagon and serum low-density lipoprotein concentrations and reduces the serum high-density lipoprotein concentration. 2. Associations between these disturbances were studied in 17 women receiving danazol therapy for endometriosis. Eleven women underwent intravenous glucose tolerance tests with measurement of plasma glucose, insulin, C-peptide and glucagon concentrations and modelling analysis of intravenous glucose tolerance test concentration profiles. Six women underwent glucagon sensitivity tests. Serum concentrations of lipids and lipoproteins were measured in all cases. 3. Danazol reduced the fasting plasma glucose and insulin concentrations, but markedly raised the fasting plasma glucagon concentration. The insulin and C-peptide responses to the intravenous glucose tolerance test were increased twofold and the net decrement in glucagon concentration was increased tenfold. The glucose response to the intravenous glucose tolerance test was unaffected. Insulin sensitivity was reduced by 55%. Both first-phase plasma insulin responsiveness and net first-phase pancreatic insulin secretion were increased; insulin half-life was prolonged. The glucose response to the glucagon sensitivity test was reduced on treatment. The calculated low-density lipoprotein cholesterol level rose by 20%, whereas high-density lipoprotein cholesterol level fell by 47%. None of these changes in serum lipoprotein levels correlated with changes in insulin metabolism. In general, metabolic changes normalized after 3 months. 4. Danazol increases the sensitivity of pancreatic insulin and glucagon secretion to glucose. Danazol-induced insulin and glucagon resistance could be due to receptor down-regulation resulting from hypersecretion of insulin and glucagon.

Topics: Adult; Blood Glucose; C-Peptide; Cholesterol; Danazol; Endometriosis; Female; Glucagon; Humans; Insulin; Insulin Resistance; Models, Biological

Insulin resistance and hyperinsulinaemia are, in some prospective studies, linked to an increased cardiovascular risk, at least in men. We tested the hypothesis that hyperinsulinaemia may be reduced by non-pharmacological methods independently of other cardiovascular risk factors.. In a non-pharmacological intervention study for 1 year three groups of subjects (hypertensives as well as normotensives) were selected after stratification for insulin level at baseline. Half of the hyperinsulinaemic subjects were randomly assigned to active intervention with physical exercise and dietary regulation (HI-A group), the other half were followed passively during the study period (HI-P group). Normo-insulinaemics and hypo(low)-insulinaemics also underwent active intervention (NI-A and LI-A groups, respectively).. Primary health care in Sweden.. During the 1-year follow-up subjects in the HI-A group reduced their weight, waist:hip ratio and systolic and diastolic blood pressure, as well as their low:high-density lipoprotein (LDL:HDL)-cholesterol ratio. Glucose levels before and during an oral glucose tolerance test did not change. However, plasma insulin and plasma-C-peptide decreased both in the fasting state and after 1 and 2 h of oral glucose tolerance testing. This decrease was independent of the previously mentioned reduction in weight, waist:hip ratio, blood pressure and LDL:HDL-cholesterol ratio. No reduction in insulin levels was seen in the HI-P, NI-A or LI-A groups, but in the HI-P group there was a slight decrease in fasting plasma-C-peptide levels. In the HI-A group dietary improvements were observed during the study period, with a reduction in energy intake, fat consumption and cholesterol intake. Fibre intake was increased. No major changes were seen in the HI-P group.. We conclude that in hypertensive and normotensive subjects with hyperinsulinaemia insulin levels can be reduced by active non-pharmacological treatment for 1 year without altering glucose tolerance. This shows that insulin resistance may be lowered by non-pharmacological treatment, which may be of considerable importance, and not only for hypertensives.

Topics: Adult; Aged; Blood Glucose; C-Peptide; Cholesterol, HDL; Female; Follow-Up Studies; Humans; Hyperinsulinism; Hypertension; Insulin; Insulin Resistance; Life Style; Male; Middle Aged; Multivariate Analysis; Smoking Prevention; Surveys and Questionnaires; Sweden; Weight Loss

We demonstrated similar plasma concentrations and urinary losses but lower erythrocyte magnesium concentrations (2.18 +/- 0.04 vs 1.86 +/- 0.03 mmol/L, P less than 0.01) in twelve aged (77.8 +/- 2.1 y) vs 25 young (36.1 +/- 0.4 y), nonobese subjects. Subsequently, aged subjects were enrolled in a double-blind, randomized, crossover study in which placebo (for 4 wk) and chronic magnesium administration (CMA) (4.5 g/d for 4 wk) were provided. At the end of each treatment period an intravenous glucose tolerance test (0.33 g/kg body wt) and a euglycemic glucose clamp with simultaneous [D-3H]glucose infusion and indirect calorimetry were performed. CMA vs placebo significantly increased erythrocyte magnesium concentration and improved insulin response and action. Net increase in erythrocyte magnesium significantly and positively correlated with the decrease in erythrocyte membrane microviscosity and with the net increase in both insulin secretion and action. In aged patients, correction of a low erythrocyte magnesium concentration may allow an improvement of glucose handling.

Topics: Adult; Aged; Aged, 80 and over; Blood Glucose; Blood Viscosity; Body Mass Index; C-Peptide; Double-Blind Method; Erythrocytes; Female; Glucagon; Homeostasis; Humans; Insulin; Insulin Resistance; Lactates; Magnesium; Male; Pyruvates

The effects of metformin on glycaemia, insulin and c-peptide levels, hepatic glucose production and insulin sensitivity (using the euglycaemic, hyperinsulinaemic clamp) were evaluated at fortnightly intervals in 9 Type 2 diabetic patients using a stepwise dosing protocol: Stage 1--no metformin for four weeks; stage 2--metformin 500mg mane; stage 3--metformin 500mg thrice daily; stage 4--metformin 1000mg thrice daily. Results are expressed as Mean +/- SEM. Fasting blood glucose decreased from basal values (9.7 +/- 1.0 mmol/L) by 13% at stage 2, 34% at stage 3 and 41% at stage 4 (p less than 0.02 vs basal for all stages; p less than 0.02 stage 2 vs stage 3). Post-prandial glycaemia was significantly improved only with metformin 3000mg/day (p less than 0.05). Fasting, meal-stimulated and total insulin and c-peptide levels showed no change. Hepatic glucose output did not change significantly with metformin. Insulin sensitivity, measured as total glucose utilisation during hyperinsulinaemia, increased from stage 1 (10.3 +/- 2.1 mumoL/kg/min) by 23% at stage 3 (p less than 0.05) and by 29% at stage 4 (p less than 0.02). Basal metabolic clearance of glucose increased compared to stage 1 (1.69 +/- 0.16 mL/kg/min) by 30% at stage 2, 53% at stage 3 and 44% at stage 4 (all p less than 0.02). This study demonstrates that improved efficiency of glucose utilisation, both basally and under conditions of euglycaemic hyperinsulinaemia, is the basis of metformin's antihyperglycaemic action.

Topics: Adult; Aged; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucose; Humans; Insulin; Insulin Resistance; Liver; Male; Metformin; Middle Aged; Prospective Studies

To determine whether hyperinsulinaemia of human obesity is dependent on the activity of the parasympathetic nervous system, and whether activation of the parasympathetic nervous system plays a role in glucose-induced thermogenesis, the metabolic effect of a continuous intravenous glucose infusion [44.4 mumol kg-1 body weight (bw) min-1] with or without atropine infusion was assessed in 11 obese patients and 10 lean controls. Compared with lean controls, obese patients had increased basal and glucose-stimulated plasma insulin and C-peptide concentrations and increased plasma glucose concentrations during glucose infusion. Glucose oxidation during i.v. glucose was lower in obese patients than in lean controls. Glucose-induced thermogenesis was similar in obese patients and in lean controls. Atropine infusion did not affect basal plasma glucose, insulin or free fatty acid concentrations nor glucose-stimulated plasma glucose, insulin, C-peptide, glucagon or free fatty acid concentrations in both groups of subjects. Glucose and lipid oxidation rates and glucose-induced thermogenesis were also unaffected by atropine administration. It is concluded that (1) glucose-stimulated hyperinsulinaemia in human obesity is not dependent on a hyperactivity of the parasympathetic nervous system, which indicates that human obesity is different from most animal models of obesity; (2) glucose-induced thermogenesis is similar in obese and lean subjects when a similar load of glucose is administered; (3) inhibition of the parasympathetic nervous system does not affect the thermic effect of i.v. glucose.

Topics: Adult; Atropine; Blood Glucose; Body Temperature Regulation; C-Peptide; Female; Glucose; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Insulin Secretion; Male; Obesity; Parasympathetic Nervous System

It is well established that patients with non-insulin-dependent diabetes mellitus (NIDDM) are resistant to insulin. However, the contribution of hepatic and extrahepatic tissues to insulin resistance remains controversial. The uncertainty may be at least in part due to errors introduced by the unknowing use in previous studies of impure isotopes to measure glucose turnover. To determine hepatic and extrahepatic responses to insulin in the absence of these errors, steady-state glucose turnover was measured simultaneously with [6-3H]- and [6-14C]glucose during sequential 5- and 4-h infusions of insulin at rates of 0.4 and 10 mU.kg-1.min-1 in diabetic and nondiabetic subjects. At low insulin concentrations, [6-3H]- and [6-14C]glucose gave similar estimates of glucose turnover. Hepatic glucose release was equal to but not below zero in the nondiabetic subjects, but persistent glucose release (P less than 0.001) and decreased glucose uptake (P less than 0.001) was observed in the diabetic patients. At high insulin concentrations, both isotopes underestimated glucose turnover during the 1st h after initiation of the high-dose insulin infusion. More time (P less than 0.05) was required to reachieve steady state in NIDDM than nondiabetic subjects. At steady state, [6-3H]- but not [6-14C]glucose systematically underestimated (P less than 0.05) glucose turnover in both groups due to the presence of a tritiated nonglucose contaminant. The percentage of radioactivity in plasma due to tritiated contaminants was linearly related to turnover.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Blood Glucose; C-Peptide; Carbon Radioisotopes; Chromatography, High Pressure Liquid; Diabetes Mellitus, Type 2; Female; Glucose; Humans; Infusion Pumps; Insulin; Insulin Resistance; Liver; Male; Middle Aged; Tritium

Hyperthyroidism is considered to be an insulin-resistant state, but a quantitative evaluation of some action of insulin is still lacking. We performed euglycaemic clamp at about 350 and 7000 pmol l-1 plasma insulin concentration in combination with the 3H-glucose infusion in 12 patients with Graves' disease and in 12 matched controls. Fasting plasma insulin (126 +/- 6.5 vs. 77.5 +/- 5.7 pmol l-1; P less than 0.001), C-peptide (502 +/- 36 vs. 363 +/- 41 pmol l-1; P less than 0.001) and glucagon (47 +/- 3.3 vs. 33.3 +/- 3 pmol l-1; P less than 0.01) were significantly higher in hyperthyroids than in euthyroids. Basal hepatic glucose production was significantly higher in hyperthyroids than in euthyroids (18.3 +/- 1.4 vs. 9.2 +/- 0.5 mumol l-1; P less than 0.0001), and its suppression during physiological hyperinsulinaemia was only 50% in hyperthyroids. Glucose utilization and suppression of lipolysis were normally stimulated by insulin. All parameters altered during hyperthyroidism were normalized during methimazole-induced euthyroidism. We conclude that insulin resistance involves mainly glucose rather than lipid and is selective at the hepatic level.

Topics: Adult; Blood Glucose; C-Peptide; Female; Glucagon; Glucose; Graves Disease; Humans; Insulin; Insulin Resistance; Insulin Secretion; Liver; Male; Middle Aged

An insulin suppression test performed in random order with either biosynthetic human insulin or purified pork insulin was used to compare biological activity of these two insulins in obese patients suffering from varying degrees of glucose intolerance. Blood glucose curve, steady-state blood glucose levels, insulin sensitivity indices and steady-state plasma insulin levels were identical during the two sets of tests. Furthermore endogenous insulin and glucagon secretion were similarly suppressed. The insulin suppression test is a simple and rapid procedure to compare the biological activity of fast-acting insulins. Our results confirm the insulin-resistance in obesity and clearly show that biosynthetic human and porcine insulins have similar biological potency.

Topics: Adult; Aged; Animals; Blood Glucose; C-Peptide; Diabetes Mellitus; Diabetes Mellitus, Type 2; Female; Glucagon; Glucose; Humans; Insulin; Insulin Resistance; Insulin, Regular, Pork; Male; Middle Aged; Obesity; Recombinant Proteins; Somatostatin; Swine

This study was performed in two randomly defined groups of obese patients with polycystic ovaries to investigate the overall effects of hypocaloric diet combined (group 2) or not combined (group 1) with an antiandrogenic therapy (cyproterone acetate, 50 mg/day, plus ethinyl estradiol, 0.05 mg/day) on sex hormone plasma levels, insulin secretion and resistance, and body weight loss and on their reciprocal interrelationships. All obese patients with polycystic ovaries showed elevated luteinizing hormone and androgen levels, hyperinsulinemia, and marked insulin resistance. After an average period of 3 months both groups showed a similar weight loss and a similar reduction in the insulin-resistant state. During treatment in group 1 three patients had a greater frequency of menstrual bleeding, and in one of them an ovulatory cycle was documented. Whereas, no changes in gonadotropin and sex steroid levels were found in group 1, a significant fall was observed in group 2. No relationships were observed between these changes and those which occurred on insulin levels. We conclude that hyperandrogenism in obese patients with polycystic ovaries does not appear to be a primary factor leading to the insulin-resistant state.

Topics: Adolescent; Adult; Androgen Antagonists; Body Weight; C-Peptide; Energy Intake; Female; Glucose Tolerance Test; Gonadal Steroid Hormones; Humans; Insulin; Insulin Resistance; Male; Obesity; Polycystic Ovary Syndrome

To determine whether sulfonylureas and exogenous insulin have different effects on insulin action, we studied eight patients with non-insulin-dependent diabetes mellitus before and after three months of treatment with tolazamide and exogenous semisynthetic human insulin, using a randomized crossover design. Therapy with tolazamide and therapy with insulin resulted in similar improvement of glycemic control, as measured by a decrease in mean glycosylated hemoglobin (+/- SEM) from 9.4 +/- 0.7 percent to 7.7 +/- 0.5 percent with tolazamide and to 7.1 +/- 0.2 percent with exogenous insulin (P less than 0.01 for both comparisons). Therapy with either tolazamide or exogenous insulin resulted in a similar lowering (P less than 0.05) of postabsorptive glucose-production rates (from 2.3 +/- 0.1 to 2.0 +/- 0.2 and 1.8 +/- 0.1 mg per kilogram of body weight per minute, respectively) but not to normal (1.5 +/- 0.1 mg per kilogram per minute). Both tolazamide and exogenous insulin increased (P less than 0.05) glucose utilization at supraphysiologic insulin concentrations (from 6.2 +/- 0.7 to 7.7 +/- 0.6 mg per kilogram per minute with tolazamide and to 7.8 +/- 0.6 mg per kilogram per minute with exogenous insulin) to nondiabetic rates (7.9 +/- 0.5 mg per kilogram per minute). Neither agent altered erythrocyte insulin binding at physiologic insulin concentrations. We conclude that treatment with sulfonylureas or exogenous insulin results in equivalent improvement in insulin action in patients with non-insulin-dependent diabetes mellitus. Therefore, the choice between these agents should be based on considerations other than their ability to ameliorate insulin resistance.

Topics: Blood Glucose; C-Peptide; Clinical Trials as Topic; Diabetes Mellitus, Type 2; Erythrocytes; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Middle Aged; Random Allocation; Tolazamide

Fifteen Type 2 diabetics were treated for 4-week periods with once daily (10 mg) glibenclamide, glipizide and placebo according to a double-blind cross-over protocol. Post-dose glipizide concentrations were three times higher than those of glibenclamide, due to the incomplete bioavailability of the latter. On the other hand, pre-dose drug levels were similar, as an expression of the slower absorption and/or elimination of glibenclamide. Both active treatments reduced postprandial blood glucose concentrations and 24-hour urinary glucose excretion to a similar degree, but fasting blood glucose concentrations were slightly lower during glibenclamide treatment. Both active treatments enhanced fasting and postprandial insulin and C-peptide concentrations, the C-peptide response being greater after glipizide than after glibenclamide. Plasma glucagon and GIP concentrations were not significantly affected. Insulin sensitivity was increased by glibenclamide but not by glipizide. Neither therapy affected insulin binding to erythrocytes. It appears that both glibenclamide and glipizide improved glucose metabolism by sustained stimulation of insulin secretion, which was most pronounced with glipizide. Only glibenclamide improved insulin sensitivity and was slightly more active than glipizide on fasting blood glucose levels. The differences may be consequences of the pharmacokinetics, but differences in pharmacodynamics cannot be excluded.

Topics: Aged; Blood Glucose; Body Weight; C-Peptide; Diabetes Mellitus, Type 2; Double-Blind Method; Erythrocytes; Female; Gastric Inhibitory Polypeptide; Glipizide; Glucagon; Glyburide; Glycosuria; Humans; Insulin; Insulin Resistance; Kinetics; Male; Middle Aged; Random Allocation; Sulfonylurea Compounds

The utilisation of blood glucose may be used for definition of insulin resistance in type II diabetes mellitus. To evaluate this possibility we adapted an infusion test of somatostatin in 10 normal persons (age 26 +/- 3 years, relative body weight 26 +/- 10% according to Broca) in a randomized cross-over therapy with bezafibrate (3 X 200 mg/die). As the coefficient of variation (VC) of measured blood glucose continuously increased the best time of a steady state was between 90 and 130 min after beginning the infusion (mean VC 8.9%). While insulin remained nearly constant (41 (45; 38) microU/ml) blood glucose dropped by about 14% and reached a steady state of 89 (134; 45) mg/dl. During the therapy of bezafibrate blood glucose was significantly decreased by 36% 130 min after beginning the infusion. Although the effect was not significant during the whole time of the steady state it became evident by a negative correlation with lactate (r = -0.687) and pyruvate (r = -0.843). A correlation with a concomitant decrease of triglyceride and cholesterol also induced by bezafibrate could not be proven. The results show that the infusion test of somatostatin is fitted to measure a steady state of blood glucose and insulin and that it is possible by this technique to quantify a changed utilisation of blood glucose induced by specific therapy.

Topics: Adult; Bezafibrate; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Glucagon; Humans; Insulin; Insulin Resistance; Somatostatin; Time Factors

Using a targeted proteomics approach, we aimed to identify and validate circulating proteins associated with impaired glucose metabolism (IGM) and type 2 diabetes in a Black South African cohort. In addition, we assessed sex-specific associations between the validated proteins and pathophysiological pathways of type 2 diabetes.. This cross-sectional study included Black South African men (n=380) and women (n=375) who were part of the Middle-Aged Soweto Cohort (MASC). Dual-energy x-ray absorptiometry was used to determine fat mass and visceral adipose tissue, and fasting venous blood samples were collected for analysis of glucose, insulin and C-peptide and for targeted proteomics, measuring a total of 184 pre-selected protein biomarkers. An OGTT was performed on participants without diabetes, and peripheral insulin sensitivity (Matsuda index), HOMA-IR, basal insulin clearance, insulin secretion (C-peptide index) and beta cell function (disposition index) were estimated. Participants were classified as having normal glucose tolerance (NGT; n=546), IGM (n=116) or type 2 diabetes (n=93). Proteins associated with dysglycaemia (IGM or type 2 diabetes) in the MASC were validated in the Swedish EpiHealth cohort (NGT, n=1706; impaired fasting glucose, n=550; type 2 diabetes, n=210).. We identified 73 proteins associated with dysglycaemia in the MASC, of which 34 were validated in the EpiHealth cohort. Among these validated proteins, 11 were associated with various measures of insulin dynamics, with the largest number of proteins being associated with HOMA-IR. In sex-specific analyses, IGF-binding protein 2 (IGFBP2) was associated with lower HOMA-IR in women (coefficient -0.35; 95% CI -0.44, -0.25) and men (coefficient -0.09; 95% CI -0.15, -0.03). Metalloproteinase inhibitor 4 (TIMP4) was associated with higher insulin secretion (coefficient 0.05; 95% CI 0.001, 0.11; p for interaction=0.025) and beta cell function (coefficient 0.06; 95% CI 0.02, 0.09; p for interaction=0.013) in women only. In contrast, a stronger positive association between IGFBP2 and insulin sensitivity determined using an OGTT (coefficient 0.38; 95% CI 0.27, 0.49) was observed in men (p for interaction=0.004). A posteriori analysis showed that the associations between TIMP4 and insulin dynamics were not mediated by adiposity. In contrast, most of the associations between IGFBP2 and insulin dynamics, except for insulin secretion, were mediated by either fat mass index or visceral adipose tissue in men and women. Fat mass index was the strongest mediator between IGFBP2 and insulin sensitivity (total effect mediated 40.7%; 95% CI 37.0, 43.6) and IGFBP2 and HOMA-IR (total effect mediated 39.1%; 95% CI 31.1, 43.5) in men.. We validated 34 proteins that were associated with type 2 diabetes, of which 11 were associated with measures of type 2 diabetes pathophysiology such as peripheral insulin sensitivity and beta cell function. This study highlights biomarkers that are similar between cohorts of different ancestry, with different lifestyles and sociodemographic profiles. The African-specific biomarkers identified require validation in African cohorts to identify risk markers and increase our understanding of the pathophysiology of type 2 diabetes in African populations.

Topics: C-Peptide; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Female; Glucose; Humans; Insulin; Insulin Resistance; Middle Aged; Proteomics; South Africa

Sleeve gastrectomy (SG) successfully recovers metabolic homeostasis in obese humans and rodents while also resulting in the normalization of insulin sensitivity and insulinemia. Reduced insulin levels have been attributed to lower insulin secretion and increased insulin clearance in individuals submitted to SG. Insulin degradation mainly occurs in the liver in a process controlled, at least in part, by the insulin-degrading enzyme (IDE). However, research has yet to explore whether liver IDE expression or activity is altered after SG surgery. In this study, C57BL/6 mice were fed a chow (CTL) or high-fat diet (HFD) for 10 weeks. Afterward, the HFD mice were randomly assigned to two groups: sham-surgical (HFD-SHAM) and SG-surgical (HFD-SG). Here, we confirmed that SG improves glucose-insulin homeostasis in obese mice. Additionally, SG reduced insulinemia by reducing insulin secretion, assessed by the analysis of plasmatic C-peptide content, and increasing insulin clearance, which was evaluated through the calculation of the plasmatic C-peptide:insulin ratio. Although no changes in hepatic IDE activity were observed, IDE expression was higher in the liver of HFD-SG compared with HFD-SHAM mice. These results indicate that SG may be helpful to counteract obesity-induced hyperinsulinemia by increasing insulin clearance, likely through enhanced liver IDE expression.

Topics: Animals; C-Peptide; Diet, High-Fat; Gastrectomy; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Insulin, Regular, Human; Mice; Mice, Inbred C57BL; Mice, Obese; Obesity; Weight Loss

The primary purpose of the current study was to test the hypothesis that the proinsulin-to-C-peptide (PI-to-CP) ratio, as an index of proinsulin secretion, would be higher and associated with indices of β-cell function in African American adults relative to European American adults without type 2 diabetes.. Participants were 114 African American and European American adult men and women. A 2-h oral glucose tolerance test was conducted to measure glucose, insulin, C-peptide, and proinsulin and derive indices of β-cell response to glucose. The Matsuda index was calculated as a measure of insulin sensitivity. The disposition index (DI), the product of insulin sensitivity and β-cell response, was calculated for each phase of β-cell responsivity. Pearson correlations were used to investigate the relationship of the PI-to-CP ratio with each phase of β-cell response (basal, Φb; dynamic, Φd; static, Φs; total, Φtot), disposition indices (DId, DIs, DItot), and insulin sensitivity. Multiple linear regression analysis was used to evaluate independent contributions of race, BMI, and glucose tolerance status on PI-to-CP levels before and after adjustment for insulin sensitivity.. African American participants had higher fasting and 2-h PI-to-CP ratios. The fasting PI-to-CP ratio was positively associated with Φb, and the fasting PI-to-CP ratio and 2-h PI-to-CP ratio were inversely associated with DId and insulin sensitivity only in African American participants.. The PI-to-CP ratio could be useful in identifying African American individuals at highest risk for β-cell dysfunction and ultimately type 2 diabetes.

Topics: Adult; Black or African American; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucose; Humans; Insulin; Insulin Resistance; Male; Proinsulin

We investigated the relationship between hs-CRP, a marker of low-grade inflammation, alone or in combination with C-peptide, a marker of hyperinsulinemia/insulin resistance, and risk for cardiovascular events (CVEs) and mortality in patients recently diagnosed with type 2 diabetes (T2D).. In patients with recent-onset T2D, we measured serum hs-CRP (n = 7,301) and C-peptide (n = 5,765) in the prospective Danish Centre for Strategic Research in Type 2 Diabetes cohort study. Patients with no prior CVE (n = 6,407) were followed until first myocardial infarction, stroke, coronary revascularization, or cardiovascular death, and all patients (n = 7,301) were followed for all-cause mortality. We computed adjusted hazard ratios (aHRs) by Cox regression and tested for the interaction between hs-CRP and C-peptide.. During follow-up (median 4.8 years), high (>3 mg/L) versus low (<1 mg/L) hs-CRP was associated with increased CVE risk (aHR 1.45 [95% CI 1.07-1.96]) and with even greater risk of all-cause mortality (2.47 [1.88-3.25]). Compared with patients with low hs-CRP (≤3 mg/L) and low C-peptide (<1,470 pmol/L), those with high levels of both biomarkers had the highest CVE (1.61 [1.10-2.34]) and all-cause mortality risk (2.36 [1.73-3.21]). Among patients with high C-peptide, risk of CVEs did not differ by low or high hs-CRP, whereas risk of all-cause mortality did.. The finding of high hs-CRP as a stronger prognostic biomarker of all-cause mortality than of CVEs may facilitate improved early detection and prevention of deadly diseases besides CVEs. Conversely, elevated C-peptide as a strong CVE biomarker supports the need to target hyperinsulinemia/insulin resistance in T2D CVE prevention.

Topics: Biomarkers; C-Peptide; C-Reactive Protein; Cardiovascular Diseases; Cohort Studies; Denmark; Diabetes Mellitus, Type 2; Humans; Insulin Resistance; Myocardial Infarction; Prospective Studies; Risk Factors

Metabolic zones were developed to characterize heterogeneity of individuals with islet autoantibodies.. Baseline 2-h oral glucose tolerance test data from 6,620 TrialNet Pathway to Prevention Study (TNPTP) autoantibody-positive participants (relatives of individuals with type 1 diabetes) were used to form 25 zones from five area under the curve glucose (AUCGLU) rows and five area under the curve C-peptide (AUCPEP) columns. Zone phenotypes were developed from demographic, metabolic, autoantibody, HLA, and risk data.. As AUCGLU increased, changes of glucose and C-peptide response curves (from mean glucose and mean C-peptide values at 30, 60, 90, and 120 min) were similar within the five AUCPEP columns. Among the zones, 5-year risk for type 1 diabetes was highly correlated with islet antigen 2 antibody prevalence (r = 0.96, P < 0.001). Disease risk decreased markedly in the highest AUCGLU row as AUCPEP increased (0.88-0.41; P < 0.001 from lowest AUCPEP column to highest AUCPEP column). AUCGLU correlated appreciably less with Index60 (an indicator of insulin secretion) in the highest AUCPEP column (r = 0.33) than in other columns (r ≥ 0.78). AUCGLU was positively related to "fasting glucose × fasting insulin" and to "fasting glucose × fasting C-peptide" (indicators of insulin resistance) before and after adjustments for Index60 (P < 0.001).. Phenotypes of 25 zones formed from AUCGLU and AUCPEP were used to gain insights into type 1 diabetes heterogeneity. Zones were used to examine GCRC changes with increasing AUCGLU, associations between risk and autoantibody prevalence, the dependence of glucose as a predictor of risk according to C-peptide, and glucose heterogeneity from contributions of insulin secretion and insulin resistance.

Topics: Autoantibodies; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 1; Glucose; Humans; Insulin; Insulin Resistance; Phenotype

Both obesity and a poor diet are considered major risk factors for triggering insulin resistance syndrome (IRS) and the development of type 2 diabetes mellitus (T2DM). Owing to the impact of low-carbohydrate diets, such as the keto diet and the Atkins diet, on weight loss in individuals with obesity, these diets have become an effective strategy for a healthy lifestyle. However, the impact of the ketogenic diet on IRS in healthy individuals of a normal weight has been less well researched. This study presents a cross-sectional observational study that aimed to investigate the effect of low carbohydrate intake in healthy individuals of a normal weight with regard to glucose homeostasis, inflammatory, and metabolic parameters.. The study included 120 participants who were healthy, had a normal weight (BMI 25 kg/m. Low carbohydrate intake (<45% of total energy) was found to significantly correlate with dysregulated glucose homeostasis as measured by elevations in HOMA-IR, HOMA-β% assessment, and C-peptide levels. Low carbohydrate intake was also found to be coupled with lower serum bicarbonate and serum albumin levels, with an increased anion gap indicating metabolic acidosis. The elevation in C-peptide under low carbohydrate intake was found to be positively correlated with the secretion of IRS-related inflammatory markers, including FGF2, IP-10, IL-6, IL-17A, and MDC, but negatively correlated with IL-3.. Overall, the findings of the study showed that, for the first time, low-carbohydrate intake in healthy individuals of a normal weight might lead to dysfunctional glucose homeostasis, increased metabolic acidosis, and the possibility of triggering inflammation by C-peptide elevation in plasma.

Topics: Acidosis; Blood Glucose; C-Peptide; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Dietary Carbohydrates; Humans; Insulin; Insulin Resistance; Metabolic Syndrome; Obesity

Sex-specific differences exist in insulin secretion (ISec) and sensitivity (IS) in humans. However, current fasting indices used to estimate them, such as HOMA and QUICKI, are not sex-specific. We aimed to develop sex-specific models to improve the prediction of ISec and IS by fasting measures in adults with overweight/obesity. A post hoc analysis was conducted on baseline data of two clinical trials completed between 2010 and 2020 (37 men and 61 postmenopausal women, 45-73 years, BMI > 25 kg/m

Topics: Adult; Blood Glucose; C-Peptide; Female; Glucose; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin, Regular, Human; Male; Obesity; Overweight

Observational studies suggest that abnormal glucose metabolism and insulin resistance contribute to colorectal cancer; however, the causal association remains unknown, particularly in Asian populations. A two-sample Mendelian randomisation analysis was performed to determine the causal association between genetic variants associated with elevated fasting glucose, haemoglobin A1c (HbA1c), and fasting C-peptide and colorectal cancer risk. In the single nucleotide polymorphism (SNP)-exposure analysis, we meta-analysed study-level genome-wide associations of fasting glucose (~ 17,289 individuals), HbA1c (~ 52,802 individuals), and fasting C-peptide (1,666 individuals) levels from the Japanese Consortium of Genetic Epidemiology studies. The odds ratios of colorectal cancer were 1.01 (95% confidence interval [CI], 0.99-1.04, P = 0.34) for fasting glucose (per 1 mg/dL increment), 1.02 (95% CI, 0.60-1.73, P = 0.95) for HbA1c (per 1% increment), and 1.47 (95% CI, 0.97-2.24, P = 0.06) for fasting C-peptide (per 1 log increment). Sensitivity analyses, including Mendelian randomisation-Egger and weighted-median approaches, revealed no significant association between glycaemic characteristics and colorectal cancer (P > 0.20). In this study, genetically predicted glycaemic characteristics were not significantly related to colorectal cancer risk. The potential association between insulin resistance and colorectal cancer should be validated in further studies.

Topics: Blood Glucose; C-Peptide; Colorectal Neoplasms; Diabetes Mellitus, Type 2; East Asian People; Genome-Wide Association Study; Glucose; Glycated Hemoglobin; Humans; Insulin Resistance; Mendelian Randomization Analysis; Polymorphism, Single Nucleotide; Risk Factors

To observe the effect of electroacupuncture (EA) on liver protein kinase B (Akt)/forkhead box transcription factor 1 (FoxO1) signaling pathway in Zucker diabetic fatty (ZDF) rats, and to explore the possible mechanism of EA on improving liver insulin resistance of type 2 diabetes mellitus.. Twelve male 2-month-old ZDF rats were fed with high-fat diet for 4 weeks to establish diabetes model. After modeling, the rats were randomly divided into a model group and an EA group, with 6 rats in each group. In addition, six male Zucker lean (ZL) rats were used as the blank group. The rats in the EA group were treated with EA at bilateral "Zusanli" (ST 36), "Sanyinjiao" (SP 6), "Weiwanxiashu" (EX-B 3), and "Pishu" (BL 20). The ipsilateral "Zusanli" (ST 36) and "Weiwanxiashu" (EX-B 3) were connected to EA device, continuous wave, frequency of 15 Hz, 20 min each time, once a day, six times a week, for a total of 4 weeks. The fasting blood glucose (FBG) in each group was compared before modeling, before intervention and after intervention; the serum levels of insulin (INS) and C-peptide were measured by radioimmunoassay method, and the insulin resistance index (HOMA-IR) was calculated; HE staining method was used to observe the liver tissue morphology; Western blot method was used to detect the protein expression of Akt, FoxO1 and phosphoenolpyruvate carboxykinase (PEPCK) in the liver.. Before intervention, compared with the blank group, FBG was increased in the model group and the EA group (. EA could reduce FBG and HOMA-IR in ZDF rats, improve liver insulin resistance, which may be related to regulating Akt/FoxO1 signaling pathway.

Topics: Animals; C-Peptide; Diabetes Mellitus, Type 2; Electroacupuncture; Insulin; Insulin Resistance; Lipids; Liver; Male; Proto-Oncogene Proteins c-akt; Rats; Rats, Zucker; Signal Transduction

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators have been shown to have a beneficial effect on pulmonary function and nutritional status in patients with cystic fibrosis (CF), but the extent to which they affect glucose tolerance is not fully understood. In the current study, we evaluated the change in glucose tolerance and insulin secretion after first-generation CFTR modulator treatment in adults with CF.. We performed a longitudinal observational study with an oral glucose tolerance test performed at baseline and after three and a half years of follow-up. The test comprised glucose, C-peptide and insulin measured at fasting, 1 h, and 2 h, and HbA1c at fasting. We compared changes in parameters of glucose tolerance and insulin secretion from baseline to follow-up.. Among 55 participants, 37 (67%) were treated with a first-generation CFTR modulator for a median of 21 months. Glucose levels were unchanged in both the treated and untreated group. In the treated group, C-peptide levels declined, yet no significant differences in glucose, insulin, and C-peptide levels were observed between the groups. HbA1c increased in both groups, while no significant change in the insulin sensitivity indices was detected in either group. However, homeostatic model assessment for insulin resistance tended to decline in the treated group, whilst tending towards an increase in the untreated group. The difference between the groups reached statistical significance (p = 0.040).. Treatment with first-generation CFTR modulators, mainly tezacaftor/ivacaftor, did not seem to be associated with glucose tolerance nor insulin secretion in adults with CF. However, CFTR modulators may still have a beneficial effect on insulin sensitivity.

Topics: Adult; Aminophenols; Benzodioxoles; C-Peptide; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Glucose; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Mutation

(1) Background: Pregnancy presents a challenge to maternal glucose homeostasis; suboptimal adaptations can lead to gestational diabetes mellitus (GDM). Human milk oligosaccharides (HMOs) circulate in maternal blood in pregnancy and are altered with GDM, suggesting influence of glucose homeostasis on HMOs. We thus assessed the HMO response to glucose load during an oral glucose tolerance test (OGTT) and investigated HMO associations with glucose tolerance/insulin sensitivity in healthy pregnant women. (2) Methods: Serum of 99 women, collected at 0 h, 1 h and 2 h during a 75 g OGTT at 24-28 gestational weeks was analyzed for HMOs (2'FL, 3'SLN, LDFT, 3'SL) by HPLC; plasma glucose, insulin and C-peptide were analyzed by standard biochemistry methods. (3) Results: Serum 3'SL concentrations significantly increased from fasting to 1 h after glucose load, while concentrations of the other HMOs were unaltered. Higher 3'SL at all OGTT time points was associated with a generally more diabetogenic profile, with higher hepatic insulin resistance (HOMA-IR), lower insulin sensitivity (Matsuda index) and higher insulin secretion (C-peptide index 1). (4) Conclusions: Rapid increase in serum 3'SL post-oral glucose load (fasted-fed transition) indicates utilization of plasma glucose, potentially for sialylation of lactose. Associations of sialylated HMOs with a more diabetogenic profile suggest sustained adaptations to impaired glucose homeostasis in pregnancy. Underlying mechanisms or potential consequences of observed HMO changes remain to be elucidated.

Topics: Blood Glucose; C-Peptide; Diabetes, Gestational; Female; Glucose; Humans; Insulin; Insulin Resistance; Milk, Human; Oligosaccharides; Pregnancy

To investigate the value of C-peptide-based insulin resistance index in evaluating the correlation between insulin resistance and serum uric acid (Ua) level in subjects undergoing health examination.. The data of 46 017 subjects undergoing health examination were retrospectively collected from the Second Medical Center of PLA General Hospital from January, 2017 to December, 2021. The subjects were divided into Ua≤420 μmol/L group and Ua>420 μmol/L group for comparison of HOMA insulin resistance index (HOMA2-IR) and HOMA insulin resistance-C peptide (HOMA2 IR-CP). The correlations of HOMA2-IR and HOMA2 IR-CP with Ua level were analyzed using Pearson correlation analysis and linear regression analysis. Hierarchical interaction analysis was conducted to assess the differences in the association between insulin resistance index and Ua level in different subgroups. The ROC curve was used to evaluate the predictive ability of insulin resistance index for an increased Ua level.. The levels of HOMA2-IR and HOMA2 IR-CP were significantly lower in Ua≤420 μmol/L group than in Ua>420 μmol/L group. Univariate Pearson correlation analysis showed a weak correlation of HOMA2-IR with Ua (. HOMA2 IR-CP is a more accurate indicator for assessing the correlation between insulin resistance and Ua level.

Topics: C-Peptide; Humans; Insulin; Insulin Resistance; Retrospective Studies; Uric Acid

Glucolipid metabolism plays an important role in the occurrence and development of diabetes mellitus. However, there is limited research on the characteristics of glucolipid metabolism and complications in different subgroups of newly diagnosed diabetes. This study aimed to investigate the characteristics of glucolipid metabolism and complications in novel cluster-based diabetes subgroups and explore the contributions of different glucolipid metabolism indicators to the occurrence of complications and pancreatic function.. This retrospective study included 547 newly diagnosed type 2 diabetes patients. Age, body mass index (BMI), glycated hemoglobin (HbA. Total cholesterol (TC), triglycerides (TG), triglyceride glucose index (TyG), HbA. There were differences in the characteristics of glucolipid metabolism as well as complications among different subgroups of newly diagnosed type 2 diabetes. 2hCP, FCP, FINS, FPG, TyG, HbA

Topics: Blood Glucose; C-Peptide; Cholesterol, HDL; Diabetes Mellitus, Type 2; Humans; Insulin; Insulin Resistance; Lipoproteins, HDL; Non-alcoholic Fatty Liver Disease; Renal Insufficiency, Chronic; Retrospective Studies; Triglycerides

Oxidative stress and apoptosis are involved in the pathogenesis of obesity-related diseases. This observational study investigates the antioxidant and apoptotic markers response to an oral glucose tolerance test (OGTT) in a population of overweight children and adolescents, with normal (NGT) or impaired glucose tolerance (IGT). Glucose, insulin, and C-peptide concentrations, as well as oxidative stress (SOD, GPx3) and apoptotic markers (Apo1fas, cck18), were determined at T = 0, 30, 60, 90, 120, and 180 min after glucose intake during OGTT. The lipid profile, thyroid function, insulin-like growth factor1, leptin, ghrelin, and adiponectin were also measured at baseline. The 45 participants, with a mean age of 12.15 (±2.3) years old, were divided into two subcategories: those with NGΤ (n = 31) and those with IGT (n = 14). The area under the curve (AUC) of glucose, insulin, and C-peptide was greater in children with IGT; however, only glucose differences were statistically significant. SOD and GPx3 levels were higher at all time points in the IGT children. Apo1fas and cck18 levels were higher in the NGT children at most time points, whereas Adiponectin was lower in the IGT group. Glucose increased during an OGTT accompanied by a simultaneous increase in antioxidant factors, which may reflect a compensatory mechanism against the impending increase in oxidative stress in children with IGT.

Topics: Adiponectin; Adolescent; Antioxidants; Blood Glucose; C-Peptide; Child; Glucose; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Obesity; Superoxide Dismutase; Weight Gain

Interactions between polymorphisms of the melatonin receptor 1B (MTNR1B) gene and lifestyle intervention for gestational diabetes have been described. Whether these are specific for physical activity or the healthy eating intervention is unknown.. The aim was to assess the interaction between MTNR1B rs10830962 and rs10830963 polymorphisms and lifestyle interventions during pregnancy.. Women with a BMI (in kg/m2) of ≥29 (n = 436) received counseling on healthy eating (HE), physical activity (PA), or both. The control group received usual care. This secondary analysis had a factorial design with comparison of HE compared with no HE and PA compared with no PA. Maternal outcomes at 24-28 wk were gestational weight gain (GWG), maternal fasting glucose, insulin, insulin resistance (HOMA-IR), disposition index, and development of GDM. Neonatal outcomes were cord blood leptin and C-peptide and estimated neonatal fat percentage. The interaction between receiving either the HE or PA intervention and genotypes of both rs10830962 and rs10830963 was assessed using multilevel regression analysis.. GDM risk was increased in women homozygous for the G allele of rs10830962 (OR: 2.60; 95% CI: 1.34, 5.06) or rs10830963 (OR: 2.83; 95% CI: 1.24, 6.47). Significant interactions between rs10830962 and interventions were found: in women homozygous for the G allele but not in the other genotypes, the PA intervention reduced maternal fasting insulin (β: -0.16; 95% CI: -0.33, 0.02; P = 0.08) and HOMA-IR (β: -0.17; 95% CI: -0.35, 0.01; P = 0.06), and reduced cord blood leptin (β: -0.84; 95% CI: -1.42, -0.25; P = 0.01) and C-peptide (β: -0.62; 95% CI: -1.07, -0.17; P = 0.01). In heterozygous women, the HE intervention had no effect, whereas in women homozygous for the C allele, HE intervention reduced GWG (β: -1.6 kg; 95% CI: -2.4, -0.8 kg). No interactions were found.. In women homozygous for the risk allele of MTNR1B rs10830962, GDM risk was increased and PA intervention might be more beneficial than HE intervention for reducing maternal insulin resistance, cord blood C-peptide, and cord blood leptin.

Topics: Adult; Alleles; Blood Glucose; C-Peptide; Diabetes, Gestational; Diet, Healthy; Exercise; Female; Fetal Blood; Genotype; Gestational Weight Gain; Humans; Infant, Newborn; Insulin; Insulin Resistance; Leptin; Life Style; Polymorphism, Genetic; Pregnancy; Pregnancy Outcome; Prenatal Care; Receptor, Melatonin, MT2

Obesity is associated with insulin resistance (IR). Identifying high-risk obese children affected with IR is crucial to apply preventive management. We aimed to assess the diagnostic value of urinary C-peptide (UCP) and urinary C-peptide creatinine ratio (UCPCR) to diagnose IR in obese children.. This prospective cross-sectional study was performed on 60 children with obesity as the study group. Sixty healthy children of matched age and sex with normal body mass index (BMI) served as the control group. Hemostasis model for the assessment of IR (HOMA-IR), glycated hemoglobin (HbA1c), fasting blood glucose and insulin, UCP, and UCPCR were assessed in all included children.. UCP and UCPCR were significantly higher in children with obesity (2.075 ± 0.783) ng/ml, (0.200 ± 0.021) nmol/mmol compared to the control group (1.012 ± 0.465) ng/ml, (0.148 ± 0.016) nmol/mmol, respectively. Both UCP and UCPCR were positively correlated with each other and with HOMA-IR, HbA1c, acanthosis nigricans, waist circumference, and BMI. At cutoff ≥2.45, the sensitivity of UCP to diagnose IR in obese children was 71.4%. At cutoff ≥0.20, the sensitivity of UCPCR to diagnose IR in obese children was 87.6%.. UCP and UCPCR are promising surrogate markers of IR in children and adolescents with obesity. However, UCPCR is a better marker than UCP.. Obesity is associated with IR. Identifying high-risk obese children affected with IR is crucial to apply preventive management. We aimed to assess the diagnostic value of UCP and UCPCR to detect IR in obese children. To the best of our knowledge, we are the first to use UCP and UCPCR to assess IR in obese children. We found that UCP and UCPCR are practical, easy, dependable noninvasive markers to assess IR in children with obesity and could potentially be useful in epidemiological studies and clinical practice.

Topics: Adolescent; Biomarkers; Blood Glucose; Body Mass Index; C-Peptide; Child; Creatinine; Cross-Sectional Studies; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Pediatric Obesity; Prospective Studies

More than one-third of chronic pancreatitis patients will eventually develop diabetes, recently classified as post-chronic pancreatitis diabetes mellitus (PPDM-C). This study was aimed to investigate the pancreatic and gut hormone responses to a mixed meal test in PPDM-C patients, compared with non-diabetic chronic pancreatitis (CP), and type 2 diabetes patients or healthy controls.. Sixteen patients with PPDM-C, 12 with non-diabetic CP as well as 10 with type 2 diabetes and healthy controls were recruited. All participants underwent mixed meal tests, and blood samples were collected for measurements of blood glucose, C-peptide, insulin, glucagon, pancreatic polypeptide (PP), ghrelin, peptide YY, glucagon like peptide-1 (GLP-1) and gastric inhibitory peptide (GIP). Indices of insulin sensitivity and secretion were calculated. Repeated measures analysis of variance was performed.. Participants with PPDM-C exhibited decreases in both fasting and postprandial responses of C-peptide (P < 0.001), insulin (P < 0.001), ghrelin (P < 0.001) and PYY (P = 0.006) compared to participants with type 2 diabetes and healthy controls. Patients with CP showed blunted glucagon, PP and incretin reactions, while the responses were increased in patients with PPDM-C compared to controls. The level of insulin sensitivity was higher for PPDM-C than type 2 diabetes (P < 0.01), however the indices for early/late-phase and overall insulin secretion (P < 0.01) were lower.. Patients with PPDM-C are characterized by decreased C-peptide, insulin, ghrelin and PYY responses, and similar levels of glucagon, PP, GIP and GLP-1 compared to those with type 2 diabetes. The above findings, when confirmed in a larger population, may prove helpful to establish the diagnosis of PPDM-C, and should promote study on underlying pathophysiological mechanisms.

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Gastric Inhibitory Polypeptide; Ghrelin; Glucagon; Glucagon-Like Peptide 1; Humans; Insulin; Insulin Resistance; Pancreatitis, Chronic; Peptide YY

Systemic lupus erythematosus (SLE) has been associated with insulin resistance and beta-cell dysfunction. Apolipoprotein C3 (ApoC3) is a component of very low-density lipoproteins. Since ApoC3 has been linked to beta-cell impairment in the general population, in this study we aimed to discover if this lipoprotein is related to glucose homeostasis disturbance in patients with SLE.. One hundred and forty non diabetic patients with SLE who had a glycaemia lower than 110 mg/dl were recruited. Insulin, C-peptide, and ApoC3 were assessed. Insulin resistance and beta-cell function were calculated using the Homeostasis Model Assessment (HOMA2) indices. A multivariable regression analysis was performed to study the relationship of ApoC3 to those molecules and indices adjusting for classical factors associated with insulin resistance that included glucocorticoids.. In the multivariable regression analysis that included prednisone intake, a significant relation of ApoC3 to C-peptide was found (beta coef. 0.27 [95%CI 0.03-0.51) ng/ml, p=0.030). Similarly, ApoCa3 was associated with higher degree of beta-cell dysfunction (HOMA2-%B) although in this case statistical significance was not achieved (beta coef. 8 [95%CI-1-18], p=0.086). This relationship was not found with serum insulin levels or IR indices. Furthermore, in the univariable analysis, but not after multivariable adjustment, the disease damage score was found to significantly mediate the effect of ApoC3 on circulating C-peptide. and HOMA2-%B.. Beta-cell dysfunction and ApoC3 are linked in patients with SLE.

Topics: Apolipoprotein C-III; C-Peptide; Humans; Insulin; Insulin Resistance; Lupus Erythematosus, Systemic

Prediabetes and type 2 diabetes are highly prevalent in Asia. Understanding the pathophysiology of abnormal glucose homeostasis in Asians will have important implications for reducing disease burden, but there have been conflicting reports on the relative contributions of insulin secretion and action in disease progression. In this study, we aimed to assess the contribution of β-cell dysfunction and insulin resistance in the Asian prediabetes phenotype.. We recruited 1679 Asians with prediabetes (n = 659) or normoglycemia (n = 1020) from a multi-ethnic population in Singapore. Participants underwent an oral glucose tolerance test, an intravenous glucose challenge, and a hyperinsulinemic-euglycemic clamp procedure to determine glucose tolerance, β-cell responsivity, insulin secretion, insulin clearance and insulin sensitivity.. Participants with prediabetes had significantly higher glucose concentrations in the fasting state and after glucose ingestion than did normoglycemic participants. Insulin sensitivity (M/I ratio) was ~15% lower, acute insulin response (AIR) to intravenous glucose and β-cell responsivity to oral glucose were ~35% lower, but total insulin secretion rate in the fasting state and after glucose ingestion was ~10% greater in prediabetic than in normoglycemic participants. The decrease in β-cell function with worsening glucose homeostasis in Asians with prediabetes was associated with progressively greater defects in AIR rather than M/I. However, analysis using static surrogate measures (HOMA indices) of insulin resistance and β-cell function revealed a different pattern.. Lower AIR to intravenous glucose and β-cell responsivity to oral glucose, on a background of mild insulin resistance, are the major contributors to the dysregulation of glucose homeostasis in Asians with prediabetes.

Topics: Adult; Asian People; C-Peptide; Female; Glucose Tolerance Test; Humans; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Middle Aged; Prediabetic State

Disordered hepatic energy metabolism is found in obese rats with insulin resistance (IR). There are insufficient experimental studies of electroacupuncture (EA) for IR and type 2 diabetes mellitus (T2DM). The aim of this study was to probe the effect of EA on disordered hepatic energy metabolism and the adenosine monophosphate (AMP)-activated protein kinase (AMPK)/mammalian target of rapamycin complex 1 (mTORC1)/ribosomal protein S6 kinase, 70-kDa (p70S6K) signaling pathway.. Zucker Diabetic Fatty (ZDF) rats were randomly divided into three groups: EA group receiving EA treatment; Pi group receiving pioglitazone gavage; and ZF group remaining untreated (n = 8 per group). Inbred non-insulin-resistant Zucker lean rats formed an (untreated) healthy control group (ZL, n = 8). Fasting plasma glucose (FPG), fasting insulin (FINS), C-peptide, C-reactive protein (CRP) and homeostatic model assessment of insulin resistance (HOMA-IR) indices were measured. Hematoxylin-eosin (H&E) staining was used to investigate the liver morphologically. The mitochondrial structure of hepatocytes was observed by transmission electron microscopy (TEM). Western blotting was adopted to determine protein expression of insulin receptor substrate 1 (IRS-1), mTOR, mTORC1, AMPK, tuberous sclerosis 2 (TSC2) and p70S6K, and their phosphorylation. RT-PCR was used to quantify IRS-1, mTOR, mTORC1, AMPK and p70S6K mRNA levels.. Compared with the ZF group, FPG, FINS, C-peptide, CRP and HOMA-IR levels were significantly reduced in the EA group (. EA can effectively ameliorate IR and regulate energy metabolism in the ZDF rat model. AMPK/mTORC1/p70S6K and related molecules may represent a potential mechanism of action underlying these effects.

Topics: AMP-Activated Protein Kinases; Animals; C-Peptide; Diabetes Mellitus, Type 2; Electroacupuncture; Energy Metabolism; Insulin; Insulin Resistance; Mammals; Mechanistic Target of Rapamycin Complex 1; Rats; Rats, Zucker; Ribosomal Protein S6 Kinases, 70-kDa; Signal Transduction; TOR Serine-Threonine Kinases

The early distinction of pancreatic cancer associated diabetes (PaCDM) in patients with elderly diabetes is critical. However, PaCDM and type 2 diabetes mellitus (T2DM) remain indistinguishable. We aim to address the differences between the pancreatic and gut endocrine hormones of patients with PaCDM and T2DM.. A total of 44 participants underwent mixed meal tolerance test (MMTT). Fasting and postprandial concentrations of insulin, C-peptide, glucagon, pancreatic polypeptide (PP), glucagon-like peptide-1 (GLP-1), and gastric inhibitory peptide (GIP) were measured. Insulin sensitivity and secretion indices were calculated. One-way ANOVA with post-hoc analysis was used for statistical analysis.. Insulin and C-peptide responses to MMTT were blunted in PaCDM patients compared with T2DM. Baseline concentrations and AUCs differed. PaCDM patients showed lower insulin secretion capacity but better insulin sensitivity than T2DM patients. The peak concentration and AUC of PP in T2DM group were higher than healthy controls, but in accordance with PaCDM. PaCDM patients presented lower baseline GLP-1 concentration than T2DM patients. No between-group differences were found for glucagon and GIP.. PaCDM patients had a lower baseline and postprandial insulin and C-peptide secretion than T2DM patients. Reduced insulin secretion and improved peripheral sensitivity were found in PaCDM patients compared with T2DM.

Topics: Aged; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Gastric Inhibitory Polypeptide; Glucagon; Glucagon-Like Peptide 1; Humans; Insulin; Insulin Resistance; Pancreatic Neoplasms

Bariatric surgery is evolving as a successful tool for managing morbid obesity and T2DM. This study aimed to identify predictors of diabetes remission after two types of bariatric procedures.. This prospective study enrolled 172 patients with morbid obesity associated with T2DM scheduled for bariatric surgery. Two laparoscopic bariatric procedures were done; single anastomosis gastric bypass (SAGB, n = 83) and sleeve gastrectomy (LSG, n = 68). Lipid accumulation product index (LAP) and quantitative insulin sensitivity check index (QUICKI) were used to evaluate lipid profile and insulin sensitivity. Two years after surgery condition of DM was evaluated as complete remission (CR), partial remission (PR), or improvement. The primary outcome measure was predictors of diabetes remission.. Two years after surgery, 151 patients were available for evaluation, where 75 patients (49.7%) achieved CR, while PR was found in 36 (23.8%). CR was significantly associated with younger age, shorter duration of DM (p < 0.001, for both), higher C-peptide and GLP-1 levels (p < 0.001 and p = 0.002, respectively), and bypass surgery (p = 0.027). On multivariate analysis, shorter duration of DM, lower BMI, and higher C-peptide levels were the independent factors predicting CR.. Complete remission of T2DM can be achieved in nearly half of the patients two years after SG or SAGB. The duration of diabetes and preoperative BMI and C-peptide levels are the independent factors predicting complete remissions.

Topics: Bariatric Surgery; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Follow-Up Studies; Gastrectomy; Gastric Bypass; Humans; Insulin Resistance; Laparoscopy; Obesity, Morbid; Prospective Studies; Retrospective Studies; Treatment Outcome

The correlation of abnormal glucose metabolism and thyroid carcinoma, especially the aggressiveness of thyroid cancer, still remains controversial. We conducted this study to investigate the relationship between abnormal glucose metabolism parameters and differentiated thyroid carcinoma (DTC) in the Chinese population.. The study was designed as a hospital-based case-control study and was approved by the Ethics Committee of our hospital and registered in the Clinical Trial Protocol Registration and Results System (Registration code: NCT03006289). From January 1, 2018 to June 30, 2021, a total of 377 DTC patients were enrolled in the study. Demographic and general characteristics, details of thyroid surgery and histopathological results, hematological test indicators were collected. Glucose metabolism parameters were calculated. Variables were analyzed by t-test, ANOVA, chi-squared analysis and Fisher's exact test. Pearson bi-variate correlation and Spearman's correlation analysis were used for bi-variate analysis.. More than 40% of patients with DTC were multifocality, more than half were extra-glandular invasion, and nearly 85% complied by lymph node metastasis. The prevalence of diabetes mellitus (DM) was about 10.08% in DTC patients. It was found that the proportion of postprandial 2 h blood glucose ≥11.1mmol/L and HbA1c ≥6.5% was significantly higher than the known proportion of DM (17.8%, 16.7% vs. 10.08%). Additionally, 87.3% of the DTC patients in this study had varying degrees of insulin resistance. Further analysis found that higher T staging was associated with higher levels of area under curve of C-peptide (. Abnormal glucose metabolism, namely, DM, hyperinsulinemia and insulin resistance, were significantly associated with the carcinogensis and aggressiveness of DTC.

Topics: Adenocarcinoma; C-Peptide; Case-Control Studies; China; Glucose; Hospitals; Humans; Insulin Resistance; Thyroid Neoplasms

Severe insulin resistance syndromes, such as lipodystrophy, lead to diabetes, which is challenging to control. This study explored the safety and efficacy of sodium-glucose cotransporter 2 inhibitors (SGLT2is) in a series of 12 patients with severe insulin resistance due to partial lipodystrophy.. A retrospective chart review of the safety (N = 22) and efficacy (N = 12) of SGLT2is in patients with partial lipodystrophy was conducted at our institution. The efficacy outcomes included hemoglobin A1C level, insulin dose, fasting plasma glucose level, C-peptide level, lipid profile, 24-hour urinary glucose excretion, estimated glomerular filtration rate, and blood pressure before and after 12 months of SGLT2i treatment.. The hemoglobin A1C level decreased after SGLT2i treatment (at baseline: 9.2% ± 2.0% [77.0 ± 21.9 mmol/mol]; after 12 months: 8.4% ± 1.8% [68.0 ± 19.7 mmol/mol]; P = .028). Significant reductions were also noted in systolic (P = .011) and diastolic blood pressure (P = .013). There was a trend toward a decreased C-peptide level (P = .071). The fasting plasma glucose level, lipid level, and estimated glomerular filtration rate remained unchanged. The adverse effects included extremity pain, hypoglycemia, diabetic ketoacidosis (in a patient who was nonadherent to insulin), pancreatitis (in a patient with prior pancreatitis), and fungal infections.. SGLT2is reduced the hemoglobin A1C level in patients with partial lipodystrophy, with a similar safety profile compared with that in patients with type 2 diabetes. After individual consideration of the risks and benefits of SGLT2is, these may be considered a part of the treatment armamentarium for these rare forms of diabetes, but larger trials are needed to confirm these findings.

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Glucose Transporter Type 2; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Lipodystrophy; Pancreatitis; Retrospective Studies; Sodium-Glucose Transporter 2 Inhibitors

Cushing’s disease (CD) causes diabetes mellitus (DM) through different mechanisms in a significant proportion of patients. Glucose metabolism has rarely been assessed with appropriate testing in CD; we aimed to evaluate hormonal response to a mixed meal tolerance test (MMTT) in CD patients and analyzed the effect of pasireotide (PAS) on glucose homeostasis. To assess gastro-entero-pancreatic hormones response in diabetic (DM+) and non-diabetic (DM−) patients, 26 patients with CD underwent an MMTT. Ten patients were submitted to a second MMTT after two months of PAS 600 µg twice daily. The DM+ group had significantly higher BMI, waist circumference, glycemia, HbA1c, ACTH levels and insulin resistance indexes than DM− (p < 0.05). Moreover, DM+ patients exhibited increased C-peptide (p = 0.004) and glucose area under the curve (AUC) (p = 0.021) during MMTT, with a blunted insulinotropic peptide (GIP) response (p = 0.035). Glucagon levels were similar in both groups, showing a quick rise after meals. No difference in estimated insulin secretion and insulin:glucagon ratio was found. After two months, PAS induced an increase in both fasting glycemia and HbA1c compared to baseline (p < 0.05). However, this glucose trend after meal did not worsen despite the blunted insulin and C-peptide response to MMTT. After PAS treatment, patients exhibited reduced insulin secretion (p = 0.005) and resistance (p = 0.007) indexes. Conversely, glucagon did not change with a consequent impairment of insulin:glucagon ratio (p = 0.009). No significant differences were observed in incretins basal and meal-induced levels. Insulin resistance confirmed its pivotal role in glucocorticoid-induced DM. A blunted GIP response to MMTT in the DM+ group might suggest a potential inhibitory role of hypercortisolism on enteropancreatic axis. As expected, PAS reduced insulin secretion but also induced an improvement in insulin sensitivity as a result of cortisol reduction. No differences in incretin response to MMTT were recorded during PAS therapy. The discrepancy between insulin and glucagon trends while on PAS may be an important pathophysiological mechanism in this iatrogenic DM; hence restoring insulin:glucagon ratio by either enhancing insulin secretion or reducing glucagon tone can be a potential therapeutic target.

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus; Diabetes Mellitus, Type 2; Gastric Inhibitory Polypeptide; Glucagon; Glucagon-Like Peptide 1; Glycated Hemoglobin; Humans; Incretins; Insulin; Insulin Resistance; Meals; Pituitary ACTH Hypersecretion; Somatostatin

We evaluated the role of the p66Shc redox adaptor protein in pancreatic β-cell insulin resistance that develops under lipotoxic conditions and with excess body fat. Prolonged exposure to palmitate in vitro or the presence of overweight/obesity augmented p66Shc expression levels and caused an impaired ability of exogenous insulin to increase cellular insulin content and secreted C-peptide levels in INS-1E cells and human and murine islets. In INS-1E cells, p66Shc knockdown resulted in enhanced insulin-induced augmentation of insulin content and C-peptide secretion and prevented the ability of palmitate to impair these effects of insulin. Conversely, p66Shc overexpression impaired insulin-induced augmentation of insulin content and C-peptide secretion in both the absence and presence of palmitate. Under lipotoxic condition, the effects of p66Shc are mediated by a p53-induced increase in p66Shc protein levels and JNK-induced p66Shc phosphorylation at Ser36 and appear to involve the phosphorylation of the ribosomal protein S6 kinase at Thr389 and of insulin receptor substrate 1 at Ser307, resulting in the inhibition of insulin-stimulated protein kinase B phosphorylation at Ser473. Thus, the p66Shc protein mediates the impaired β-cell function and insulin resistance induced by saturated fatty acids and excess body fat.

Topics: Animals; Apoptosis; C-Peptide; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Mice; Palmitates; Signal Transduction; Src Homology 2 Domain-Containing, Transforming Protein 1

Type A Insulin resistance syndrome (TAIRS) is an autosomal dominant or recessive genetic disorder caused by insulin dysfunction resulting from insulin receptor (INSR) gene mutation. The main features of TAIRS include hyperinsulinemia, abnormal glucose metabolism, and changes in acanthosis nigricans. We identified, in China, a TAIRS family with a novel heterozygous missense gene mutation type. One patient from the Chinese Han family exhibited signs and symptoms of TAIRS and was presented for evaluation. Whole-exome sequencing revealed a heterozygous mutation. Both the patient proband and his father were identified with insulin receptor exon 19c.3472C>T(p.Arg1158Trp), which resulted in a missense mutation that led to replace by a base in the amino acid codon. We found that the patient proband and his father exhibited high insulin and C-peptide release after glucose stimulation by insulin and C-peptide release tests. At the same time, we also ruled out the possibility of islet βcell tumor through relevant examinations. These findings indicate that the INSR gene mutation may cause pancreatic β cell functional impairment and contribute to the development of diabetes.

Topics: C-Peptide; Diabetes Mellitus; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Mutation, Missense; Receptor, Insulin

Insulin resistance and beta-cell dysfunction are manifestations of rheumatoid arthritis (RA). Apolipoprotein C-III (ApoC3) has been associated with such insulin resistance and beta-cell dysfunction in the general population. Our purpose was to study whether ApoC3 is also related to the insulin resistance and beta-cell dysfunction that are present in patients with RA.. Three hundred thirty-eight non-diabetic patients with RA who had a glycemia lower than 110 mg/dl were recruited. Insulin, C-peptide, and ApoC3 were assessed. Insulin resistance and beta-cell function were calculated using the Homeostasis Model Assessment (HOMA2) indices. A multivariable regression analysis was performed to study the relationship of ApoC3 with those molecules and indices adjusting for classic factors associated with insulin resistance that included glucocorticoids.. ApoC3 was related to significant higher levels of circulating insulin (beta coef. 0.37 [95%CI 0.01-0.73] µU/ml, p = 0.044) and C-peptide (beta coef. 0.13 [95%CI 0.05-0.22] ng/ml, p = 0.003), and higher insulin resistance -HOMA2-IR- (beta coef. 0.05 [95%CI 0.00-0.09], p = 0.041) and beta-cell dysfunction -HOMA2-%B- (beta coef. 2.94 [95%CI 0.07-5.80], p = 0.044) indices. This was found after a fully multivariable analysis that included, among others, prednisone intake and the classic factors associated with carbohydrate metabolism such as triglycerides, waist circumference, and obesity.. ApoC3, insulin resistance, and beta-cell dysfunction are independently associated in patients RA.

Topics: Apolipoprotein C-III; Arthritis, Rheumatoid; C-Peptide; Humans; Insulin; Insulin Resistance

Lipocalin-2 and visfatin are proinflammatory adipokines involved in the regulation of glucose homeostasis. Their role has been described in numerous inflammatory skin diseases such as atopic dermatitis and psoriasis. Recently, an increased prevalence of metabolic abnormalities has been reported in patients with alopecia areata. The aim of the study is to determine the serum levels of lipocalin-2 and visfatin in patients with alopecia areata in comparison with healthy controls. Moreover, the serum levels of total cholesterol, low-density lipoprotein cholesterol (LDL-cholesterol), high-density lipoprotein cholesterol (HDL-cholesterol), triglycerides, fasting glucose, insulin, c-peptide, and homeostasis model assessment for insulin resistance (HOMA-IR) were evaluated. Fifty-two patients with alopecia areata and 17 control subjects were enrolled in the study. The serum levels of lipocalin-2 [mean ± standard deviation, SD: 224.55 ± 53.58 ng/ml vs. 188.64 ± 44.75, p = 0.01], insulin [median (interquartile range, IQR): 6.85 (4.7-9.8) μIU/ml vs. 4.5 (3.5-6.6), p<0.05], c-peptide [median (IQR): 1.63 (1.23-2.36) ng/ml vs. 1.37 (1.1-1.58), p<0.05)], and HOMA-IR [median (IQR): 1.44 (0.98-2.15) vs. 0.92 (0.79-1.44), p<0.05) were significantly higher in patients with alopecia areata compared to the controls. The serum concentration of insulin and HOMA-IR correlated with the number of hair loss episodes (r = 0.300, p<0.05 and r = 0.322, p<0.05, respectively). Moreover, a positive correlation occurred between insulin, HOMA-IR, c-peptide and BMI (r = 0.436, p <0.05; r = 0.384, p<0.05 and r = 0.450, p<0.05, respectively). In conclusion, lipocalin-2 and insulin may serve as biomarkers for alopecia areata. Further studies are needed to evaluate the role of insulin as a prognostic factor in alopecia areata.

Topics: Alopecia Areata; Biomarkers; C-Peptide; Cholesterol, HDL; Glucose; Humans; Insulin; Insulin Resistance; Lipocalin-2; Nicotinamide Phosphoribosyltransferase

We investigated quantitative expression, mutual aggregation and relation with hyperglycemia of insulin resistance (IR) and beta-cell dysfunction (BCD) in newly diagnosed type 2 diabetes.. We assessed IR with euglycemic hyperinsulinemic clamp and BCD with modelled glucose/C-peptide response to oral glucose in 729 mostly drug-naïve patients. We measured glycated hemoglobin, pre-prandial, post-prandial and meal-related excursion of blood glucose.. IR was found in 87.8% [95% confidence intervals 85.4-90.2] and BCD in 90.0% [87.8-92.2] of subjects, ranging from mild to moderate or severe. Approximately 20% of subjects had solely one defect: BCD 10.8% [8.6-13.1] or IR 8.6% [6.6-10.7]. Insulin resistance and BCD aggregated in most subjects (79.1% [76.2-82.1]). We arbitrarily set nine possible combinations of mild, moderate or severe IR and mild, moderate or severe BCD, finding that each had a similar frequency (∼10%). In multiple regression analyses parameters of glucose control were related more strongly with BCD than with IR.. In newly-diagnosed type 2 diabetes, IR and BCD are very common with a wide range of expression but no specific pattern of aggregation. Beta-cell dysfunction is likely to play a greater quantitative role than IR in causing/sustaining hyperglycemia in newly-diagnosed type 2 diabetes.

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Glucose; Glycated Hemoglobin; Humans; Hyperglycemia; Insulin; Insulin Resistance

The. 13 persons were diagnosed with T2DM, 119 had impaired fasting blood glucose (IFG) and/or impaired glucose tolerance (IGT). 1074 participants showed normal results and formed a control group. A higher frequency of minor allele G was found in the IFG/IGT group in comparison with controls. The GG constellation was present in 23% of diabetics, in 17% of IFG/IGT probands and in 11% of controls. Compared to CC and CG genotypes, GG homozygotes showed higher stimulated glycemia levels during the OGTT. Homozygous as well as heterozygous carriers of the G allele showed lower very early phase of insulin and C-peptide secretion with unchanged insulin sensitivity. These differences remained significant after excluding diabetics and the IFG/IGT group from the analysis. No associations of the genotype with the shape of OGTT-based trajectories, with glucagon or with chronobiological patterns were observed. However, the shape of the trajectories differed significantly between men and women.. In a representative sample of the Czech population, the G allele of the rs10830963 polymorphism is associated with impaired early phase of beta cell function, and this is evident even in healthy individuals.

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucagon; Glucose; Glucose Intolerance; Humans; Insulin; Insulin Resistance; Kinetics; Male; Prediabetic State; Receptor, Melatonin, MT2

The aim: To investigate the relationship between leptin resistance, lipid and carbohydrate metabolism, blood pressure in obese pregnant women.. Materials and methods: Under observation were 65 women (main group) with obesity (I degree -27 women, II degree - 24 women, III degree - 14 women) in the II trimester of pregnancy, who were hospitalized in the Department of Pathology of Pregnancy KNP «Maternity Clinical house №1 "in Lviv during 2017-2020 on preeclampsia of varying severity, which were sent for inpatient treatment by women's clinics. The control group consisted of 30 healthy pregnant women without obesity.. Results: Serum leptin in obese women was directly correlated with BMI (r = 0.66, p<0.001), body weight (r = 0.29, p<0.05), total cholesterol (cholesterol) (r = 0, 37, p<0,009), low density lipoproteins (LDL cholesterol) (r = 0.33, p<0.05) and inversely with high density particles (HDL cholesterol) (r = -0.37, p<0.02 ). Studies of carbohydrate metabolism indicate the following correlation coefficients of BMI with glucose level r = 0.351; p<0,001, BMI with the level of C-peptide r = 0,450; p<0,001, BMI with HOMA index r = 0,1504; p = 0.036. Inverse correlations of C-peptide were detected with the level of P (r = -0.169; p = 0.025).. Conclusions: The discovery of the relationship between leptin resistance, lipid and carbohydrate metabolism, blood pressure indicates the possibility of using signs of leptin resistance to prevent complications during pregnancy in the second trimester.

Topics: Body Mass Index; C-Peptide; Cholesterol; Female; Humans; Insulin Resistance; Leptin; Obesity; Pregnancy; Pregnant Women

The optimal screening strategy for dysglycemia (including type 2 diabetes and impaired glucose tolerance) in patients with coronary artery disease (CAD) is debated. We tested the hypothesis that measures of insulin resistance by HOMA indexes may constitute good screening methods.. Insulin, C-peptide, glycated hemoglobin A1c, and an oral glucose tolerance test (OGTT) were centrally assessed in 3,534 patients with CAD without known dysglycemia from the fifth European Survey of Cardiovascular Disease Prevention and Diabetes (EUROASPIRE V). Three different HOMA indexes were calculated: HOMA of insulin resistance (HOMA-IR), HOMA2 based on insulin (HOMA2-ins), and HOMA2 based on C-peptide (HOMA2-Cpep). Dysglycemia was diagnosed based on the 2-h postload glucose value obtained from the OGTT. Information on study participants was obtained by standardized interviews. The optimal thresholds of the three HOMA indexes for dysglycemia diagnosis were obtained by the maximum value of Youden's J statistic on receiver operator characteristic curves. Their correlation with clinical parameters was assessed by Spearman coefficients.. Of 3,534 patients with CAD (mean age 63 years; 25% women), 41% had dysglycemia. Mean insulin, C-peptide, and HOMA indexes were significantly higher in patients with versus without newly detected dysglycemia (all P < 0.0001). Sensitivity and specificity of the three HOMA indexes for the diagnosis of dysglycemia were low, but their correlation with BMI and waist circumference was strong.. Screening for dysglycemia in patients with CAD by HOMA-IR, HOMA2-ins, and HOMA2-Cpep had insufficient diagnostic performance to detect dysglycemia with reference to the yield of an OGTT, which should still be prioritized despite its practical drawbacks.

Topics: Blood Glucose; C-Peptide; Coronary Artery Disease; Diabetes Mellitus, Type 2; Female; Humans; Insulin; Insulin Resistance; Male; Middle Aged

Nonalcoholic fatty liver disease (NAFLD) is the commonest etiology of chronic hepatic problems in children with obesity. This study aimed to assess whether urinary C-peptide creatinine ratio (UCPCR) might be a potential indicator of NAFLD in obese children.. The study included 240 children with simple obesity. Hepatic ultrasonic examination, anthropometric and laboratory measurements including fasting plasma glucose, fasting insulin, fasting C peptide, liver, renal profile, lipid profile, and UCPCR were obtained in all cases. According to the results of the hepatic ultrasonography, cases were classified into two categories, those with NAFLD (n=98) and without NAFLD (n= 142).. In cases with NAFLD, UCPCR was significantly higher than those without NAFLD (P &lt; 0.001). A significant positive correlation between UCPCR and waist circumference (WC SDS), triglyceride, fasting C-peptide, HOMA-IR and alanine aminotransferase (ALT) was found (P &lt; 0.001 for each). Adjusting for other variables, UCPCR was the most significant predictor of NAFLD in children with obesity with higher odds ratio (OR = 3.26) than fasting C peptide (OR = 2.87), triglyceride (OR = 1.89), ALT (OR = 2.20), WC SDS (OR = 1.32) and age (OR=1.27) . UCPCR cut-off value of 0.755 nmol/mmol was able to discriminate cases with NAFLD from those without NAFLD with a sensitivity of 95%, a specificity of 87%.. We concluded that UCPCR is a useful, practical and non-invasive predictor of NAFLD in children with obesity with high sensitivity and specificity.

Topics: Body Mass Index; C-Peptide; Child; Creatinine; Humans; Insulin Resistance; Non-alcoholic Fatty Liver Disease; Pediatric Obesity; Triglycerides

To propose a new definition of partial remission (PR) for patients with type 1 diabetes (T1D) of all-ages using insulin dose and glycated albumin (GA), and find the optimal cut-off values for stimulated C-peptide to diagnose PR in different age-groups.. Patients with newly diagnosed T1D (n=301) were included. GA/insulin dose was used to diagnose PR, and insulin dose-adjusted glycated albumin (IDAGA) was proposed to facilitate clinical application. The optimal diagnostic levels of IDAGA and stimulated C-peptide were determined in different age-groups (≤ 12y, 12-18y and ≥ 18y). Furthermore, the diagnostic consistency between different PR definitions was studied.. GA≤ 23%/insulin dose ≤ 0.5u/kg/day was used to define PR, and IDAGA (GA (%) + 40 * insulin dose(u/kg/day)) ≤ 40 was feasible in all age-groups. Whereas, the optimal diagnostic level showed difference for stimulated C-peptide (265.5, 449.3 and 241.1 pmol/L for the ≤ 12y, 12-18y and ≥ 18y age-group, respectively). About 40% of patients met the PR definition by stimulated C-peptide but not GA/insulin dose or IDAGA, who showed dyslipidemia and higher insulin resistance.. A new definition of the PR phase is proposed using GA/insulin dose, and the calculated IDAGA≤ 40 applies to all age-groups. The stimulated C-peptide to diagnose PR is the highest in the 12-18y age-group, which reflects the effect of puberty on metabolism. For patients with insulin resistance, it is not recommended to use stimulated C-peptide alone to diagnose PR.

Topics: C-Peptide; Diabetes Mellitus, Type 1; Glycated Hemoglobin; Glycated Serum Albumin; Glycation End Products, Advanced; Humans; Insulin; Insulin Resistance; Serum Albumin

Recent literature reported the biological role of C-peptide, but this role is still controversial and unclear. The primary aim of this study was to investigate associations between C-peptide and cardiovascular biomarkers as well as events.. A total of 55636 participants who had a health examination from 2017 to 2021 were included. Of them, 6727 participants visited the hospital at least twice. Cardiovascular biomarkers like high-sensitivity C-reactive protein (hs-CRP) and high-sensitivity cardiac troponin T (hs-cTnT) were measured and their relationships with fasting C-peptide were evaluated for all participants. Cardiovascular events were obtained during the last visit and their associations with C-peptide were evaluated for those participants who visited the hospital at least twice.. Among the included participants, 11.1% had a previous type 2 diabetes mellitus (T2DM). In the participants without previous T2DM, the relationships between fasting C-peptide and hs-CRP and hs-cTnT were negative if the value of fasting C-peptide was < 1.4 ng/mL and positive if the value was ≥ 1.4 ng/mL. These relationships remained significant after adjusting for hemoglobin A1c, insulin resistance index, and its interaction with C-peptide, even if the participants were stratified by glucose metabolism status or levels of insulin resistance index. Hazard ratios of cardiovascular events were first decreased and then increased with the increasing of baseline C-peptide levels, though these associations became unsignificant using the multivariate Cox regression model. Unlike the participants without previous T2DM, the associations of C-peptide with cardiovascular biomarkers and events were not significant in the patients with previous T2DM.. The associations of C-peptide with cardiovascular biomarkers and events were different between the participants without previous T2DM and those with previous T2DM. The effect of C-peptide on cardiovascular risk may be bidirectional, play a benefit role at a low level, and play a harmful role at a high level in the nondiabetic adults and the patients with newly diagnosed T2DM.

Topics: Adult; Biomarkers; C-Peptide; C-Reactive Protein; Cardiovascular Diseases; Diabetes Mellitus, Type 2; Glucose; Glycated Hemoglobin; Heart Disease Risk Factors; Humans; Insulin Resistance; Retrospective Studies; Risk Factors; Troponin T

Pancreatic fat is a form of ectopic fat. Lipid droplets (LDs) are also observed in β cells; however, the pathophysiological significance, especially for β cell function, has not been elucidated. Our aim was to assess LD accumulation in β cells in various stages of glucose intolerance and to clarify its relationship with clinical and histological parameters.. We examined 42 Japanese patients who underwent pancreatectomy. The BODIPY493/503-positive (BODIPY-positive) area in β cells was measured in pancreatic sections from 32 patients. The insulin granule numbers were counted in an additional 10 patients using electron microscopy.. The BODIPY-positive area in β cells in preexisting type 2 diabetes patients was higher than that in normal glucose tolerance patients (p = 0.031). The BODIPY-positive area in β cells was positively correlated with age (r = 0.45, p = 0.0097), HbA1c (r = 0.38, p = 0.0302), fasting plasma glucose (r = 0.37, p = 0.045), and homeostasis model assessment insulin resistance (r = 0.41, p = 0.049) and negatively correlated with an increase in the C-peptide immunoreactivity level by the glucagon test (r = -0.59, p = 0.018). The ratio of mature insulin granule number to total insulin granule number was reduced in the patients with rich LD accumulation in β cells (p = 0.039).. Type 2 diabetes patients had high LD accumulation in β cells, which was associated with insulin resistance, hyperglycemia, aging and β cell dysfunction involving decreased mature insulin granules.

Topics: Blood Glucose; Boron Compounds; C-Peptide; Diabetes Mellitus, Type 2; Glucagon; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Hyperglycemia; Insulin; Insulin Resistance; Lipid Droplets

The triglyceride-glucose index (TyG) has been proposed as a surrogate marker of insulin resistance, which is a typical trait of pregnancy. However, very few studies analyzed TyG performance as marker of insulin resistance in pregnancy, and they were limited to insulin resistance assessment at fasting rather than in dynamic conditions, i.e., during an oral glucose tolerance test (OGTT), which allows more reliable assessment of the actual insulin sensitivity impairment. Thus, first aim of the study was exploring in pregnancy the relationships between TyG and OGTT-derived insulin sensitivity. In addition, we developed a new version of TyG, for improved performance as marker of insulin resistance in pregnancy.. At early pregnancy, a cohort of 109 women underwent assessment of maternal biometry and blood tests at fasting, for measurements of several variables (visit 1). Subsequently (26 weeks of gestation) all visit 1 analyses were repeated (visit 2), and a subgroup of women (84 selected) received a 2 h-75 g OGTT (30, 60, 90, and 120 min sampling) with measurement of blood glucose, insulin and C-peptide for reliable assessment of insulin sensitivity (PREDIM index) and insulin secretion/beta-cell function. The dataset was randomly split into 70% training set and 30% test set, and by machine learning approach we identified the optimal model, with TyG included, showing the best relationship with PREDIM. For inclusion in the model, we considered only fasting variables, in agreement with TyG definition.. The relationship of TyG with PREDIM was weak. Conversely, the improved TyG, called TyGIS, (linear function of TyG, body weight, lean body mass percentage and fasting insulin) resulted much strongly related to PREDIM, in both training and test sets (R. We developed an improved version of TyG, as new surrogate marker of insulin sensitivity in pregnancy (TyGIS). Similarly to TyG, TyGIS relies only on fasting variables, but its performances are remarkably improved than those of TyG.

Topics: Biomarkers; Blood Glucose; C-Peptide; Female; Glucose; Humans; Insulin; Insulin Resistance; Pregnancy; Triglycerides

While there is an emerging role of pancreatic fat in the aetiology of type 2 diabetes mellitus (T2DM), its impact on the associated decrease in insulin secretion remains controversial. We aimed to determine whether pancreatic fat negatively affects β-cell function and insulin secretion in women with overweight or obesity but without T2DM.. 20 women, with normo- or dysglycaemia based on fasting plasma glucose levels, and low (< 4.5%) vs high (≥ 4.5%) magnetic resonance (MR) quantified pancreatic fat, completed a 1-hr intravenous glucose tolerance test (ivGTT) which included two consecutive 30-min square-wave steps of hyperglycaemia generated by using 25% dextrose. Plasma glucose, insulin and C-peptide were measured, and insulin secretion rate (ISR) calculated using regularisation deconvolution method from C-peptide kinetics. Repeated measures linear mixed models, adjusted for ethnicity and baseline analyte concentrations, were used to compare changes during the ivGTT between high and low percentage pancreatic fat (PPF) groups.. No ethnic differences in anthropomorphic variables, body composition, visceral adipose tissue (MR-VAT) or PPF were measured and hence data were combined. Nine women (47%) were identified as having high PPF values. PPF was significantly associated with baseline C-peptide (p = 0.04) and ISR (p = 0.04) in all. During the 1-hr ivGTT, plasma glucose (p<0.0001), insulin (p<0.0001) and ISR (p = 0.02) increased significantly from baseline in both high and low PPF groups but did not differ between the two groups at any given time during the test (PPF x time, p > 0.05). Notably, the incremental areas under the curves for both first and second phase ISR were 0.04 units lower in the high than low PPF groups, but this was not significant (p > 0.05).. In women with overweight or obesity but without T2DM, PPF did not modify β-cell function as determined by ivGTT-assessed ISR. However, the salient feature in biphasic insulin secretion in those with ≥4.5% PPF may be of clinical importance, particularly in early stages of dysglycaemia may warrant further investigation.

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Humans; Insulin; Insulin Resistance; Insulin Secretion; Obesity; Overweight

Melatonin (Mel) and its receptors are promising for glycaemic control in patients with type 2 diabetes mellitus (T2DM) and its complications, but there is significant heterogeneity among studies. This study aims to investigate the effects of Mel receptor agonist Neu-P11 on glucose metabolism, immunity, and islet function in T2DM rats.. In this study, SD rats were treated with a high-fat diet and streptozotocin (STZ) to establish a T2DM model. The glucose oxidase method was used to measure blood glucose levels. Glucose and insulin tolerance tests were used to assess glucose metabolism. Haematoxylin-eosin staining was used to observe pancreatic tissue injury. The apoptosis of isletβ cells was analysed by TUNEL and insulin staining. Reactive oxygen species (ROS) levels and immune cell expression were analysed by flow cytometry. IF was used to analyse the activation of microglia. The immunoglobulins: IgA, IgG, IgM, tumour necrosis factorα (TNF-α), interleukins IL-10 and IL-1β, interferonγ (IFN-γ), C-peptide, and insulin levels were determined by ELISA. The expression of CD11b, CD86, cleaved caspase 3, p21, and P16 proteins were analysed by western blot.. The results showed that the blood glucose level increased, insulin resistance occurred, spleen coefficient and ROS levels increased, humoral immunity in peripheral blood decreased, and inflammation increased in the model group compared to the control group. After Mel and Neu-P11 treatment, the blood glucose level decreased significantly, insulin sensitivity improved, spleen coefficient and ROS levels decreased, humoral immunity in peripheral blood was enhanced, and inflammation improved in T2DM rats. Brain functional analysis of T2DM rats showed that microglia cells were activated, TNF-α and IL-β levels were increased, and IL-10 levels were decreased. Mel and Neu-P11 treatment reversed these indexes. Functional analysis of islets in T2DM rats showed that islet structure inflammation was impaired, isletβ cells were apoptotic, p21 and p16 protein expressions were increased, and blood C-peptide and insulin were decreased. Mel and Neu-P11 treatment restored the function of pancreatic b cells and improved the damage of pancreatic tissue.. Melatonin and its receptor Neu-P11 can reduce the blood glucose level, enhance humoral and cellular immunity, inhibit microglia activation and inflammation, and repair isletβ cell function, and this improve the characterization of T2DM-related diseases.

Topics: Animals; Blood Glucose; C-Peptide; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Diet, High-Fat; Disease Models, Animal; Glycemic Control; Indoles; Insulin Resistance; Melatonin; Pyrans; Rats; Rats, Sprague-Dawley; Receptors, Melatonin; Streptozocin

Adult women with Turner syndrome (TS) have a high prevalence of diabetes and β-cell dysfunction that increases morbidity and mortality, but it is unknown if there is β-cell dysfunction present in youth with TS. This study aimed to determine the prevalence of β-cell dysfunction in youth with TS and the impact of traditional therapies on insulin sensitivity (SI) and insulin secretion.. Cross-sectional, observational study recruited 60 girls with TS and 60 healthy controls (HC) matched on pubertal status. Each subject had a history, physical exam, and oral glucose tolerance test (OGTT). Oral glucose and c-peptide minimal modeling was used to determine β-cell function.. Twenty-one TS girls (35%) met criteria for prediabetes. Impaired fasting glucose was present in 18% of girls with TS and 3% HC (p value = 0.02). Impaired glucose tolerance was present in 23% of TS girls and 0% HC (p value <0.001). The hemoglobin A1c was not different between TS and HC (median 5%, p = 0.42). Youth with TS had significant reductions in SI, β-cell responsivity (Φ), and disposition index (DI) compared to HC. These differences remained significant when controlling for body mass index z-score (p values: 0.0006, 0.002, <0.0001 for SI, Φ total, DI, respectively).. β-Cell dysfunction is present in youth with TS compared to controls. The presence of both reduced insulin secretion and SI suggest a unique TS-related glycemic phenotype. Based on the data from this study, we strongly suggest that providers employ serial OGTT to screen for glucose abnormalities in TS youth.

Topics: Adolescent; Blood Glucose; Body Mass Index; C-Peptide; Cross-Sectional Studies; Diabetes Mellitus; Female; Glucose Intolerance; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Insulin Resistance; Phenotype; Prediabetic State; Prevalence; Turner Syndrome

Type 2 diabetes mellitus (T2DM) and obesity are alarmingly increasing in children and adolescents. Hence, predictors for early metabolic abnormalities in childhood are urgently needed. We investigated glucose tolerance in children and adolescents with obesity, markers of insulin sensitivity between males and females and the potential association between the parameters measured during an OGTT (glucose, insulin, c-peptide) and prediabetes or stages of puberty.. Glucose tolerance in 89 children and adolescents with excess weight, aged 4-19 years, from Western Greece was studied. A 3-hour OGTT was performed and fasting glucose (FG), fasting insulin (FI), 1/FI, FG/FI, Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), Quantitative insulin sensitivity check index (QUICKI), ISI Matsuda index and Insulinogenic index (IGI30), were also calculated.. No significant differences were observed in glucose values between males and females. Insulin and c-peptide concentrations were higher in the girls at several time points. FG/FI was significantly higher in the boys. Girls with obesity may be at higher risk for future insulin resistance.. Better surveillance of pubertal girls with obesity is crucial and can be achieved using additional information provided by an OGTT, since they appear to be at a higher risk for beta-cell exhaustion. During the OGTT, not only are the baseline and 2-hour glucose and insulin measurements useful for predicting future metabolic risks and development of T2DM in children and adolescents with obesity, but additional time measurements may also be helpful.

Topics: Adolescent; Blood Glucose; C-Peptide; Child; Child, Preschool; Diabetes Mellitus, Type 2; Female; Glucose Tolerance Test; Greece; Humans; Insulin; Insulin Resistance; Male; Pediatric Obesity; Puberty; Risk Factors; Sex Factors; Time Factors; Young Adult

Decreased insulin sensitivity occurs early in type 2 diabetes (T2D). T2D is highly prevalent in the Middle East and North Africa regions. This study assessed the variations in insulin sensitivity in normal apparently healthy subjects and the levels of adiponectin, adipsin and inflammatory markers.. The subjects showed wide variations in the whole-body glucose disposal rate (M value) from 2 to 20 mg/kg/min and were divided into three groups: most responsive (M>12 mg/kg/min, n=17), least responsive (M≤6 mg/kg/min, n=14) and intermediate responsive (M=6.1-12 mg/kg/min, n=29). Insulin and C peptide responses to OGTT were highest among the least insulin sensitive group. Triglycerides, cholesterol, alanine transaminase (ALT) and albumin levels were higher in the least responsive group compared with the other groups. Among the inflammatory markers, C reactive protein (CRP) was highest in the least sensitivity group compared with the other groups; however, there were no differences in the level of soluble receptor for advanced glycation end products and Tumor Necrosis Factor Receptor Superfamily 1B (TNFRS1B). Plasma levels of insulin sensitivity markers, adiponectin and adipsin, and oxidative stress markers, oxidized low-density lipoprotein, total antioxidant capacity and glutathione peroxidase 1, were similar between the groups.. A wide range in insulin sensitivity and significant differences in triglycerides, cholesterol, ALT and CRP concentrations were observed despite the fact that the study subjects were homogenous in terms of age, gender and ethnic background, and all had normal screening comprehensive chemistry and normal glucose response to OGTT. The striking differences in insulin sensitivity reflect differences in genetic predisposition and/or environmental exposure. The low insulin sensitivity status associated with increased insulin level may represent an early stage of metabolic abnormality.

Topics: Arabs; C-Peptide; Diabetes Mellitus, Type 2; Healthy Volunteers; Humans; Insulin; Insulin Resistance; Male

Sitting time (ST) is a serious global health issue and positively associated with cardiometabolic disease. The present study investigated associations between objectively measured ST, sedentary patterns, and cardiometabolic biomarkers in physically active young males.. Cross-sectional analysis was completed in 94 males 18-35 yr of age. Total ST, prolonged sedentary bouts (≥30 min with no interruption), and sedentary breaks (transitions from sitting/lying to standing/stepping) were assessed using activPAL. Lipids, insulin, C-peptide, C-reactive protein (CRP), vascular cellular adhesion molecule-1, intercellular adhesion molecule 1, E-selectin, P-selectin, leptin, resistin, and adiponectin were measured using assay kits. The expression of specific proteins related to endothelial dysfunction was determined using quantitative real-time polymerase chain reaction. Associations between total ST, prolonged sedentary bouts, and sedentary breaks with cardiometabolic biomarkers and total ST and levels of gene expression were assessed using generalized linear models.. Total ST was significantly associated with triglycerides (B = 1.814), insulin (B = 2.117), homeostasis model assessment of insulin resistance (B = 0.071), and E-selectin (B = 2.052). Leptin (B = 0.086), E-selectin (B = 1.623), and P-selectin (B = 2.519) were significantly associated with prolonged sedentary bouts, whereas leptin (B = -0.017) and CRP (B = -0.016) were associated with sedentary breaks. After adjustment for moderate to vigorous physical activity, the associations between triglycerides (B = 2.048) and total ST, and between CRP (B = -0.016) and sedentary breaks, remained significant. E-selectin mRNA levels (B = 0.0002) were positively associated with ST with or without adjustment for moderate to vigorous physical activity.. Total ST and prolonged sedentary bouts were positively associated with several cardiometabolic biomarkers, with interruptions in ST potentially contributing to reduced cardiometabolic risk in physically active young male adults.

Topics: Adiponectin; Adult; Biomarkers; C-Peptide; C-Reactive Protein; Cross-Sectional Studies; E-Selectin; Exercise; Humans; Insulin; Insulin Resistance; Leptin; Lipids; Male; P-Selectin; Resistin; Sedentary Behavior; Sitting Position; Standing Position; Time Factors; Vascular Cell Adhesion Molecule-1; Young Adult

Recent studies have suggested C-X-C motif chemokine ligand 14 (CXCL14), secreted from adipose tissue, to play an important role in the pathogenesis of metabolic syndrome. However, the clinical significance of CXCL14 in humans has not been elucidated. This study aimed to assess correlations between serum CXCL14 levels and clinical parameters in patients with type 2 diabetes mellitus.. In total, 176 individuals with type 2 diabetes mellitus were recruited. Serum CXCL14 concentrations were determined by enzyme-linked immunosorbent assay. We examined the associations of serum CXCL14 levels with laboratory values, abdominal computed tomography image information, surrogate markers used for evaluating the pathological states of diabetes, obesity and atherosclerosis.. Serum CXCL14 levels correlated positively with body mass index, waist circumference, subcutaneous and visceral fat areas, and serum alanine transaminase, uric acid, total cholesterol, low-density lipoprotein cholesterol, triglycerides and C-peptide (CPR) levels. In contrast, CXCL14 levels correlated inversely with age, pulse wave velocity and serum adiponectin levels. Multiple linear regression analysis showed serum levels of CPR (β = 0.227, P = 0.038) and the fatty liver index (β = 0.205, P = 0.049) to be the only parameters showing independent statistically significant associations with serum CXCL14 levels.. Serum CXCL14 levels were independently associated with serum CPR and fatty liver index in patients with type 2 diabetes mellitus. In these patients, a high serum CPR concentration might reflect insulin resistance rather than β-cell function, because CXCL14 showed simple correlations with obesity-related parameters. Collectively, these data suggested that serum CXCL14 levels in type 2 diabetes patients might be useful predictors of elevated serum CPR and hepatic steatosis.

Topics: Adiponectin; Age Factors; Aged; Alanine Transaminase; Biomarkers; Body Mass Index; C-Peptide; Chemokines, CXC; Cholesterol; Diabetes Mellitus, Type 2; Fatty Liver; Female; Humans; Insulin Resistance; Intra-Abdominal Fat; Linear Models; Lipoproteins, LDL; Liver Function Tests; Male; Middle Aged; Obesity; Pulse Wave Analysis; Triglycerides; Uric Acid; Waist Circumference

To examine the hypothesis that, based on their glucose curves during a seven-point oral glucose tolerance test, people at elevated type 2 diabetes risk can be divided into subgroups with different clinical profiles at baseline and different degrees of subsequent glycaemic deterioration.. We included 2126 participants at elevated type 2 diabetes risk from the Diabetes Research on Patient Stratification (IMI-DIRECT) study. Latent class trajectory analysis was used to identify subgroups from a seven-point oral glucose tolerance test at baseline and follow-up. Linear models quantified the associations between the subgroups with glycaemic traits at baseline and 18 months.. At baseline, we identified four glucose curve subgroups, labelled in order of increasing peak levels as 1-4. Participants in Subgroups 2-4, were more likely to have higher insulin resistance (homeostatic model assessment) and a lower Matsuda index, than those in Subgroup 1. Overall, participants in Subgroups 3 and 4, had higher glycaemic trait values, with the exception of the Matsuda and insulinogenic indices. At 18 months, change in homeostatic model assessment of insulin resistance was higher in Subgroup 4 (β = 0.36, 95% CI 0.13-0.58), Subgroup 3 (β = 0.30; 95% CI 0.10-0.50) and Subgroup 2 (β = 0.18; 95% CI 0.04-0.32), compared to Subgroup 1. The same was observed for C-peptide and insulin. Five subgroups were identified at follow-up, and the majority of participants remained in the same subgroup or progressed to higher peak subgroups after 18 months.. Using data from a frequently sampled oral glucose tolerance test, glucose curve patterns associated with different clinical characteristics and different rates of subsequent glycaemic deterioration can be identified.

Topics: Aged; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Latent Class Analysis; Male; Middle Aged; Risk Assessment

We aimed to examine associations of newborn anthropometric measures with childhood glucose metabolism with the hypothesis that greater newborn birthweight, adiposity and cord C-peptide are associated with higher childhood glucose levels and lower insulin sensitivity.. Data from the international, multi-ethnic, population-based Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study and the HAPO Follow-Up Study were used. The analytic cohort included 4155 children (mean age [SD], 11.4 [1.2] years; 51.0% male). Multiple linear regression was used to examine associations of primary predictors, birthweight, newborn sum of skinfolds (SSF) and cord C-peptide, from HAPO with continuous child glucose outcomes from the HAPO Follow-Up Study.. In an initial model that included family history of diabetes and maternal BMI during pregnancy, birthweight and SSF demonstrated a significant, inverse association with 30 min and 1 h plasma glucose levels. In the primary model, which included further adjustment for maternal sum of glucose z scores from an oral glucose tolerance test during pregnancy, the associations were strengthened, and birthweight and SSF were inversely associated with fasting, 30 min, 1 h and 2 h plasma glucose levels. Birthweight and SSF were also associated with higher insulin sensitivity (Matsuda index) (β = 1.388; 95% CI 0.870, 1.906; p < 0.001; β = 0.792; 95% CI 0.340, 1.244; p < 0.001, for birthweight and SSF higher by 1 SD, respectively) in the primary model, while SSF, but not birthweight, was positively associated with the disposition index, a measure of beta cell compensation for insulin resistance (β = 0.034; 95% CI 0.012, 0.056; p = 0.002). Cord C-peptide levels were inversely associated with Matsuda index (β = -0.746; 95% CI -1.188, -0.304; p < 0.001 for cord C-peptide higher by 1 SD) in the primary model.. This study demonstrates that higher birthweight and SSF are associated with greater childhood insulin sensitivity and lower glucose levels following a glucose load, associations that were further strengthened after adjustment for maternal glucose levels during pregnancy. Graphical abstract.

Topics: Adiposity; Adult; Age Factors; Biomarkers; Birth Weight; Blood Glucose; C-Peptide; Child; Female; Fetal Blood; Follow-Up Studies; Humans; Hyperglycemia; Infant, Newborn; Insulin Resistance; Male; Pregnancy; Prenatal Exposure Delayed Effects; Prospective Studies; Risk Assessment; Risk Factors; Skinfold Thickness; Young Adult

The fasting proinsulin to insulin ratio is elevated in people with type 2 diabetes and has been suggested as a marker of β-cell health. However, its utility in discriminating between individuals with varying degrees of β-cell dysfunction is unclear. Proinsulin has a very different half-life to insulin and unlike insulin does not undergo hepatic extraction prior to reaching the systemic circulation. Given these limitations, we sought to examine the relationship between fasting and postprandial concentrations of β-cell polypeptides (proinsulin, insulin and C-peptide) in people with normal and impaired glucose tolerance in differing metabolic environments.. Subjects were studied on two occasions in random order while undergoing an oral challenge. During one study day, free fatty acids were elevated (to induce insulin resistance) by infusion of Intralipid with heparin. Proinsulin to insulin and proinsulin to C-peptide ratios were calculated for the 0-, 30-, 60- and 240-minute time points. Insulin action (Si) and β-cell responsivity (Φ) indices were calculated using the oral minimal model.. The fasting proinsulin to c-peptide or fasting proinsulin to insulin ratios did not differ between groups and did not predict subsequent β-cell responsivity to glucose during the glycerol or Intralipid study days in either group.. Among nondiabetic individuals, the fasting proinsulin to insulin ratio is not a useful marker of β-cell function.

Topics: Adult; Biomarkers; Blood Glucose; C-Peptide; Case-Control Studies; Diabetes Mellitus, Type 2; Fasting; Female; Glucose Intolerance; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Middle Aged; Proinsulin

To investigate how markers of beta-cell secretion (proinsulin-processing metabolites) are expressed in SLE patients and their potential relation to features associated with the disease such as activity or damage.. One hundred and forty-four SLE patients and 69 nondiabetic sex- and age-matched controls were assessed. Beta-cell secretion molecules, as measured by insulin, split and intact proinsulins, and C-peptide levels were analysed in both groups. Multiple regression analysis was performed to compare proinsulin propeptides between groups and to explore the interrelations with SLE features. Analyses were adjusted for glucocorticoid intake and for insulin resistance classic risk factors.. Fully multivariable analysis demonstrated that regardless of glucocorticoid use, SLE patients exhibited higher levels of split proinsulin. Likewise, the split proinsulin-to-insulin ratio was upregulated in patients with SLE undergoing glucocorticoid therapy [beta coeficient 0.19 (95% Confidence Interval 0.07, 0.30), P = 0.002] or not [beta coef. 0.09 (95% CI: 0.01, 0.17), P = 0.025]. Similar results were found for the intact proinsulin-to-insulin ratio, although differences were only statistically significant for patients taking glucocorticoids [beta coef. 0.08 (95% CI: 0.03, 0.12), P = 0.001]. SLE damage score was associated with higher serum levels of intact [beta coef. 0.51 (95% CI 0.17, 0.86) pmol/l, P = 0.004] and split proinsulins [beta coef. 1.65 (95% CI 0.24, 3.06) pmol/l, P = 0.022] after multivariable analysis, including disease duration and prednisone use.. Among patients with SLE, proinsulin-processing metabolites, a marker of beta-cell disruption, are upregulated compared with matched controls. This disproportionate hyperproinsulinemia can be explained by the damage produced by the disease and occurs independently of prednisone use.

Topics: Adult; C-Peptide; Diabetes Mellitus; Female; Glucocorticoids; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Lupus Erythematosus, Systemic; Male; Middle Aged; Proinsulin

Type 2 diabetes (T2D), the most common form of diabetes, is recognized as being a heterogenous disorder, and presents a universal threat to health. In T2D, the pathophysiology and phenotype differ significantly by ethnicity, particularly among Asian Indians, who are known to have the 'Asian Indian phenotype', which makes them more susceptible to develop T2D than white Caucasians. The recent subclassification of T2D into different subtypes or clusters, which behave differently with respect to clinical presentation and risk of developing complications is a remarkable development. Five unique "clusters" of individuals with diabetes were described in the Scandinavian population [Severe Autoimmune Diabetes (SAID), Severe Insulin Deficient Diabetes (SIDD), Severe Insulin Resistant Diabetes (SIRD), Mild Obesity-related Diabetes (MOD) and Mild Age-Related Diabetes (MARD)]. For the first time in India, identification of clusters of diabetes was done on 19,084 individuals with T2D, using 8 clinically relevant variables (age at diagnosis, BMI, waist circumference, HbA1c, triglycerides, HDL cholesterol and fasting and stimulated C-peptide). Four replicable clusters were identified [SIDD, MARD, IROD (Insulin Resistant Obese Diabetes) and CIRDD (Combined Insulin Resistant and Deficient Diabetes)], two of which were unique to the Indian population (IROD and CIRDD). Clustering of T2D helps i) to accurately subclassify diabetes into different subtypes, ii) plan therapies based on the pathophysiology, iii) predict prognosis and prevent diabetic complications and iv) helps in our approach to precision diabetes. Further studies would help us to refine the usefulness of these clusters of T2D particularly in the Indian population, with respect to selection of appropriate therapies and hopefully in the prevention of complications of diabetes.

Topics: C-Peptide; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Humans; India; Insulin Resistance

Pulsatile insulin secretion is impaired in diseases such as type 2 diabetes that are characterized by insulin resistance. This has led to the suggestion that changes in insulin pulsatility directly impair insulin signaling. We sought to examine the effects of pulse characteristics on insulin action in humans, hypothesizing that a decrease in pulse amplitude or frequency is associated with impaired hepatic insulin action.. We studied 29 nondiabetic subjects on two occasions. On 1 occasion, hepatic and peripheral insulin action was measured using a euglycemic clamp. The deuterated water method was used to estimate the contribution of gluconeogenesis to endogenous glucose production. On a separate study day, we utilized nonparametric stochastic deconvolution of frequently sampled peripheral C-peptide concentrations during fasting to reconstruct portal insulin secretion. In addition to measuring basal and pulsatile insulin secretion, we used approximate entropy to measure orderliness and Fourier transform to measure the average, and the dispersion of, insulin pulse frequencies.. In univariate analysis, basal insulin secretion (R2 = 0.16) and insulin pulse amplitude (R2 = 0.09) correlated weakly with insulin-induced suppression of gluconeogenesis. However, after adjustment for age, sex, and weight, these associations were no longer significant. The other pulse characteristics also did not correlate with the ability of insulin to suppress endogenous glucose production (and gluconeogenesis) or to stimulate glucose disappearance.. Overall, our data demonstrate that insulin pulse characteristics, considered independently of other factors, do not correlate with measures of hepatic and peripheral insulin sensitivity in nondiabetic humans.

Topics: Adult; Blood Glucose; C-Peptide; Fasting; Female; Gluconeogenesis; Glucose; Glucose Clamp Technique; Humans; Insulin; Insulin Resistance; Insulin Secretion; Liver; Male; Middle Aged

To investigate the predictive value of baseline serum triglyceride (TG) levels for improvements of metabolism after laparoscopic sleeve gastrectomy (LSG).. In the whole cohort, the metabolic parameters were significantly improved at 6 months after LSG. BMI and waist circumference (WC) decreased significantly in the two groups. The ΔBMI among group A and group B were 11.42±3.23 vs 9.13±2.77 kg/m. Obese patients with baseline TG levels under 1.7 mmol/L had greater loss of weight at six months follow-up later LSG. This finding suggests that baseline TG level may have a predictive value for weight loss, at least in the short-term follow-up.

Topics: Adult; Anthropometry; Blood Glucose; Body Mass Index; C-Peptide; Female; Gastrectomy; Homeostasis; Humans; Insulin; Insulin Resistance; Laparoscopy; Male; Middle Aged; Obesity, Morbid; Odds Ratio; Postoperative Period; Regression Analysis; Retrospective Studies; Triglycerides; Weight Loss

Evaluate the relationship between measures of glycemia with β-cell function and insulin sensitivity in adults with early type 2 diabetes mellitus (T2DM).. This cross-sectional analysis evaluated baseline data from 3108 adults with T2DM <10 years treated with metformin alone enrolled in the Glycemia Reduction Approaches in Diabetes. A Comparative Effectiveness (GRADE) Study. Insulin and C-peptide responses and insulin sensitivity were calculated from 2-h oral glucose tolerance tests. Regression models evaluated the relationships between glycemic measures (HbA1c, fasting and 2-h glucose), measures of β-cell function and insulin sensitivity.. Insulin and C-peptide responses were inversely associated with insulin sensitivity. Glycemic measures were inversely associated with insulin and C-peptide responses adjusted for insulin sensitivity. HbA1c demonstrated modest associations with β-cell function (range: r - 0.22 to -0.35). Fasting and 2-h glucose were associated with early insulin and C-peptide responses (range: r - 0.37 to -0.40) as well as late insulin and total insulin and C-peptide responses (range: r - 0.50 to -0.60).. Glycemia is strongly associated with β-cell dysfunction in adults with early T2DM treated with metformin alone. Efforts to improve glycemia should focus on interventions aimed at improving β-cell function. This Trial is registered in Clinicaltrials.gov as NCT01794143.

Topics: Blood Glucose; C-Peptide; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin-Secreting Cells; Metformin; Randomized Controlled Trials as Topic

Metabolic effects of intermittent unhealthy lifestyle in young adults are poorly studied. We investigated the gluco-metabolic and hepatic effects of participation in Roskilde Festival (1 week of binge drinking and junk food consumption) in young, healthy males.. Fourteen festival participants (FP) were studied before, during and after 1 week's participation in Roskilde Festival. Fourteen matched controls (CTRL) who did not participate in Roskilde Festival or change their lifestyle in other ways were investigated along a similar timeline.. The FP group consumed more alcohol compared to their standard living conditions (2.0 ± 3.9 vs 16.3 ± 8.3 units/day, P < 0.001). CTRLs did not change their alcohol consumption. AUC for glucose during OGTT did not change in either group. C-peptide responses increased in the FP group (206 ± 24 vs 236 ± 17 min × nmol/L, P = 0.052) and the Matsuda index of insulin sensitivity decreased (6.2 ± 2.4 vs 4.7 ± 1.4, P = 0.054). AUC for glucagon during oral glucose tolerance test (OGTT) increased in the FP group (1037 ± 90 vs 1562 ± 195 min × pmol/L, P = 0.003) together with fasting fibroblast growth factor 21 (FGF21) (62 ± 30 vs 132 ± 72 pmol/L, P < 0.001), growth differentiation factor 15 (GDF5) (276 ± 78 vs 330 ± 83 pg/mL, P = 0.009) and aspartate aminotransferase (AST) levels (37.6 ± 6.8 vs 42.4 ± 11 U/L, P = 0.043). Four participants (29%) developed ultrasound-detectable steatosis and a mean strain elastography-assessed liver stiffness increased (P = 0.026) in the FP group.. Participation in Roskilde Festival did not affect oral glucose tolerance but was associated with a reduction in insulin sensitivity, increases in glucagon, FGF21, GDF15 and AST and lead to increased liver stiffness and, in 29% of the participants, ultrasound-detectable hepatic steatosis.

Topics: Adult; Aspartate Aminotransferases; Binge Drinking; Blood Glucose; C-Peptide; C-Reactive Protein; Denmark; Diet; Elasticity Imaging Techniques; Fast Foods; Fatty Liver; Fibroblast Growth Factors; Glucagon; Glucose Tolerance Test; Growth Differentiation Factor 15; Holidays; Humans; Insulin Resistance; Liver; Male; Young Adult

Insulin resistance is a major risk factor for coronary artery disease (CAD). The C-peptide-to-insulin ratio (C/I) is associated with hepatic insulin clearance and insulin resistance. The current study was designed to establish a novel C/I index (CPIRI) model and provide early risk assessment of CAD.. A total of 865 adults diagnosed with new-onset diabetes mellitus (DM) within one year and 54 healthy controls (HC) were recruited to develop a CPIRI model. The CPIRI model was established with fasting C/I as the independent variable and homeostasis model assessment of insulin resistance (HOMA-IR) as the dependent variable. Associations between the CPIRI model and the severity of CAD events were also assessed in 45 hyperglycemic patients with CAD documented via coronary arteriography (CAG) and whom underwent stress echocardiography (SE) and exercise electrocardiography test (EET).. Fasting C-peptide/insulin and HOMA-IR were hyperbolically correlated in DM patients and HC, and log(C/I) and log(HOMA-IR) were linearly and negatively correlated. The respective correlational coefficients were -0.83 (p < 0.001) and -0.76 (p < 0.001). The equations CPIRI(DM) = 670/(C/I)2.24 + 0.25 and CPIRI(HC) = 670/(C/I)2.24 - 1 (F = 1904.39, p < 0.001) were obtained. Patients with insulin resistance exhibited severe coronary artery impairment and myocardial ischemia. In CAD patients there was no significant correlation between insulin resistance and the number of vessels involved.. CPIRI can be used to effectively evaluate insulin resistance, and the combination of CPIRI and non-invasive cardiovascular examination is of great clinical value in the assessment of CAD.

Topics: Adult; C-Peptide; Coronary Angiography; Coronary Artery Disease; Humans; Insulin; Insulin Resistance; Risk Factors

We aimed to examine prospective associations between circulating fatty acids in early pregnancy and incident gestational diabetes mellitus (GDM) among Chinese pregnant women.. Analyses were based on two prospective nested case-control studies conducted in western China (336 GDM cases and 672 matched controls) and central China (305 cases and 305 matched controls). Fasting plasma fatty acids in early pregnancy (gestational age at enrollment: 10.4 weeks(s.d., 2.0)) and 13.2 weeks (1.0), respectively) were determined by gas chromatography-mass spectrometry, and GDM was diagnosed based on the International Association of Diabetes in Pregnancy Study Groups criteria during 24-28 weeks of gestation. Multiple metabolic biomarkers (HOMA-IR (homeostatic model assessment for insulin resistance), HbA1c, c-peptide, high-sensitivity C-reactive protein, adiponectin, leptin, and blood lipids) were additionally measured among 672 non-GDM controls at enrollment.. Higher levels of saturated fatty acids (SFAs) 14:0 (pooled odds ratio, 1.41 for each 1-s.d. increase; 95% CI: 1.25, 1.59) and 16:0 (1.19; 1.05, 1.35) were associated with higher odds of GDM. Higher levels of n-6 polyunsaturated fatty acid (PUFA) 18:2n-6 were strongly associated with lower odds of GDM (0.69; 0.60, 0.80). In non-GDM pregnant women, higher SFAs 14:0 and 16:0 but lower n-6 PUFA 18:2n-6 were generally correlated with unfavorable metabolic profiles.. We documented adverse associations of 14:0 and 16:0 but a protective association of 18:2n-6 with GDM among Chinese pregnant women. Our findings highlight the distinct roles of specific fatty acids in the onset of GDM.

Topics: Adiponectin; Adult; Blood Glucose; C-Peptide; C-Reactive Protein; Case-Control Studies; China; Diabetes, Gestational; Fasting; Fatty Acids; Fatty Acids, Monounsaturated; Fatty Acids, Omega-3; Fatty Acids, Omega-6; Female; Glycated Hemoglobin; Humans; Insulin Resistance; Leptin; Pregnancy; Prospective Studies; Risk Factors; Young Adult

The urinary C-peptide/creatinine ratio (UCPCR) is low in patients with type 1 diabetes mellitus, but it has not been well characterized in patients with type 2 diabetes mellitus (T2DM). We aimed to measure the UCPCRs in patients with T2DM and explore the relationships among UCPCR, insulin resistance (IR), and chronic vascular complications of diabetes.. A cross-sectional study was performed of 1299 Chinese hospitalized patients with T2DM. Binary logistic regression was used to evaluate the relationships between the chronic vascular complications of diabetes and UCPCR. K-means analysis was used to allocate participants to subgroups with five to six variables (age at diagnosis, body mass index [BMI], glycosylated hemoglobin, homoeostasis model assessment 2-estimated beta-cell function (HOMA2-B), and HOMA2-insulin resistance (HOMA2-IR), with or without UCPCR).. UCPCR positively correlated with HOMA2-IR (r = 0.448, P < .001). After adjustment for sex, age, duration of diabetes, and other cardiovascular risk factors, UCPCR was positively associated with diabetic kidney disease (DKD) (odds ratio [OR] = 1.198, 95% CI 1.019-1.408, P = .029) and coronary heart disease (CHD) (OR = 1.312, 95% CI 1.079-1.594, P = .006). When UCPCR was added, cluster analysis using the six variables identified five subgroups of T2DM, characterized by differing age at diagnosis, BMI, beta-cell function, IR, and prevalence of vascular complications.. UCPCR is positively associated with IR, DKD, and CHD and represents a promising biomarker that could refine the classification of T2DM.. 背景: 1型糖尿病患者尿C肽/肌酐比值水平低。但尿C肽/肌酐比值在2型糖尿病患者中并没有被充分评估, 本研究拟测定2型糖尿病患者的尿C肽/肌酐比值水平, 探讨尿C肽/肌酐比值与胰岛素抵抗及糖尿病慢性血管并发症的相关性, 并评估尿C肽/肌酐比值改善2型糖尿病精准分型的可能性。 方法: 本研究共纳入北京大学人民医院内分泌科住院2型糖尿病患者1299名。采集所有患者的临床资料, 测定其空腹尿C肽/肌酐比, 通过二元Logistic回归分析尿C肽/肌酐比值与糖尿病血管并发症的相关性。并分别用传统的五个变量[诊断年龄, 体重指数, 糖化血红蛋白, 改良稳态模型计算的β细胞功能指数(HOMA2-B)及胰岛素抵抗指数(HOMR2-IR)]和加入尿C肽/肌酐比值后的六个变量, 通过相同的k-means聚类算法对2型糖尿病患者进行聚类分组, 比较不同亚组的临床特点。 结果: 尿C肽/肌酐比值与HOMA2-IR水平 (r=0.448, P<0.001)正相关。在调整了性别, 年龄, 病程及其他心血管疾病危险因素后, 尿C肽/肌酐比值水平与糖尿病肾病 [比值比(OR) =1.198, 95%CI (1.019, 1.408), P=0.029]及冠状动脉粥样硬化性心脏病的发生风险呈正相关 [OR=1.312, 95%CI (1.079, 1.594), P=0.006]。在五个传统临床变量基础上, 加入尿C肽/肌酐比值后再进行聚类分型, 可以清晰地将患者分为五组:两组具有早发糖尿病特征[早发胰岛素缺乏型糖尿病(n=350)和早发胰岛素抵抗型糖尿病(n=176)], 两组具有晚发糖尿病特征[晚发胰岛素缺乏型糖尿病(n=318)和晚发胰岛素抵抗型糖尿病(n=133)]及轻型糖尿病(n=299)。各组间诊断年龄, 体重指数, 胰岛β细胞功能, 胰岛素抵抗水平以及糖尿病血管并发症比例显著不同。 结论: 尿C肽/肌酐比值与胰岛素抵抗水平及糖尿病肾病, 冠状动脉粥样硬化性心脏病发生风险正相关。在传统临床变量基础上引入尿C肽/肌酐比值, 可以改善2型糖尿病的精准分型。.

Topics: Biomarkers; Blood Glucose; C-Peptide; Cardiovascular Diseases; Creatinine; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Female; Follow-Up Studies; Glucose Intolerance; Glycated Hemoglobin; Humans; Insulin Resistance; Male; Middle Aged; Prognosis

ANGPTL3 is an important regulator of lipid metabolism. Its inhibition in people with hypercholesteremia reduces plasma lipid levels dramatically. Genome-wide association studies have associated ANGPTL3 variants with lipid traits. Irisin, an exercise-modulated protein, has been associated with lipid metabolism. Intracellular accumulation of lipids impairs insulin action and contributes to metabolic disorders. In this study, we evaluate the impact of ANGPTL3 variants on levels of irisin and markers associated with lipid metabolism and insulin resistance. ANGPTL3 rs1748197 and rs12130333 variants were genotyped in a cohort of 278 Arab individuals from Kuwait. Levels of irisin and other metabolic markers were measured by ELISA. Significance of association signals was assessed using Bonferroni-corrected

Topics: Adult; Angiopoietin-Like Protein 3; Angiopoietin-like Proteins; Arabs; C-Peptide; Female; Fibronectins; Heterozygote; Humans; Insulin Resistance; Interleukin-13; Male; Middle Aged; Polymorphism, Single Nucleotide

Five clusters based on clinical characteristics have been suggested as diabetes subtypes: one autoimmune and four subtypes of type 2 diabetes. In the current study we replicate and cross-validate these type 2 diabetes clusters in three large cohorts using variables readily measured in the clinic.. In three independent cohorts, in total 15,940 individuals were clustered based on age, BMI, HbA. Five distinct type 2 diabetes clusters were identified and mapped back to the original four All New Diabetics in Scania (ANDIS) clusters. Using C-peptide and HDL-cholesterol instead of HOMA2-B and HOMA2-IR, three of the clusters mapped with high sensitivity (80.6-90.7%) to the previously identified severe insulin-deficient diabetes (SIDD), severe insulin-resistant diabetes (SIRD) and mild obesity-related diabetes (MOD) clusters. The previously described ANDIS mild age-related diabetes (MARD) cluster could be mapped to the two milder groups in our study: one characterised by high HDL-cholesterol (mild diabetes with high HDL-cholesterol [MDH] cluster), and the other not having any extreme characteristic (mild diabetes [MD]). When these two milder groups were combined, they mapped well to the previously labelled MARD cluster (sensitivity 79.1%). In the cross-validation between cohorts, particularly the SIDD and MDH clusters cross-validated well, with sensitivities ranging from 73.3% to 97.1%. SIRD and MD showed a lower sensitivity, ranging from 36.1% to 92.3%, where individuals shifted from SIRD to MD and vice versa. People belonging to the SIDD cluster showed the fastest progression towards insulin requirement, while the MDH cluster showed the slowest progression.. Clusters based on C-peptide instead of HOMA2 measures resemble those based on HOMA2 measures, especially for SIDD, SIRD and MOD. By adding HDL-cholesterol, the MARD cluster based upon HOMA2 measures resulted in the current clustering into two clusters, with one cluster having high HDL levels. Cross-validation between cohorts showed generally a good resemblance between cohorts. Together, our results show that the clustering based on clinical variables readily measured in the clinic (age, HbA

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Humans; Insulin; Insulin Resistance

Patients with nonalcoholic fatty liver disease (NAFLD) are characterized by insulin resistance and hyperinsulinism. However, insulin resistance measurements have not been shown to be good diagnostic tools to predict NAFLD in prior studies.. We aimed to assess a newly validated method to measure intact molecules of insulin by mass spectrometry to predict NAFLD.. Patients underwent a 2-hour oral glucose tolerance test (OGTT), a liver magnetic resonance spectroscopy (1H-MRS), and a percutaneous liver biopsy if they had a diagnosis of NAFLD. Mass spectrometry was used to measure intact molecules of insulin and C-peptide.. A total of 180 patients were recruited (67% male; 52 ± 11 years of age; body mass index [BMI] 33.2 ± 5.7 kg/m2; 46% with diabetes and 65% with NAFLD). Intact fasting insulin was higher in patients with NAFLD, irrespective of diabetes status. Patients with NAFLD without diabetes showed ~4-fold increase in insulin secretion during the OGTT compared with all other subgroups (P = 0.008). Fasting intact insulin measurements predicted NAFLD in patients without diabetes (area under the receiver operating characteristic curve [AUC] of 0.90 [0.84-0.96]). This was significantly better than measuring insulin by radioimmunoassay (AUC 0.80 [0.71-0.89]; P = 0.007). Intact fasting insulin was better than other clinical variables (eg, aspartate transaminase, triglycerides, high-density lipoprotein, glucose, HbA1c, and BMI) to predict NAFLD. When combined with alanine transaminase (ALT) (intact insulin × ALT), it detected NAFLD with AUC 0.94 (0.89-0.99) and positive and negative predictive values of 93% and 88%, respectively. This newly described approach was significantly better than previously validated noninvasive scores such as NAFLD-LFS (P = 0.009), HSI (P < 0.001), and TyG index (P = 0.039).. In patients without diabetes, accurate measurement of fasting intact insulin levels by mass spectrometry constitutes an easy and noninvasive strategy to predict presence of NAFLD.

Topics: Adult; Alanine Transaminase; Body Mass Index; C-Peptide; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Fasting; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Liver; Magnetic Resonance Spectroscopy; Male; Mass Spectrometry; Middle Aged; Non-alcoholic Fatty Liver Disease; Reproducibility of Results

Chronic inflammation damaged the islet and resulted in dysfunction of T2D. Circular RNA is stable and better for biomarker in many diseases. Here, we aimed to identify potential circular RNA hsa_circ_0054633 that can be a biomarkers for the effects of insulin therapy in T2D.. In this retrospective case-control study, patients were from Li Huili Hospital, Ningbo, China, from February 10, 2019, to August 15, 2019. We included 47 healthy adults, 46 new-onset T2D with insulin resistance, and 51 patients with insulin therapy. Serum inflammation factors were tested by ELISA assays. We selected hsa_circ_0054633 as a candidate biomarker and measured its concentration in serum by qRT-PCR. The Pearson correlation test was used to evaluate the correlation between this circRNA and clinical variables.. Clinical data indicated that serum C peptide was increased in T2D treatment with insulin. Serum hsa_circ_0054633 was decreased in insulin treatment group. Hsa_circ_0054633 was negative correlated with C peptide (r = -0.2841, p = 0.0433,). IL-1 and IL-6, IL-17, and TNF-α were higher in T2D patients and decreased after insulin treatment, only IL-17 and TNF-α showed a positive correlation to hsa_circ_0054633 (r = 0.4825, p < 0.0001, and r = 0.6190, p < 0.0001). The area under ROC curve was 0.7432, 0.5839, and 0.7573 for Hsa_circ_0054633, C peptide, and their combination.. Hsa_circ_0054633 level was lower in T2D with insulin treatment than untreated and was a negative correlation with C peptide, and positively correlated with IL-17 and TNF-α, suggesting that hsa_circ_0054633 may be a potential early indicator of insulin treatment effect to improve inflammation condition.

Topics: Aged; C-Peptide; Case-Control Studies; Diabetes Mellitus, Type 2; Humans; Inflammation; Insulin; Insulin Resistance; Interleukin-1; Interleukin-17; Interleukin-6; Middle Aged; RNA, Circular; Treatment Outcome; Tumor Necrosis Factor-alpha

One of the therapeutic approaches in the treatment of obesity is the use of histamine H. Histamine ligands were selected based on the preliminary studies which included determination of intrinsic activity and selected pharmacokinetic parameters. Female Wistar rats were fed palatable feed for 28 days and simultaneously the tested compounds were administered intraperitoneally at a dose of 10 mg/kg b.w./day. Rats' weight was evaluated daily and calories intake was evaluated once per week. At the end of experiment insulin and glucose tolerance tests was performed. Plasma levels of cholesterol, triglycerides, leptin, insulin, glucose, C-peptide and CRP were also determined. In order to rule out false-positive results the influence of tested compounds on spontaneous activity of rats was monitored.. Animals fed palatable feed and treated with KSK-61 or KSK-63 compounds showed the slowest weight gain which was comparable to the one observed in control animals. Both compounds with the highest pharmacological activity have also similar pharmacokinetic properties with quite long half-life and high volume of distribution indicating that they can freely cross most biological barriers. Some compounds, especially KSK-63, compensated for metabolic disorders.. The presented study proves that search among the active histamine H

Topics: Adipose Tissue; Animals; Body Weight; C-Peptide; Carrier Proteins; Cholesterol; Energy Intake; Feeding Behavior; Female; Glucose Tolerance Test; Histamine Agonists; Histamine Antagonists; Injections, Intraperitoneal; Insulin; Insulin Resistance; Leptin; Ligands; Metformin; Models, Animal; Obesity; Rats, Wistar; Receptors, Histamine H3; Triglycerides

Chemerin is an adipokine and a chemoattractant for leukocytes. Increased chemerin levels were observed in patients with coronary artery disease (CAD). We investigated associations between chemerin and biochemical measurements or body composition in CAD patients.. In the study, we included patients with stable CAD who had undergone percutaneous coronary intervention (PCI) in the past. All patients had routine blood tests, and their insulin and chemerin serum levels were routinely measured. Body composition was assessed with the DEXA method.. The study group comprised 163 patients (mean age 59.8 ± years, 26% of females, n = 43). There was no significant difference in serum chemerin concentrations between patients with diabetes and the remaining ones: 306.8 ± 121 vs. 274.15 ± 109 pg/mL,. In patients with CAD, serum chemerin levels are correlated with inflammation markers, insulin resistance, and an unfavorable lipid profile. Correlation with fat mass is dependent on glucose metabolism status. Depending on the presence of diabetes/prediabetes, the mechanisms regulating chemerin secretion may be different.

Topics: Aged; Blood Glucose; Blood Platelets; Body Composition; C-Peptide; C-Reactive Protein; Chemokines; Cholesterol, HDL; Cholesterol, LDL; Coronary Artery Disease; Diabetes Mellitus, Type 2; Female; Humans; Inflammation; Insulin; Insulin Resistance; Lymphocytes; Male; Middle Aged; Neutrophils; Percutaneous Coronary Intervention; Pilot Projects; Triglycerides

The study focused on changes or cut-offs of glycaemia, insulin resistance and body mass index within the C-peptide reference range (260-1730 pmol/l). The metabolic profile of individuals in the Czech Republic without diabetes (n = 3186) was classified by whiskers and quartiles of C-peptide into four groups with the following ranges: 290-510 (n = 694), 511-710 (n = 780), 711-950 (n = 720) and 951-1560 pmol/l (n = 673). Fasting levels of glucose, insulin, HOMA IR (Homeostasis Model Assessment for Insulin Resistance) and BMI (body mass index) were compared by a relevant C-peptide range. Participants taking medication to control glycaemia were excluded. The evaluation involved correlations between C-peptides and the above parameters, F-test and t-test. Changes in glucose levels (from 5.3 to 5.6 mmol/l) between the groups were lower in comparison to insulin, which reached relatively greater changes (from 4.0 to 14.2 mIU/l). HOMA IR increased considerably with growing C-peptide concentrations (0.9, 1.5, 2.2 and 3.5) and BMI values showed a similar trend (28.3, 31.0, 33.6 and 37.4). Considerable changes were observed for insulin (5.2 mIU/l, 57.8%) and HOMA IR (1.3, 61.3%) between groups with C-peptide ranges of 711-950 and 951-1560 pmol/l. Although correlations involving C-peptide, insulin, glucose and BMI seemed to be non-significant (up to rxy = 0.25), the mean values of insulin, HOMA IR and BMI showed statistically significant changes between all groups with various C-peptide concentrations (p ≤ 0.001). Generally, most important differences appeared in glucose metabolism and body mass index between C-peptide ranges of 711-950 and 951-1560 pmol/l. Absolute and relative changes of C-peptide concentrations are possible to use for the assessment of glucose regulatory mechanism. The spectrum of investigated parameters could be a useful tool to prevent the risks linked with the alterations of glycaemia.

Topics: Blood Glucose; Body Mass Index; C-Peptide; Humans; Insulin; Insulin Resistance

Autoimmune pancreatitis (AIP) is frequently complicated by diabetes mellitus (DM), but DM associated with AIP is reported to improve after steroid therapy. The aim of this study is to investigate glucose intolerance during steroid therapy according to the onset of DM.. Sixty-one patients who underwent steroid therapy for AIP were included into this study. We evaluated C peptide index (CPI), homeostasis model assessment for insulin resistance (HOMA-R), and the pancreatic diameter at AIP diagnosis and after 4 weeks, 1 year, and 2 years of steroid therapy. Patients were categorized into three groups according to DM onset: Pre-existing DM (pDM), concurrent DM (cDM), and non-DM (nDM).. Forty-three patients (71%) had DM: 15 pDM and 28 cDM. At AIP diagnosis, CPI was lower in patients with pDM (0.7, P = 0.007) and cDM (0.9, P = 0.018) than nDM (1.3). After 4 weeks of steroid therapy, CPI improved in cDM (P < 0.001) and in nDM (P = 0.021). After 2 years of steroid therapy, HOMA-R increased (2.1-3.0, P = 0.007) but CPI gradually improved (1.0-2.1, P = 0.004). DM improved in 23% of cDM, and 55% of insulin users in cDM discontinued using insulin. Pancreatic atrophy was seen in 30%, and was associated with DM.. DM in patients with AIP was associated with impaired insulin secretion rather than insulin resistance. Insulin secretion improved during steroid therapy for AIP in patients with concurrent DM. Thus, glucose intolerance can be an indication for AIP treatment.

Topics: Aged; Anti-Inflammatory Agents; Atrophy; Autoimmune Pancreatitis; Blood Glucose; C-Peptide; Diabetes Mellitus; Female; Glucose Intolerance; Homeostasis; Humans; Insulin Resistance; Insulin Secretion; Male; Middle Aged; Pancreas; Prednisolone

Objective The correlation between the insulin secretion levels and the risk of hepatocarcinogenesis is clinically important. The aim of the present study was to determine the effects of various clinical parameters on C-peptide (CPR) levels in patients with non-alcoholic fatty liver disease (NAFLD). Methods In this retrospective cohort study, the effects of clinical parameters on insulin resistance (HOMA-IR) and insulin secretion levels (HOMA-β and fasting CPR) were investigated. Patients A total of 244 Japanese patients with histopathologically confirmed NAFLD were evaluated. Of these, 77 underwent the meal tolerance test (MTT) to evaluate the association of various clinical parameters with the CPR levels at 120 minutes. Results A multivariate analysis identified fasting plasma glucose (FPG) (≥110 mg/dL), aspartate aminotransferase (≥1.0×ULN IU/L), and a large waist circumference as independent predictors of insulin resistance (HOMA-IR ≥2.5) or high fasting CPR levels. Significant parameters for a low insulin secretion capacity (HOMA-β <30%) were not detected, except for the parameters mentioned in the diagnostic criteria of diabetes mellitus. Regarding the MTT, the CPR levels at 120 minutes were significantly higher in patients with fibrosis stage 3-4 than in those with stage 0-2. Body composition and genetic variation did not affect the CPR levels at 120 minutes. A multivariate analysis identified fibrosis stage (3-4), hyperuricemia, FPG (≥110 mg/dL), and procollagen III peptide (>1.0 U/mL) as independent predictors of high CPR levels at 120 minutes. Conclusion The present study showed that high plasma glucose levels and severe liver fibrosis stage influence insulin secretion levels in Japanese patients with NAFLD. Conservation of delayed insulin secretion levels was confirmed in patients with severe liver fibrosis.

Topics: Adult; Aged; Aged, 80 and over; Asian People; Blood Glucose; C-Peptide; Female; Humans; Insulin; Insulin Resistance; Insulin Secretion; Japan; Liver Cirrhosis; Male; Middle Aged; Non-alcoholic Fatty Liver Disease; Predictive Value of Tests; Retrospective Studies; Risk Factors; Young Adult

Although the associations between first-episode psychosis (FEP) and metabolic abnormalities on one side, and childhood trauma (CT) and risk of developing psychosis on the other are both well established, evidence on the relationship between CT and metabolic dysregulation in terms of abnormal glucose metabolism is very limited. We tested whether, already at illness onset, FEP patients with a history of CT show dysregulation of a broad range of glucose metabolism markers. In particular, in 148 FEP patients we evaluated serum concentrations of c-peptide, insulin, plasminogen-activator-inhibitor-1 (PAI-1), resistin, visfatin, glucagon, glucagon-like peptide-1 (GLP-1), gastric-inhibitor-peptide (GIP), leptin, and ghrelin. We also assessed CT with the Childhood Experience of Care and Abuse Questionnaire, and stressful life events (SLEs) with a semi-structured interview. Psychopathology, cannabis and tobacco habits, Body Mass Index (BMI) were recorded. Serum concentrations of markers were analyzed from peripheral blood. Ninety-five patients (56 % males, mean age 29.5) reported CT. Multivariate models showed that CT is associated only with the concentrations of c-peptide and insulin after adjusting for age, sex, BMI and SLEs. FEP patients who had experienced CT showed higher c-peptide and insulin serum concentrations. Our study reports that CT might be associated with the metabolic abnormalities in the first stage of psychosis, suggesting that a thorough anamnestic evaluation at psychosis onset that would include the history of CT could be helpful for clinicians in order to implement early programmes of healthy lifestyle education and to guide choice of therapeutic interventions for trauma.

Topics: Adult; Adverse Childhood Experiences; Antipsychotic Agents; Biomarkers; C-Peptide; Female; Ghrelin; Glucagon; Glucagon-Like Peptide 1; Glucose; Humans; Insulin; Insulin Resistance; Leptin; Male; Middle Aged; Nicotinamide Phosphoribosyltransferase; Plasminogen Activator Inhibitor 1; Psychotic Disorders; Resistin

Diabetic cardiomyopathy (DCM) is a nonischemic myocardial disorder characterized by metabolic disturbances and oxidative stress in diabetic patients. The present paper aims to determine the protective effect of the phlebotrophic drug, diosmin, on DCM in a model of high-fat diet-fed and streptozotocin-induced type 2 diabetes in the rat.. The animals were divided into 4 groups (8 rats/group) as follows: vehicle-treated nondiabetic control group, vehicle-treated diabetic group, diosmin (50 mg/kg)-treated diabetic group and diosmin (100 mg/kg)-treated diabetic group. Treatment was given once daily orally by gavage for 6 weeks. Oxidant and antioxidant stress markers, inflammatory markers and proapoptotic and antiapoptotic gene expression using quantified real-time polymerase chain reaction were investigated.. Diosmin treatment in diabetic rats lowered elevated blood glucose levels, homeostatic model assessment for insulin resistance, cardiac creatine kinase and lactate dehydrogenase enzymes, cardiac malondialdehyde and nitric oxide. Moreover, diosmin increased plasma insulin and c-peptide levels, cardiac glutathione content, superoxide dismutase, catalase and glutathione S-transferase activities. Also, diosmin treatment significantly (P < 0.05) lowered the levels of interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α), down-regulated cardiac Bcl-2-associated X protein and caspase 3 and 9 and up-regulated B-cell lymphoma 2 mRNA expression levels.. Diosmin may have a sizeable therapeutic potential in the treatment of DCM due to antidiabetic, antioxidative stress, anti-inflammatory and antiapoptotic effects. Detailed studies are needed to disclose the precise mechanisms motivating the protective effect of diosmin‏.

Topics: Animals; Apoptosis; Biomarkers; Blood Glucose; C-Peptide; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Diabetic Cardiomyopathies; Diosmin; Dose-Response Relationship, Drug; Gene Expression Regulation; Homeostasis; Insulin; Insulin Resistance; Rats

We aimed to determine the immediacy of exercise intervention on liver-specific metabolic processes in nonalcoholic fatty liver disease.. We undertook a short-term (7-d) exercise training study (60 min·d treadmill walking at 80%-85% of maximal heart rate) in obese adults (N = 13, 58 ± 3 yr, 34.3 ± 1.1 kg·m, >5% hepatic lipid by H-magnetic resonance spectroscopy). Insulin sensitivity index was estimated by oral glucose tolerance test using the Soonthorpun model. Hepatic insulin extraction (HIE) was calculated as the molar difference in area under the curve (AUC) for insulin and C-peptide (HIE = 1 - (AUCInsulin/AUCC-Pep)).. The increases in HIE, V˙O2max, and insulin sensitivity index after the intervention were 9.8%, 9.8%, and 34%, respectively (all, P < 0.05). Basal fat oxidation increased (pre: 47 ± 6 mg·min vs post: 65 ± 6 mg·min, P < 0.05) and carbohydrate oxidation decreased (pre: 160 ± 20 mg·min vs post: 112 ± 15 mg·min, P < 0.05) with exercise training. After the intervention, HIE correlated positively with adiponectin (r = 0.56, P < 0.05) and negatively with TNF-α (r = -0.78, P < 0.001).. By increasing HIE along with peripheral insulin sensitivity, aerobic exercise training rapidly reverses some of the underlying physiological mechanisms associated with nonalcoholic fatty liver disease, in a weight loss-independent manner. This reversal could potentially act through adipokine-related pathways.

Topics: Blood Glucose; C-Peptide; Carbohydrate Metabolism; Exercise; Glucagon-Like Peptide 1; Heart Rate; Humans; Insulin; Insulin Resistance; Lipid Metabolism; Liver; Middle Aged; Non-alcoholic Fatty Liver Disease; Obesity; Oxygen Consumption

More and more studies focus on the relationship between the gastrointestinal microbiome and type 2 diabetes, but few of them have actually explored the relationship between enterotypes and type 2 diabetes.. Gut microbiota in type 2 diabetes group exhibited lower bacterial diversity compared with nondiabetic controls. The fecal communities from all subjects clustered into two enterotypes distinguished by the levels of. We identified two enterotypes,

Topics: Actinobacteria; Aged; Amine Oxidase (Copper-Containing); Bacteroides; Bacteroidetes; Biodiversity; Blood Glucose; C-Peptide; Case-Control Studies; Cholesterol, HDL; Diabetes Mellitus, Type 2; Female; Firmicutes; Fusobacteria; Gastrointestinal Microbiome; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Lipopolysaccharides; Logistic Models; Male; Middle Aged; Pilot Projects; Postprandial Period; Prevotella; Proteobacteria; Risk Factors; RNA, Ribosomal, 16S; Triglycerides; Tumor Necrosis Factor-alpha; Verrucomicrobia

Circulating follistatin (Fst) binds activin A and thereby regulates biological functions such as muscle growth and β-cell survival. However, Fst and activin A's implication in metabolic regulation is unclear.. To investigate circulating Fst and activin A in obesity and type 2 diabetes (T2D) and determine their association with metabolic parameters. Further, to examine regulation of Fst and activin A by insulin and the influence of obesity and T2D hereon.. Plasma Fst and activin A levels were analyzed in obese T2D patients (N = 10) closely matched to glucose-tolerant lean (N = 12) and obese (N = 10) individuals in the fasted state and following a 4-h hyperinsulinemic-euglycemic clamp (40 mU·m-2·min-1) combined with indirect calorimetry.. Circulating Fst was ~30% higher in patients with T2D compared with both lean and obese nondiabetic individuals (P < .001), while plasma activin A was unaltered. In the total cohort, fasting plasma Fst correlated positively with fasting plasma glucose, serum insulin and C-peptide levels, homeostasis model assessment of insulin resistance, and hepatic and adipose tissue insulin resistance after adjusting for age, gender and group (all r > 0.47; P < .05). However, in the individual groups these correlations only achieved significance in patients with T2D (not plasma glucose). Acute hyperinsulinemia at euglycemia reduced circulating Fst by ~30% (P < .001) and this response was intact in patients with T2D. Insulin inhibited FST expression in human hepatocytes after 2 h and even further after 48 h.. Elevated circulating Fst, but not activin A, is strongly associated with measures of insulin resistance in patients with T2D. However, the ability of insulin to suppress circulating Fst is preserved in T2D.

Topics: Activins; Blood Glucose; C-Peptide; Case-Control Studies; Diabetes Mellitus, Type 2; Fasting; Female; Follistatin; Hep G2 Cells; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Obesity

Different polycystic ovary syndrome (PCOS) phenotypes are correlated with different clinical severity levels. Insulin resistance correlates with higher severity. In a retrospective study, 130 patients with polycystic ovary syndrome were examined for insulin resistance. The aim of the study was to investigate relationships between glucose metabolism and different PCOS phenotypes and to identify biomarkers or combinations thereof to obtain information on the type of metabolic disorder or the severity of PCOS.. A total of 130 patients with PCOS were included in the study. Biometric data such as weight, height, cycle day and cycle length were compared with glucose metabolism parameters such as fasting glucose, insulin before and 60 and 120 minutes after 75 g glucose intake, intact proinsulin, C-peptide and ovarian function parameters including Anti-Müllerian hormone (AMH) and the soluble AMH receptor (sAMHR2). The parameters were correlated, and their diagnostic performance with respect to different expressions of PCOS was evaluated.. The biomarkers of impaired glucose metabolism showed strong significant difference in HOMA Index, adiponectin, proinsulin and body mass index (BMI) and Insulin levels in 0-60-120 minutes of glucose tolerance test but also with parameters of ovarian function as AMH, AMH z-score sAMHR2, and sAMHR2/AMH ratio. A strong correlation between sAMHR2 and adiponectin (r = .818, P < .0001) was found indicating a relationship between the degree of glucose metabolic impairment and ovarian function.. The parameters glucose, insulin, insulin 60 minutes after intake of 75 g glucose and adiponectin or sAMHR2 enable a biochemical classification of PCOS patients that correlates with morphological PCOS phenotypes. By determining biomarkers, it is possible to classify PCOS patients into subgroups that correlate with different PCOS phenotypes and the clinical severity.

Topics: Anti-Mullerian Hormone; C-Peptide; Female; Glucose; Humans; Insulin Resistance; Phenotype; Polycystic Ovary Syndrome; Retrospective Studies

This study is aimed at assessing the association of previously developed indices of glucose homeostasis derived from principal component analysis (PCA) with parameters of insulin action, secretion, and beta cell function during pregnancy.. In this prospective longitudinal study, an oral glucose tolerance test was performed in sixty-seven pregnant women at two prepartum (12+0 to 22+6 and 24+0 to 28+6) and one postpartum (2 to 11 months) visits. Three principal component scores (PCS) were calculated based on measurements of glucose, insulin, C-peptide, age, and BMI to assess their association with fasting and dynamic indices of insulin action, secretion, and. PCS1 was positively associated with fasting and dynamic parameters of insulin sensitivity (Matsuda index:. PCS1 to 3 behaved similarly as compared to previous observations in nonpregnant women and were furthermore associated with the development of GDM. These findings support our hypothesis that PCS1 to 3 could be used as novel indices of glucose disposal during pregnancy.

Topics: Adult; Blood Glucose; C-Peptide; Diabetes, Gestational; Female; Glucose Tolerance Test; Homeostasis; Humans; Insulin; Insulin Resistance; Insulin Secretion; Pregnancy; Principal Component Analysis; Prospective Studies; Young Adult

The Disposition Index (DI) is widely used in clinical studies of β-cell function. However, direct physiologic interpretation of the DI value and the inverse exponential slope relating insulin secretion and insulin sensitivity terms is difficult. We evaluated a linearization of the relationship that allows separate evaluation of the DI term and the slope.. Insulin secretion and sensitivity indices were derived from standardized oral glucose tolerance testing, including commonly used terms and model-derived terms. The population included participants with normoglycemia, dysglycemia or Type 2 diabetes. Logarithmic transformation of the DI equation to linearize the secretion-sensitivity relationship was performed, and the resulting secretion-sensitivity relationships were evaluated using standard linear regression methods.. Simple logarithmic transformation linearized the secretion-sensitivity relationships available from a variety of OGTT-derived metrics. In normoglycemic subjects the slopes approximated -1 in insulin-basedsecretion-sensitivity pairs, and approximated -0.6 in C-peptide based secretion-sensitivity pairs. Group differences in DI terms were observed as expected. These analyses also revealed differing secretion-sensitivity slopes, with IGT and T2D demonstrating progressively impaired coupling.. Linearization of the secretion-sensitivity relationship provides simplified interpretation of the DI value and allows simple analysis and meaningful interpretation of the secretion-sensitivity slope. This linear relationship is amenable to standard statistical evaluations for comparisons of insulin secretion responses and of secretion-sensitivity coupling across groups.

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance

Endocrine insufficiency following severe acute pancreatitis (SAP) leads to diabetes of the exocrine pancreas, (type 3c diabetes mellitus), however it is not known how this metabolic phenotype differs from that of type 2 diabetes, or how the two subtypes can be differentiated. We sought to determine the prevalence of diabetes following SAP, and to analyse the behaviour of glucose and pancreatic hormones across a 2-h oral glucose tolerance test (OGTT).. Twenty-six patients following SAP (mean (range) duration of first SAP episode to study time of 119.3 (14.8-208.9) months) along with 26 matched controls underwent an OGTT with measurement of glucose, insulin, c-peptide, glucagon and pancreatic polypeptide (PP) at fasting/15/90/120min. Beta-cell area was estimated using the 15min c-peptide/glucose ratio, and insulin resistance (IR) using homeostasis model assessment (HOMA) and oral glucose insulin sensitivity (OGIS) models.. The prevalence of diabetes/prediabetes was 54% following SAP (38.5% newly-diagnosed compared to 19.2% newly-diagnosed controls). Estimated beta-cell area and IR did not differ between groups. AUC c-peptide was lower in SAP versus controls. AUC insulin and AUC c-peptide were lower in SAP patients with diabetes versus controls with diabetes; between-group differences were observed at the 90 and 120 min time-points only. Half of new diabetes cases in SAP patients were only identified at the 120min timepoint.. Diabetes and pre-diabetes occur frequently following SAP and are difficult to distinguish from type 2 diabetes in controls but are characterised by reduced insulin and c-peptide at later stages of an OGTT. Consistent with this observation, most new post SAP diabetes cases were diagnosed by 2-h glucose levels only.

Topics: Acute Disease; Adult; Aged; Blood Glucose; C-Peptide; Case-Control Studies; Diabetes Mellitus; Female; Follow-Up Studies; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Insulin Resistance; Insulin-Secreting Cells; Male; Metabolic Diseases; Middle Aged; Pancreatic Hormones; Pancreatitis; Prediabetic State; Prevalence

Topics: Adult; Aged; Blood Glucose; C-Peptide; Cross-Sectional Studies; Female; Humans; Insulin; Insulin Resistance; Lipids; Male; Middle Aged; Spondylarthritis

Identification of biomarkers associated with protection from developing diabetic complications is a prerequisite for an effective prevention and treatment. The aim of the present study was to identify clinical and plasma metabolite markers associated with freedom from vascular complications in people with very long duration of type 1 diabetes (T1D). Individuals with T1D, who despite having longer than 30 years of diabetes duration never developed major macro- or microvascular complications (non-progressors; NP) were compared with those who developed vascular complications within 25 years from diabetes onset (rapid progressors; RP) in the Scandinavian PROLONG (n = 385) and DIALONG (n = 71) cohorts. The DIALONG study also included 75 healthy controls. Plasma metabolites were measured using gas and/or liquid chromatography coupled to mass spectrometry. Lower hepatic fatty liver indices were significant common feature characterized NPs in both studies. Higher insulin sensitivity and residual ß-cell function (C-peptide) were also associated with NPs in PROLONG. Protection from diabetic complications was associated with lower levels of the glycolytic metabolite pyruvate and APOCIII in PROLONG, and with lower levels of thiamine monophosphate and erythritol, a cofactor and intermediate product in the pentose phosphate pathway as well as higher phenylalanine, glycine and serine in DIALONG. Furthermore, T1D individuals showed elevated levels of picolinic acid as compared to the healthy individuals. The present findings suggest a potential beneficial shunting of glycolytic substrates towards the pentose phosphate and one carbon metabolism pathways to promote nucleotide biosynthesis in the liver. These processes might be linked to higher insulin sensitivity and lower liver fat content, and might represent a mechanism for protection from vascular complications in individuals with long-term T1D.

Topics: Aged; Biomarkers; Blood Glucose; C-Peptide; Diabetes Complications; Diabetes Mellitus, Type 1; Female; Genetic Predisposition to Disease; Humans; Insulin Resistance; Liver; Male; Metabolomics; Middle Aged; Nucleotides

Type 2 diabetes (T2D) is characterized by islet β-cell dysfunction and impaired suppression of glucagon secretion of α-cells in response to oral hyperglycaemia. Bile acid (BA) metabolism plays a dominant role in maintaining glucose homeostasis. So we evaluated the association of fasting serum total bile acids (S-TBAs) with insulin sensitivity, islet β-cell function and glucagon levels in T2D. Total 2,952 T2D patients with fasting S-TBAs in the normal range were recruited and received oral glucose tolerance tests for determination of fasting and postchallenge glucose, C-peptide and glucagon. Fasting and systemic insulin sensitivity were assessed by homeostasis model assessment (HOMA) and Matsuda index using C-peptide, i.e., IS

Topics: Adult; Bile Acids and Salts; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucagon; Glucose Tolerance Test; Humans; Hypoglycemic Agents; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Middle Aged

In view of the association of Ramadan intermittent fasting with profound changes in lifestyle both in nondiabetic and diabetic patients, the aim of this study was to investigate the effect of Ramadan fasting on adiponectin, leptin and leptin to adiponectin ratio (LAR), growth hormone (GH), human-sensitive C-reactive protein (hs-CRP), and diabetic and metabolic syndrome factors in patients with Type 2 Diabetes Mellitus (Type 2 DM), their first-degree relatives (FDRs), and healthy controls.. This cohort study involved 98 Yemeni male subjects aged 30-70 years old: 30 Type 2 DM, 37 FDRs of Type 2 diabetic patients, and 31 healthy control subjects. Subjects' body mass index (BMI), waist circumference (WC), and blood pressure (BP) were measured, and venous blood samples were collected twice: the first samples were collected a couple of days prior to Ramadan fasting (baseline) and the second samples after 3 weeks of fasting.. Ramadan fasting did not affect BMI, WC, and BP in Type 2 DM and their FDRs with respect to the baseline levels prior to Ramadan, whereas triglyceride and cholesterol were borderline significantly decreased in Type 2 DM with no effect in FDRs. Fasting blood glucose was not affected in Type 2 DM but was significantly increased in FDRs and control groups, whereas glycated haemoglobin (HbA1c) was slightly decreased in Type 2 DM, FDRs, and healthy controls. C-peptide, insulin, and insulin resistance (HOMA-IR) were significantly increased in Type 2 DM and FDRs, with no effect in the control group, whereas. Ramadan intermittent fasting decreased adiponectin and increased leptin, LAR, insulin, and insulin resistance in both Type 2 DM and FDRs as well as decreased GH in both FDRs and healthy controls and increased hs-CRP in healthy controls. Moreover, Ramadan intermittent fasting neither worsens a patient's glycemic parameters nor improves it, with the exception of a slight improvement in HbA1c in Type 2 DM, FDRs, and healthy controls.

Topics: Adipokines; Adiponectin; Adult; Aged; Blood Glucose; Blood Pressure; Body Mass Index; C-Peptide; C-Reactive Protein; Cohort Studies; Diabetes Mellitus, Type 2; Fasting; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Leptin; Male; Metabolic Syndrome; Middle Aged; Triglycerides; Waist Circumference

Type 2 diabetes (T2D) is defined by a single metabolite, glucose, but is increasingly recognized as a highly heterogeneous disease, including individuals with varying clinical characteristics, disease progression, drug response, and risk of complications. Identification of subtypes with differing risk profiles and disease etiologies at diagnosis could open up avenues for personalized medicine and allow clinical resources to be focused to the patients who would be most likely to develop diabetic complications, thereby both improving patient health and reducing costs for the health sector. More homogeneous populations also offer increased power in experimental, genetic, and clinical studies. Clinical parameters are easily available and reflect relevant disease pathways, including the effects of both genetic and environmental exposures. We used six clinical parameters (GAD autoantibodies, age at diabetes onset, HbA

Topics: C-Peptide; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Female; Humans; Insulin Resistance; Male

Vitamin D3 (vit. D3) deficiency is considered as one of the main factors involved in the development of type 2 diabetes (T2D). We assessed insulin resistance (IR), β-cell functional activity and metabolic profile according to 25(OH) vit. D3 status in patients with T2D.. The study included 109 patients with T2D, divided in 3 groups: group 1 (N.=11) with normal levels of vit. D3 (>30 ng/mL); group 2 (N.=38) with vit. D3 insufficiency (21-29 ng/mL); and group 3 (N.=60) with vit. D3 deficiency (<20 ng/mL). IR and β-cell functional activity were assessed as change in C-peptide concentration and homeostasis model assessment-estimated (HOMA) β-cell function which was calculated using HOMA2 calculator.. Patients with vit. D3 deficiency presented significantly higher C-peptide concentration compared to other groups. HOMA2 (3.29±1.89 vs. 2.12±0.71; P=0.049) and hemoglobin (H8b)A1c (9.11±1.63 vs. 7.75±1.06; P=0.016) levels changed significantly only in patients with vit. D3 deficiency compared to diabetics with normal vit. D3 levels. Furthermore, in univariate Pearson's correlation analysis, we observed significant association between vit. D3 levels and C-peptide, insulin sensitivity, HOMA2, triglyceride-glucose index, HbA1c and Body Mass Index, only in the vit. D3 deficiency group. In multivariate logistic regression analysis, poor glycemic control, as defined by HbA1c levels, was independent from metformin use while high density lipoprotein-cholesterol levels were associated with vit. D3 deficiency.. Our study demonstrated that vit. D3 deficiency in patients with T2D was associated with more severe IR, poor glycemic control and obesity compared to normal status or vit. D3 insufficiency.

Topics: Adolescent; Adult; Aged; Body Mass Index; C-Peptide; Cholecalciferol; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Ergocalciferols; Female; Glycemic Control; Humans; Hypoglycemic Agents; Insulin Resistance; Male; Metformin; Middle Aged; Obesity; Vitamin D Deficiency; Young Adult

At present, glycated hemoglobin (HbA1c) and glycated albumin (GA) are used to evaluate glycemic control in diabetic patients, but they cannot reflect insulin deficiency and/or insulin resistance.We investigated the feasibility of using estimated average glucose to fasting plasma glucose ratio (eAG/fPG ratio) to estimate insulin resistance in young adult diabetes. A total of 387 patients with type 2 diabetes were included and were stratified into 2 groups based on median values of the glycemic index ratio: the GA/A1c ratio <2.09 (n = 91) and ≥2.09 (n = 296); the eAG/fPG ratio <1.69 (n = 155) and ≥1.69 (n = 232). HbA1c, GA, fructosamine, insulin, and C-peptide levels were measured. The ratio of GA to HbA1c was calculated, and the homeostasis model assessment of β-cell function and insulin resistance were determined. The homeostasis model assessment of insulin resistance level was significantly associated with the eAG/fPG ratio, but not with the ratio of GA to HbA1c, GA, HbA1c, and fructosamine levels. The ratio of estimated average glucose to fasting plasma glucose level correlates with insulin resistance in young adult diabetes.

Topics: Adolescent; Adult; Blood Glucose; C-Peptide; Child; Diabetes Mellitus, Type 2; Fasting; Female; Fructosamine; Glycated Hemoglobin; Glycated Serum Albumin; Glycation End Products, Advanced; Glycemic Index; Humans; Insulin; Insulin Resistance; Male; Serum Albumin; Young Adult

We investigated the impact of postreperfusion syndrome (PRS) on hyperglycemia occurrence and connecting (C) peptide release, which acts as a surrogate marker for insulin resistance, during the intraoperative period after graft reperfusion in patients undergoing living donor liver transplantation (LDLT) using propensity score (PS)-matching analysis.. Medical records from 324 adult patients who underwent elective LDLT were retrospectively reviewed, and their data were analyzed according to PRS occurrence (PRS vs. non-PRS groups) using the PS-matching method. Intraoperative levels of blood glucose and C-peptide were measured through the arterial or venous line at each surgical phase. Hyperglycemia was defined as a peak glucose level >200 mg/dL, and normal plasma concentrations of C-peptide in the fasting state were taken to range between 0.5 and 2.0 ng/mL.. After PS matching, there were no significant differences in pre- and intra-operative recipient findings and donor-graft findings between groups. Although glucose and C-peptide levels continuously increased through the surgical phases in both groups, glucose and C-peptide levels during the neohepatic phase were significantly higher in the PRS group than in the non-PRS group, and larger changes in levels were observed between the preanhepatic and neohepatic phases. There were higher incidences of C-peptide levels >2.0 ng/mL and peak glucose levels >200 mg/dL in the neohepatic phase in patients with PRS than in those without. PRS adjusted for PS with or without exogenous insulin infusion was significantly associated with hyperglycemia occurrence during the neohepatic phase.. Elucidating the association between PRS and hyperglycemia occurrence will help with establishing a standard protocol for intraoperative glycemic control in patients undergoing LDLT.

Topics: Adult; Blood Glucose; C-Peptide; Female; Humans; Hyperglycemia; Insulin Infusion Systems; Insulin Resistance; Liver Transplantation; Living Donors; Male; Middle Aged; Propensity Score; Reperfusion; Stress, Physiological; Syndrome

The determinants of type 2 diabetes (T2D) remission and/or relapse after gastric bypass (RYGB) remain fully unknown. This study characterized β- and α-cell function, in cretin hormone release and insulin sensitivity in individuals with (remitters) or without (non-remitters) diabetes remission after RYGB.. This is a cross-sectional study of two distinct cohorts of individuals with or without diabetes remission at least 2 years after RYGB. Each individual underwent-either an oral glucose (remitters) or a mixed meal (non-remitters) test; glucose, proinsulin, insulin, C-peptide, glucagon, incretins and leptin were measured.. Compared to remitters (n = 23), non-remitters (n = 31) were older (mean [±SD] age 56.1 ± 8.2 vs. 46.0 ± 8.9 years, P < 0.001), had longer diabetes duration (13.1 ± 10.1 vs. 2.2 ± 2.4 years, P < 0.001), were further out from the surgery (5.6 ± 3.3 vs. 3.5 ± 1.7 years, P < 0.01), were more insulin resistant (HOMA-IR 4.01 ± 3.65 vs. 2.08 ± 1.22, P < 0.001), but did not differ for body weight. As predicted, remitters had higher β-cell glucose sensitivity (1.95 ± 1.23 vs. 0.86 ± 0.55 pmol/kg/min/mmol, P < 0.001) and disposition index (1.55 ± 1.75 vs 0.33 ± 0.27, P = 0.003), compared to non-remitters, who showed non-suppressibility of glucagon during the oral challenge (time × group P = 0.001). Higher proinsulin (16.55 ± 10.45 vs. 6.62 ± 3.50 PM, P < 0.0001), and proinsulin: C-peptide (40.83 ± 29.43 vs. 17.13 ± 7.16, P < 0.001) were strongly associated with non-remission status, while differences in incretins between remitters and non-remitters were minimal.. Individual without diabetes remission after gastric bypass have poorer β-cell response and lesser suppression of glucagon to an oral challenge; body weight and incretins differ minimally according to remission status.. 背景: 目前尚未完全明确2型糖尿病(T2D)患者接受胃旁路术(RYGB)后病情缓解或复发的决定因素。这项研究描述了RYGB术后糖尿病缓解或未缓解个体的β-与α-细胞功能、肠促胰岛素激素释放及胰岛素敏感性。 方法: 这是一项横断面研究, 对RYGB术后至少2年后糖尿病缓解或未缓解的不同队列个体进行了研究。每个个体均进行口服葡萄糖(缓解者)或者混合餐(非缓解者)耐量试验；测量血糖、胰岛素原、胰岛素、C肽、胰高血糖素、肠促胰岛素以及瘦素水平。 结果: 与缓解者(n=23)相比, 未缓解者(n=31)年龄更大(平均[±SD]年龄56.1±8.2 vs. 46.0±8.9岁, P<0.001)、糖尿病病程更长(13.1±10.1 vs. 2.2±2.4年, P<0.001)、距离手术时间更长(5.6±3.3 vs. 3.5±1.7年, P<0.01)、胰岛素抵抗更严重(HOMA-IR为4.01±3.65 vs. 2.08±1.22, P<0.001), 但体重无差异。正如预期, 与未缓解者相比, 缓解者具有较高的β细胞葡萄糖敏感性(1.95±1.23 vs. 0.86±0.55 pmol/kg/min/mmol, P<0.001)以及处置指数(1.55±1.75 vs. 0.33±0.27, P=0.003), 后者在口服耐量试验期间的胰高血糖素水平并未受到抑制(时间×分组, P=0.001)。较高水平的胰岛素原(16.55±10.45 vs. 6.62±3.50PM, P<0.0001)以及胰岛素原:C肽比值(40.83±29.43与17.13±7.16, P<0.001)与未缓解状态密切相关, 但是缓解者与未缓解者之间的肠促胰岛素差异非常小。 结论: 胃旁路术后糖尿病无缓解的个体对口服耐量试验中β细胞的应答较差, 对胰高血糖素的抑制也较小；根据糖尿病缓解状态进行分组, 发现体重与肠促胰岛素的差异非常小。.

Topics: Adult; Blood Glucose; Body Weight; C-Peptide; Cohort Studies; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Female; Gastric Bypass; Glucagon; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Recurrence

In nondiabetic healthy individuals, insulin secretion and sensitivity are linked by a negative feedback loop characterized by a hyperbolic function. We aimed to study the association of traditional insulin resistance (IR) factors with insulin secretion and sensitivity, and to determine whether the hyperbolic equilibrium of this relation is preserved in patients with rheumatoid arthritis (RA).. This was a cross-sectional study encompassing 361 nondiabetic individuals: 151 with RA and 210 controls. Insulin, C-peptide, and IR indices by homeostatic model (HOMA2) were assessed. A multivariable analysis was performed to evaluate the differences in the correlation of traditional IR-related factors with glucose homeostasis molecules, as well as IR indices between patients and controls. Nonlinear regression analysis was used to assess the hyperbolic relation of insulin sensitivity and secretion.. The traditional factors associated with IR in healthy individuals are less related to IR in patients with RA. Insulin sensitivity and secretion yield a different hyperbolic equilibrium in RA.

Topics: Adult; Aged; Arthritis, Rheumatoid; Blood Glucose; C-Peptide; C-Reactive Protein; Cohort Studies; Cross-Sectional Studies; Female; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged

(1) Examine associations of a branched-chain amino acid (BCAA) metabolite pattern with metabolic risk across adolescence; (2) use Least Absolute Shrinkage and Selection Operator (LASSO) to identify novel metabolites of metabolic risk.. We used linear regression to examine associations of a BCAA score with change (∆) in metabolic biomarkers over 5-year follow-up in 179 adolescents 8-14 years at baseline. Next, we applied LASSO, a regularized regression technique well suited for reduction of high-dimensional data, to identify metabolite predictors of ∆biomarkers.. In boys, the BCAA score corresponded with decreasing C-peptide, C-peptide-based insulin resistance (CP-IR), total cholesterol (TC), and low-density-lipoprotein cholesterol (LDL). In pubertal girls, the BCAA pattern corresponded with increasing C-peptide and leptin. LASSO identified asparagine as a predictor of decreasing C-peptide (β = -0.33) and CP-IR (β = -0.012), and acetyl-carnitine (β = 2.098), 4-hydroxyproline (β = -0.050), ornithine (β = -0.353), and α-aminoisobutyric acid (β = -0.793) as determinants of TC in boys. In girls, histidine was a negative determinant of TC (β = -0.033).. The BCAA pattern was associated with ∆glycemia and ∆lipids in a sex-specific manner. LASSO identified asparagine, which influences growth hormone secretion, as a determinant of decreasing C-peptide and CP-IR in boys, and metabolites on lipid metabolism pathways as determinants of decreasing cholesterol in both sexes.

Topics: Acetylcarnitine; Adolescent; Amino Acids, Branched-Chain; Aminoisobutyric Acids; Asparagine; Biomarkers; Blood Glucose; Body Composition; Body Mass Index; C-Peptide; Carnitine; Child; Cholesterol; Female; Humans; Hydroxyproline; Hyperglycemia; Insulin Resistance; Leptin; Male; Metabolome; Ornithine; Prospective Studies; Puberty; Regression Analysis; Risk Factors

To investigate the differences in glucose metabolism among women with paraplegic, and tetraplegic spinal cord injury (SCI) in comparison to their able-bodied (AB) counterparts after adjusting for differences in body composition.. Cross-sectional study. After an overnight fast, each participant consumed a 75-g glucose solution for oral glucose tolerance test (OGTT). Blood glucose, insulin, and C-peptide concentrations were analyzed before and 30, 60, 90, and 120 minutes after ingesting glucose solution. Insulin sensitivity index (ISI) was estimated using the Matsuda index. Percentage fat mass (%FM) and total body lean mass (TBLM) were estimated using data from dual-energy x-ray absorptiometry. Visceral fat (VF) was quantified using computed tomography. Outcome measures were compared among groups using analysis of covariance with %FM (or VF) and TBLM as covariates.. Research university.. Women (N=42) with SCI (tetraplegia: n=8; paraplegia: n=14) and their race-, body mass index-, and age-matched AB counterparts (n=20).. Not applicable.. At fasting, there was no difference in glucose homeostasis (glucose, insulin, C-peptide concentrations) among 3 groups of women. In contrast, glucose, insulin, and C-peptide concentrations at minute 120 during OGTT were higher in women with tetraplegia versus women with paraplegia and AB women (P<.05, adjusted for TBLM and %FM). In addition, women with tetraplegia had lower ISI (P<.05, adjusted for TBLM and %FM) versus AB women. These differences remained after adjusting for VF and TBLM.. Our study confirms that impaired glucose metabolism among women with tetraplegia may not be fully explained by changes in their body composition. Future studies exploring additional factors involved in glucose metabolism are warranted.

Topics: Adult; Body Composition; C-Peptide; Case-Control Studies; Cross-Sectional Studies; Fasting; Female; Glucose; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Intra-Abdominal Fat; Middle Aged; Paraplegia; Quadriplegia; Spinal Cord Injuries; Time Factors

To determine the association of insulin sensitivity and metabolic status with declining cognition in HIV-infected individuals.. We conducted targeted clinical and metabolic measures in longitudinal plasma samples obtained from HIV-infected patients enrolled in the Central Nervous System HIV Anti-Retroviral Therapy Effects Research Study (CHARTER). Findings were validated with plasma samples from the Multicenter AIDS Cohort Study (MACS). Patients were grouped according to longitudinally and serially assessed cognitive performance as having stably normal or declining cognition.. Patients with declining cognition exhibited baseline hyperinsulinemia and elevated plasma c-peptide levels with normal c-peptide/insulin ratios, suggesting that insulin production was increased, but insulin clearance was normal. The association of hyperinsulinemia with worsening cognition was further supported by low high-density lipoprotein (HDL), high low-density lipoprotein/HDL ratio, and elevated cholesterol/HDL ratio compared to patients with stably normal cognition.. These findings suggest that hyperinsulinemia and impaired insulin sensitivity are associated with cognitive decline in antiretroviral therapy-treated HIV-infected patients.

Topics: Adult; Anti-HIV Agents; C-Peptide; Case-Control Studies; Cognition; Cognitive Dysfunction; Cohort Studies; Female; HIV Infections; Humans; Hyperinsulinism; Insulin Resistance; Lipoproteins; Male; Middle Aged

Chronic hyperglycemia worsens skeletal muscle insulin resistance and β-cell function. However, the effect of sustained physiologic hyperglycemia on hepatic insulin sensitivity is not clear.. To examine the effect of sustained physiologic hyperglycemia (similar to that observed in patients with type 2 diabetes) on endogenous (primarily reflecting hepatic) glucose production (EGP) in healthy individuals.. Volunteers participated in a three-step hyperinsulinemic (10, 20, 40 mU/m2 per minute) euglycemic clamp before and after a 48-hour glucose infusion to increase plasma glucose concentration by ∼40 mg/dL above baseline. EGP was measured with 3-3H-glucose before and after chronic glucose infusion.. Sixteen persons with normal glucose tolerance [eight with and eight without a family history (FH) of diabetes] participated in the study.. EGP.. Basal EGP increased following 48 hours of glucose infusion (from a mean ± SEM of 2.04 ± 0.08 to 3.06 ± 0.29 mg/kgffm⋅ min; P < 0.005). The hepatic insulin resistance index (basal EGP × fasting plasma insulin) markedly increased following glucose infusion (20.1 ± 1.8 to 51.7 ± 6.6; P < 0.005) in both FH+ and FH- subjects.. Sustained physiologic hyperglycemia for as little as 48 hours increased the rate of basal hepatic glucose production and induced hepatic insulin resistance in health persons with normal glucose tolerance, providing evidence for the role of glucotoxicity in the increase in hepatic glucose production in type 2 diabetes.

Topics: Adult; Blood Glucose; C-Peptide; Female; Glucagon; Gluconeogenesis; Glucose; Glucose Clamp Technique; Glycogenolysis; Healthy Volunteers; Humans; Hyperglycemia; Insulin; Insulin Resistance; Liver; Male; Middle Aged; Tritium

Impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) are highly pathophysiologic heterogeneous prediabetes conditions that can occur in all age groups, from youth to elderly people.. We evaluated whether distinct age-related phenotypes exist among individuals with IFG or IGT.. 479 young (aged 18 to 35 years), 699 adult (45 to 55 years) and 240 older (≥65 years) subjects underwent an oral glucose tolerance test (OGTT). From the OGTT results, the participants were grouped as follows: young age and normal glucose tolerance (NGT), adult age and NGT, older age and NGT, IFG young subjects, IFG adult subjects, IFG older subjects, IGT young (Y-IGT) subjects, IGT adult (A-IGT) subjects, and IGT older (O-IGT) subjects.. Insulin sensitivity and secretion, insulin clearance, and β-cell function.. Peripheral insulin sensitivity assessed using the Matsuda index, basal and glucose-stimulated insulin secretion, and β-cell function estimated using the disposition index were decreased in IFG adult subjects and IFG older subjects compared with IFG young subjects. A-IGT and Y-IGT subjects exhibited a progressively greater degree of hepatic insulin resistance assessed using the liver insulin resistance index, and reduced insulin clearance compared with O-IGT subjects. In contrast, the Matsuda index did not differ among Y-IGT, A-IGT, and O-IGT subjects. Basal and glucose-stimulated insulin secretion and β-cell function were lower in A-IGT and O-IGT subjects compared with Y-IGT individuals.. Subjects with IFG or IGT exhibited different age-related pathophysiologic characteristics. A more precise phenotyping of subjects with IGT or IFG could help to better design individualized preventive approaches to counteract diabetes progression.

Topics: Adolescent; Adult; Age Factors; Aged; Blood Glucose; Body Mass Index; C-Peptide; Cholesterol, HDL; Female; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Male; Middle Aged; Prediabetic State; Triglycerides; Young Adult

An early identification of the risk groups might be beneficial in reducing morbidities in patients with gestational diabetes mellitus (GDM). Therefore, this study aimed to assess the biochemical predictors of glycemic conditions, in addition to fasting indices of glucose disposal, to predict the development of GDM in later stage and the need of glucose-lowering medication.. A total of 574 pregnant females (103 with GDM and 471 with normal glucose tolerance [NGT]) were included. A metabolic characterization was performed before 15⁺⁶ weeks of gestation by assessing fasting plasma glucose (FPG), fasting insulin (FI), fasting C-peptide (FCP), and glycosylated hemoglobin (HbA1c). Thereafter, the patients were followed-up until the delivery.. Females with NGT had lower levels of FPG, FI, FCP, or HbA1c at the early stage of pregnancy, and therefore, showed an improved insulin action as compared to that in females who developed GDM. Higher fasting levels of FPG and FCP were associated with a higher risk of developing GDM. Moreover, the predictive accuracy of this metabolic profiling was also good to distinguish the patients who required glucose-lowering medications. Indices of glucose disposal based on C-peptide improved the predictive accuracy compared to that based on insulin. A modified quantitative insulin sensitivity check index (QUICKIc) showed the best differentiation in terms of predicting GDM (area under the receiver operating characteristics curve [ROC-AUC], 72.1%) or need for pharmacotherapy (ROC-AUC, 83.7%).. Fasting measurements of glucose and C-peptide as well as the surrogate indices of glycemic condition could be used for stratifying pregnant females with higher risk of GDM at the beginning of pregnancy.

Topics: Adult; Age Factors; Area Under Curve; Blood Glucose; C-Peptide; Diabetes, Gestational; Fasting; Female; Follow-Up Studies; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Pregnancy; Prognosis; Prospective Studies; Risk Factors; ROC Curve

To investigate the cord blood levels of adipokine and to assess their association with the fetal insulin resistance and fetal outcomes in newborns of gestational diabetic women (GDM). Methods: This cross-sectional study was performed in 40 GDM women and 40 healthy pregnant women (HPW) in the Department of Obstetrics and Gynecology at Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER) hospital in Puducherry, India, during the period from May 2016 to December 2017. Cord blood samples were collected at delivery from GDM and HPW groups. Cord plasma biochemical parameters such as insulin, C-peptide, adiponectin, leptin, resistin, and visfatin concentrations were measured. Leptin/adiponectin ratio (L/A), homeostasis model assessment of insulin resistance (HOMA2-IR), insulin sensitivity (HOMA2-%S) and beta cell function (HOMA2-%B) were calculated. The pregnancy outcomes such as birth weight (BW), Ponderal index and Apgar scores of the baby were measured. Results: The BW and Ponderal index of the baby were found to be significantly higher in GDM newborns compared to HPW newborns. Cord plasma insulin, C-peptide, HOMA2 -IR, visfatin, leptin, and L/A ratio were significantly higher whereas adiponectin level was lower in GDM compared to HPW. A significant positive correlation was observed between L/A ratio and fetal HOMA2-IR. Conclusion: Altered adipokine levels with increased L/A ratio was observed among the new-borns of Indian gestational diabetic mothers. There was an association between increased L/A ratio, insulin resistance and increased Ponderal index among the new-borns.

Topics: Adipokines; Apgar Score; Biomarkers; Birth Weight; C-Peptide; Cross-Sectional Studies; Diabetes, Gestational; Female; Fetal Blood; Humans; India; Infant, Newborn; Insulin; Insulin Resistance; Leptin; Nicotinamide Phosphoribosyltransferase; Pregnancy; Pregnancy Outcome; Resistin

β-Cell dysfunction is central to the pathogenesis of impaired glucose tolerance (IGT) and type 2 diabetes. Compared with adults, youth have hyperresponsive β-cells and their decline in β-cell function appears to be more rapid. However, there are no direct comparisons of β-cell responses to pharmacological intervention between the two age-groups. The Restoring Insulin Secretion (RISE) Adult Medication Study and the RISE Pediatric Medication Study compared interventions to improve or preserve β-cell function. Obese youth (

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin Glargine; Insulin Resistance; Male; Metformin; Middle Aged

The Restoring Insulin Secretion (RISE) Adult Medication Study compared pharmacological approaches targeted to improve β-cell function in individuals with impaired glucose tolerance (IGT) or treatment-naive type 2 diabetes of <12 months duration.. All three active treatments produced on-treatment reductions in weight and improvements in HbA. In adults with IGT or recently diagnosed type 2 diabetes, interventions that improved β-cell function during active treatment failed to produce persistent benefits after treatment withdrawal. These observations suggest that continued intervention may be required to alter the progressive β-cell dysfunction in IGT or early type 2 diabetes.

Topics: Adult; Arginine; B-Lymphocytes; Blood Glucose; Body Weight; C-Peptide; Diabetes Mellitus, Type 2; Fasting; Female; Glucose Intolerance; Humans; Hypoglycemic Agents; Insulin Glargine; Insulin Resistance; Liraglutide; Male; Metformin; Middle Aged; Withholding Treatment

In patients with type 2 diabetes, non-alcoholic fatty liver disease (NAFLD) and liver fibrosis is frequent and presumably associated with increased cardiovascular disease risk and mortality. The objective was to investigate risk factors associated with hepatic fibrosis in patients with type 2 diabetes and NAFLD to provide a basis for the prevention and treatment.. Liver stiffness measurements (LSM) expressed in kilopascals (kPa) and controlled attenuation parameter (CAP) expressed in dB/m were diagnosed by transient elastography. Hepatic steatosis and significant fibrosis were defined as having a CAP score ≥ 260 dB/m and an LSM score ≥ 8 kPa, respectively. Associations between fibrosis categories with anthropometric and metabolic variables were determined; then, variables with statistical significance in the univariate analysis were included in multivariate model.. A total of 108 participant with type 2 diabetes and NAFLD (mean age: 44.69 ± 5.57 years; mean duration of diabetes 4.68 ± 4.24 years) were recruited. In these patients, body mass index, obesity, fat mass, waist circumferences, resting energy expenditure, CAP score, fasting insulin, C-peptide, HbA1C, hs-CRP as well as liver enzymes and systolic blood pressure and diastolic blood pressure were positively associated with fibrosis (all p < 0.05). Using multivariate logistic regression, serum aspartate aminotransferase (OR 1.12; 95% CI 1.06-1.19), waist circumferences (odds ratio [OR] 1.15; 95% CI 1.05-1.25) and C-peptide (OR 3.81; 95% CI 1.5-9.7) remained as independently associated with liver fibrosis.. For participants with type 2 diabetes with coexisting NAFLD, stratification by independent risk factors for fibrosis could have important prognostic value.

Topics: Adult; Aspartate Aminotransferases; Blood Pressure; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Female; Humans; Insulin; Insulin Resistance; Liver Cirrhosis; Male; Middle Aged; Non-alcoholic Fatty Liver Disease; Waist Circumference

The analytical performance and clinical application of measuring insulin and connecting peptide (C-peptide) by point of care (POC) assay were evaluated. A POC assay system (SelexOn, Osang Healthcare Inc., Anyang-si, Korea) was evaluated for precision, linearity, limit of blank (LOB), and limit of detection (LOD). Method comparison was performed with the Cobas Elecsys insulin and C-peptide assay (Roche Diagnostics GmbH, Mannheim, Germany) using 215 and 201 patient specimens for insulin and C-peptide, respectively. For clinical application, insulin resistance indices were studied. Homeostasis model assessment (HOMA) 1 and 2, Quantitative insulin sensitivity check index (QUIKI), fasting insulin resistance index (FIRI), and other indices were evaluated. The coefficient of variation (CV) of imprecision for low, medium, and high concentrations was 10.8%1, 15.99%, and 12.05%, respectively, for insulin and 9.21%, 13.51%, and 13.77%, respectively, for C-peptide. The linearity was validated to 839.78 pmol/L for insulin and to 17.30 nmol/L for C-peptide. LOB and LOD were 8.05 and 9.72 pmol/L for insulin and 0.05 and 0.08 nmol/L for C-peptide, respectively. For the method comparison, the regression equation was

Topics: Biological Assay; C-Peptide; Female; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Point-of-Care Systems; ROC Curve

To investigate any associations between blood glucose (BG) and lipid levels in patients with different glucose tolerance statuses, including type 2 diabetes (T2DM) and impaired glucose regulation (IGR) cases as well as normal glucose tolerance (NGT) individuals.. A total of 354 participants were recruited to this study including 174 in the T2DM group, 112 in the IGR group and 68 in the NGT group. We compared BG, insulin and C-peptide (CP), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) serum levels during a 3 h oral glucose tolerance test (OGTT) in the 3 groups.. Basic overall HbA1c serum concentration percentages were 5.52, 6.33 and 9.76% for the NTG, IGR and T2DM cases. During the OGTT, insulin secretion in the IGR group was almost double that of the T2DM group. CP levels were highest in the IGR patients and OGTT related BG concentrations were highest in the T2DM group followed by IGR, but in the IGR group hyperglycemia was less pronounced than in T2DM patients (P <  0.001). Compared to the NGT group, TC, TG and LDL-C serum concentrations were significantly higher (P ≤ 0.001) and HDL-C concentrations were significantly lower (P ≤ 0.001) in IGR and T2DM cases compared to the NTG group.. IGR led to similar unfavorable blood lipid patterns compared with T2DM patients and an imbalance of insulin and CP serum concentrations during an OGTT.

Topics: Adult; Aged; C-Peptide; Female; Glucose; Glucose Intolerance; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Lipids; Male; Middle Aged

To compare the performance of population-based kinetics with that of directly measured C-peptide kinetics when used to calculate β-cell responsivity indices, and to study people with and without acute insulin resistance to ensure that population-based kinetics apply to all conditions where β-cell function is measured.. Somatostatin was used to inhibit endogenous insulin secretion in 56 people without diabetes. Subsequently, a C-peptide bolus was administered and the changing concentrations were used to calculate individual kinetic measures of C-peptide clearance. In addition, the participants were studied on 2 occasions in random order using an oral glucose tolerance test (OGTT). On one occasion, free fatty acid elevation, to cause insulin resistance, was achieved by infusion of Intralipid + heparin. The Disposition Index (DI) was then estimated by the oral minimal model using either population-based or individual C-peptide kinetics.. There were marked differences in the exchange variables (k. These data support the use of population-based measures of C-peptide kinetics to estimate β-cell function during an OGTT.

Topics: C-Peptide; Diabetes Mellitus, Type 2; Female; Glucose; Glucose Tolerance Test; Glycerol; Hormones; Humans; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Solvents; Somatostatin; Sweetening Agents

It is unclear to which extent altered insulin sensitivity/secretion contribute to the development of diabetic cardiovascular autonomic neuropathy (CAN) characterized by diminished heart rate variability (HRV). We hypothesised that lower HRV is differentially associated with measures of insulin resistance and insulin secretion in recent-onset type 1 and type 2 diabetes.. This cross-sectional study included participants from the German Diabetes Study with type 1 (n=275) or type 2 diabetes (n=450) with known diabetes duration ≤1year and glucose-tolerant controls (n=81). Four time domain and frequency domain HRV measures each, reflecting vagal and/or sympathetic modulation were determined over 3h during a hyperinsulinaemic-euglycaemic clamp. Insulin sensitivity was calculated as the M-value, while insulin secretion was determined by glucagon-stimulated incremental C-peptide (ΔC-peptide).. After adjustment for sex, age, BMI, smoking, and HbA1c, both M-value and ΔC-peptide were lower in the diabetes groups compared to controls (P<0.05). In multiple linear regression analyses after Bonferroni correction, vagus-mediated HRV indices were positively associated with M-value in both diabetes types (P<0.05) and inversely associated with ΔC-peptide only in participants with type 1 diabetes (P<0.05). In type 2 diabetes, the low-frequency/high-frequency (LF/HF) power as an indicator of sympathovagal balance was weakly inversely associated with M-value.. Insulin resistance may contribute to the development of early cardiovagal suppression rather than sympathetic predominance in both diabetes types, while in type 1 diabetes a lower glucagon-stimulated insulin secretion is linked to a possibly compensatory higher parasympathetic tone. Whether interventions aimed at reducing insulin resistance could also reduce the risk of CAN remains to be established.

Topics: Adolescent; Adult; Aged; C-Peptide; Cross-Sectional Studies; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Female; Glucagon; Glucose Clamp Technique; Heart; Heart Rate; Humans; Insulin; Insulin Resistance; Lipids; Male; Middle Aged; Vagus Nerve; Young Adult

Abnormal glucagon concentrations contribute to hyperglycemia, but the mechanisms of α-cell dysfunction in prediabetes are unclear.. We sought to determine the relative contributions of insulin secretion and action to α-cell dysfunction in nondiabetic participants across the spectrum of glucose tolerance.. This was a cross-sectional study. A subset of participants (n = 120) was studied in the presence and absence of free fatty acid (FFA) elevation, achieved by infusion of Intralipid (Baxter Healthcare, Deerfield, IL) plus heparin, to cause insulin resistance.. An inpatient clinical research unit at an academic medical center.. A total of 310 nondiabetic persons participated in this study.. Participants underwent a seven-sample oral glucose tolerance test. Subsequently, 120 participants were studied on two occasions. On one day, infusion of Intralipid plus heparin raised FFA. On the other day, participants received glycerol as a control.. We examined the relationship of glucagon concentration with indices of insulin action after adjusting for the effects of age, sex, and weight. Subsequently, we sought to determine whether an acute decrease in insulin action, produced by FFA elevation, altered glucagon concentrations in nondiabetic participants.. Fasting glucagon concentrations correlated positively with fasting insulin and C-peptide concentrations and inversely with insulin action. Fasting glucagon was not associated with any index of β-cell function in response to an oral challenge. As expected, FFA elevation decreased insulin action and also raised glucagon concentrations.. In nondiabetic participants, glucagon secretion was altered by changes in insulin action.

Topics: Biomarkers; Blood Glucose; C-Peptide; Cross-Sectional Studies; Female; Follow-Up Studies; Glucagon; Glucagon-Secreting Cells; Glucose Tolerance Test; Humans; Hyperglycemia; Hypoglycemic Agents; Insulin; Insulin Resistance; Male; Middle Aged; Prediabetic State; Prognosis

To examine the relationship between hormones involved in bone remodeling and glucose metabolism alterations in prediabetes.. OPN was higher in IGR compared to NGT (5.3 ± 0.5 vs. 3.3 ± 0.2 μg/mL; p = 0.008) and in isolated IGT compared to IFG and IFG-IGT (6.3 ± 0.5 vs. 4.5 ± 0.3 and 5.4 ± 0.5 μg/mL; p = 0.02). OCN was similar in IFG and NGT but lower in IGT and IFG-IGT compared to NGT (7.2 ± 0.3 and 5.4 ± 0.2 vs. 8.3 ± 0.3 ng/mL; p < 0.01). OPN was positively correlated with HbA1c, fasting and 2 h plasma glucose and PTH. OCN was negatively correlated with body fat, 2 h plasma glucose, insulin and positively correlated with Stumvoll index. OPG correlated with TGD/SSPI (r = - 0.29; p < 0.05), EGP, and hepatic insulin resistance index in IGR (r = 0.51, r = 0.43; p < 0.01). There was no correlation between PTH and insulin sensitivity or Beta-cell function parameters.. In prediabetes, hormones known to be involved in bone remodeling may affect glucose metabolism before overt T2DM occurs with tissue-specific mechanisms.

Topics: Adult; Blood Glucose; C-Peptide; Case-Control Studies; Fasting; Female; Glucose Clamp Technique; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Osteocalcin; Osteopontin; Osteoprotegerin; Prediabetic State

Gamma-glutamyltranspeptidase (GGT) levels are an independent risk marker for the development of type 2 diabetes (T2DM). We investigated the relationship between the newly identified serum GGT fractions and glucose metabolism in obese subjects before and after bariatric surgery.. Twenty-nine T2DM subjects, wait-listed for Roux-en-Y gastric bypass (RYGB; n = 21) or laparoscopic sleeve gastrectomy (LSG; n = 8), received a 5-h mixed meal test before (T0), 15 days (T15), and 1 year after surgery (T365). Insulin sensitivity was assessed by the OGIS index and β-cell function by C-peptide analysis; fractional GGT (b-, s-, m-, and f-GGT) analysis was performed by gel-filtration chromatography.. At T15, total GGT activity decreased by 40% after LSG (p = 0.007) but remained unchanged after RYGB. At T365, all patients showed a reduction in total GGT, in particular b-GGT (≥ 60%) and m-GGT (≥ 50%). In patients with biopsy-proven steatohepatitis (n = 10), total, b-, s-, and m-GGT fractions at T0 were significantly higher than in patients with low-grade steatosis (p = 0.016, 0.0003, and 0.005, respectively); at T365, there was a significant fall in total GGT as well as in each fraction in both groups. In a multiple regression model, b-GGT was the only fraction related to insulin sensitivity (p = 0.016; β coeff. = - 14.0) independently of BMI, fasting glucose, and triglycerides.. While GGT activity is generally associated with impaired glucose metabolism, fractional GGT analysis showed that the b-GGT fraction specifically and independently tracks with insulin resistance.

Topics: Adult; Aged; Bariatric Surgery; C-Peptide; Diabetes Mellitus, Type 2; Fasting; Fatty Liver; Female; gamma-Glutamyltransferase; Gastrectomy; Gastric Bypass; Humans; Insulin Resistance; Male; Middle Aged; Obesity; Obesity, Morbid; Triglycerides

There is growing evidence that fruit polyphenols exert beneficial effects on the metabolic syndrome, but the underlying mechanisms remain poorly understood. In the present study, we aimed to analyse the effects of polyphenolic extracts from five types of Arctic berries in a model of diet-induced obesity.. Male C57BL/6 J mice were fed a high-fat/high-sucrose (HFHS) diet and orally treated with extracts of bog blueberry (BBE), cloudberry (CLE), crowberry (CRE), alpine bearberry (ABE), lingonberry (LGE) or vehicle (HFHS) for 8 weeks. An additional group of standard-chow-fed, vehicle-treated mice was included as a reference control for diet-induced obesity. OGTTs and insulin tolerance tests were conducted, and both plasma insulin and C-peptide were assessed throughout the OGTT. Quantitative PCR, western blot analysis and ELISAs were used to assess enterohepatic immunometabolic features. Faecal DNA was extracted and 16S rRNA gene-based analysis was used to profile the gut microbiota.. Treatment with CLE, ABE and LGE, but not with BBE or CRE, prevented both fasting hyperinsulinaemia (mean ± SEM [pmol/l]: chow 67.2 ± 12.3, HFHS 153.9 ± 19.3, BBE 114.4 ± 14.3, CLE 82.5 ± 13.0, CRE 152.3 ± 24.4, ABE 90.6 ± 18.0, LGE 95.4 ± 10.5) and postprandial hyperinsulinaemia (mean ± SEM AUC [pmol/l × min]: chow 14.3 ± 1.4, HFHS 31.4 ± 3.1, BBE 27.2 ± 4.0, CLE 17.7 ± 2.2, CRE 32.6 ± 6.3, ABE 22.7 ± 18.0, LGE 23.9 ± 2.5). None of the berry extracts affected C-peptide levels or body weight gain. Levels of hepatic serine phosphorylated Akt were 1.6-, 1.5- and 1.2-fold higher with CLE, ABE and LGE treatment, respectively, and hepatic carcinoembryonic antigen-related cell adhesion molecule (CEACAM)-1 tyrosine phosphorylation was 0.6-, 0.7- and 0.9-fold increased in these mice vs vehicle-treated, HFHS-fed mice. These changes were associated with reduced liver triacylglycerol deposition, lower circulating endotoxins, alleviated hepatic and intestinal inflammation, and major gut microbial alterations (e.g. bloom of Akkermansia muciniphila, Turicibacter and Oscillibacter) in CLE-, ABE- and LGE-treated mice.. Our findings reveal novel mechanisms by which polyphenolic extracts from ABE, LGE and especially CLE target the gut-liver axis to protect diet-induced obese mice against metabolic endotoxaemia, insulin resistance and hepatic steatosis, which importantly improves hepatic insulin clearance. These results support the potential benefits of these Arctic berries and their integration into health programmes to help attenuate obesity-related chronic inflammation and metabolic disorders.. All raw sequences have been deposited in the public European Nucleotide Archive server under accession number PRJEB19783 ( https://www.ebi.ac.uk/ena/data/view/PRJEB19783 ).

Topics: Animals; C-Peptide; Diet, High-Fat; Endotoxemia; Fatty Liver; Fruit; Glucose; Homeostasis; Insulin; Insulin Resistance; Intestines; Liver; Male; Mice; Mice, Inbred C57BL; Mice, Obese; Obesity; Plant Extracts; RNA, Ribosomal, 16S; Time Factors

Salt, promoting oxidative stress, contributes to insulin resistance, whereas K, inhibiting oxidative stress, improves insulin sensitivity. Oxidative stress activation of NLRP3 inflammasome is a central player in the induction of insulin resistance. Therefore, we hypothesised that NLRP3 inflammasome may mediate the effects of salt and K on insulin resistance. In all, fifty normotensive subjects were recruited from a rural community of Northern China. The protocol included a low-salt diet for 7 d, then a high-salt diet for 7 d and a high-salt diet with K supplementation for another 7 d. In addition, THP-1 cells were cultured in different levels of Na with and without K. The results showed that salt loading elevated fasting blood glucose, insulin and C-peptide levels, as well as insulin resistance, whereas K supplementation reversed them. Meanwhile, additional K reversed the active effects of high salt on NLRP3 inflammasome in both the subjects and THP-1 cells, and the change of insulin resistance index notably related with the alteration of plasma IL-1β, the index of NLRP3 inflammasome activation, during intervention in the subjects. Additional K ameliorated oxidative stress induced by high salt in both the subjects and cultured THP-1 cells, and the change of oxidative stress related with the alteration of plasma IL-1β during intervention in the subjects. In vitro, antioxidant N-acetyl-l-cysteine significantly prevented the active effects of high Na or oxidant Rosup on NLRP3 inflammasome, so did K. Our study indicates that oxidative stress modulation of NLRP3 inflammasome may be involved in the impacts of Na and K on insulin resistance.

Topics: Adult; Aged; Asian People; Blood Glucose; Blood Pressure; C-Peptide; Cells, Cultured; China; Diet; Drug Interactions; Female; Humans; Inflammasomes; Insulin; Insulin Resistance; Interleukin-1beta; Male; Middle Aged; NLR Family, Pyrin Domain-Containing 3 Protein; Oxidative Stress; Potassium; Rural Population; Sodium, Dietary; THP-1 Cells

The intermittent energy restriction (IER) approach to weight loss involves short periods of substantial (>70 %) energy restriction (ER) interspersed with normal eating. Studies to date comparing IER to continuous energy restriction (CER) have predominantly measured fasting indices of cardiometabolic risk. This study aimed to compare the effects of IER and CER on postprandial glucose and lipid metabolism following matched weight loss. In all, twenty-seven (thirteen male) overweight/obese participants (46 (sem 3) years, 30·1 (sem 1·0) kg/m2) who were randomised to either an IER intervention (2638 kJ for 2 d/week with an overall ER of 22 (sem 0·3) %, n 15) or a CER intervention (2510 kJ below requirements with overall ER of 23 (sem 0·8) %) completed the study. Postprandial responses to a test meal (over 360 min) and changes in anthropometry (fat mass, fat-free mass, circumferences) were assessed at baseline and upon attainment of 5 % weight loss, following a 7-d period of weight stabilisation. The study found no statistically significant difference in the time to attain a 5 % weight loss between groups (median 59 d (interquartile range (IQR) 41-80) and 73 d (IQR 48-128), respectively, P=0·246), or in body composition (P≥0·437). For postprandial measures, neither diet significantly altered glycaemia (P=0·266), whereas insulinaemia was reduced comparatively (P=0·903). The reduction in C-peptide tended (P=0·057) to be greater following IER (309 128 (sem23 268) to 247781 (sem20 709) pmol×360 min/l) v. CER (297 204 (sem25 112) to 301 655 (sem32 714) pmol×360 min/l). The relative reduction in TAG responses was greater (P=0·045) following IER (106 (sem30) to 68 (sem 15) mmol×360 min/l) compared with CER (117 (sem 43) to 130 (sem 31) mmol×360 min/l). In conclusion, these preliminary findings highlight underlying differences between IER and CER, including a superiority of IER in reducing postprandial lipaemia, which now warrant targeted mechanistic evaluation within larger study cohorts.

Topics: Adult; Blood Glucose; Body Composition; Body Weight; C-Peptide; Caloric Restriction; Diet, Reducing; Energy Intake; Fasting; Female; Humans; Hyperinsulinism; Insulin Resistance; Lipid Metabolism; Male; Middle Aged; Obesity; Overweight; Postprandial Period; Weight Loss

Previous studies have shown that glucose peak time during the oral glucose tolerance test varies in type 2 diabetes patients; however, characteristics of this heterogeneity remain unclear. This research aimed to investigate the characteristics of delayed glucose peak time in type 2 diabetes.. A total of 178 participants who underwent the oral glucose tolerance test were divided into five groups according to glucose peak time.. A total of 25 participants with normal glucose tolerance had a glucose peak at 30 min. Among participants with type 2 diabetes, 28 had a glucose peak at 60 min, 48 at 90 min, 45 at 120 min and 32 at 150 min. With the glucose peak time delayed, glycated hemoglobin, area under the glucose curve and homeostatic model assessment of insulin resistance increased gradually (P = 0.038, P < 0.0001, P < 0.0001, respectively), and oral glucose insulin sensitivity, homeostatic model assessment of β-cell function, insulinogenic index, modified β-cell function index and disposition indices decreased (P < 0.0001 for all). On multinominal logistic regression, insulinogenic index (odds ratio 0.73, 95% confidence interval 0.57-0.93, P = 0.01), modified β-cell function index (odds ratio 0.67, 95% confidence interval 0.47-0.94, P = 0.023) and oral glucose insulin sensitivity (odds ratio 0.91, 95% confidence interval 0.87-0.96, P < 0.0001) were independently correlated with delayed glucose peak time.. Delay in glucose peak time indicated an increase in blood glucose and a decrease in insulin sensitivity and secretion. Furthermore, insulinogenic index, modified β-cell function index and oral glucose insulin sensitivity contributed to delayed glucose peak time.

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Male; Middle Aged

Exposure to high altitude has been shown to enhance both glucose and lipid utilization depending on experimental protocol. In addition, high and low blood glucose levels have been reported at high altitude. We hypothesized that gradual ascent to high altitude results in changes in glucose levels in healthy young adults.. Twenty-five adult volunteers, split into two teams, took part in the British Services Dhaulagiri Medical Research Expedition completing 14 d of trekking around the Dhaulagiri circuit in Nepal reaching a peak altitude of 5300 m on day 11 of the trek. Participants wore blinded continuous glucose monitors (CGM) throughout. Blood samples for C-peptide, proinsulin, and triacylglycerides were taken at sea level (United Kingdom) and in acclimatization camps at 3600, 4650, and 5120 m. Energy intake was determined from food diaries.. There was no difference in time spent in hypoglycemia stratified by altitude. Nocturnal CGM readings (2200-0600 h) were chosen to reduce the short-term effect of physical activity and food intake and showed a significant (P < 0.0001) increase at 3600 m (5.53 ± 0.22 mmol·L), 4650 m (4.77 ± 0.30 mmol·L), and 5120 m (4.78 ± 0.24 mmol·L) compared with baseline altitude 1100 m (vs 4.61 ± 0.25 mmol·L). Energy intake did not differ by altitude. Insulin resistance and beta-cell function, calculated by homeostatic model assessment, were reduced at 3600 m compared with sea level.. We observed a significant increase in nocturnal CGM glucose at 3600 m and greater despite gradual ascent from 1100 m. Taken with the changes in insulin resistance and beta-cell function, it is possible that the stress response to high altitude dominates exercise-enhanced insulin sensitivity, resulting in relative hyperglycemia.

Topics: Acclimatization; Adolescent; Adult; Altitude; Altitude Sickness; Blood Glucose; Blood Glucose Self-Monitoring; C-Peptide; Energy Intake; Female; Homeostasis; Humans; Hypoglycemia; Insulin Resistance; Insulin-Secreting Cells; Male; Proinsulin; Triglycerides; Young Adult

Insulin secretion (IS) declines with age, which increases the risk of impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2DM) in older adults. IS is regulated by the incretin hormones glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP). Here we tested the hypotheses that incretin release is lower in older adults and that this decline is associated with β-cell dysfunction.. A total of 40 young (25 ± 3 years) and 53 older (74 ± 7 years) lean nondiabetic subjects underwent a 2-hour oral glucose tolerance test (OGTT). Based on the OGTT, subjects were divided into three groups: young subjects with normal glucose tolerance (Y-NGT; n = 40), older subjects with normal glucose tolerance (O-NGT; n = 32), and older subjects with IGT (O-IGT; n = 21).. Plasma insulin, C-peptide, GLP-1, and GIP concentrations were measured every 15 to 30 minutes. We quantitated insulin sensitivity (Matsuda index) and insulin secretory rate (ISR) by deconvolution of C-peptide with the calculation of β-cell glucose sensitivity.. Matsuda index, early phase ISR (0 to 30 minutes), and parameters of β-cell function were lower in O-IGT than in Y-NGT subjects but not in O-NGT subjects. GLP-1 concentrations were elevated in both older groups [GLP-1 area under the curve (AUC)0-120 was 2.8 ± 0.1 in Y-NGT, 3.8 ± 0.5 in O-NGT, and 3.7 ± 0.4 nmol/L∙120 minutes in O-IGT subjects; P < 0.05], whereas GIP secretion was higher in O-NGT than in Y-NGT subjects (GIP AUC0-120 was 4.7 ± 0.3 in Y-NGT, 6.0 ± 0.4 in O-NGT, and 4.8 ± 0.3 nmol/L∙120 minutes in O-IGT subjects; P < 0.05).. Aging is associated with an exaggerated GLP-1 secretory response. However, it was not sufficient to increase insulin first-phase release in O-IGT and overcome insulin resistance.

Topics: Adult; Aged; Aging; Blood Glucose; C-Peptide; Female; Gastric Inhibitory Polypeptide; Glucagon-Like Peptide 1; Glucose Intolerance; Glucose Tolerance Test; Humans; Incretins; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male

Diabetes mellitus (DM) is prevalent in patients with pancreatic cancer and tends to improve after tumor resection. However, the glycemic response of non-pancreatic cancer patients after surgery has not been examined in detail. We aimed to investigate the changes in glucose metabolism in patients with pancreatic cancer or non-pancreatic cancer after pancreatoduodenectomy (PD).We prospectively enrolled 48 patients with pancreatic cancer and 56 patients with non-pancreatic cancer, who underwent PD. Glucose metabolism was assessed with fasting glucose, glycated hemoglobin (HbA1c), plasma C-peptide and insulin, quantitative insulin check index (QUICKI), and a homeostatic model assessment of insulin resistance (HOMA-IR) and β cell (HOMA-β) before surgery and 6 months after surgery. Patients were divided into 2 groups: "improved" and "worsened" postoperative glycemic response, according to the changes in HbA1c and anti-diabetic medication. New-onset DM was defined as diagnosis of DM ≤ 2 years before PD, and cases with DM diagnosis >2 years preceding PD were described as long-standing DM.After PD, insulin resistance (IR), as measured by insulin, HOMA-IR and QUICKI, improved significantly, although C-peptide and HOMA-β decreased. At 6 months after PD, new-onset DM patients showed improved glycemic control in both pancreatic cancer patients (75%) and non-pancreatic cancer patients (63%). Multivariate analysis showed that long-standing DM was a significant predictor for worsening glucose control (odds ratio = 4.01, P = .017).Favorable glycemic control was frequently observed in both pancreatic cancer and non-pancreatic cancer after PD. PD seems to contribute improved glucose control through the decreased IR. New-onset DM showed better glycemic control than long-standing DM.

Topics: Aged; Ampulla of Vater; Blood Glucose; C-Peptide; Common Bile Duct Neoplasms; Diabetes Mellitus; Duodenal Neoplasms; Female; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Pancreatic Neoplasms; Pancreaticoduodenectomy

Type 1 diabetes mellitus (T1DM) is associated with a disturbance of carbohydrate and lipid metabolism.. To determine whether T1DM alters maternal and neonatal fatty acid (FA) levels.. Observational study.. Academic hospital.. Sixty pregnant women (30 women with T1DM with good glycemic control and 30 healthy women) were included in the study. Maternal blood, umbilical vein, and artery blood samples were collected immediately upon delivery. Following lipid extraction, the FA profiles of the total FA pool of maternal serum and umbilical vein and artery serum were determined by gas chromatography.. Total FA concentration in maternal serum did not differ between the study groups; it was significantly higher in umbilical vein serum of the T1DM group compared with that in the control group [median (interquartile range)]: T1DM 2126.2 (1446.4 to 3181.3) and control 1073.8 (657.5 to 2226.0; P < 0.001), and in umbilical artery vein serum: T1DM 1805.7 (1393.1 to 2125.0) and control 990.0 (643.3 to 1668.0; P < 0.001). Composition of FAs in umbilical vein serum showed significantly higher concentrations of saturated, monounsaturated, and polyunsaturated FAs (SFAs, MUFAs, and PUFAs, respectively) in the T1DM group than compared with those in the control group (P = 0.001). Furthermore, cord blood levels of leptin (P < 0.001), C-peptide (P < 0.001), and insulin resistance (P = 0.015) were higher in the T1DM group compared with controls.. The neonates born to mothers with T1DM had higher concentrations of total FAs, SFAs and MUFAs, as well as PUFAs, compared with control newborns.

Topics: Adult; C-Peptide; Diabetes Mellitus, Type 1; Fatty Acids; Fatty Acids, Monounsaturated; Fatty Acids, Unsaturated; Female; Fetal Blood; Humans; Infant, Newborn; Insulin Resistance; Leptin; Pregnancy; Pregnancy in Diabetics; Umbilical Arteries; Umbilical Veins; Young Adult

To assess urinary C peptide creatinine ratio (UCPCR) used in a modified Matsuda equation to measure insulin sensitivity (IS) in pregnancy.. In this cross-sectional study, two IS measurements were calculated in 73 pregnant women at ~28 weeks of gestation by two separate methods using modified Matsuda equations. The first using the 0 and 120 min serum C peptide concentration during a 75 g oral glucose tolerance test (OGTT) and the second using the 0 and 120 min UCPCR values. The calculated IS measurements from the two methodologies were evaluated using Person's test and linear regression analysis. The relationship between IS. The IS measured using serum C peptide (IS. The UCPCR provides a practical methodology to assess IS and β-cell function in pregnancy.

Topics: Adult; Blood Glucose; C-Peptide; Creatinine; Cross-Sectional Studies; Diabetes, Gestational; Female; Gestational Age; Glucose Tolerance Test; Humans; Insulin Resistance; Predictive Value of Tests; Pregnancy; Prospective Studies; Regression Analysis

The World Health Organization (WHO) estimates that approximately 300 million people will suffer from diabetes mellitus by 2025. Type 2 diabetes mellitus (T2DM) is much more prevalent. T2DM comprises approximately 90% of diabetes mellitus cases, and it is caused by a combination of insulin resistance and inadequate compensatory insulin secretory response. In this study, we aimed to compare the plasma vitronectin (VN) levels between patients with T2DM and insulin resistance (IR) and healthy controls. Seventy patients with IR and 70 age- and body mass index (BMI)-matched healthy controls were included in the study. The insulin, Waist-to-Hip Ratio (WHR), C-peptide (CP) and VN levels of all participants were examined. The homeostasis model of assessment for insulin resistence index (HOMA-IR (CP)) formula was used to calculate insulin resistance. The levels of BMI, fasting plasma gluose (FPG), 2-hour postprandial glucose (2hPG), glycated hemoglobins (HbA1c), and HOMA-IR (CP) were significantly elevated in case group compared with controls. VN was found to be significantly decreased in case group. (VN Mean (Std): 8.55 (2.92) versus 12.88 (1.26) ng/mL p < 0.001). Multiple linear regression analysis was performed. This model explained 43.42% of the total variability of VN. Multiple linear regression analysis showed that HOMA-IR (CP) and age independently predicted VN levels. The VN may be a candidate target for the appraisal of hepatic insulin resistance in patients with T2DM.

Topics: Adolescent; Adult; Age Factors; Aged; Aged, 80 and over; Blood Glucose; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Liver; Male; Middle Aged; Vitronectin; Young Adult

Increased hepatic insulin clearance (HIC) is important in the pathophysiology of type 2 diabetes mellitus (T2DM). The aim of this study is to analyze an effective insulin resistance (IR) index that is minimally affected by HIC.. Our study involved 20 participants with T2DM and 21 healthy participants without diabetes (Non-DM). Participants underwent a meal tolerance test from which plasma glucose, insulin and serum C-peptide immunoreactivity (CPR) were measured, and HOMA-IR and HIC were calculated. Participants then underwent a hyperinsulinemic-euglycemic clamp from which the glucose disposal rate (GDR) was measured.. The index CPR-IR = 20/(fasting CPR × fasting plasma glucose) was correlated more strongly with GDR, than was HOMA-IR, and CPR-IR could be used to estimate GDR. In T2DM participants with HIC below the median, HOMA-IR and CPR-IR were equally well correlated with GDR. In T2DM with high HIC, CPR-IR correlated with GDR while HOMA-IR did not. In Non-DM, CPR-IR and HOMA-IR were equally well correlated with GDR regardless of HIC. The mean HIC value in T2DM was significantly higher than that of Non-DM.. CPR-IR could be a simple and effective index of insulin resistance for patients with type 2 diabetes that is minimally affected by HIC.

Topics: Adult; C-Peptide; Diabetes Mellitus, Type 2; Eating; Fasting; Female; Glucose Clamp Technique; Humans; Insulin; Insulin Resistance; Liver; Male; Middle Aged; Severity of Illness Index

HIV infection has been associated with increased diabetes risk, but prior work has mostly focused on insulin resistance, as opposed to beta cell effects, or included patients on antiretroviral therapies (ART) directly linked to metabolic toxicity. In this analysis, we measured markers of glucose homeostasis and beta cell function, stress, and death in fasting sera from a cross section of HIV+ individuals off ART (n = 43), HIV+ individuals on ART (n = 23), and HIV- controls (n = 39). Markers included glucose, HOMA%S, HOMA%B, proinsulin:C-peptide ratio (PI:C ratio), and circulating preproinsulin (INS) DNA. We performed multiple linear regressions with adjustments for age, sex, race, BMI, and smoking status. Compared to HIV- controls, HIV+ participants off ART exhibited similar beta cell function and insulin sensitivity, without increases in markers of beta cell stress or death. Specifically, in HIV+ participants with CD4 counts <350 cells/μL, PI:C ratios were lower than in HIV- controls (p<0.01), suggesting a reduction in intrinsic beta cell stress among this group. By contrast, HIV+ participants on ART had higher fasting glucose (p<0.0001) and lower HOMA%B (p<0.001) compared to HIV- controls. Among the entire HIV+ population, higher HIV RNA correlated with lower fasting glucose (r = -0.57, p<0.001), higher HOMA%B (r = 0.40, p = 0.001), and lower PI:C ratios (r = -0.42, p<0.001), whereas higher CD4 counts correlated with higher PI:C ratios (r = 0.2, p = 0.00499). Our results suggest that HIV seropositivity in the absence of ART does not worsen beta cell function or glucose homeostasis, but immune reconstitution with ART may be associated with worsened beta cell function.

Topics: Adult; Age Factors; Anti-HIV Agents; Antiretroviral Therapy, Highly Active; Biomarkers; Blood Glucose; Body Mass Index; C-Peptide; Case-Control Studies; CD4 Lymphocyte Count; Cell-Free Nucleic Acids; Fasting; Female; HIV Infections; Humans; Immune Reconstitution; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Proinsulin; Protein Precursors; Sex Factors; Smoking

Adult African American (AA) women have one third of the hepatic insulin clearance of European American (EA) women. This lower hepatic (but not extra-hepatic) insulin clearance in AA individuals is associated with higher plasma insulin concentrations. This study aims to understand whether impairment of hepatic insulin clearance is seen in AA individuals since childhood, possibly suggesting that genetic/epigenetic factors, rather than lifestyle only, contribute to this.. A total of 203 children (105 male and 98 female (55 AA, 88 EA and 60 Hispanic American [HA]; ages, 7-13 years; mean BMI, 19 kg/m

Topics: Adolescent; Black or African American; Blood Glucose; C-Peptide; Child; Female; Glucose Tolerance Test; Hispanic or Latino; Humans; Insulin; Insulin Resistance; Liver; Male; Models, Theoretical; Sex Factors; White People

The relationship between hepatitis B virus (HBV) infection, leptin and insulin resistance remains unclear. We hypothesised links between serum leptin and insulin resistance in non-diabetic patients with chronic viral hepatitis B infection and their relation to liver fibrosis.. We recruited 190 untreated patients with chronic HBV infection and 72 healthy controls. Serum leptin, fasting glucose, insulin, liver function tests (LFTs), C-peptide and Homeostasis model assessment-IR (HOMA-IR) were measured/calculated by ELISA and standard techniques.. Serum leptin, C-peptide (both P < 0.001), HOMA-IR (P = 0.021) and several LFTs were increased in patients with chronic HBV-infection. In multivariate regression analysis, both HOMA-IR (P = 0.003) and leptin (P = 0.002) were significant independent predictors of HBV infection. There were significant positive correlations (P < 0.01) between leptin and HOMA-IR (r = 0.81), between serum leptin and METAVIR activity (r = 0.95), and between HOMA-IR and BMI (r = 0.75), fasting glucose (r = 0.005), and fasting insulin (r = 0.81). Several LFTs, glucose and insulin correlated modestly (r = 0.61-0.69, P < 0.05) with leptin.. Serum leptin may be related to the rate of fibrosis progression in nondiabetic patients with chronic HBV infection. Follow-up by serial measurement of serum leptin and HOMA-IR in non diabetic HBV-infected patients may be used as a non-invasive marker of early liver fibrosis.

Topics: Adult; Biomarkers; Blood Glucose; C-Peptide; Fasting; Female; Hepatitis B virus; Hepatitis B, Chronic; Homeostasis; Humans; Insulin; Insulin Resistance; Leptin; Liver Cirrhosis; Liver Function Tests; Male; Middle Aged

Insulin autoimmune syndrome (IAS), spontaneous hyperinsulinemic hypoglycemia due to insulin-binding autoantibodies, may be difficult to distinguish from tumoral or other forms of hyperinsulinemic hypoglycemia, including surreptitious insulin administration. No standardized treatment regimen exists.. To evaluate an analytic approach to IAS and responses to different treatments.. Observational study in the UK Severe Insulin Resistance Service.. Six patients with hyperinsulinemic hypoglycemia and detectable circulating anti-insulin antibody (IA).. Glycemia, plasma insulin, and C-peptide concentrations by immunoassay or mass spectrometry (MS). Immunoreactive insulin was determined in the context of polyethylene glycol (PEG) precipitation and gel filtration chromatography (GFC). IA quantification using ELISA and RIA, and IA were further characterized using radioligand binding studies.. All patients were diagnosed with IAS (five IgG, one IgA) based on a high insulin/C-peptide ratio, low insulin recovery after PEG precipitation, and GFC evidence of antibody-bound insulin. Neither ELISA nor RIA result proved diagnostic for every case. MS provided a more robust quantification of insulin in the context of IA. One patient was managed conservatively, four were treated with diazoxide without sustained benefit, and four were treated with immunosuppression with highly variable responses. IA affinity did not appear to influence presentation or prognosis.. IAS should be considered in patients with hyperinsulinemic hypoglycemia and a high insulin/C-peptide ratio. Low insulin recovery on PEG precipitation supports the presence of insulin-binding antibodies, with GFC providing definitive confirmation. Immunomodulatory therapy should be customized according to individual needs and clinical response.

Topics: Adult; Aged; Autoimmune Diseases; Biomarkers; Blood Glucose; C-Peptide; Chromatography, Gel; Congenital Hyperinsulinism; Diazoxide; Female; Humans; Immunosuppressive Agents; Insulin; Insulin Antibodies; Insulin Resistance; Male; Middle Aged; Syndrome

Many common genetic polymorphisms are associated with glycemic traits and type 2 diabetes (T2D), but knowledge about genetic determinants of glycemic traits in pregnancy is limited. We tested genetic variants known to be associated with glycemic traits and T2D in the general population for associations with glycemic traits in pregnancy and gestational diabetes mellitus (GDM). Participants in two cohorts (Genetics of Glucose regulation in Gestation and Growth [Gen3G] and Hyperglycemia and Adverse Pregnancy Outcome [HAPO]) underwent oral glucose tolerance testing at 24-32 weeks' gestation. We built genetic risk scores (GRSs) for elevated fasting glucose and insulin, reduced insulin secretion and sensitivity, and T2D, using variants discovered in studies of nonpregnant individuals. We tested for associations between these GRSs, glycemic traits in pregnancy, and GDM. In both cohorts, the fasting glucose GRS was strongly associated with fasting glucose. The insulin secretion and sensitivity GRSs were also significantly associated with these traits in Gen3G, where insulin measurements were available. The fasting insulin GRS was weakly associated with fasting insulin (Gen3G) or C-peptide (HAPO). In HAPO (207 GDM case subjects), all five GRSs (T2D, fasting glucose, fasting insulin, insulin secretion, and insulin sensitivity) were significantly associated with GDM. In Gen3G (43 GDM case subjects), both the T2D and insulin secretion GRSs were associated with GDM; effect sizes for the other GRSs were similar to those in HAPO. Thus, despite the profound changes in glycemic physiology during pregnancy, genetic determinants of fasting glucose, fasting insulin, insulin secretion, and insulin sensitivity discovered outside of pregnancy influence GDM risk.

Topics: Adult; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Diabetes, Gestational; Female; Genetic Predisposition to Disease; Genotype; Glucose Tolerance Test; Humans; Insulin Resistance; Polymorphism, Single Nucleotide; Pregnancy; Risk Factors; Young Adult

A soluble form of the leptin receptor (soluble Ob-R) in the circulation regulates leptin's bioactivity, and is inversely associated with body adiposity and circulating leptin levels. However, no study has examined the clinical impact of soluble Ob-R on glucose metabolism in diabetes. The present study aimed to investigate the association of plasma soluble Ob-R levels with insulin resistance and pancreatic β-cell function in patients with type 2 diabetes.. A total of 289 Japanese patients with type 2 diabetes were included in the present study. Fasting plasma soluble Ob-R levels and plasma leptin levels were measured by enzyme-linked immunosorbent assay. Insulin resistance and pancreatic β-cell function were estimated by homeostasis model assessment of insulin resistance, homeostasis model assessment of β-cell function and fasting C-peptide index.. The median plasma soluble Ob-R level and plasma leptin level were 3.4 ng/mL and 23.6 ng/mL, respectively. Plasma soluble Ob-R levels were negatively correlated with homeostasis model assessment of insulin resistance, homeostasis model assessment of β-cell function and the C-peptide index, whereas plasma leptin levels were positively correlated with each index in univariate analyses. Multivariate analyses including plasma soluble Ob-R levels, plasma leptin levels and use of sulfonylureas, along with age, sex, body mass index and other covariates, showed that soluble Ob-R levels were independently and negatively associated with homeostasis model assessment of β-cell function and the C-peptide index, but not significantly associated with homeostasis model assessment of insulin resistance.. Plasma soluble Ob-R levels are independently associated with pancreatic β-cell function, but not with insulin resistance, in patients with type 2 diabetes. The present study implicates the role of soluble Ob-R in pancreatic β-cell dysfunction in type 2 diabetes.

Topics: Aged; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Humans; Insulin Resistance; Insulin-Secreting Cells; Leptin; Male; Middle Aged; Receptors, Leptin

Post-prandial hypertriglyceridaemia (P-HTG) is associated with cardiovascular disease. This association is of paramount importance during menopause, which is also related to reduced high-density lipoprotein-cholesterol (HDLc) and elevated triglyceride (TG) levels. We aimed to provide a self-assesing tool to screen for P-HTG in menopausal women who were normotriglyceridaemic at fasting and adhered to a Mediterranean-style eating pattern.. We performed oral fat loading tests (OFLT) in combination with self-measurements of diurnal capillary TG at fixed time-points (DC-TG) in 29 healthy menopausal women. TG levels >220 mg dL. We found that, despite having normal fasting TG levels, P-HTG was highly prevalent (approximately 40%). Moreover, self-assessed 3-h post-lunch TG levels >165 mg dL. Self-assessed 3-h post-lunch TG can be used to study post-prandial TG metabolism in Southern European menopausal women who are normotriglyceridaemic at fasting. Characterising an individual's post-prandial response may help menopausal women to evaluate their risk of cardiovascular disease.

Topics: Blood Glucose; Body Mass Index; C-Peptide; Cholesterol, HDL; Diet, Mediterranean; Fasting; Female; Glycated Hemoglobin; Humans; Hypertriglyceridemia; Insulin; Insulin Resistance; Lunch; Menopause; Middle Aged; Patient Compliance; Postprandial Period; Triglycerides; Waist Circumference

Type 2 diabetes mellitus (T2DM) is caused by insulin resistance and β cell dysfunction. In recent studies reported that several markers associated with insulin sensitivity in skeletal muscle, Adiponectin and other parameters, such as fatty acid-binding protein (FABP4), have been reported to regulate insulin resistance, but it remains unclear which factor mostly affects insulin resistance in T2DM. In this cross-sectional study, we evaluated the relationships between several kinds of biomarkers and insulin resistance, and insulin secretion in T2DM and healthy controls. We recruited 30 participants (12 T2DM and 18 non-diabetic healthy controls). Participants underwent a meal tolerance test during which plasma glucose, insulin and serum C-peptide immunoreactivity were measured. We performed a hyperinsulinemic-euglycemic clamp and measured the glucose-disposal rate (GDR). The fasting serum levels of adiponectin, insulin-like growth factor-1, irisin, autotaxin, FABP4 and interleukin-6 were measured by ELISA. We found a strong negative correlation between FABP4 concentration and GDR in T2DM (r = -0.657, p = 0.020). FABP4 also was positively correlated with insulin secretion during the meal tolerance test in T2DM (IRI (120): r = 0.604, p = 0.038) and was positively related to the insulinogenic index in non-DM subjects (r = 0.536, p = 0.022). Autotaxin was also related to GDR. However, there was no relationship with insulin secretion. We found that serum FABP4 concentration were associated with insulin resistance and secretion in T2DM. This suggests that FABP4 may play an important role in glucose homeostasis.

Topics: Adiponectin; Adult; Aged; Blood Glucose; C-Peptide; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Fatty Acid-Binding Proteins; Female; Fibronectins; Humans; Insulin; Insulin Resistance; Insulin-Like Growth Factor I; Interleukin-6; Male; Middle Aged; Phosphoric Diester Hydrolases; Young Adult

Metabolic syndrome (MetS) is a collection of clinical conditions, including central obesity, hypertension, glucose intolerance and dyslipidemia. The long-term inflammatory and metabolic dysfunction associated with MetS may contribute to osteoarthritic processes leading up to total joint arthroplasty (TJA). The purpose of this study was to investigate levels of metabolic biomarkers and the prevalence of MetS in patients undergoing TJA.. Under IRB approval, citrated plasma samples were collected from 41 patients undergoing total hip and knee arthroplasty (THA/TKA) preoperatively and day 1 postoperatively. Control group consisted of 25 healthy human plasma samples (female and male, 18-35 years old) purchased from George King Biomedical Inc. (Overland Park, KS, USA). Samples were profiled for c-peptide, ferritin, IL-6, insulin, resistin, TNF-α, IL-1a, leptin, and PAI-1 using metabolic biochips purchased from RANDOX Co. (Antrim, Northern Ireland). NCEP/ATP III guidelines were used to evaluate which patients met MetS criteria.. Levels of IL-6, resistin, TNF-a, IL-1a, leptin, and PAI-1 were significantly elevated in patients undergoing TJA compared to normal. C-peptide and insulin were both decreased in TJA compared to normal. No significance was found when comparing TJA to normal for ferritin. TNFα was significantly lower in TJA+MetS compared to TJA-MetS, while other biomarkers showed no difference in TJA±MetS populations. Insulin & c-peptide both showed a significant decrease in TJA-MetS compared to normal, but levels in TJA+MetS patients were not significantly different from controls. Resistin showed significant increases in TJA+MetS vs. normal, but not in TJA-MetS vs. normal.. Overall, the differing metabolic profile seen in patients undergoing TJA suggest ongoing metabolic dysfunction. Insulin and c-peptide patterns among the different test groups hint toward a complex and dysfunctional metabolic process involved, with leptin and underlying insulin resistance playing a role. Increased resistin in TJA+MetS, but not in TJA-MetS, compared to normal, suggests that while elevated resistin levels may be associated with the osteoarthritic process, levels are further attenuated by MetS, which is highly prevalent in this population. Increased TNFα in TJA-MetS compared to TJA+MetS may be an artifact of differing sample populations or a true complication of the complex pathophysiology and medical regimen seen in patients with both OA and MetS. The lack of difference seen in the remaining biomarkers suggest that having MetS as a comorbidity does not contribute to the elevated levels seen in patients undergoing TJA.

Topics: Adolescent; Adult; Aged; Arthroplasty, Replacement; Biomarkers; C-Peptide; Case-Control Studies; Female; Ferritins; Humans; Insulin Resistance; Leptin; Male; Metabolic Syndrome; Tumor Necrosis Factor-alpha; United States; Young Adult

Tobacco smoking is known to increase the long-term risk of developing Type 2 diabetes mellitus, but the mechanisms involved are poorly understood. This observational, cross-sectional study aims to compare measures of insulin sensitivity and β-cell function in current, ex- and never-smokers.. The study population included 1246 people without diabetes (mean age 44 years, 55% women) from the EGIR-RISC population, a large European multicentre cohort. Insulin sensitivity was measured using a hyperinsulinaemic, euglycaemic clamp and the homeostatic model assessment - insulin resistance (HOMA-IR) index. Two β-cell function parameters were derived from measures during an oral glucose tolerance test: the early insulin response index and β-cell glucose sensitivity. Additionally, the areas under the curve during the oral glucose tolerance test were calculated for glucose, insulin and C-peptide.. According to smoking habits, there were differences in insulin sensitivity, which was lower in women who smoked, and in β-cell glucose sensitivity, which was lower in men who smoked, but these associations lost significance after adjustment. However, after adjustment, the areas under the glucose and the C-peptide curves during the oral glucose tolerance test were significantly higher in men who smoked.. Smoking habits were not independently associated with insulin sensitivity or β-cell function in a healthy middle-aged European population. Health-selection bias, methodological shortcomings or a true lack of causal links between smoking and impaired insulin sensitivity/secretion are possible explanations. The mechanisms behind the observed increased glucose and C-peptide areas under the curve during the oral glucose tolerance test in male smokers need to be further evaluated.

Topics: Adult; Blood Glucose; C-Peptide; Cross-Sectional Studies; Europe; Female; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Middle Aged; Regression Analysis; Smoking

Limited data are available regarding the long-term metabolic outcomes of functioning pancreas transplants in patients with type 2 diabetes mellitus (T2DM).. To compare the long-term effects of pancreas transplantation in terms of insulin resistance and β cell function, comparison of metabolic variables was performed between type 1 diabetes mellitus (T1DM) and T2DM patients from 1-month posttransplant to 5 years using generalized, linear-mixed models for repeated measures.. Among 217 consecutive patients who underwent pancreas transplantation at our center between August 2004 and January 2015, 193 patients (151 T1DM and 42 T2DM) were included in this study. Throughout the follow-up period, postoperative hemoglobin A1c did not differ significantly between T1DM and T2DM patients, and the levels were constantly below 6% (42 mmol/mol) until 5 years posttransplant, whereas C-peptide was significantly higher in T2DM (P = 0.014). There was no difference in fasting insulin, homeostasis model assessment (HOMA) of insulin resistance, HOMA β cell, or the insulinogenic index between the groups. Furthermore, fasting insulin and HOMA-insulin resistance steadily decreased in both groups during the follow-up period.. There was no significant difference in the insulin resistance or β-cell function after pancreas transplantation between T1DM and T2DM patients. We demonstrated that pancreas transplantation is capable of sustaining favorable endocrine functions for more than 5 years in T2DM recipients.

Topics: Adult; Biomarkers; Blood Glucose; C-Peptide; Chi-Square Distribution; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Female; Glycated Hemoglobin; Graft Survival; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Kaplan-Meier Estimate; Linear Models; Male; Middle Aged; Pancreas Transplantation; Retrospective Studies; Risk Factors; Time Factors; Treatment Outcome

Topics: C-Peptide; Cohort Studies; Diabetes Mellitus, Type 2; Fasting; Female; Humans; Insulin Resistance; Intra-Abdominal Fat; Japan; Male

To explore the relationships between postmenstrual age (PMA), insulin, C-peptide, glucagon and blood glucose concentrations (BGCs) in preterm and term neonates. To compare glucagon-like peptide-1 (GLP-1) concentrations in fed versus never-fed neonates.. Observational.. Dunedin Hospital Neonatal Intensive Care Unit, New Zealand.. Term or preterm euglycaemic neonates (102) receiving routine blood tests (343 samples).. None: plasma was obtained from surplus samples from routine clinical care.. Insulin, C-peptide, GLP-1 and glucagon concentrations were measured in temporal association with BGC.. Insulin and C-peptide concentrations were elevated in very preterm infants (PMA≤32 weeks) and decreased to term; this relationship persisted when BGCs were accounted for. Generalised linear mixed models showed that insulin:C-peptide ratio and insulin:BGC ratio decreased significantly with increasing PMA (p<0.001). GLP-1 increased following initial oral feeds regardless of PMA (p<0.001).. Preterm neonates exhibit insulin resistance in the absence of hyperglycaemia. Enteral feeds result in an increase in GLP-1. These factors are likely to contribute to the increased risk of hyperglycaemia in premature neonates (PMA<32 weeks).

Topics: Blood Glucose; C-Peptide; Female; Glucagon; Glucagon-Like Peptide 1; Homeostasis; Humans; Infant, Newborn; Infant, Premature; Insulin; Insulin Resistance; Intensive Care Units, Neonatal; Male; New Zealand

The Treatment Options for type 2 Diabetes in Adolescents and Youth (TODAY) study demonstrated that glycemic failure rates in the three treatments combined-metformin plus rosiglitazone, metformin alone, and metformin plus lifestyle-were higher in non-Hispanic blacks (NHB; 52.8%) versus non-Hispanic whites (NHW; 36.6%) and Hispanics (H; 45.0%). Moreover, metformin alone was less effective in NHB versus NHW versus H youth. This study describes treatment-associated changes in adiponectin, insulin sensitivity, and β-cell function over time among the three racial/ethnic groups to understand potential mechanism(s) responsible for this racial/ethnic disparity.. TODAY participants underwent periodic oral glucose tolerance tests to determine insulin sensitivity, C-peptide index, and oral disposition index (oDI), with measurements of total and high-molecular-weight adiponectin (HMWA).. At baseline NHB had significantly lower HMWA than NHW and H and exhibited a significantly smaller increase (17.3% vs. 33.7% vs. 29.9%, respectively) during the first 6 months overall. Increases in HMWA were associated with reductions in glycemic failure in the three racial/ethnic groups combined (hazard ratio 0.61, P < 0.0001) and in each race/ethnicity separately. Over time, HMWA was significantly lower in those who failed versus did not fail treatment, irrespective of race/ethnicity. There were no differences in treatment-associated temporal changes in insulin sensitivity, C-peptide index, and oDI among the three racial/ethnic groups.. HMWA is a reliable biomarker of treatment response in youth with type 2 diabetes. The diminutive treatment-associated increase in HMWA in NHB (∼50% lower) compared with NHW and H may explain the observed racial/ethnic disparity with higher therapeutic failure rates in NHB in TODAY.

Topics: Adiponectin; Adolescent; Black People; Blood Glucose; C-Peptide; Child; Diabetes Mellitus, Type 2; Drug Combinations; Ethnicity; Female; Glucose Tolerance Test; Health Status Disparities; Hispanic or Latino; Humans; Hypoglycemic Agents; Insulin Resistance; Life Style; Male; Metformin; Thiazoles; Treatment Failure; White People

Fiber intake is associated with a reduction in the occurrence of cardiovascular events and diabetes.. To investigate whether the addition of fiber to a high-fat, high-calorie (HFHC) meal prevents proinflammatory changes induced by the HFHC meal.. Ten normal fasting subjects consumed an HFHC meal with or without an additional 30 g of insoluble dietary fiber on 2 separate visits. Blood samples were collected over 5 hours, and mononuclear cells (MNCs) were isolated.. Fiber addition to the HFHC meal significantly lowered glucose excursion in the first 90 minutes and increased insulin and C-peptide secretion throughout the 5-hour follow-up period compared with the meal alone. The HFHC meal induced increases in lipopolysaccharide (LPS) concentrations, MNC reactive oxygen species generation, and the expression of interleukin (IL)-1β, tumor necrosis factor α (TNF-α), Toll-like receptor (TLR)-4, and CD14. The addition of fiber prevented an increase in LPS and significantly reduced the increases in ROS generation and the expression of IL-1β, TNF-α, TLR-4, and CD14. In addition, the meal increased Suppressor of cytokine signaling (SOCS)-3 and protein tyrosine phosphatase 1B (PTP-1B) messenger RNA and protein levels, which were inhibited when fiber was added.. The addition of fiber to a proinflammatory HFHC meal had beneficial anti-inflammatory and metabolic effects. Thus, the fiber content of the American Heart Association meal may contribute to its noninflammatory nature. If these actions of dietary fiber are sustained following long-term intake, they may contribute to fiber's known benefits in the prevention of insulin resistance, type 2 diabetes, and atherosclerosis.

Topics: Adult; Blood Glucose; C-Peptide; Diet, High-Fat; Dietary Fiber; Energy Intake; Female; Humans; Insulin; Insulin Resistance; Interleukin-1beta; Leukocytes, Mononuclear; Lipopolysaccharide Receptors; Lipopolysaccharides; Male; Meals; Middle Aged; Postprandial Period; Protein Tyrosine Phosphatase, Non-Receptor Type 1; Reactive Oxygen Species; RNA, Messenger; Suppressor of Cytokine Signaling 3 Protein; Toll-Like Receptor 4; Tumor Necrosis Factor-alpha; Young Adult

The aim of this study was to investigate whether insulin sensitivity, beta-cell function or glycaemic control at diagnosis predict initiation of second-line treatment in newly diagnosed type 2 diabetes.. Type 2 diabetes patients (n = 138) undergoing initial metformin monotherapy (age [mean ± SD], 52 ± 10 years; 67% males; BMI, 32 ± 6 kg/m. Second-line treatment was initiated in 26% of newly diagnosed type 2 diabetes patients within the first 3.3 years after diagnosis, using mostly DPP-4 inhibitors or GLP-1 receptor agonists (64%). In age-, sex- and BMI-adjusted survival models, higher baseline HbA1c and fasting glucose values were associated with earlier treatment intensification. Lower baseline M value and C-peptide secretion (CP iAUC) were also related to an earlier initiation of second-line treatment. In the best multivariable model, baseline HbA1c ≥ 7% (hazard ratio, HR; 95% CI: 3.18; 1.35-7.50) and fasting glucose ≥140 mg/dL (HR, 2.45; 95% CI, 1.04-5.78) were associated with shorter time to second-line therapy, adjusting for age, sex and BMI.. Baseline hyperglycaemia is a strong predictor of requirement of early intensification of glucose-lowering therapy in newly diagnosed type 2 diabetes.

Topics: Adult; Area Under Curve; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Drug Therapy, Combination; Fasting; Female; Germany; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Hyperglycemia; Hypoglycemic Agents; Insulin Resistance; Insulin-Secreting Cells; Liraglutide; Male; Middle Aged; Multivariate Analysis; Prospective Studies; Time Factors

Beta-cell dysfunction is the critical determinant for type 2 diabetes. The novel PANcreatic DERived factor (PANDER) has been identified as interesting islet-secreted cytokine that might be involved in beta-cell dysfunction, a role that has n"ot been clinically elucidated yet. Therefore, this study was designed to study the potential clinical association of this cytokine with beta-cell dysfunction in type 2 diabetes.. Anthropometric parameters, routine biochemical markers and serum levels of PANDER were measured in 63 diabetic subjects including; recently diagnosed type 2 diabetic patients with duration of diabetes ≤6months and long-standing type 2 diabetic patients with duration of diabetes ≥5years then compared to 16 healthy control volunteers. Proinsulin, C-peptide, insulin and PANDER were measured by ELISA. Beta-cell dysfunction was assessed by HOMA2-%β, proinsulin, proinsulin-to-insulin (PI/I) ratio and proinsulin-to-C-peptide (PI/C-pep) ratio. Relations among various parameters were studied using simple and multiple linear regressions.. Serum PANDER levels were found to be significantly elevated in long-standing diabetics as compared to recently diagnosed diabetics and controls. In addition, PANDER was found to be significantly correlated negatively to HOMA2-%β, as well as positively to proinsulin, PI/I and PI/C-pep ratios.. PANDER is associated with beta-cell dysfunction in diabetic patients.

Topics: Algorithms; Biomarkers; C-Peptide; Cytokines; Diabetes Mellitus, Type 2; Disease Progression; Egypt; Enzyme-Linked Immunosorbent Assay; Female; Hospitals, Special; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Linear Models; Male; Middle Aged; Neoplasm Proteins; Outpatient Clinics, Hospital; Proinsulin; Up-Regulation

Insulin-resistance and hyperinsulinemia could have a role in the growing incidence of esophageal adenocarcinoma (EAC) and its pre-cancerous lesion Barrett's Esophagus (BE). HER2 activation has also a pivotal role in EAC carcinogenesis but no data correlate these two phenomena in this disease context.. To investigate the role of hyperinsulinemia in BE-dysplasia-adenocarcinoma sequence and the possible relationship between insulin-mediated and HER2 signaling in EAC development.. Serum insulin, C-peptide, IGF1, glucagon, IL-6, TNF-alpha, leptin, adiponectin and Insulin-Resistance-index were analyzed in 19 patients with gastro-esophageal reflux disease, 51 with BE, 24 with dysplastic-BE and 14 with EAC. Insulin/IGF1/HER2 pathways were analyzed in esophageal biopsies using Luminex. Insulin-Resistance-index, insulin and C-peptide levels increased along with disease progression (p=0.019, p=0.002, p<0.0001, respectively) and correlated with HER2 expression and with downstream mediators phospho-Akt and phospho-mTOR in esophageal tissue. In vitro, insulin was also able to induce cell proliferation through HER2 activation.. Our data pinpoint a possible role of hyperinsulinemia in the Barrett's Esophagus metaplasia-dysplasia-adenocarcinoma sequence through HER2 activation in esophageal epithelial cells.

Topics: Adenocarcinoma; Adult; Aged; Barrett Esophagus; C-Peptide; Disease Progression; Esophageal Neoplasms; Esophagus; Female; Gastroesophageal Reflux; Humans; Immunohistochemistry; Insulin; Insulin Resistance; Interleukin-6; Italy; Male; Middle Aged; Receptor, ErbB-2; Signal Transduction; TOR Serine-Threonine Kinases; Tumor Necrosis Factor-alpha

Obesity and late-night food consumption are associated with impaired glucose tolerance. Late-night carbohydrate consumption may be particularly detrimental during late pregnancy because insulin sensitivity declines as pregnancy progresses. Further, women who were obese (Ob) prior to pregnancy have lower insulin sensitivity than do women of normal weight (NW). The aim of this study is to test the hypothesis that night-time carbohydrate consumption is associated with poorer glucose tolerance in late pregnancy and that this association would be exacerbated among Ob women. Forty non-diabetic African American women were recruited based upon early pregnancy body mass index (NW, <25 kg m(-2) ; Ob, ≥30 kg m(-2) ). Third trimester free-living dietary intake was assessed by food diary, and indices of glucose tolerance and insulin action were assessed during a 75-g oral glucose tolerance test. Women in the Ob group reported greater average 24-h energy intake (3055 kcal vs. 2415 kcal, P < 0.05). Across the whole cohort, night-time, but not day-time, carbohydrate intake was positively associated with glucose concentrations after the glucose load and inversely associated with early phase insulin secretion (P < 0.05). Multiple linear regression modelling within each weight group showed that the associations among late-night carbohydrate intake, glucose concentrations and insulin secretion were present only in the Ob group. This is the first study to report an association of night-time carbohydrate intake specifically on glucose tolerance and insulin action during pregnancy. If replicated, these results suggest that late-night carbohydrate intake may be a potential target for intervention to improve metabolic health of Ob women in late pregnancy.

Topics: Adolescent; Adult; Black or African American; Blood Glucose; Body Mass Index; Body Weight; C-Peptide; Diet; Diet Records; Dietary Carbohydrates; Feeding Behavior; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Linear Models; Metabolic Diseases; Nutrition Assessment; Obesity; Pregnancy; Time Factors; Young Adult

The role of incretins in type 2 diabetes is controversial. This study investigated the association between incretin levels in obese Korean children and adolescents newly diagnosed with type 2 diabetes.. We performed a 2-hr oral glucose tolerance test (OGTT) in obese children and adolescents with type 2 diabetes and with normal glucose tolerance.. Twelve obese children and adolescents with newly diagnosed type 2 diabetes (DM group) and 12 obese age-matched subjects without type 2 diabetes (NDM group) were included.. An OGTT was conducted and insulin, C-peptide, glucagon, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) were measured during the OGTT.. The mean age of the patients was 13·8 ± 2·0 years, and the mean body mass index (BMI) Z-score was 2·1 ± 0·5. The groups were comparable in age, sex, BMI Z-score and waist:hip ratio. The DM group had significantly lower homeostasis model assessment of β and insulinogenic index values (P < 0·001). The homeostasis model assessment of insulin resistance index was not different between the two groups. Insulin and C-peptide secretions were significantly lower in the DM group than in the NDM group (P < 0·001). Total GLP-1 secretion was significantly higher in the DM group while intact GLP-1 and GIP secretion values were not significantly different between the two groups.. Impaired insulin secretion might be important in the pathogenesis of type 2 diabetes in obese Korean children and adolescents, however, which may not be attributed to incretin secretion.

Topics: Adolescent; Analysis of Variance; Asian People; Blood Glucose; Body Mass Index; C-Peptide; Case-Control Studies; Child; Diabetes Mellitus, Type 2; Female; Gastric Inhibitory Polypeptide; Glucagon; Glucagon-Like Peptide 1; Glucose Tolerance Test; Humans; Incretins; Insulin; Insulin Resistance; Male; Obesity; Republic of Korea

The purpose of this study was to examine whether the over-the-counter herbal medicinal plant St. John's wort affects glucose tolerance in healthy men. To do this, we included 10 healthy men who were examined by a 2-hr oral glucose tolerance test on three occasions: A: baseline; B: after 21 days of treatment with St. John's wort; and C: at least 6 weeks after the last capsule of St. John's wort was ingested. Plasma glucose, serum insulin and C-peptide levels were measured during an oral glucose tolerance test and used for estimation of area under the concentration-time curve (AUC) as well as indices of insulin sensitivity and insulin secretion. We found that treatment with St. John's wort increased total and incremental glucose AUC and 2-hr plasma glucose levels. Surprisingly, this effect was sustained and even further increased 6 weeks after the last capsule of St. John's wort was taken. No effect on indices of insulin sensitivity was seen, but indices of insulin secretion were reduced even after adjustment for insulin sensitivity. In conclusion, this study indicates that long-term treatment with St. John's wort may impair glucose tolerance by reducing insulin secretion in young, healthy men. The unregulated use of this over-the-counter drug might be a risk factor for impaired glucose tolerance and type 2 diabetes.

Topics: Adolescent; Adult; Biomarkers; Blood Glucose; Body Mass Index; C-Peptide; Dose-Response Relationship, Drug; Glucose Intolerance; Glycated Hemoglobin; Humans; Hypericum; Insulin; Insulin Resistance; Insulin Secretion; Male; Plants, Medicinal; Sample Size; Young Adult

Gastric bypass surgery produces clear antidiabetic effects in a substantial proportion of morbidly obese patients. In view of the recent trend away from 'bariatric' surgery and toward 'metabolic' surgery, it is important to elucidate the enhancing effect of bypass surgery on pancreatic β-cell mass, which is related to diabetes remission in non-obese patients. We investigated the effects of gastric bypass surgery on glycemic control and other pancreatic changes in a spontaneous non-obese type 2 diabetes Goto-Kakizaki rat model. Significant improvements in postprandial hyperglycemia and plasma c-peptide level were observed when glucose was administered orally post-surgery. Other important events observed after surgery were enhanced first phase insulin secretion in a in site pancreatic perfusion experiment, pancreatic hyperplasia, improved islet structure (revealed by immunohistochemical analysis), striking increase in β-cell mass, slight increase in ratio of β-cell area to total pancreas area, and increased number of small islets closely related to exocrine ducts. No notable changes were observed in ratio of β-cell to non-β endocrine cell area, β-cell apoptosis, or β-cell proliferation. These findings demonstrate that gastric bypass surgery in this rat model increases endocrine cells and pancreatic hyperplasia, and reflect the important role of the gastrointestinal system in regulation of metabolism.

Topics: Animals; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Disease Models, Animal; Fasting; Gastric Bypass; Gastric Inhibitory Polypeptide; Glucose Tolerance Test; Hyperglycemia; Hyperplasia; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Pancreas; Rats; Rats, Wistar

Herein, we investigated the hypoglycemic effect of plant gallic acid (GA) on glucose uptake in an insulin-resistant cell culture model and on hepatic carbohydrate metabolism in rats with a high-fructose diet (HFD)-induced diabetes. Our hypothesis is that GA ameliorates hyperglycemia via alleviating hepatic insulin resistance by suppressing hepatic inflammation and improves abnormal hepatic carbohydrate metabolism by suppressing hepatic gluconeogenesis and enhancing the hepatic glycogenesis and glycolysis pathways in HFD-induced diabetic rats. Gallic acid increased glucose uptake activity by 19.2% at a concentration of 6.25 μg/mL in insulin-resistant FL83B mouse hepatocytes. In HFD-induced diabetic rats, GA significantly alleviated hyperglycemia, reduced the values of the area under the curve for glucose in an oral glucose tolerance test, and reduced the scores of the homeostasis model assessment of insulin resistance index. The levels of serum C-peptide and fructosamine and cardiovascular risk index scores were also significantly decreased in HFD rats treated with GA. Moreover, GA up-regulated the expression of hepatic insulin signal transduction-related proteins, including insulin receptor, insulin receptor substrate 1, phosphatidylinositol-3 kinase, Akt/protein kinase B, and glucose transporter 2, in HFD rats. Gallic acid also down-regulated the expression of hepatic gluconeogenesis-related proteins, such as fructose-1,6-bisphosphatase, and up-regulated expression of hepatic glycogen synthase and glycolysis-related proteins, including hexokinase, phosphofructokinase, and aldolase, in HFD rats. Our findings indicate that GA has potential as a health food ingredient to prevent diabetes mellitus.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Antioxidants; C-Peptide; Carbohydrate Metabolism; Cell Line; Diabetes Mellitus, Type 2; Dietary Carbohydrates; Dietary Supplements; Fructosamine; Fructose; Gallic Acid; Gene Expression Regulation; Hepatitis; Hepatocytes; Hyperglycemia; Hypoglycemic Agents; Insulin Resistance; Male; Mice; Oxidative Stress; Rats, Wistar

Betatrophin and irisin are two recently identified hormones which may participate in regulating pancreatic β-cell function. However, the associations of these two hormones with β-cell function remain unclear. The present study aims to demonstrate the associations of circulating betatrophin and irisin levels with β-cell function, assessed by the area under the curve (AUC) of C-peptide, and the possible correlation between these two hormones in previously diagnosed type 2 diabetes mellitus (T2DM) patients. In total, 20 age-, sex-, and body mass index- (BMI-) matched normal glucose tolerance (NGT) subjects and 120 previously diagnosed T2DM patients were included in this study. Partial correlation analysis was used to evaluate the relationships between these two hormones and indexes of β-cell function and insulin resistance. Our results showed that betatrophin levels were significantly elevated, while irisin levels were significantly decreased, in patients with T2DM compared with NGT subjects. However, partial correlation analysis showed that betatrophin levels did not correlate with β-cell function-related variables or insulin resistance-related variables before or after controlling multiple covariates, while irisin correlated positively with insulin sensitivity but is not associated with β-cell function-related variables. Besides, no correlation was observed between betatrophin and irisin levels. Hence we concluded that betatrophin and irisin were not associated with β-cell function in previously diagnosed T2DM patients.

Topics: Angiopoietin-Like Protein 8; Angiopoietin-like Proteins; C-Peptide; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Female; Fibronectins; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Peptide Hormones

Bed rest and physical inactivity are the consequences of hospital admission for many patients. Physical inactivity induces changes in glucose metabolism, but its effect on the incretin effect, which is reduced in, e.g., Type 2 diabetes, is unknown. To investigate how 8 days of strict bed rest affects the incretin effect, 10 healthy nonobese male volunteers underwent 8 days of strict bed rest. Before and after the intervention, all volunteers underwent an oral glucose tolerance test (OGTT) followed by an intravenous glucose infusion (IVGI) on the following day to mimic the blood glucose profile from the OGTT. Blood glucose, serum insulin, serum C-peptide, plasma incretin hormones [glucagon-like peptide (GLP-1) and glucose-dependent insulinotropic peptide (GIP)], and serum glucagon were measured serially during both the OGTT and the IVGI. The incretin effect is calculated as the relative difference between the area under the curve for the insulin response during the OGTT and that of the corresponding IVGI, respectively. Concentrations of glucose, insulin, C-peptide, and GIP measured during the OGTT were higher after the bed rest intervention (all P < 0.05), whereas there was no difference in the levels of GLP-1 and Glucagon. Bed rest led to a mean loss of 2.4 kg of fat-free mass, and induced insulin resistance evaluated by the Matsuda index, but did not affect the incretin effect (P = 0.6). In conclusion, 8 days of bed rest induces insulin resistance, but we did not see evidence of an associated change in the incretin effect.

Topics: Adolescent; Adult; Bed Rest; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Gastric Inhibitory Polypeptide; Glucagon; Glucose; Glucose Tolerance Test; Healthy Volunteers; Humans; Incretins; Insulin; Insulin Resistance; Male; Young Adult

Metabolic Syndrome (MetS) is associated with elevated risk for developing diabetes and cardiovascular disease. A key component of MetS is the development of insulin resistance (IR). The homeostatic model assessment (HOMA) model can determine IR by using insulin or C-peptide concentrations; however, the efficiency of insulin and C-peptide to determine MetS has not been compared. The aim of the study was to compare the efficiency of C-peptide and insulin to determine MetS in Mexicans.. Anthropometrics, glucose, insulin, C-peptide, triglycerides, and high-density lipoproteins were determined in 156 nonpregnant females and 114 males. Subjects were separated into normal or positive for MetS. IR was determined by the HOMA2 calculator using insulin or C-peptide. Correlations were calculated using the Spearman correlation coefficient (ρ). Differences between correlations were determined by calculating Steiger's Z. The sensitivity was determined by the area under receiver operating characteristics curve (AUC) analysis.. Independent of the MetS definition [Adult Treatment Panel III (ATP III), International Diabetes Federation (IDF), or World Health Organization (WHO)], C-peptide and insulin were significantly higher in MetS subjects (P < 0.05). C-peptide and insulin correlated with all components of MetS; however, for waist circumference, waist-to-hip ratio, and fasting plasma glucose, C-peptide correlated better than insulin (P < 0.05). Moreover, C-peptide (AUC = 0.72-0.78) was a better marker than insulin (AUC = 0.62-0.72) for MetS (P < 0.05). Finally, HOMA2-IR calculated with C-peptide (AUC = 0.80-0.84) was more accurate than HOMA2-IR calculated with insulin (AUC = 0.68-0.75, P < 0.05) at determining MetS.. C-peptide is a strong indicator of MetS. Since C-peptide has recently emerged as a biomolecule with significant importance for inflammatory diseases, monitoring C-peptide levels will aid clinicians in preventing MetS.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Anthropometry; Area Under Curve; C-Peptide; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Female; Humans; Inflammation; Insulin; Insulin Resistance; Lipoproteins, HDL; Male; Metabolic Syndrome; Mexico; Middle Aged; Postprandial Period; Reproducibility of Results; ROC Curve; Triglycerides; Waist Circumference; Waist-Hip Ratio; Young Adult

To study gender differences in insulin and C-peptide concentrations at birth using cord blood collection.. This study was conducted in a maternity hospital, in Jammu province of Jammu and Kashmir, India. All women with pregnancy who were hospitalized for delivery were followed. All pregnant ladies who had no medical condition affecting insulin levels, as per history and routine antenatal blood testing, were included in the study. The test for cord plasma insulin and C-peptide was done in 60 (30 males) full-term (≥ 37 completed weeks) normal delivery babies within 4 hours of the collection of samples using the electro-chemiluminescence immunoassay (ECLIA) on Roche elecsys module immunoassay analyzer. Weight of the babies was taken immediately after birth using digital scales.. Cord plasma insulin and C-peptide measured in EDTA were compared between boys and girls and also related to birth weight. Girls were lighter (2,830 ± 37 vs. 3,236 ± 46 g; p = < 0.001) but had higher cord insulin (16.48 ± 4.88 vs. 10.53 ± 4.04 µU/mL; p = < 0.001), and C-peptide (2.47 ± 0.66 vs. 0.834 ± 0.26 ng/mL; p = < 0.001) concentrations than newborn boys.. Female newborn babies have higher cord plasma insulin and C-peptide concentrations than male newborns, despite being smaller, suggesting intrinsic insulin resistance in girls.

Topics: Birth Weight; C-Peptide; Female; Fetal Blood; Gestational Age; Humans; India; Infant, Newborn; Insulin; Insulin Resistance; Male; Pregnancy; Sex Characteristics; Sex Factors

Metabolic alterations after burn injury have been well described in children; however, in adult patients, glucose metabolism and insulin sensitivity are essentially unknown. We sought to characterize metabolic alterations and insulin resistance after burn injury and determine their magnitude and persistence at discharge.. Prospective, cohort study.. Tertiary burn centre.. Nondiabetic adults with an acute burn involving greater than or equal to 20% total body surface area.. An oral glucose tolerance test was administered at discharge.. Glucose, insulin, and C-peptide levels were measured to derive surrogate measures of insulin resistance and β-cell function, including quantitative insulin sensitivity check index, homeostasis model assessment of β-cell function, homeostasis model assessment of insulin sensitivity, homeostasis model assessment of insulin resistance, and the composite whole-body insulin sensitivity index. Patients were grouped according to the degree of glucose tolerance: normal glucose tolerance, impaired fasting glucose/impaired glucose tolerance, or diabetes. Forty-five adults, 44 ± 15 years old and with 38% ± 14% total body surface area burned, underwent an oral glucose tolerance test at discharge. Median quantitative insulin sensitivity check index (0.348 [0.332-0.375]) and median homeostasis model assessment of insulin resistance (1.13 [0.69-1.45]) were abnormal, indicating insulin resistance and impaired insulin production at discharge. Two-thirds of patients (n = 28) met criteria for impaired fasting glucose/impaired glucose tolerance or diabetes.. We have demonstrated that burn-injured adults remain hyperglycemic, are insulin resistant, and express defects in insulin secretion at discharge. Patients with lower burn severity (total body surface area, 20-30%) express similar metabolic alterations as patients with larger burns (total body surface area, ≥ 30%). Glucose tolerance testing at discharge offers an opportunity for early identification of burn patients who may be at high risk of prediabetes and diabetes. Our findings demonstrated that two-thirds of burn patients had some degree of glucose intolerance. With this in mind, surveillance of glucose intolerance post discharge should be considered. As hyperglycemia and insulin resistance are associated with poor outcomes, studies should focus on how long these profound alterations persist.

Topics: Adult; Aged; Blood Glucose; Body Surface Area; Burns; C-Peptide; Female; Glucose; Glucose Tolerance Test; Humans; Hyperglycemia; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Middle Aged; Patient Discharge; Prospective Studies; Young Adult

Insulin clearance is a highly variable and important factor that affects circulating insulin concentrations. We developed a novel model-based method to estimate both hepatic and extrahepatic insulin clearance using plasma insulin and C-peptide profiles obtained from the insulin-modified frequently sampled intravenous glucose tolerance test. Data from 100 African immigrants without diabetes (mean age 38 years, body weight 81.7 kg, fasting plasma glucose concentration 83 mg/dL, and fasting insulin concentration 37 pmol/L) were used. Endogenous insulin secretion (calculated by C-peptide deconvolution) and insulin infusion rates were used as inputs to a new two-compartment model of insulin kinetics and hepatic and extrahepatic clearance parameters were estimated. Good agreement between modeled and measured plasma insulin profiles was observed (mean normalized root mean square error 6.8%), and considerable intersubject variability in parameters of insulin clearance among individuals was identified (the mean [interquartile range] for hepatic extraction was 25.8% [32.7%], and for extrahepatic insulin clearance was 20.7 mL/kg/min [11.7 mL/kg/min]). Parameters of insulin clearance were correlated with measures of insulin sensitivity and acute insulin response to glucose. The method described appears promising for future research aimed at characterizing variability in insulin clearance and the mechanisms involved in the regulation of insulin clearance.

Topics: Adult; Black People; Blood Glucose; C-Peptide; Fasting; Female; Glucose; Glucose Tolerance Test; Humans; Injections, Intravenous; Insulin; Insulin Resistance; Liver; Male; Models, Biological

What is the prevalence of reactive hypoglycemia (RH) in polycystic ovary syndrome (PCOS) versus age- and body mass index (BMI)-matched healthy controls.. The prevalence of RH was increased in PCOS versus controls.. Previous studies suggested an increased prevalence of RH in PCOS.. Cross-sectional study of 88 women with PCOS and 34 healthy age- and BMI-matched controls.. Eighty-eight women with PCOS and 34 age- and BMI-matched controls were included. The study was conducted at Odense University Hospital, Denmark. Participants underwent 5 h oral glucose tolerance test (5 h OGTT). Indices of insulin resistance, β-cell function, and area under the curve (AUC) for glucose, insulin and C-peptide were calculated. Insulin clearance was estimated as 5 h AUC C-peptide/insulin. RH was defined as blood glucose ≤3.3 mmol/l during 5 h OGTT.. RH occurred in 15/88 (17%) women with PCOS versus 0/34 controls ( ITALIC! P = 0.01). Nine out of 15 women with RH were obese and 6 were lean ( ITALIC! P = 0.42). Obese patients with RH had significantly higher 5 h AUCs insulin and C-peptide compared with lean patients with RH ( ITALIC! P = 0.02 and 0.04, respectively). Obese patients with RH had significantly lower 5 h AUC C-peptide/insulin versus obese patients without RH ( ITALIC! P = 0.02). In lean patients with RH, 5 h AUCs insulin and C-peptide were similar to lean controls.. The 5 h OGTT was used to diagnose RH and may be a limitation of the study. Although the 5 h OGTT is the most widely accepted method, no gold standard exists in terms of diagnosing RH. The 5 h OGTT was suggested to over-estimate the incidence of RH compared with meal test.. The study supports previous suggestions of increased prevalence of RH in women with PCOS compared with controls.. This study was funded by Jacob Madsen's and Olga Madsen's Foundation, Institute of Clinical Research, Odense University Hospital, Kolding Hospital, AP Møller's Foundation, Bernhard and Marie Kleins Foundation, The Novo Nordisk Foundation, and The Danish Medical Association. The authors declare no conflict of interest.. The trial was registered at www.clinicaltrials.gov (registration numbers NCT00451568 (patients) and NCT01995773 (controls)).

Topics: Adolescent; Adult; Area Under Curve; Blood Glucose; Body Mass Index; C-Peptide; Cross-Sectional Studies; Denmark; Female; Glucose Tolerance Test; Humans; Hypoglycemia; Insulin; Insulin Resistance; Obesity; Polycystic Ovary Syndrome; Prevalence

Secreted frizzled-related protein (Sfrp)5 improves insulin sensitivity, but impairs beta-cell function in rodents. However, the relationship between Sfrp5, insulin sensitivity and secretion in humans is currently unclear. Therefore, the aim of the study was to characterize the associations between serum Sfrp5 and indices of insulin sensitivity and beta-cell function from dynamic measurements using oral glucose tolerance tests (OGTT) in humans.. This study enrolled 194 individuals with nonalcoholic fatty liver disease (NAFLD), who were diagnosed based on ultrasound and liver transaminases and underwent a frequent sampling 75-g OGTT. Fasting serum Sfrp5 was measured by ELISA. Associations were assessed with several indices of insulin sensitivity and beta-cell function derived from glucose, insulin and C-peptide concentrations during the OGTT.. Circulating Sfrp5 associated inversely with the insulinogenic index based on C-peptide (rs = -0·244, P = 0·001), but not with the insulinogenic index based on insulin levels (rs = -0·007, P = 0·926) after adjustment for age, sex and body mass index. Sfrp5 inversely correlated only with QUICKI as a marker of insulin sensitivity in the model adjusted for age and sex (rs = -0·149, P = 0·039). These associations were not influenced by the additional adjustment for hepatic steatosis index.. The inverse association of serum Sfrp5 with beta-cell function suggests a detrimental role of Sfrp5 for insulin secretion also in humans. The severity of NAFLD does not appear to affect this relationship. The weak association between serum Sfrp5 and insulin sensitivity was partially explained by body mass.

Topics: Adaptor Proteins, Signal Transducing; Adult; Aged; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Eye Proteins; Female; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Membrane Proteins; Middle Aged; Non-alcoholic Fatty Liver Disease; Obesity

This substudy of the AWARD-3 trial evaluated the effects of the once-weekly glucagon-like peptide-1 receptor agonist, dulaglutide, versus metformin on glucose control, pancreatic function and insulin sensitivity, after standardized test meals in patients with type 2 diabetes. Meals were administered at baseline, 26 and 52 weeks to patients randomized to monotherapy with dulaglutide 1.5 mg/week (n = 133), dulaglutide 0.75 mg/week (n = 136), or metformin ≥1500 mg/day (n = 140). Fasting and postprandial serum glucose, insulin, C-peptide and glucagon levels were measured up to 3 h post-meal. β-cell function and insulin sensitivity were assessed using empirical variables and mathematical modelling. At 26 weeks, similar decreases in area under the curve for glucose [AUCglucose (0-3 h)] were observed among all groups. β-cell function [AUCinsulin /AUCglucose (0-3 h)] increased with dulaglutide and was unchanged with metformin (p ≤ 0.005, both doses). Dulaglutide improved insulin secretion rate at 9 mmol/l glucose (p ≤ 0.04, both doses) and β-cell glucose sensitivity (p = 0.004, dulaglutide 1.5 mg). Insulin sensitivity increased more with metformin versus dulaglutide. In conclusion, dulaglutide improves postprandial glycaemic control after a standardized test meal by enhancing β-cell function, while metformin exerts a greater effect on insulin sensitivity.

Topics: Adult; Aged; Area Under Curve; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Fasting; Female; Glucagon; Glucagon-Like Peptide-1 Receptor; Glucagon-Like Peptides; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Immunoglobulin Fc Fragments; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Metformin; Middle Aged; Postprandial Period; Recombinant Fusion Proteins; Treatment Outcome

This paper aimed to assess the physiological effects of p53 on glucose homeostasis in vivo.. A recombinant adenoviral p53 (rAd-p53) vector was administered to insulin-resistant diabetic mice. Intraperitoneal glucose tolerance test was performed in all groups of mice. Changes in fasting blood glucose, serum triglycerides, C-peptide, and insulin concentrations in treated and untreated mice were measured. Analyses of the target genes related to glucose metabolism were performed.. Treatment with the rAd-p53 improved glucose control in a dose- and time-dependent manner and lowered significantly the fasting blood glucose, the serum triglycerides, and improved tolerance test of glucose as compared to control. Lowered blood glucose was associated with up-regulation of genes in the glycogenesis pathways, and down-regulation of genes in the gluconeogenesis pathways in the liver. Overexpressions of GLUT2, GK, PPAR-γ, and insulin receptor precursor were also observed in the liver and the pancreas of treated animals.. Activation of p53-mediated glucose metabolism led to insulin-like antidiabetic effect in the mouse model especially by changing hepatic insulin sensitivity in the diabetic mouse model.

Topics: Animals; Blood Glucose; Blotting, Western; C-Peptide; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Diet, High-Fat; Disease Models, Animal; Gene Expression; Gluconeogenesis; Glucose Transporter Type 2; Humans; Insulin; Insulin Resistance; Male; Mice, Inbred BALB C; PPAR gamma; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Triglycerides; Tumor Suppressor Protein p53; Up-Regulation

The body compensates for early-stage insulin resistance by increasing insulin secretion. A reliable and easy-to-use mathematical assessment of insulin secretion and disposal could be a valuable tool for identifying patients at risk for the development of type 2 diabetes. Because the pathophysiology of insulin resistance is incompletely understood, assessing insulin metabolism with minimal assumptions regarding its metabolic regulation is a major challenge. To assess insulin secretion and indexes of insulin disposal, our marginalized and regularized absorption approach (MRA) was applied to a sparse sampling oral glucose tolerance test (OGTT) protocol measuring the insulin and C-peptide concentrations. Identifiability and potential bias of metabolic parameters were estimated from published data with dense sampling. The MRA was applied to OGTT data from 135 obese adolescents to demonstrate its clinical applicability. Individual prehepatic basal and dynamic insulin secretion and clearance levels were determined with a precision and accuracy greater than 10% of the nominal value. The intersubject variability in these parameters was approximately four times higher than the intrasubject variability, and there was a strong negative correlation between prehepatic secretion and plasma clearance of insulin. MRA-based analysis provides reliable estimates of insulin secretion and clearance, thereby enabling detailed glucose homeostasis characterization based on restricted datasets that are obtainable during routine patient care.

Topics: Adolescent; C-Peptide; Child; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Liver; Obesity; Young Adult

There is increasing evidence that serum betatrophin levels, a hormone derived from adipose tissue and liver, are elevated in type 2 diabetes (T2D).. To investigate the relationships among betatrophin and metabolic control, insulin resistance, and pancreatic β-cell function in obese Chinese patients with T2D who underwent Roux-en-Y gastric bypass (RYGB).. University hospital, China.. This 1-year follow-up study included 34 obese individuals with T2D (18 males, 16 females) who underwent RYGB in our hospital. Anthropometric results, glucose levels, lipid profiles, and serum betatrophin levels were determined before and 1 year after RYGB.. The serum betatrophin level decreased significantly after RYGB (72.0 ng/mL [33.4-180.9] versus 35.7 ng/mL [14.8-103.3]); P<.001]. The change in betatrophin was significantly positively correlated with the changes in hemoglobin A1c and fasting plasma glucose and negatively correlated with the changes in the 2-hour C-peptide/fasting C-peptide and homeostasis model of assessment of β-cell function (P<.05). Multiple stepwise regression analysis indicated that the change in the serum betatrophin level was independently and significantly associated with the changes in fasting plasma glucose (β = .586, P<.001) and 2-hour C-peptide/fasting C-peptide (β = -.309, P = .021).. Circulating betatrophin might be involved in the regulation of glucose control and insulin secretion in obese Chinese with T2D soon after RYGB.

Topics: Angiopoietin-Like Protein 8; Angiopoietin-like Proteins; Biomarkers; Blood Glucose; C-Peptide; China; Diabetes Mellitus, Type 2; Fasting; Female; Follow-Up Studies; gamma-Glutamyltransferase; Gastric Bypass; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Lipids; Male; Middle Aged; Obesity; Peptide Hormones; Postoperative Care; Postprandial Period

The severity of non-alcoholic fatty liver disease (NAFLD) in type 2 diabetes mellitus (T2DM) population compared with that in normal glucose tolerance (NGT) individuals has not yet been quantitatively assessed. We investigated the prevalence and the severity of NAFLD in a T2DM population using controlled attenuation parameter (CAP).. Subjects who underwent testing for biomarkers related to T2DM and CAP using Fibroscan® during a regular health check-up were enrolled. CAP values of 250 dB/m and 300 dB/m were selected as the cutoffs for the presence of NAFLD and for moderate to severe NAFLD, respectively. Biomarkers related to T2DM included fasting glucose/insulin, fasting C-peptide, hemoglobin A1c (HbA1c), glycoalbumin, and homeostasis model assessment of insulin resistance of insulin resistance (HOMA-IR).. Among 340 study participants (T2DM, n=66; pre-diabetes, n=202; NGT, n=72), the proportion of subjects with NAFLD increased according to the glucose tolerance status (31.9% in NGT; 47.0% in pre-diabetes; 57.6% in T2DM). The median CAP value was significantly higher in subjects with T2DM (265 dB/m) than in those with pre-diabetes (245 dB/m) or NGT (231 dB/m) (all p<0.05). Logistic regression analysis showed that subjects with moderate to severe NAFLD had a 2.8-fold (odds ratio) higher risk of having T2DM than those without NAFLD (p=0.02; 95% confidence interval, 1.21-6.64), and positive correlations between the CAP value and HOMA-IR (ρ0.407) or fasting C-peptide (ρ0.402) were demonstrated.. Subjects with T2DM had a higher prevalence of severe NAFLD than those with NGT. Increased hepatic steatosis was significantly associated with the presence of T2DM, and insulin resistance induced by hepatic fat may be an important mechanistic connection.

Topics: Adult; Aged; Biomarkers; C-Peptide; Case-Control Studies; Diabetes Mellitus, Type 2; Female; Glycated Hemoglobin; Humans; Insulin Resistance; Male; Middle Aged; Non-alcoholic Fatty Liver Disease; Odds Ratio; Prevalence

GH treatment (GHT) can lead to glucose metabolism impairment through decreased insulin sensitivity and impaired pancreatic β-cell function, which are the two key components of the pathogenesis of diabetes. Therefore, in addition to insulin sensitivity, during GHT it is very important to perform a reliable evaluation of insulin secretion. However, conflicting data exist regarding the insulin secretion in children during GHT. C-peptide provides a more reliable estimate of β-cell function than insulin, but few studies evaluated it during GHT. Our aim was to assess the usefulness of C-peptide in the evaluation of insulin secretion in GH deficiency (GHD) children.. In 48 GHD children, at baseline and after 12 and 24months of GHT, and in 56 healthy subjects we evaluated fasting and glucagon-stimulated (AUCCpep) C-peptide levels in addition to other commonly used secretion indexes, such as fasting and oral glucose tolerance test-stimulated insulin levels (AUCINS), Homa-β, and insulinogenic index. The main outcomes were the change in C-peptide during GHT and its correlation with the auxological and hormonal parameters.. At baseline GHD children showed a significant lower AUCCpep (p=0.006), while no difference was found for the other indexes. Both fasting C-peptide (beta 0.307, p=0.016) and AUCCpep (beta 0.379, p=0.002) were independently correlated with IGF-I SDS, while no correlation was found for all other indexes. After 12months an increase in Homa-β (p<0.001), fasting C-peptide (p=0.002) and AUCCpep (p<0.001) was found. At multivariate analysis, only fasting C-peptide (beta 0.783, p=0.001) and AUCCpep (beta 0.880, p<0.001) were independently correlated with IGF-I SDS.. C-peptide, rather than the insulin-derived indexes, has proved to be the most useful marker of insulin secretion correlated to IGF-I levels in GHD children. Therefore, we suggest the use of glucagon test both as diagnostic test for the GH assessment and as a useful tool for the evaluation of insulin secretion during GHT in children.

Topics: Area Under Curve; C-Peptide; Case-Control Studies; Child; Child, Preschool; Fasting; Female; Glucagon; Glucose Tolerance Test; Hormones; Human Growth Hormone; Humans; Hypopituitarism; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Like Growth Factor I; Insulin-Secreting Cells; Male; Prospective Studies

We assessed whether insulin sensitivity improved after renal denervation (RDN) for resistant hypertension. Twenty-three patients underwent a two-step hyperinsulinemic-euglycemic clamp (HEC) with glucose tracer and labeled glucose infusion and oral glucose tolerance test (OGTT) before and 6 months after RDN. Eighteen patients had metabolic syndrome at baseline. Blood pressure declined significantly after RDN, whereas mean (SD) fasting plasma glucose concentration (5.9 ± 0.7 mmol/L), median (minimum-maximum) insulin concentration (254 pmol/L [88-797 pmol/L]), and median C-peptide concentration (2.4 nmol/L [0.9-5.7 nmol/L]) remained unchanged. Endogenous glucose release during HEC was less suppressed after RDN, suggesting a slight decrease in hepatic insulin sensitivity. During high-dose insulin infusion, whole-body glucose disposal was low and remained unchanged after RDN, indicating persistent peripheral insulin resistance (IR). Area under the curve for 0-120 min for glucose and insulin during OGTT, Quantitative Insulin Sensitivity Check Index, Simple Index Assessing Insulin Sensitivity Oral Glucose Tolerance, and HOMA-IR were high, and did not improve after RDN. Despite a significant decrease in blood pressure, neither peripheral nor hepatic insulin sensitivity improved 6 months after RDN treatment in this group of insulin-resistant patients without diabetes and with resistant hypertension, as measured with gold standard methods.

Topics: Blood Glucose; Blood Pressure; C-Peptide; Denervation; Fasting; Female; Glucose; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Hypertension; Insulin; Insulin Resistance; Kidney; Male; Middle Aged

A low-carbohydrate diet is effective to improve hyperglycemia via insulin-independent actions. We report here that a low-carbohydrate diet combined with an SGLT2 inhibitor was effective and safe to treat refractory hyperglycemia in the perioperative period in a type 2 diabetes patient complicated with a high titer of insulin antibodies.

Topics: Adamantane; Aged; Benzhydryl Compounds; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Diet, Carbohydrate-Restricted; Drug Therapy, Combination; Glucosides; Humans; Hypoglycemic Agents; Insulin; Insulin Antibodies; Insulin Resistance; Male; Metformin; Nitriles; Pyrrolidines; Sodium-Glucose Transporter 2 Inhibitors; Vildagliptin

In vitro, beta cells immediately secrete stored but readily releasable insulin in response to a rise of glucose. During a prolonged insulin response, this is followed by newly synthesized insulin. Our aim was to develop an in vivo test to determine the ratio between readily available and newly synthesized insulin after a stimulus in humans by labelling newly synthesized insulin.. A stable isotope tracer of 1.0 g. We found that during a 75-g OGTT, newly synthesized insulin contributed approximately 20 % of total insulin secretion. The pattern of isotope enrichment obtained by collecting multiple urine voids was suggestive that the newly synthesized insulin contributes to the late phase of insulin secretion. De novo C-peptide correlated negatively with both early plasma insulin AUC (r = -0.629, P = 0.028) and early plasma glucose AUC (r = -0.605, P = 0.037).. With stable isotope technique added to OGTT, we were able to measure newly synthesized insulin in healthy individuals. This new technique holds the promise that it is feasible to develop a direct in vivo beta cell function test.

Topics: Adult; Blood Glucose; C-Peptide; Chromatography, Affinity; Feasibility Studies; Female; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Isotope Labeling; Leucine; Male; Reproducibility of Results

To evaluate the impact of continuous subcutaneous insulin infusion (CSII) on β-cell function assessment.. One hundred and twenty-five patients with type 2 diabetes (T2DM) admitted to Third Affiliated Hospital of Sun Yat-sen University treated with CSII were enrolled from May to December 2015. Blood samples were collected to measure their fasting blood glucose, haemoglobin A1c, blood lipids and plasma C peptide levels (fasting, 30 min and 120 min after a mixed meal) on the next day of their admission before CSII started. When patients achieved the target of fasting capillary glucose ≤ 7.0 mmol/L, C-peptide levels (0 min, 30 min and 120 min after a mixed meal) were measured. Then CSII were stopped at 10 pm with the same tests repeated on the next day.. Compared with those measured before CSII [0 min: (0.35±0.20) nmol/L, 30 min: (0.57±0.31) nmol/L, 120 min: (0.84±0.54) nmol/L], C-peptide levels after stopping CSII at all time points [0 min: (0.41±0.16) nmol/L, 30 min: (0.71±0.33) nmol/L, 120 min: (1.37±0.75) nmol/L] increased (P=0.015, P=0.005, P<0.001) even glucose control was achieved, but significantly decreased immediately before CSII was stopped [0 min: (0.23±0.13)nmol/L, 30 min: (0.39±0.26) nmol/L, 120 min: (0.67± 0.50) nmol/L] (P<0.001, P<0.001, P=0.023). The C-peptide after stopping CSII increased to 141% (0 min), 127% (30 min) and 219% (120 min) respectively compared to those before stopping CSII.. CSII therapy should be stopped for accurate evaluation of β-cell function due to its"β-cell rest"effect in T2DM.

Topics: C-Peptide; Diabetes Mellitus, Type 2; Fasting; Glycated Hemoglobin; Homeostasis; Humans; Insulin; Insulin Infusion Systems; Insulin Resistance; Insulin-Secreting Cells; Lipids

The hyperglycemic clamp test, the gold standard of beta cell function, predicts impending type 1 diabetes in islet autoantibody-positive individuals, but the latter may benefit from less invasive function tests such as the proinsulin:C-peptide ratio (PI:C). The present study aims to optimize precision of PI:C measurements by automating a dual-label trefoil-type time-resolved fluorescence immunoassay (TT-TRFIA), and to compare its diagnostic performance for predicting type 1 diabetes with that of clamp-derived C-peptide release.. Between-day imprecision (n = 20) and split-sample analysis (n = 95) were used to compare TT-TRFIA (AutoDelfia, Perkin-Elmer) with separate methods for proinsulin (in-house TRFIA) and C-peptide (Elecsys, Roche). High-risk multiple autoantibody-positive first-degree relatives (n = 49; age 5-39) were tested for fasting PI:C, HOMA2-IR and hyperglycemic clamp and followed for 20-57 months (interquartile range).. TT-TRFIA values for proinsulin, C-peptide and PI:C correlated significantly (r2 = 0.96-0.99; P<0.001) with results obtained with separate methods. TT-TRFIA achieved better between-day %CV for PI:C at three different levels (4.5-7.1 vs 6.7-9.5 for separate methods). In high-risk relatives fasting PI:C was significantly and inversely correlated (rs = -0.596; P<0.001) with first-phase C-peptide release during clamp (also with second phase release, only available for age 12-39 years; n = 31), but only after normalization for HOMA2-IR. In ROC- and Cox regression analysis, HOMA2-IR-corrected PI:C predicted 2-year progression to diabetes equally well as clamp-derived C-peptide release.. The reproducibility of PI:C benefits from the automated simultaneous determination of both hormones. HOMA2-IR-corrected PI:C may serve as a minimally invasive alternative to the more tedious hyperglycemic clamp test.

Topics: Adolescent; Adult; Autoantibodies; C-Peptide; Child; Child, Preschool; Diabetes Mellitus, Type 1; Fasting; Female; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Hyperglycemia; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Prognosis; Proinsulin; Regression Analysis

To date, the association between diabetes mellitus (DM) and gastric cancer has been controversial, including the underlying mechanism. We investigated the association between plasma diabetic biomarkers (insulin, C-peptide, and blood glucose) and gastric cancer risk. In addition, homeostasis model assessment of insulin resistance (HOMA-IR) and homeostasis model assessment of β-cell function (HOMA-β) were calculated. A total of 36,745 subjects aged 40-69 years in the Japan Public Health Center-based prospective study (JPHC) who returned the baseline questionnaire and provided blood samples were followed from 1990 to 2004. In the present analysis, 477 cases and 477 matched controls were used. The odds ratios (ORs) and their corresponding 95% confidence intervals (CIs) for developing gastric cancer were calculated using conditional logistic regression models. Plasma insulin was positively associated with increased risk of gastric cancer; compared to tertile 1, ORs were 1.69 (95% CI = 1.11-2.59) and 2.01 (1.19-3.38) for tertiles 2 and 3, respectively (p for trend = 0.009). In men, C-peptide was also positively associated with a significant risk; corresponding ORs were 1.42 (0.85-2.38) and 1.91 (1.03-3.54), respectively (p for trend = 0.04). These findings were confirmed for blood samples from the fasting group (≥8 hr after a meal). Higher HOMA-IR was also associated with increased risk, whereas no association was observed for blood glucose. Our findings suggest that Japanese population with higher insulin and C-peptide levels derived from insulin resistance have an elevated risk of gastric cancer.

Topics: Adult; Aged; Alcohol Drinking; Blood Glucose; C-Peptide; Female; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Prospective Studies; Public Health; Risk; Stomach Neoplasms

Macrophage markers in skeletal muscle of obese subjects are elevated and inversely relate to insulin sensitivity. The present study aimed to investigate whether short-term high-fat high-calorie (HFHC) diet already increases macrophage markers and affects glucose metabolism in skeletal muscle of healthy lean subjects. Muscle biopsies were obtained from 24 healthy lean young men before and after a 5-day HFHC-diet. mRNA expression levels of relevant genes in muscle and glucose, insulin, C-peptide and cholesteryl ester transfer protein (CETP) levels in plasma were measured. In addition, we assessed hepatic triacylglycerol ('triglyceride') (HTG) content by magnetic resonance spectroscopy and subcutaneous white adipose tissue (sWAT) biopsies were analysed histologically from a subset of subjects (n=8). A 5-day HFHC-diet markedly increased skeletal muscle mRNA expression of the general macrophage markers CD68 (3.7-fold, P<0.01) and CD14 (3.2-fold, P<0.01), as well as the M1 macrophage markers MARCO (11.2-fold, P<0.05), CD11c (1.8-fold, P<0.05) and MRC1 (1.7-fold, P<0.05). This was accompanied by down-regulation of SLC2A4 and GYS1 mRNA expression, and elevated plasma glucose (+4%, P<0.001) and insulin (+55%, P<0.001) levels together with homoeostasis model assessment of insulin resistance (HOMA-IR) (+48%, P<0.001), suggesting development of insulin resistance (IR). Furthermore, the HFHC-diet markedly increased HTG (+118%, P<0.001) and plasma CETP levels (+21%, P<0.001), a marker of liver macrophage content, whereas sWAT macrophage content remained unchanged. In conclusion, short-term HFHC-diet increases expression of macrophage markers in skeletal muscle of healthy men accompanied by reduced markers of insulin signalling and development of IR. Therefore, recruitment of macrophages into muscle may be an early event in development of IR in response to short-term HFHC-feeding.

Topics: Adipose Tissue; Adult; Biomarkers; Blood Glucose; C-Peptide; Cholesterol Ester Transfer Proteins; Diet, High-Fat; Humans; Insulin; Insulin Resistance; Liver; Macrophages; Male; Muscle, Skeletal; Triglycerides

Polycystic ovary syndrome (PCOS) is a common endocrine disorder associated with metabolic complications. Metabolic biomarkers with roles in obesity, glycaemic control and lipid metabolism are potentially relevant in PCOS. The aim was to investigate metabolic biomarkers in lean and overweight women with and without PCOS and to determine whether any biomarker was able to predict insulin resistance in PCOS.. Cross-sectional study.. Eighty-four women (22 overweight and 22 lean women with PCOS, 18 overweight and 22 lean women without PCOS) were recruited from the community and categorized based on PCOS and BMI status.. Primary outcomes were metabolic biomarkers [ghrelin, resistin, visfatin, glucagon-like peptide-1 (GLP-1), leptin, plasminogen activator inhibitor -1 (PAI-1), glucose-dependent insulinotropic polypeptide (GIP) and C-Peptide] measured using the Bio-Plex Pro Diabetes assay and insulin sensitivity as assessed by glucose infusion rate on euglycaemic-hyperinsulinaemic clamp.. The biomarkers C-peptide, leptin, ghrelin and visfatin were different between overweight and lean women, irrespective of PCOS status. The concentration of circulating biomarkers did not differ between women with PCOS diagnosed by the Rotterdam criteria or National Institute of Health criteria. PAI-1 was the only biomarker that significantly predicted insulin resistance in both control women (P = 0.04) and women with PCOS (P = 0.01).. Biomarkers associated with metabolic diseases appear more strongly associated with obesity rather than PCOS status. PAI-1 may also be a novel independent biomarker and predictor of insulin resistance in women with and without PCOS.

Topics: Adult; Biomarkers; C-Peptide; Case-Control Studies; Cross-Sectional Studies; Cytokines; Female; Gastric Inhibitory Polypeptide; Ghrelin; Glucagon-Like Peptide 1; Glucose Clamp Technique; Humans; Insulin Resistance; Leptin; Nicotinamide Phosphoribosyltransferase; Overweight; Plasminogen Activator Inhibitor 1; Polycystic Ovary Syndrome; Predictive Value of Tests; Resistin; Young Adult

The role of glucose metabolism disorders in periodontal diseases including recurrent aphthous stomatitis (RAS) is currently attracting attention. The aim of this study is to investigate insulin resistance (IR) in patients with RAS in otherwise healthy individuals.. The study enrolled 81 patients with RAS and 61 healthy control subjects. Blood glucose, insulin, C-peptide, hemoglobin A1c, total cholesterol (TC), high-density lipoprotein (HDL) cholesterol, and HOMA-IR were measured in each individual.. Forty-two of the RAS group were in the active, and 39 of the RAS group were in the passive stage. The levels of c-peptide, insulin, and HOMA-IR were remarkably higher in the RAS group (p = 0.015; p < 0.0001; p < 0.0001, respectively) than the control group. The levels of HbA1c, glucose (p = 0,045), TC (p = 0,008), HDL cholesterol (p = 0,002), and HOMA-IR (p = 0.022) were significantly higher in patients with RAS in the active stage.. The study revealed an elevated IR in patients with RAS that was not previously shown. IR was more prominent when the patients were in the active stage that elevated inflammatory cytokines may induce IR by interfering with insulin signaling. Further studies, investigating the interplay between RAS, inflammation, and IR are needed.. Patients who admitted the hospital with RAS might be screened for prediabetes.

Topics: Adult; Biomarkers; Blood Glucose; C-Peptide; Case-Control Studies; Cholesterol; Female; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Male; Recurrence; Stomatitis, Aphthous

To evaluate circulating adipokines in people with ketosis-prone diabetes, a heterogeneous disorder characterized by unprovoked ketoacidosis in people with previously unrecognized diabetes.. Patients presenting with ketoacidosis with no previous diabetes diagnosis were compared with patients with previously established Type 1 diabetes. Baseline assessments of autoimmune status (A+/A-), and β-cell function (B+/B-), as well as leptin and adiponectin levels during a standardized mixed-meal tolerance test of 120 min, were performed. In all, 20 patients with heterogeneous ketosis-prone diabetes and 12 patients with Type 1 diabetes were evaluated at baseline, 12 and 24 months.. At baseline, during a mixed-meal tolerance test, glucose and adiponectin concentrations were lower in patients with ketosis-prone diabetes than in those with Type 1 diabetes (P = 0.0023 and P < 0.0001, respectively), whereas C-peptide concentrations were higher, with no significant difference in leptin concentrations. Within 12 months, 11 patients with ketosis-prone diabetes (all A-/B+) were discontinued from insulin treatment (ketosis-prone diabetes - insulin group), while nine patients (four A-B-, four A+B- and one A-B+) were maintained on insulin (ketosis-prone diabetes + insulin group). Fasting C-peptide levels increased significantly over 24 months in the ketosis-prone diabetes - insulin group (P = 0.01), while HbA1c levels decreased (P < 0.0001). Overall, the ketosis-prone diabetes - insulin group had a higher BMI (P = 0.018), yet a lower fasting glucose concentration (P = 0.003) compared with the ketosis-prone diabetes + insulin group. Over 24 months, the mixed-meal tolerance test area-under-the-curve of C-peptide increased in the ketosis-prone diabetes - insulin group, with no change in ketosis-prone diabetes + insulin (P < 0.0001). At 24 months, in spite of the higher BMI in the ketosis-prone diabetes - insulin group, mixed-meal tolerance test glucose and leptin concentrations were significantly lower (P < 0.0001 and P = 0.017, respectively), while adiponectin levels were higher (P = 0.023) compared with the ketosis-prone diabetes + insulin group.. In spite of the higher BMI in the ketosis-prone diabetes - insulin group, lower leptin and higher adiponectin levels may contribute to improved β-cell function and insulin sensitivity, as evidenced by lower glucose and higher C-peptide levels. This allows insulin therapy to be withdrawn.

Topics: Adiponectin; Adolescent; Adult; Blood Glucose; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 1; Female; Follow-Up Studies; Glycated Hemoglobin; Humans; Insulin Resistance; Insulin-Secreting Cells; Leptin; Male; Middle Aged; Postprandial Period; Prospective Studies; Time Factors; Young Adult

In this study, we compared predialysis and dialysis patients with the controls in terms of insulin resistance and evaluated the association with inflammation that is a risk factor for cardiovascular disease.. A total of 134 non-diabetic patients with controls (n=33), predialysis (n=29) and dialysis patient group (n=72) were included in the study. Fasting blood glucose, insulin, C-peptide, albumin, CRP (C-reactive protein) and homocysteine plasma levels were simultaneously analyzed in all the patients. HOMA-IR index was calculated to show existence of insulin resistance.. Mean insulin and HOMA-IR index values were found to be higher in the predialysis and dialysis patient groups than in the control group (p=0.019, p=0.014; respectively). When three groups were compared in terms of C-peptide levels; these values were found to be statistically significantly higher in the predialysis patients than in controls (p=0.017) and in the dialysis group than in the predialysis patients and controls (p=0.0001, p=0.0001; respectively). CRP and homocysteine levels were found to be statistically higher (p=0.0001, p=0.0001; respectively), while albumin levels were significantly lower (p=0.0001) in the dialysis patient group.. In our study, we demonstrated that insulin resistance was higher in patients in the various stages of chronic kidney disease compared to healthy population. We found that insulin resistance, C-peptid and inflammation related cardiovascular risk factors increased.

Topics: Adult; Biomarkers; Blood Glucose; C-Peptide; C-Reactive Protein; Cardiovascular Diseases; Female; Homocysteine; Humans; Inflammation; Insulin; Insulin Resistance; Kidney Function Tests; Male; Middle Aged; Renal Insufficiency, Chronic; Risk Factors; Statistics as Topic; Turkey

To determine whether modestly severe obesity modifies glucose homeostasis, levels of cardiometabolic markers, and HDL function in African Americans (AAs) and white Americans (WAs) with prediabetes.. We studied 145 subjects with prediabetes (N = 61 WAs, N = 84 AAs, mean age 46.5 ± 11.2 years, mean BMI 37.8 ± 6.3 kg/m(2)). We measured fasting levels of lipids, lipoproteins, and an inflammatory marker (C-reactive protein [CRP]); HDL functionality (i.e., levels of paraoxonase 1 [PON1]); and levels of oxidized LDL, adiponectin, and interleukin-6 (IL-6). We measured serum levels of glucose, insulin, and C-peptide during an oral glucose tolerance test. Values for insulin sensitivity index (Si), glucose effectiveness index (Sg), glucose effectiveness at zero insulin (GEZI), and acute insulin response to glucose (AIRg) were derived using a frequently sampled intravenous glucose tolerance test (using MINMOD software).. Mean levels of fasting and incremental serum glucose, insulin, and C-peptide tended to be higher in WAs versus AAs. The mean Si was not different in WAs versus AAs (2.6 ± 2.3 vs. 2.9 ± 3.0 × 10(-4) × min(-1) [μU/mL](-1)). Mean values for AIRg and disposition index as well as Sg and GEZI were lower in WAs than AAs. WAs had higher serum triglyceride levels than AAs (116.1 ± 55.5 vs. 82.7 ± 44.2 mg/dL, P = 0.0002). Mean levels of apolipoprotein (apo) A1, HDL cholesterol, PON1, oxidized LDL, CRP, adiponectin, and IL-6 were not significantly different in obese AAs versus WAs with prediabetes.. Modestly severe obesity attenuated the ethnic differences in Si, but not in Sg and triglyceride levels in WAs and AAs with prediabetes. Despite the lower Si and PON1 values, AAs preserved paradoxical relationships between the Si and HDL/apoA1/triglyceride ratios. We conclude that modestly severe obesity has differential effects on the pathogenic mechanisms underlying glucose homeostasis and atherogenesis in obese AAs and WAs with prediabetes.

Topics: Adiponectin; Adult; Aged; Black or African American; Blood Glucose; C-Peptide; C-Reactive Protein; Diabetes Mellitus, Type 2; Fasting; Female; Glucose Tolerance Test; Homeostasis; Humans; Insulin; Insulin Resistance; Interleukin-6; Lipid Metabolism; Lipoproteins; Lipoproteins, HDL; Male; Middle Aged; Obesity; Prediabetic State; Triglycerides; United States; White People; Young Adult

Sympathetic overactivity is one critical factor associated with the development of arterial hypertension, impaired insulin secretion and resistance. Some antihypertensives exert beneficial effects on glucose metabolism, whereas others lead to an impairment of metabolic state with consecutive weight gain. In resistant hypertension, baroreflex activation therapy (BAT) reduces arterial blood pressure (BP) by inhibition of the sympathetic nervous system. The objective of this study was to evaluate whether BAT influences metabolic state in patients with resistant hypertension.. Thirty patients with resistant hypertension (10 with known diabetes mellitus) were prospectively included into this study. Blood pressure, BMI, weight, fasting glucose, insulin, C-peptide, hemoglobin A1c, HOMA-IR, HOMA-β, ISQuickI, and glucose levels during oral glucose tolerance test were measured at baseline and 6 months after BAT activation.. Fasting glucose was significantly reduced after 6 months of BAT, whereas mean 2-h glucose levels during oral glucose tolerance test, fasting insulin levels, C-peptide levels, hemoglobin A1c, HOMA-IR, HOMA-β, ISQuickI, weight, and BMI remained unchanged.. Despite improvement in fasting glucose, BAT exerts neither sustained additional beneficial effects nor an impairment of metabolic state. Thus, chronic BAT might be an effective interventional method to reduce BP without metabolic disadvantages.

Topics: Aged; Antihypertensive Agents; Baroreflex; Blood Glucose; Blood Pressure; C-Peptide; Diabetes Complications; Female; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Hypertension; Insulin; Insulin Resistance; Male; Middle Aged; Prospective Studies; Sympathetic Nervous System

This study investigated the relationship among β-cell function, metabolic control, and diabetic microvascular complications in patients with type 2 diabetes mellitus (T2DM).. In total, 885 patients with type 2 diabetes mellitus (DM) were recruited from January 2012 to January 2014 and grouped into three groups according to the area under the curve of C-peptide [AUC(C-pep)] during the 75-g oral glucose tolerance test. Logistic regression analyses were used to evaluate the association between C-peptide and microvascular complications.. The prevalence of diabetic microvascular complications decreased from the first to the third AUC(C-pep) tertile (P < 0.01 for all), whereas the rates of nonalcoholic fatty liver disease (NAFLD) was positively associated with AUC(C-pep) values. Patients with lower AUC(C-pep) tertile exhibited higher levels of glycosylated hemoglobin and high-density lipoprotein cholesterol and longer duration of DM; however, levels of triglycerides, fasting C-peptide, 2-h C-peptide, body mass index, and homeostasis model assessment of insulin resistance index were lower compared with the third tertile. Comparison among patients with a similar DM duration showed a higher level of AUC(C-pep) was inversely associated with prevalence of microvascular complications. The odds ratios for nephropathy, retinopathy, and neuropathy in the lowest versus the highest AUC(C-pep) tertile were 3.10 (95% confidence interval, 2.01-4.78), 2.83 (1.73-4.64), and 2.04 (1.37-3.04) after adjustment for confounding factors.. Higher AUC(C-pep) levels were associated with a decreased prevalence of microvascular complications and a good level of glycemic control, whereas higher endogenous insulin levels were linked to the components of metabolic syndrome and increased rates of NAFLD.

Topics: Adult; Aged; Area Under Curve; Blood Glucose; Body Mass Index; C-Peptide; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Fasting; Female; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Insulin Resistance; Insulin-Secreting Cells; Logistic Models; Male; Middle Aged; Non-alcoholic Fatty Liver Disease; Odds Ratio; Prevalence; Triglycerides

Patients with psoriasis have increased risk of type 2 diabetes. The pathophysiology is largely unknown, but it is hypothesized that systemic inflammation causes insulin resistance. Insulin sensitivity has only been sparsely investigated in patients with psoriasis, and previous studies have used suboptimal methodology. The hyperinsulinemic euglycemic clamp remains the gold standard for quantifying whole-body insulin sensitivity.. We sought to investigate if normal glucose-tolerant patients with psoriasis exhibit impaired insulin sensitivity.. Three-hour hyperinsulinemic euglycemic clamps were performed in 16 patients with moderate to severe, untreated psoriasis and 16 matched control subjects.. The 2 groups were similar with regard to age, gender, body mass index, body composition, physical activity, fasting plasma glucose, and glycosylated hemoglobin. Mean ± SEM psoriasis duration was 23 ± 3 years and Psoriasis Area and Severity Index score was 12.7 ± 1.4. Patients with psoriasis exhibited reduced insulin sensitivity compared with control subjects (median M-value 4.5 [range 1.6-14.0] vs 7.4 [range 2.1-10.8] mg/kg/min, P = .046). There were no differences between groups in plasma glucose, insulin, C-peptide, and glucagon during the clamp.. The classic hyperinsulinemic euglycemic clamp technique does not allow assessment of endogenous glucose production.. Patients with psoriasis were more insulin resistant compared with healthy control subjects. This supports that psoriasis may be a prediabetic condition.

Topics: Adult; Anthropometry; Blood Glucose; C-Peptide; Case-Control Studies; Diabetes Mellitus, Type 2; Female; Glucagon; Gluconeogenesis; Glucose Clamp Technique; Glucose Intolerance; Humans; Hyperinsulinism; Inflammation; Insulin; Insulin Resistance; Male; Middle Aged; Prediabetic State; Psoriasis; Risk

We examined the extent to which surrogate measures of insulin release have shared genetic causes.. Genetic and phenotypic correlations were calculated in a family cohort (n = 315) in which beta cell indices were estimated based on fasting and oral glucose-stimulated plasma glucose, serum C-peptide and serum insulin levels. Furthermore, we genotyped a large population-based cohort (n = 6,269) for common genetic variants known to associate with type 2 diabetes, fasting plasma glucose levels or fasting serum insulin levels to examine their association with various indices.. We found a notable difference between the phenotypic and genetic correlations for the traits, emphasising that the phenotypic correlation is an insufficient measure of the magnitude of shared genetic impact. In addition, we found that corrected insulin response, insulinogenic index and incAUC for insulin after an oral glucose challenge shared the majority of their genetic backgrounds, with genetic correlations of 0.80-0.99. The BIGTT index for acute insulin response differed slightly more from the latter with genetic correlations of 0.78-0.87. The HOMA for beta cell function was genetically closely related to fasting insulin with a genetic correlation of 0.85. The effects of 82 selected susceptibility single nucleotide polymorphisms on these insulin secretion indices supported our interpretation of the data and added insight into the biological differences between the examined traits.. The level of shared genetic background varies between surrogate measures of insulin release, and this should be considered when designing a genetic association study to best obtain information on various mechanisms of insulin release.

Topics: Adult; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Fasting; Female; Genotype; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Polymorphism, Single Nucleotide

Insulin resistance is characterized by impaired biological response of peripheral tissues to the metabolic effects of insulin. Organic cation transporter 2 (OCT2) is responsible for 80% metformin clearance. Limited information is available on the potential relationship between genetic variants of OCT2 and insulin resistance. In this study, we examined the role of OCT2-T201M (602 C>T) variant in insulin resistance in patients with type 2 diabetes (T2D) who were treated with metformin.. Serum concentrations of insulin and C-peptide were assessed using ELISA. Homeostasis model assessment for insulin resistance (HOMA-IR) and HOMA for beta cell function (HOMA-BCF) were determined. PCR-based restriction fragment length polymorphism was used to genotype the OCT2-T201M variant.. Patients with minor alleles had higher HbA1c concentrations (p=0.019), fasting glucose levels (p=0.023), HOMA-IR (p=0.03), and HOMA-BCF (p=0.26) than patients with common alleles. Multivariate analysis identified a significant association between the variables OCT2-T201M and gender, with HOMA-IR and HOMA-BCF (Wilks' λ=0.549, F=12.71, p<0.001 for OCT2-T201M and Wilks' λ=0.369, F=26.46, p<0.001 for gender. Changes in HOMA-BCF were inversely correlated with changes in fasting glucose levels (r=-0.412, p=0.008) and HbA1c (r=-0.257, p=0.114).. Our findings suggest that the loss-of-function variant OCT2-T201M (rs145450955) contribute to changes in insulin resistance and beta cell activity in patients with T2D treated with metformin. Moreover, gender as an independent variable has a significant relationship with HOMA-BCF.

Topics: C-Peptide; Diabetes Mellitus, Type 2; DNA; Female; Genetic Variation; Genotype; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Male; Metformin; Middle Aged; Organic Cation Transport Proteins; Organic Cation Transporter 2; Polymorphism, Genetic

To analyse the association between serum C-peptide and coronary artery disease in the general population.. Follow-up study of 6630 adults from the general population. They were stratified into group 1 (no insulin resistance: C-peptide < third tercile and glycaemia < 100 mg/dL), group 2 (initial insulin resistance: C-peptide ⩾ third tercile and glycaemia < 100 mg/dL) and group 3 (advanced insulin resistance: glycaemia ⩾ 100 mg/dL).. After 3.5 years of follow-up, group 2 had a higher incidence of myocardial infarction (relative risk (RR) = 4.2, 95% confidence interval (CI) = 1.7-10.6) and coronary artery disease (RR = 3.5, 95% CI = 1.9-6.6) than group 1. Group 3 also had increased incidences of both diseases. In multivariable analysis of the entire population, groups 2 and 3 showed significant risks of myocardial infarction and coronary artery disease (RR > 3 and RR > 2, respectively). However, when people with diabetes were excluded, the increased risks were corroborated only in group 2 for myocardial infarction (RR = 2.8, 95% CI = 1.1-6.9; p = 0.025) and coronary artery disease (RR = 2.4, 95% CI = 1.3-4.6; p = 0.007).. Elevated C-peptide is associated with the incidence of myocardial infarction and coronary artery disease in the general population. It can be an earlier predictor of coronary events than impaired fasting glucose.

Topics: Adolescent; Adult; Aged; Biomarkers; Blood Glucose; C-Peptide; Chi-Square Distribution; Coronary Artery Disease; Early Diagnosis; Female; Follow-Up Studies; Humans; Incidence; Insulin Resistance; Male; Middle Aged; Myocardial Infarction; Odds Ratio; Predictive Value of Tests; Proportional Hazards Models; Risk Factors; Spain; Up-Regulation; Young Adult

Pancreatic beta-cell mass contributes to glucose tolerance. The aim of this study was to evaluate the relationships between human beta-cell mass and various clinical parameters, including insulin secretory capacity. The study included 32 Japanese patients who underwent pancreatectomy and were naive to oral hypoglycemic agents and insulin. They were classified into those with normal glucose tolerance (n=13), impaired glucose tolerance (n=9) and diabetes (n=10), and their insulin secretory capacity and insulin resistance were evaluated. Immunohistochemistry was used to determine relative beta-cell area (%) which represented the proportion of insulin-positive cell area to whole pancreatic section. Increment of C-peptide immunoreactivity level by glucagon test (ΔC-peptide, increment of serum C-peptide [nmol/L] at 6 min after intravenous injection of 1-mg glucagon; r=0.64, p=0.002), homeostasis model assessment of beta-cell function (HOMA-beta, fasting immunoreactive insulin [μIU/mL] x 20 / (fasting plasma glucose [mmol/L] - 3.5); r=0.50, p=0.003), C-peptide index (CPI, fasting C-peptide [nmol/L] / fasting plasma glucose [mmol/L]; r=0.36, p=0.042), and fasting immunoreactive insulin (F-IRI [pmol/L]; r=0.36, p=0.044) correlated significantly and positively with the relative beta-cell area. The area under the curve of plasma glucose level from 0 to 120 min by 75 g-OGTT (AUC0-120) also correlated significantly and inversely with the relative beta-cell area (r=-0.36, p=0.045). Stepwise multiple regression analysis identified ΔC-peptide as the only independent and significant determinant of the relative beta-cell area. We conclude that ΔC-peptide, HOMA-beta, CPI, F-IRI and AUC0-120 correlated closely with the relative beta-cell area, and ΔC-peptide was the most valuable index for the prediction of the area.

Topics: Aged; Blood Glucose; C-Peptide; Cell Count; Diabetes Mellitus, Type 2; Female; Glucagon; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged

Bariatric surgery often results in remission of the diabetic state in obese patients. Increased incretin effect seems to play an important role in the glycemic improvements after Roux-en-Y gastric bypass, but the impact of biliopancreatic diversion (BPD) remains unexplored.. The objective was to elucidate the effect of BPD on the incretin effect and its interplay with beta-cell function and insulin sensitivity (IS) in obese subjects with type 2 diabetes (T2DM).. Twenty-three women were studied: a control group of 13 lean, normal glucose-tolerant women (lean NGT) studied once and 10 obese patients with T2DM studied before, 1 and 12 months after BPD.. The ObeseT2DM group underwent BPD.. The main outcome measure was the change in incretin effect as measured by the isoglycemic intravenous glucose infusion test. Secondary outcomes encompassed IS and beta-cell function.. At baseline, the incretin effect was lower in obese T2DM compared to lean NGT (P < .05). One month after BPD, the incretin effect was not changed, but at 12 months it reached the level of the lean NGT group (P > .05). IS improved (P < .05) 1 month after BPD and at 12 months it resembled the levels of the lean NGT group. Insulin secretory rate and beta-cell glucose sensitivity increased after BPD and achieved levels similar to lean NGT group 1 month after BPD and even higher levels at 12 months (P < .05).. BPD has no acute impact on the reduced incretin effect, but 12 months after surgery the incretin effect normalizes alongside normalization of glucose control, IS and beta-cell function.

Topics: Adult; Biliopancreatic Diversion; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucose Tolerance Test; Humans; Incretins; Insulin; Insulin Resistance; Insulin-Secreting Cells; Middle Aged; Obesity, Morbid; Treatment Outcome

The objective of this study was to determine whether glucose tolerance status influences the associations between serum 25-hydroxyvitamin D [25(OH)D], insulin sensitivity, insulin secretion, and β-cell function.. This cross-sectional study included 112 French Canadian postmenopausal women with normal glucose tolerance (NGT; n = 65) or abnormal glucose tolerance (AGT; n = 47). Estimates of insulin sensitivity [homeostasis model assessment of insulin sensitivity (HOMA %S) and glucose disposal rate (GDR)], insulin secretion [area under the curve of C-peptide (AUC C-peptide)], and β-cell function (GDR × AUC C-peptide) were derived from a 2-hr euglycemic-hyperinsulinemic clamp and a 75-gram 3-hr oral glucose tolerance test (OGTT). Measures of adiposity were taken (waist circumference, body mass index, fat mass by the hydrostatic weighting technique, and computed tomography (CT)-derived total and visceral adiposity), questionnaires on physical activity, dietary calcium, and vitamin D intake were administered, and blood was sampled for measurement of parathyroid hormone, interleukin-6, and adiponectin.. AGT status was significantly associated with lower insulin sensitivity and β-cell function (P ≤ 0.01 for all) but not with insulin secretion. Lower serum 25(OH)D concentrations were significantly associated with lower insulin sensitivity and secretion (P ≤ 0.01 for all) but not with β-cell function. The interaction between glucose tolerance status and serum 25(OH)D concentration was not significant for either insulin sensitivity, insulin secretion, or β-cell function, even after adjustment for potential confounders.. Vitamin D and glucose tolerance status are both independently associated with measures of insulin sensitivity, insulin secretion, and β-cell function. However, the association between serum 25(OH)D and these surrogate markers of type 2 diabetes mellitus risk is not influenced by glucose tolerance status.

Topics: Adiponectin; Adiposity; Aged; Area Under Curve; Body Mass Index; C-Peptide; Canada; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Diet; Female; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Interleukin-6; Intra-Abdominal Fat; Middle Aged; Seasons; Tomography, X-Ray Computed; Vitamin D

Postprandial hyperlipidemia and hyperinsulinemia have been thought to play an important role in the development of atherosclerosis. Diabetes mellitus (DM) has an impact on lipid metabolism, however, little is known about the relationship between the postprandial lipid and glucose metabolism in normoglycemic patients with coronary artery disease (CAD).. To compare the postprandial lipid and glucose metabolism in normoglycemic patients with and without CAD, a total of 36 normoglycemic patients: 19 patients with stable CAD (CAD group, age 60.2±11.3 years) and 17 patients without CAD (Non-CAD group, age 60.4±9.6 years) were loaded with a high-fat and high-glucose test meal, and the changes in serum level of the lipid and glucose parameters were monitored before and 0, 2, 4, and 6h later.. In the Non-CAD group, postprandial serum levels of triglycerides (TG) and remnant-like particle cholesterol increased significantly and reached peak levels at the 4th hour and decreased significantly at the 6th hour of observation, whereas those levels in CAD group kept rising during 6h of observation. Although there was no significant difference in the area under the curves (AUCs) for the postprandial plasma glucose levels between CAD and Non-CAD group, the AUCs for the postprandial plasma insulin and C-peptide levels were significantly higher in the CAD group than in the Non-CAD group. The AUCs for postprandial TG levels showed good correlation with those for postprandial plasma insulin and C-peptide levels (insulin: r=0.455, p<0.005; C-peptide: r=0.462, p<0.05).. These findings suggest that postprandial hyperlipidemia and hyperinsulinemia may have a close relationship in CAD patients without DM and might play an important role in the development of atherosclerosis even before the onset of diabetes.

Topics: Aged; Area Under Curve; Atherosclerosis; Blood Glucose; C-Peptide; Cholesterol; Coronary Artery Disease; Diet, High-Fat; Female; Glucose; Humans; Hyperinsulinism; Hyperlipidemias; Insulin; Insulin Resistance; Lipid Metabolism; Lipids; Lipoproteins; Male; Middle Aged; Postprandial Period; Sweetening Agents; Time Factors; Triglycerides

Circulating levels of the adipokine adipocyte fatty acid-binding protein (AFABP) are increased in obesity. However, the influence of circulating AFABP on insulin sensitivity in vivo remains unclear.. C57BL/6NTac mice (10 weeks) were treated over 8 weeks i.p. with saline (control) or recombinant AFABP (0.5 mg/kg/d). A comprehensive characterization of metabolic parameters, body composition, and energy expenditure was performed. Furthermore, the effect of AFABP on pancreatic β-cell responsiveness, hepatic glycogen content, and peroxisome proliferator-activated receptor (PPAR) γ protein expression was elucidated.. In male mice, AFABP treatment induced insulin resistance with significantly increased fasting insulin, C-peptide, and homeostasis model assessment of insulin resistance. In female animals, a similar trend was observed. In both genders, no difference in body weight, lipid parameters, body composition, or energy expenditure could be detected between AFABP-treated and control mice. Insulin resistance in male AFABP-treated mice was accompanied by decreased PPARγ protein content in perigonadal adipose tissue and diminished circulating adiponectin. AFABP treatment did not affect pancreatic β-cell responsiveness and hepatic glycogen content.. Circulating AFABP induces insulin resistance in male mice. AFABP-mediated degradation of PPARγ in adipose tissue and subsequently decreased expression of insulin-sensitizing adiponectin are potential mechanisms for this effect.

Topics: Adipocytes; Adiponectin; Adipose Tissue; Animals; Body Weight; C-Peptide; Fatty Acid-Binding Proteins; Female; Insulin; Insulin Resistance; Male; Mice; Mice, Inbred C57BL; Obesity; PPAR gamma

Early reexamination of carbohydrate metabolism via an oral glucose tolerance test (OGTT) is recommended after pregnancy with gestational diabetes (GDM). In this report, we aimed to assess the dominant patterns of dynamic OGTT measurements and subsequently explain them by meanings of the underlying pathophysiological processes. Principal components analysis (PCA), a statistical procedure that aims to reduce the dimensionality of multiple interrelated measures to a set of linearly uncorrelated variables (the principal components) was performed on OGTT data of glucose, insulin and C-peptide in addition to age and body mass index (BMI) of 151 women (n = 110 females after GDM and n = 41 controls) at 3-6 mo after delivery. These components were explained by frequently sampled intravenous glucose tolerance test (FSIGT) parameters. Moreover, their relation with the later development of overt diabetes was studied. Three principal components (PC) were identified, which explained 71.5% of the variation of the original 17 variables. PC1 (explained 47.1%) was closely related to postprandial OGTT levels and FSIGT-derived insulin sensitivity (r = 0.68), indicating that it mirrors insulin sensitivity in the skeletal muscle. PC2 (explained 17.3%) and PC3 (explained 7.1%) were shown to be associated with β-cell failure and fasting (i.e., hepatic) insulin resistance, respectively. All three components were related with diabetes progression (occurred in n = 25 females after GDM) and showed significant changes in long-term trajectories. A high amount of the postpartum OGTT data is explained by principal components, representing pathophysiological mechanisms on the pathway of impaired carbohydrate metabolism. Our results improve our understanding of the underlying biological processes to provide an accurate postgestational risk stratification.

Topics: Age Factors; Austria; Biomarkers; Blood Glucose; Body Mass Index; C-Peptide; Case-Control Studies; Diabetes Mellitus, Type 2; Diabetes, Gestational; Disease Progression; Female; Glucose Tolerance Test; Humans; Incidence; Insulin; Insulin Resistance; Insulin-Secreting Cells; Linear Models; Muscle, Skeletal; Predictive Value of Tests; Pregnancy; Principal Component Analysis; Prognosis; Proportional Hazards Models; Risk Factors; Time Factors

Individuals with Prader-Willi syndrome (PWS) are commonly restricted to 60-75% of height-appropriate calorie intake because they rapidly become obese on a normal diet. This study measured changes in energy expenditure, glucose and lipid homeostasis, and metabolic flexibility in response to a meal in PWS adults.. 11 adults with PWS were compared with 12 adiposity-matched and 10 lean subjects. Indirect calorimetry was conducted at baseline and 210 min after a standardized 600 kCal breakfast to assess energy expenditure and substrate utilization. Circulating glucose, insulin, C-peptide, glucagon, nonesterified fatty acids, and triglycerides were measured up to 240 min. Insulin sensitivity and insulin secretion rate were assessed by HOMA-IR and C-peptide deconvolution, respectively. Body composition was determined by dual-energy X-ray absorptiometry.. The PWS group had lower lean mass than the obesity control group. Corrected for lean mass, there were no differences between the PWS and obesity groups in resting metabolic rate or metabolic flexibility. Total and abdominal fat mass, insulin sensitivity, and insulin secretion rate were also similar between these groups.. This study did not detect an intrinsic metabolic defect in individuals with PWS. Rather, lower lean mass, combined with lower physical activity, may contribute to weight gain on an apparent weight-maintenance diet.

Topics: Absorptiometry, Photon; Adiposity; Adult; Basal Metabolism; Body Composition; C-Peptide; Energy Metabolism; Female; Glucose; Humans; Insulin; Insulin Resistance; Male; Obesity; Postprandial Period; Prader-Willi Syndrome; Triglycerides

C-peptide has been reported to be a marker of subclinical atherosclerosis in type 2 diabetes mellitus (T2DM) patients, whereas its role in coronary artery disease (CAD) has not been clarified, especially in diabetics with differing body mass indices (BMIs).. This cross-sectional study included 501 patients with T2DM. First, all subjects were divided into the following two groups: CAD and non-CAD. Then, binary logistic regression was used to determine the risk factors for CAD for all patients. To clarify the role of obesity, we re-divided all subjects into two additional groups (obese and non-obese) based on BMI. Finally, binary logistic regression was used to determine the risk factors for CAD for each weight group.. The patients with CAD showed a higher BMI and fasting C-peptide level in addition to an increased prevalence of traditional risk factors for CAD, such as hypertension, insulin resistance, higher cholesterol, cysteine-C (Cys-C) and lower estimated glomerular filtration rate (eGFR). Logistic regression analysis showed that fasting C-peptide (OR=1.513, p=0.005), insulin treatment (OR=1.832, p=0.027) hypertension (OR=1.987, p=0.016) and hyperlipidemia (OR=4.159, p<0.001) significantly increased the risk of clinical CAD in the T2DM patients independent of age, gender, diabetes duration, smoking and alcohol statuses, fasting insulin and glucose, hypoglycemic episodes, UA and eGFR. Additionally, in both of the obese (OR=1.488, p=0.049) and non-obese (OR=1.686, p=0.037) DM groups, C-peptide was associated with an increased risk of CAD after multiple adjustments.. C-peptide is associated with an increased CAD risk in T2DM patients, no matter whether they are obese or not.

Topics: Body Mass Index; C-Peptide; Coronary Artery Disease; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Humans; Hyperlipidemias; Hypertension; Insulin Resistance; Logistic Models; Obesity; Risk Factors

This study aimed to evaluate the relationship between vitamin D (vitD) intake and serum concentrations and insulin secretion (assessed by C-peptide serum concentration)/insulin resistance (determined by estimated glucose disposal rate [eGDR]) in patients with latent autoimmune diabetes in adults (LADA) and type 2 diabetes (T2DM). C-peptide, serum vitD, lipid profile, insulin, glucose, and glycosylated hemoglobin (HbA1c) were assessed; vitD intake was determined; and eGDR was calculated. Groups were compared using the Student t or Mann-Whitney U test. Correlations were performed between insulin secretion, insulin resistance, and vitD, and linear regression models were adjusted for confounding variables. Of 107 patients included, age was 55.3 ± 11.84 years old, and time since diabetes diagnosis was 13.23 ± 5.96 years. There were significant intergroup differences in age, body mass index (BMI), hip measurements, glucose, and HbA1c. The correlation between vitD intake and C-peptide for the whole group was significant (r = 0.213; P = .032) as well as for vitD deficiency/sufficiency in T2DM (P = .042), whereas neither was significant in eGDR. After adjustment for age, HbA1c, disease progression, physical activity, solar exposure, sex, and BMI, vitD intake was only significant in T2DM (P = .028). In serum vitD, only the correlation between eGDR and vitD in T2DM was significant and intragroup when comparing vitD sufficiency. After adjustments, significance was lost. Patients with LADA had lower intake of vitD, poorer metabolic control, lower BMI, and younger age compared to T2DM patients. There was no association between serum vitD or vitD intake and insulin secretion when analyzed by group, although vitD intake was associated with insulin resistance in T2DM, but not LADA.

Topics: Adult; Aged; Blood Glucose; Body Mass Index; C-Peptide; Cross-Sectional Studies; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Energy Intake; Female; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Insulin Secretion; Linear Models; Male; Middle Aged; Motor Activity; Surveys and Questionnaires; Vitamin D

Serum 25-hydroxyvitamin D (25(OH)D) concentrations have been reported to increase following weight loss. Moreover, both weight loss and higher serum 25(OH)D concentrations have been associated with a lower risk of developing type 2 diabetes. The objective of the present study was to determine whether the increase in serum 25(OH)D concentration following weight loss is associated with improved insulin sensitivity, insulin secretion and disposition index (β-cell function). Data from two prospective lifestyle modification studies had been combined. Following a lifestyle-modifying weight loss intervention for 1 year, eighty-four men and women with prediabetes and a BMI ≥ 27 kg/m(2) were divided based on weight loss at 1 year: < 5% (non-responders, n 56) and ≥ 5% (responders, n 28). The association between the change in serum 25(OH)D concentration and changes in insulin sensitivity (homeostasis model assessment of insulin sensitivity (HOMA%S) and Matsuda), insulin secretion (AUC of C-peptide) and disposition index after adjustment for weight loss was examined. Participants in the responders' group lost on average 9.5% of their weight when compared with non-responders who lost only 0.8% of weight. Weight loss in responders resulted in improved insulin sensitivity (HOMA%S, P = 0.0003) and disposition index (P = 0.02); however, insulin secretion remained unchanged. The rise in serum 25(OH)D concentration following weight loss in responders was significantly higher than that in non-responders (8.9 (SD 12.5) v. 3.6 (SD 10.7) nmol/l, P = 0.05). However, it had not been associated with amelioration of insulin sensitivity and β-cell function, even after adjustment for weight loss and several confounders. In conclusion, the increase in serum 25(OH)D concentration following weight loss does not contribute to the improvement in insulin sensitivity or β-cell function.

Topics: Aged; Body Composition; Body Mass Index; C-Peptide; Dietary Supplements; Female; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Life Style; Linear Models; Male; Middle Aged; Prediabetic State; Prospective Studies; Vitamin D; Weight Loss

Topics: Adolescent; Adrenal Cortex Hormones; Adult; Aged; Allografts; Blood Glucose; Body Mass Index; C-Peptide; Cytokines; Female; Graft vs Host Disease; Hematopoietic Stem Cell Transplantation; Humans; Hyperglycemia; Inflammation; Insulin; Insulin Resistance; Male; Middle Aged; Prospective Studies; Severity of Illness Index; Time Factors; Transplantation Conditioning; Young Adult

Both maternal 25-hydroxyvitamin D (25OHD) status and pre-pregnancy BMI (pBMI) may influence offspring cardio-metabolic outcomes. Lower 25OHD concentrations have been observed in women with both low and high pBMIs, but the combined influence of pBMI and 25OHD on offspring cardio-metabolic outcomes is unknown. Therefore, this study investigated the role of pBMI in the association between maternal 25OHD concentration and cardio-metabolic outcomes in 5-6 year old children. Data were obtained from the ABCD cohort study and 1882 mother-child pairs were included. The offspring outcomes investigated were systolic and diastolic blood pressure, heart rate, BMI, body fat percentage (%BF), waist-to-height ratio, total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, glucose, C-peptide, and insulin resistance (HOMA2-IR). 62% of the C-peptide samples were below the detection limit and were thus imputed using survival analysis. Models were corrected for maternal and offspring covariates and tested for interaction with pBMI. Interaction with pBMI was observed in the associations with insulin resistance markers: in offspring of overweight mothers (≥25.0 kg/m2), a 10 nmol/L increase in maternal 25OHD was associated with a 0.007(99%CI:-0.01,-0.001) nmol/L decrease in C-peptide and a 0.02(99%CI:-0.03,-0.004) decrease in HOMA2-IR. When only non-imputed data were analyzed, there was a trend for interaction in the relationship but the results lost significance. Interaction with pBMI was not observed for the other outcomes. A 10 nmol/L increase in maternal 25OHD was significantly associated with a 0.13%(99%CI:-0.3,-0.003) decrease in %BF after correction for maternal and child covariates. Thus, intrauterine exposure to both low 25OHD and maternal overweight may be associated with increased insulin resistance in offspring, while exposure to low 25OHD in utero may be associated with increased offspring %BF with no interactive effects from pBMI. Due to the limitations of this study, these results are not conclusive, however the observations of this study pose important research questions for future studies to investigate.

Topics: Adult; Blood Pressure; Body Mass Index; C-Peptide; Child; Child, Preschool; Female; Humans; Insulin Resistance; Lipids; Male; Pregnancy; Prenatal Exposure Delayed Effects; Risk Factors; Vitamin D; Waist-Height Ratio

Type 2 diabetes is a progressive disease characterized by insulin resistance and insulin secretory dysfunction. In this study, we assessed the factors contributing to an insulin secretory defect in type 2 diabetes patients.. The subjects consisted of 382 patients with type 2 diabetes, aged 57±13 years. We estimated the β-cell function using 6-min post-glucagon increments in C-peptide (ΔCPR).. A significant inverse correlation was observed between the time since the diagnosis of diabetes and ΔCPR. A simple liner regression analysis showed that ΔCPR decreases at a rate of 0.056 ng/mL/year. According to a multiple regression model, body mass index (BMI) and log (triglyceride) were positively correlated with ΔCPR. Time since the diagnosis of diabetes, diabetes in 1st degree relatives, the presence of diabetic retinopathy, and HbA1c were inversely correlated with ΔCPR. In 50 patients who underwent the glucagon stimulation test twice, the ΔCPR decreased from 2.27±1.47 to 1.72±1.08 ng/mL over a period of 6.5±0.9 years. A multiple regression analysis revealed the BMI and fasting plasma glucose level to be significant contributing factors to the decline in ΔCPR.. The duration of diabetes, a low BMI, genetic factors, and the presence of microangiopathy may be associated with β-cell dysfunction in diabetic patients. The observations in this study suggest that obese subjects showed a rapid decline in the β-cell function despite an initial high CPR response. Environmental factors causing insulin resistance and glucotoxicity may therefore be involved in progressive β-cell failure.

Topics: Adult; Aged; Body Mass Index; C-Peptide; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Disease Progression; Female; Glucagon; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Longitudinal Studies; Male; Middle Aged; Overweight; Regression Analysis; Thinness; Triglycerides

Diabetes and dyslipidemia are common in patients with psychosis; this association may be partly related to adverse metabolic effects of antipsychotic medications. We assessed glucose and lipid metabolism during the fasted state in drug-naïve patients with psychosis. Fasting serum concentrations of total cholesterol, triglycerides, high density lipoprotein (HDL), glucose, insulin, connecting peptide (C-peptide), homeostatic model assessment index (HOMA-IR), glycated hemoglobin (HbA1C) and serum cortisol were compared between a group of 40 newly diagnosed drug-naïve, first-episode patients with psychosis and a group of 40 healthy controls, matched for age, sex and BMI. Total cholesterol, triglycerides and fasting glucose levels were similar, whereas insulin and C-peptide levels were higher and HDL marginally lower in the patients' group compared to those in healthy controls. Drug-naïve patients with psychosis were more insulin resistant (as assessed by the HOMA-R index) compared to healthy controls. Serum cortisol did not differ between the two groups. There is evidence that drug-naïve, first-episode patients with psychosis are more insulin resistant compared to healthy controls.

Topics: Adult; Blood Glucose; Body Mass Index; C-Peptide; Case-Control Studies; Cholesterol; Fasting; Female; Glycated Hemoglobin; Homeostasis; Humans; Hydrocortisone; Insulin; Insulin Resistance; Lipid Metabolism; Male; Psychotic Disorders; Triglycerides

Betatrophin has been suggested as an inducer of β-cell proliferation in mice in addition to its function in regulating triglyceride. Recent data showed that betatrophin was increased in Type 2 Diabetes (T2D), however, its ability to induce insulin production has been questioned. We hypothesized that the increased betatrophin in T2D is not affecting insulin production from β-cells. To test this hypothesis, we investigated the association between betatrophin and C-peptide level in humans, which acts as a measure of endogenous insulin production from β-cells.. This study was designed to examine the association between plasma betatrophin level and C-peptide in 749 T2D and non-diabetics.. Betatrophin and C-peptide levels were higher in T2D subjects compared with non-diabetics subjects. Betatrophin showed strong correlation with C-peptide in non-diabetics subjects (r = 0.28, p = < 0.0001). No association between betatrophin and C-peptide were observed in T2D subjects (r = 0.07, p = 0.3366). Dividing obese and non-obese subjects into tertiles according to betatrophin level showed significantly higher C-peptide levels at higher tertiles of betatrophin in obese non-diabetics subjects P-trend = 0.0046. On the other hand, C-peptide level was significantly higher in subject with higher betatrophin level in non-diabetics subjects across all age groups but not in T2D subjects. Multiple logistic regression models adjusted for age, BMI, gender, ethnicity as well as C-peptide level showed that subjects in the highest tertiles of betatrophin had higher odds of having T2D [odd ratio (OR) = 7.3, 95% confidence interval (CI) 4.0-13.3].. Increased betatrophin level in obese subjects is correlated with an increase in C-peptide level; which is possibly caused by the increased insulin resistance. On the other hand, no correlation is observed between increased betatrophin level and C-peptide in T2D subjects. In conclusion, the increased betatrophin in T2D subject does not cause any increase in insulin production as indicated by C-peptide level.

Topics: Adult; Angiopoietin-Like Protein 8; Angiopoietin-like Proteins; Arabs; Asian People; Biomarkers; C-Peptide; Case-Control Studies; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Female; Humans; India; Insulin Resistance; Kuwait; Male; Middle Aged; Obesity; Pakistan; Peptide Hormones; Up-Regulation

Several well-known risk factors play an important role in the development of new-onset diabetes mellitus after orthotopic liver transplantation (OLT). Immunosuppressant drugs and hepatitis C virus (HCV) infection have a direct effect on pancreatic beta cells resulting insulin hyposecretion. Steroids mainly cause peripheral insulin resistance. Although in type 2 diabetes mellitus the incretin-insulin axis is impaired and incretin hormones are advantageous targets of many antidiabetic drugs, the endocrinologic background of new-onset diabetes mellitus after transplantation (NODAT) is still not completely understood.. During the first postoperative year the oral glucose tolerance test (OGTT) was performed on 21 patients after OLT. Patients' glycemic metabolic status was determined according to the results of OGTT. The level of incretin hormones, namely glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP), were measured with competitive enzyme-linked immunoassay reaction.. Six patients had normal glucose tolerance (NGT), 9 had impaired glucose tolerance (IGT, serum glucose 7.8-11.0 mmol/L), and 6 were diagnosed with NODAT (serum glucose >11.1 mmol/L). Fasting insulin and c-peptide levels were higher if IGT/NODAT was found. Insulin secretion was not further stimulated after OGTT. GIP and GLP-1 levels did not differ significantly, not even after glucose load. HCV infection had not influenced the levels of incretin hormones [GLP-1 (0 min): 1.21 ± 0.27 vs 1.38 ± 0.65; P = ns; GLP-1 (120 min): 1.46 ± 0.61 vs 1.07 ± 0.58; P = ns; GIP (0 min): 2.55 ± 0.95 vs 1.99 ± 0.63; P = ns, GIP (120 min): 2.62 ± 0.6 vs 2.33 ± 0.77; P = ns].. The stimulation of insulin secretion in NODAT is limited. Incretin hormones are present independently from the current glycemic status. The use of dipeptidyl peptidase-4 inhibitors through their positive effect on the incretin-insulin axis can be beneficial in the therapy of NODAT after liver transplantation.

Topics: Adult; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Fasting; Female; Glucose Tolerance Test; Hepatitis C; Humans; Incretins; Insulin; Insulin Resistance; Insulin Secretion; Liver Transplantation; Male; Middle Aged; Postoperative Period

Tyrosine kinase inhibitors (TKIs) have dramatically changed the prognosis of patients with chronic myeloid leukemia (CML). They have a distinct toxicity profile that includes glycometabolic alterations: i.e. diabetes mellitus (DM), impaired fasting glucose (IFG), and the metabolic syndrome (MS). The aim of this study was to evaluate the prevalence of these alterations in a cohort of CML-chronic phase patients treated with imatinib, dasatinib or nilotinib.. The study involved 168 consecutive CML-chronic phase patients with no history of DM/IFG or MS. Anthropometric and metabolic parameters were assessed, and DM/IFG and MS were diagnosed based on the criteria of the American Diabetes Association and the National Cholesterol Education Program-Adult Treatment Panel III, respectively.. The nilotinib group had significantly higher levels of fasting plasma glucose, insulin, C-peptide, insulin resistance, and total and LDL cholesterol than the imatinib and dasatinib groups. DM/IFG were identified in 25% of the imatinib- and dasatinib-treated patients, and 33% of those in the nilotinib cohort (p = 0.39 vs imatinib and p = 0.69 vs dasatinib). A diagnosis of MS was made in 42.4% of the imatinib-treated patients, 37.5% of the dasatinib-treated patients, and 36.1% of the nilotinib-treated patients (p = 0.46 vs imatinib and p = 0.34 vs dasatinib).. Treatment with nilotinib does not seem to induce DM/IFG or the MS to a significantly higher extent than imatinib or dasatinib, though it causes a worse glycometabolic profile. These findings suggest the need for a close monitoring of glucose and lipid metabolism and a multidisciplinary approach in patients treated with nilotinib.

Topics: Adult; Aged; Aged, 80 and over; Anthropometry; Blood Glucose; C-Peptide; Cohort Studies; Dasatinib; Female; Glucose; Humans; Imatinib Mesylate; Insulin; Insulin Resistance; Leukemia, Myelogenous, Chronic, BCR-ABL Positive; Lipid Metabolism; Male; Middle Aged; Protein Kinase Inhibitors; Protein-Tyrosine Kinases; Pyrimidines; Young Adult

Since insulin resistance is genetically determined and observed in type 1 diabetes, the study was designed to elucidate an involvement of Ala 12 Pro PPARg2 gene polymorphism in residual C-peptide secretion and BMI variation in children with type 1 diabetes.. In 103 patients with type 1 diabetes genetic analysis of PPARg2 polymorphism, C-peptide measurements and evaluation of BMI and clinical parameters were performed. Control group consisted of 109 healthy subjects.. In diabetic patients, only three individuals exhibited Ala 12 Ala genotype (2.9%) and 29 patients were heterozygous Ala 12 Pro (28.2%). Interestingly, Ala12+ variants were associated with higher C-peptide levels in 6 th , 12 th and 24 th months after the onset than Pro 12 Pro genotype (0.39±0.24 pmol/mL vs. 0.22±0.14 pmol/mL, P=0.007 and 0.19±0.09 vs. 0.11±0.07, P=0.01 and 0.13±0.09 vs. 0.07±0.05, P=0.021, respectively). Similarly, C-peptide was also significantly increased in patients with history of type 2 diabetes in the first-degree relatives. The observation was even more evident when Ala12+ variants were taken together with family history of type 2 diabetes. Besides, in 24 th and 36 th months after the onset, Ala12+ variants revealed to be associated with higher BMI normalized by age and sex as compared to Pro 12 Pro (0.557±0.84 vs. -0.119±0.73, P=0.001 and 0.589±0.919 vs. 0.066±0.630, P=0.016, respectively).. Thus, it is likely that PPARg2 gene polymorphism and/or the genetically determined insulin resistance may be associated with residual C-peptide secretion and involve excessive BMI in type 1 diabetes.. Wprowadzenie i cel pracy. Z uwagi na występowanie w cukrzycy typu 1 (T1D) zjawiska insulinooporności oraz możliwość jej genetycznego uwarunkowania celem pracy była ocena wpływu polimorfizmu Ala 12 Pro genu PPARg2 na resztkową insulinosekrecję mierzoną stężeniem peptydu C oraz zmiany wartości indeks BMI u dzieci z cukrzycą typu 1. Materiał i metody. W grupie 103 pacjentów z T1D została przeprowadzona analiza genetyczna polimorfizmu genu PPARg2, pomiary stężenia peptydu C oraz ocena indeksu BMI i parametrów klinicznych. Grupa kontrolna obejmowała 109 zdrowe osoby. Wyniki. U pacjentów z T1D jedynie 3 dzieci posiadało genotyp Ala 12 Ala (2.9%), podczas gdy 29 pacjentów było heterozygotami Ala 12 Pro (28.2%). Interesujące, że warianty Ala12+ były związane z wyższym stężeniem peptydu C w 6, 12 oraz 24 miesiącu trwania choroby w porównaniu z genotypem Pro 12 Pro (0.39±0.24 pmol/mL vs. 0.22±0.14 pmol/mL, P=0.007 i 0.19±0.09 vs. 0.11±0.07, P=0.01 oraz 0.13±0.09 vs. 0.07±0.05, P=0.021, odpowiednio). Podobnie stężenie peptydu C było istotnie wyższe u pacjentów z dodatnim wywiadem w kierunku cukrzycy typu 2 u krewnych pierwszego stopnia. Obserwacja ta była jeszcze bardziej wyraźna, gdy warianty Ala12 + były oceniane łącznie z rodzinnym wywiadem cukrzycy typu 2. Ponadto pacjenci, u których stwierdzono warianty Ala12+ charakteryzowali się w 24 i 36 miesiącu trwania cukrzycy wyższym indeksem BMI znormalizowanym pod względem płci i wieku w porównaniu do nosicieli Pro 12 Pro (0.557±0.84 vs. -0.119±0.73, P=0.001 i 0.589±0.919 vs. 0.066±0.630, P=0.016, odpowiednio). Wnioski. Wydaje się prawdopodobne, że polimorfizm genu PPARg2 i/lub genetycznie uwarunkowana insulinooporność mogą być związane z resztkową insulinosekrecją oraz wzrostem BMI w cukrzycy typu 1 u dzieci.

Topics: Adolescent; Body Mass Index; C-Peptide; Child; Diabetes Mellitus, Type 1; Female; Genetic Predisposition to Disease; Humans; Insulin Resistance; Male; Obesity; Poland; Polymorphism, Genetic; PPAR gamma; Risk Factors

The study was undertaken to assess the selected carbohydrate parameters in children exposed to gestational diabetes in utero.. 50 children exposed to gestational diabetes were compared with 46 control subjects. Anthropometric parameters of a newborn were obtained from the medical records. In all participants height, body mass, waist and hip circumferences were measured; BMI, WHR and WHtR were calculated. Values of fasting glucose, insulin, C-peptide and HbA1c were measured and HOMA2-IR, HOMA2-S, HOMA2-B were calculated. In obese children (BMI ≥95th percentile) OGTT was performed.. The prevalence of overweight/obesity in the study group was 38%, in the control group 41% (p=0.19). Higher fasting glucose level (p=0.02) and HbA1c (p=0.00004) were found in the study group comparing to the control. In children exposed to GDM in utero a positive correlation of fasting insulin and WHR (Rs=0.31, p=0.028) as well as significantly lower HOMA2-B (p=0.03) were observed. In the study group higher HOMA2-IR (p=0.0002) and HOMA2-B (p=0.0000039) and also lower HOMA2-S (p=0.0002) were observed among participants with overweight/obesity comparing to children with normal body weight. In the study group a correlation of HOMA2-IR and SD of the birth weight was found (Rs=0.28, p=0.049).. Children exposed to gestational diabetes in utero, in spite of similar prevalence of overweight/obesity comparing to their non-exposed peers, could have higher risk of glucose intolerance and diabetes mellitus in future. Towards observed decreased insulin sensitivity and compensatory increase in insulin secretion, prevention of overweight and obesity in this group seems to be essential.

Topics: Adolescent; Birth Weight; Blood Glucose; Body Mass Index; C-Peptide; Case-Control Studies; Child; Diabetes, Gestational; Female; Glucose Intolerance; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Male; Obesity; Overweight; Pregnancy; Prenatal Exposure Delayed Effects; Prevalence; Waist-Height Ratio; Waist-Hip Ratio

To investigate the situations of abnormal glucose metabolism and dysfunction of pancreatic islet beta cells in subjects of chronic hepatitis B (CHB) with cirrhosis.. 106 hepatitis B virus (HBV) positive subjects with liver cirrhosis as well as with different grade of Child-Pugh and 37 healthy subjects were included in this study. The oral glucose tolerance test (OGTT), C-peptide and insulin release test were detected. Plasma glucose and insulin levels were analyzed periodically for 2 h after oral glucose loading.. There was no significant difference in the level of fasting plasma glucose and C-peptide between cirrhosis group and control group (P>0.05). The levels of OGTT 2 h glucose, insulin and C peptide were significantly higher in cirrhosis group than control group (P<0.01). Peak plasma glucose levels were obtained at 60 min in normal group and cirrhosis group. The peak insulin and C-peptide response occurred at 60 min in normal group, whereas it was delayed to 120 min in cirrhosis group. There was a significant difference between two groups in the pattern of plasma glucose levels at corresponding time points (P<0.05). The OGTT 2 h glucose and insulin levels were positively correlated with Child-Pugh Score (r1 = 0.389, r2 = 0.508, P<0.01).. These findings implied that there was a certain degree of insulin resistance and abnormal glucose metabolism in the patients with liver cirrhosis.

Topics: Adult; Aged; Blood Glucose; C-Peptide; Female; Glucose; Glucose Tolerance Test; Hepatitis B, Chronic; Humans; Insulin; Insulin Resistance; Insulin Secretion; Liver Cirrhosis; Male; Middle Aged; Pancreas

To investigate the clinical features of non-alcoholic fatty liver disease (NAFLD) and its relationship with serum C-peptide levels in patients with latent autoimmune diabetes in adults (LADA).. A total of 155 patients with LADA who had no drinking history and were hospitalized in department of endocrinology and metabolism from January 2007 to June 2009 were divided into two groups, including patients with LADA but without NAFLD and patients with both LADA and NAFLD, according to Chinese medical association's guidelines of NAFLD and hepatic ultrasound result. Their clinical data and results of laboratory examinations were collected and analyzed, including medications, blood pressure, weight, height, waist circumference, hip circumference, fasting plasma glucose, 2 h postprandial plasma glucose, fasting C-peptide, 2 h postprandial C-peptide, hemoglobin A1c, renal function, liver function, blood lipid and C-reactive protein. The clinical features between two groups were compared and the relationship between serum C-peptide and NAFLD were also analyzed.. Compared to the patients with LADA but without NAFLD, patients with both LADA and NAFLD had higher alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyl transferase (γ-GT) (all P<0.01), but the serum total bilirubin (TBI) and direct bilirubin (DBI) level had no significant inter-group difference (P>0.05). The patients with both LADA and NAFLD had higher fasting C-peptide [0.62(0.33-0.93) vs 0.17 (0.05-0.50) nmol/L, P<0.001], 2 h postprandial C-peptide [1.57(0.78-1.88) vs 0.42(0.06-1.01) nmol/L, P<0.001] and more severe insulin resistance [0.8(1.0-2.5) vs 0.6(0.2-1.3), P<0.001]. Logistic regression analysis showed that there was a significant association between fasting C-peptide and the presence of NAFLD after controlling other confounding factors in patients with LADA.. The patients with both LADA and NAFLD had more severe metabolic disorders and insulin resistance. Serum fasting C peptide was independently associated with the presence of NAFLD in patients with LADA.

Topics: Adult; Alanine Transaminase; Asian People; Aspartate Aminotransferases; C-Peptide; C-Reactive Protein; Diabetes Mellitus, Type 1; gamma-Glutamyltransferase; Glucose Intolerance; Glycated Hemoglobin; Humans; Insulin Resistance; Non-alcoholic Fatty Liver Disease; Waist Circumference

Metabolically healthy obese (MHO) are relatively insulin sensitive and have a favorable cardio-metabolic risk profile compared with metabolically abnormal obese (MAO). To evaluate whether MAO individuals have a decreased insulin clearance compared with MHO individuals, 49 MHO, 147 MAO, and 172 non-obese individuals were analyzed in this cross-sectional study. Insulin clearance and insulin sensitivity were assessed through euglycemic hyperinsulinemic clamp. MHO subjects exhibited significant lower triglycerides, total cholesterol, 2-h post-challenge glucose, fasting and 2-h post-challenge insulin, steady-state plasma insulin, alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyltransferase as compared with MAO individuals. Disposition index was higher in MHO subjects as compared with MAO individuals after adjusting for gender and age (P = 0.04). Insulin clearance was significantly lower in MAO individuals as compared with MHO and non-obese individuals. The difference between the two obese subgroups remained significant after adjusting for gender, age, waist circumference, fat mass, and insulin-stimulated glucose disposal (P = 0.03). The hepatic insulin extraction (C-peptide/insulin) in the fasting state was significantly higher in MHO subjects as compared with MAO individuals (P < 0.0001). In univariate analysis adjusted for gender and age, insulin clearance was correlated with hepatic insulin extraction (P = 0.01). In conclusion, insulin clearance differs among obese subjects with different metabolic phenotypes. Impaired insulin clearance may contribute to sustained fasting and post-meal hyperinsulinemia observed in MAO individuals.

Topics: Adult; Alanine Transaminase; Aspartate Aminotransferases; C-Peptide; Chi-Square Distribution; Cholesterol; Cross-Sectional Studies; Female; gamma-Glutamyltransferase; Glucose Clamp Technique; Humans; Insulin; Insulin Resistance; Male; Obesity; Triglycerides; Waist Circumference

Weight gain in breast cancer patients during treatment is prevalent; the metabolic implications of this weight gain are poorly understood. We aimed to characterize glucose metabolism in breast cancer patients near the initiation of chemotherapy.. Stage I-II breast cancer patients (n = 8) were evaluated near the initiation of chemotherapy and compared with a group of age- and body mass index-matched, as well as a group of young healthy, non-malignant females. Fasting blood samples (analyzed for lipids and cytokines) were taken and an oral glucose tolerance test was performed. Body composition, waist circumference, diet, cardiovascular fitness and muscle strength were evaluated.. Breast cancer patients were abdominally obese (mean ± SD: 94.6 ± 14.0 cm), overweight (28.8 ± 6.0 kg/m(2)) and dyslipidemic (triacylglycerides: 1.84 ± 1.17 mM; high-density lipoprotein cholesterol: 1.08 ± 0.23 mM). Compared to non-malignant matched females, fasting glucose and insulin concentrations were similar but fasting c-peptide was greater in patients (2.6 ± 1.2 ng/mL vs. 1.9 ± 0.8 ng/mL, p = 0.005). Glucose was elevated to a greater extent in patients during the oral glucose tolerance test compared with all non-malignant females. During the glucose tolerance test, c-peptide, but not insulin, remained elevated in patients compared with all non-malignant females. No differences in body composition, serum cytokines, nutrition or exercise capacity between patients and matched, non-malignant females emerged.. Breast cancer patients present with unhealthy metabolic features early in the disease trajectory. Future investigations need to examine the underlying mechanisms and the potential longitudinal changes following chemotherapy.

Topics: Adolescent; Adult; Blood Glucose; Body Composition; Body Mass Index; Breast Neoplasms; C-Peptide; Cholesterol, HDL; Cytokines; Diet Records; Dyslipidemias; Energy Intake; Energy Metabolism; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Middle Aged; Motor Activity; Muscle Strength; Obesity; Waist Circumference; Weight Gain; Young Adult

Diabetes mellitus is thought to be progressive. Insufficient insulin secretion in compensation for insulin resistance leads to glucose intolerance. A previously reported proband with type A insulin resistance syndrome and her younger twin brothers with and without the R1174W missense mutation in the insulin receptor gene were followed for 9 years to study the progression of glucose metabolism, insulin sensitivity, and β-cell function around puberty. Five-hour OGTT was performed in them at each visit. Areas under the curves of glucose, insulin and C-peptides, insulinogenic index, AIR, and Homa indices were assessed. Intramyocellular lipids (IMCLs) were quantified in the proband and compared to those of 12 nondiabetic subjects, 118 newly diagnosed type 2 diabetic patients. The proband maintained normal HbA1c (27-37 mmol/mol) and fasting plasma glucose (3.7-4.5 mmol/l), and her glucose tolerance ameliorated over years. The proband's Homa-IR decreased into adulthood, while her Homa-B, insulinogenic index, AIR, AUCs of insulin, and C-peptide decreased accordingly. Homa-B to Homa-IR ratios stayed significantly higher than normal. Homa-B, AUCs of insulin, and C-peptide of the twin brothers increased in response to the increment of Homa-IR as they entered middle and late puberty. The changes were more dramatic in the twin brothers carrying the mutation. IMCLs of the proband were lower than those of the nondiabetic counterparts and were disproportional for the degree of insulin resistance. Our longitudinal data of type A insulin resistance syndrome around puberty provide significant information for the study of insulin secretion in compensation for insulin resistance.

Topics: Adolescent; Adult; Amino Acid Substitution; Blood Glucose; C-Peptide; Child; Diabetes Mellitus, Type 2; Female; Follow-Up Studies; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Lipid Metabolism; Male; Puberty; Receptor, Insulin; Syndrome; Twins; Young Adult

Genome-wide association studies have revealed an association of the transcription factor ETS variant gene 5 (ETV5) with human obesity. However, its role in glucose homeostasis and energy balance is unknown.. Etv5 knockout (KO) mice were monitored weekly for body weight (BW) and food intake. Body composition was measured at 8 and 16 weeks of age. Glucose metabolism was studied, and glucose-stimulated insulin secretion was measured in vivo and in vitro.. Etv5 KO mice are smaller and leaner, and have a reduced BW and lower fat mass than their wild-type controls on a chow diet. When exposed to a high-fat diet, KO mice are resistant to diet-induced BW gain. Despite a greater insulin sensitivity, KO mice have profoundly impaired glucose tolerance associated with impaired insulin secretion. Morphometric analysis revealed smaller islets and a reduced beta cell size in the pancreatic islets of Etv5 KO mice. Knockdown of ETV5 in an insulin-secreting cell line or beta cells from human donors revealed intact mitochondrial and Ca(2+) channel activity, but reduced insulin exocytosis.. This work reveals a critical role for ETV5 in specifically regulating insulin secretion both in vitro and in vivo.

Topics: Animals; Body Composition; Body Weight; C-Peptide; Diet, High-Fat; DNA-Binding Proteins; Eating; Exocytosis; Genome-Wide Association Study; Glucose; Glucose Tolerance Test; Homeostasis; Insulin; Insulin Resistance; Insulin Secretion; Mice; Mice, Knockout; Transcription Factors

Nonalcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM) often coexist and have adverse outcomes. The aim of our study was to elucidate metabolic abnormalities in patients with DM-NAFLD versus those with T2DM alone.. Patients were divided into two groups: 26 T2DM patients with NAFLD and 26 gender-, age-, and body mass index-matched patients with T2DM alone. Patients took a 75-g oral glucose tolerance test (OGTT), which measured serum insulin and C-peptide (C-p) levels at baseline (0 min), 30 min, 60 min, and 120 min after glucose challenge.. Patients with DM-NAFLD or T2DM alone had similar blood glucose levels. β-cell hypersecretion was more obvious in patients with DM-NAFLD. In addition, fasting, early-phase, and late-phase C-peptide levels were significantly increased in patients with DM-NAFLD (ΔC-p 0-30 min, P < 0.05; Area Under the Curve (AUC) C-p/PG 30-120 min ratio, P < 0.01; and AUC C-p 30-120 min, P < 0.01). Hepatic and extrahepatic insulin resistance during the OGTT did not differ significantly between groups. Hepatic insulin sensitivity independently contributed to the early phase (0-30 min) of the OGTT in patients with T2DM and NAFLD, whereas a significant deficit in late insulin secretion independently contributed to the 30-120 min glucose status in patients with T2DM only.. In patients with similar levels of insulin resistance and hyperglycemia, DM-NAFLD was associated with higher serum insulin levels than T2DM alone. Hyperinsulinemia is caused mainly by β-cell hypersecretion. The present study demonstrates pathophysiological differences in mechanisms of insulin resistance in patients with DM-NAFLD versus T2DM alone.

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Fatty Liver; Female; Humans; Insulin; Insulin Resistance; Insulin Secretion; Liver; Male; Middle Aged; Non-alcoholic Fatty Liver Disease

Recent research has indicated a relationship between skeletal muscle mass and insulin resistance in patients with type 2 diabetes mellitus (T2DM). However, no study has examined the relationship between skeletal muscle mass and insulin secretion in patients with Japanese T2DM. This study aimed to fill this research gap by investigating the relationship between skeletal muscle mass and clinical parameters of T2DM with special reference to the effect of sex or age on the relationship. We examined 138 consecutive T2DM patients who presented at a single center. Anthropomorphic measurement was conducted and skeletal muscle mass was determined by bioelectrical impedance analysis for calculating skeletal muscle index (SMI) as the ratio of appendicular muscle mass (AMM) to total body weight. Fasting plasma glucose (FPG) and glycosylated hemoglobin (HbA1c) were levels, and values of stimulated C-peptide immunoreactivity (CPR) were determined by glucagon stimulation testing. Statistical analysis showed that AMM was negatively correlated with age in T2DM patients, whereas SMI had no correlation with either FPG or HbA1c levels. On the other hand, SMI was found to be negatively correlated with the log-transformed stimulated CPR values in male patients <65 years (r = -0.40, p < 0.05) and in female patients <65 years (r = -0.40, p < 0.05). The results of multivariate analysis suggest a strong association between the log-transformed stimulated CPR value and SMI. These findings indicate that increased endogenous insulin secretion is associated with lower skeletal muscle mass in T2DM patients who are <65 years of age.

Topics: Adult; Aged; Asian People; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Insulin Secretion; Male; Middle Aged; Muscle, Skeletal

Role of impaired suppression of glucagon secretion in the pathogenesis of pancreatic cancer-associated diabetes has been suggested. We examined the correlation between glucagon/insulin ratio (G/I) after glucose challenge and hemoglobin A1C (A1C) in subjects with and without pancreatic cancer. Data were gathered from a preoperative screening 75-g oral glucose tolerance test in patients who would eventually undergo pancreatic resection. A multiple linear regression analysis was conducted using the following covariates: age, body mass index, hemoglobin, glucose and insulin levels at the corresponding time points, indices of insulin resistance, duration of diabetes, insulinogenic index, and use of glucose-lowering drugs. In subject group with pancreatic cancer (n = 45), but not in subject group without pancreatic cancer (n = 101), participants with A1C ≥ 6.5 % had significantly higher glucagon levels, lower insulin levels, and higher G/I ratios after the glucose challenge than those of the subjects with A1C <5.7 %. In the multiple linear regression analysis, there was an independent correlation between post-challenge G/I ratio and A1C in both groups. Some of the patients without pancreatic cancer had inappropriately elevated G/I ratios despite A1C <6.5 %. These patients were characterized by lower insulinogenic indices (p = 0.004) and less insulin resistance (p = 0.008). In conclusion, post-challenge G/I ratio independently correlated with A1C in patients with pancreatic cancer. Although significant, the degree of correlation was weakened in the subjects without pancreatic cancer because some had lower insulin secretory reserve compensated by less insulin resistance, resulting in inappropriately elevated G/I ratios relative to A1C.

Topics: Aged; Blood Glucose; C-Peptide; Female; Glucagon; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Pancreas; Pancreatic Neoplasms; Preoperative Period

We aimed to evaluate disproportional proinsulinemia in the pre-diabetic state by analyzing the cross-sectional differences between proinsulin (PI) ratios across the entire range of fasting and 2-h plasma glucose. The study sample was 1,016 participants in the insulin resistance atherosclerosis study, who had no previous diagnosis of diabetes. Insulin sensitivity index (SI) and acute insulin response (AIR) were measured by the frequently sampled intravenous glucose tolerance test. Fasting intact and split PI-to-insulin ratios (PI/I, SPI/I), intact and split PI-to-C-peptide ratios (PI/C-pep, SPI/C-pep), and SI-adjusted AIR were assessed as a function of fasting and 2-h glucose levels. SI-adjusted AIR was decreased (fasting glucose 96-98 mg/dl; 2-h glucose 120-131 mg/dl) and SPI/C-pep increased at modestly elevated fasting glucose and 2-h glucose within the normal glucose tolerance range (fasting glucose 96-98 mg/dl; 2-h glucose 132-142 mg/dl). PI/I was not increased until plasma glucose values were in the diabetic range of fasting glucose (>126 mg/dl) or the impaired glucose tolerance range of 2-h glucose (143-156 mg/dl). SPI/I and PI/C-pep as a function of fasting and 2-h glucose were situated between the curves for SPI/C-pep and PI/I. In conclusion, inappropriate amounts of PI and conversion intermediaries are demonstrated at modestly elevated glucose levels within the normoglycemic range. Ratios that use SPI in the numerator or C-pep in the denominator (and especially SPI/C-pep) are more sensitive to early glycemic excursions than PI/I. Disordered processing of PI may accompany derangements in early insulin secretory response.

Topics: Adult; Aged; Blood Glucose; C-Peptide; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Fasting; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Prediabetic State; Proinsulin

Previously we reported studies of XMetA, an agonist antibody to the insulin receptor (INSR). We have now utilized phage display to identify XMetS, a novel monoclonal antibody to the INSR. Biophysical studies demonstrated that XMetS bound to the human and mouse INSR with picomolar affinity. Unlike monoclonal antibody XMetA, XMetS alone had little or no agonist effect on the INSR. However, XMetS was a strong positive allosteric modulator of the INSR that increased the binding affinity for insulin nearly 20-fold. XMetS potentiated insulin-stimulated INSR signaling ∼15-fold or greater including; autophosphorylation of the INSR, phosphorylation of Akt, a major enzyme in the metabolic pathway, and phosphorylation of Erk, a major enzyme in the growth pathway. The enhanced signaling effects of XMetS were more pronounced with Akt than with Erk. In cultured cells, XMetS also enhanced insulin-stimulated glucose transport. In contrast to its effects on the INSR, XMetS did not potentiate IGF-1 activation of the IGF-1 receptor. We studied the effect of XMetS treatment in two mouse models of insulin resistance and diabetes. The first was the diet induced obesity mouse, a hyperinsulinemic, insulin resistant animal, and the second was the multi-low dose streptozotocin/high-fat diet mouse, an insulinopenic, insulin resistant animal. In both models, XMetS normalized fasting blood glucose levels and glucose tolerance. In concert with its ability to potentiate insulin action at the INSR, XMetS reduced insulin and C-peptide levels in both mouse models. XMetS improved the response to exogenous insulin without causing hypoglycemia. These data indicate that an allosteric monoclonal antibody can be generated that markedly enhances the binding affinity of insulin to the INSR. These data also suggest that an INSR monoclonal antibody with these characteristics may have the potential to both improve glucose metabolism in insulinopenic type 2 diabetes mellitus and correct compensatory hyperinsulinism in insulin resistant conditions.

Topics: Allosteric Site; Animals; Antibodies, Monoclonal; Antigens, CD; C-Peptide; Cell Separation; CHO Cells; Cricetinae; Cricetulus; Diabetes Mellitus, Type 2; Flow Cytometry; Glucose; Humans; Hyperglycemia; Hyperinsulinism; Insulin; Insulin Resistance; Mice; Mice, Inbred C57BL; Obesity; Peptide Library; Phosphorylation; Protein Structure, Tertiary; Receptor, Insulin; Signal Transduction

Insulin-sensitizer treatment with metformin is common in polycystic ovary syndrome (PCOS). OCT alleles were investigated in PCOS patients to identify genetic 'bad responders' and 'nonresponders' to metformin including their possible effects on glucose metabolism without treatment. We genotyped eight SNPs in OCT1, OCT2 and ATM genes in 676 women with PCOS and 90 control women, we also measured oral glucose tolerance tests prior to treatment. Nonfunctional alleles were present in 29.8% and low-functional alleles in 57.9% of our PCOS cohort. OCT variants were significantly associated with elevated baseline and glucose-induced C-peptide levels in PCOS. Metformin bad responders or nonresponders based on OCT genotypes might be relevant in clinical practice - their modulation of metformin pharmacokinetics and pharmacodynamics and metformin-independent glucose effects remain to be elucidated.

Topics: Adult; Ataxia Telangiectasia Mutated Proteins; C-Peptide; Drug Resistance; Female; Genetic Association Studies; Glucose; Glucose Tolerance Test; Humans; Insulin Resistance; Metformin; Organic Cation Transport Proteins; Organic Cation Transporter 1; Organic Cation Transporter 2; Polycystic Ovary Syndrome; Polymorphism, Single Nucleotide

This study aims to investigate if the benefits on glycemic control following Roux-en-Y gastric bypass (RYGB) in morbidly obese type 2 diabetes (T2DM) patients are maintained in the 30-35 kg/m(2) BMI (body mass index) range, comparing results with those in literature.. The study participants were twenty T2DM patients aging 35-70 years, BMI 30.0-34.9 kg/m(2), minimum diabetes duration 3 years, glycosylated haemoglobin (HbA1c) ≥7.5% despite good clinical practice medical therapy, submitted to laparoscopic RYGB, and monitored during 36 months. Twenty-seven matched diabetic patients as controls.. Five females, mean age 57 (42-69) years, weight 96.0 (70-111) kg, BMI 32.9 (30.3-34.9) kg/m(2), waist circumference 112 (100-128) cm, diabetes duration 14 (3-28) years, HbA1c 9.5 (7.5-14.2) %, and C-peptide 3.2 (1,6-9.1) mcg/l. Ten patients were on insulin. There was no mortality, and there were two major late complications. BMI and waist decreased stabilizing around 25 kg/m(2) and 92 cm. Fasting serum glucose and HbA1c reached values around 150 mg/dl and 7%, which subsequently maintained. There was remission in 25% of cases, control 45%, and all the others improved. HOMA-IR and insulin sensitivity index normalized at 1 month, then maintained. AIR and insulinogenic index showed no postoperative changes. Diabetes remission correlated negatively with duration (p < 0.05; r (2) = 0.61), while control positively with C-peptide (p < 0.05; r (2) = 0.19). In the control group, FSG, HbA1c, serum triglyceride, and cholesterol significantly decreased with considerable progressive increase of antidiabetic/antihyperlipemic therapy. All patients had HbA1c >7% at 2-3 years.. Glycemic control obtained by RYGB in this study was less good than that reported by others, apparently due to different patient selection criteria. Our results do not support RYGB weight loss-independent effect on beta-cell function in the T2DM patients with BMI 30-35 kg/m(2).

Topics: Adult; Aged; Blood Glucose; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Female; Gastric Bypass; Glycated Hemoglobin; Humans; Insulin Resistance; Laparoscopy; Male; Middle Aged; Obesity; Patient Selection; Remission Induction; Treatment Outcome; Waist Circumference; Weight Loss

This study was designed to evaluate the impact of fructose-rich diet and chronic kidney disease (CKD) on the in vitro function of pancreatic islets.. Fifty-four rats were divided into 3 equal groups as follows: control, rats with CKD 1/2 that underwent surgical uninephrectomy, and rats with CKD 5/6 that underwent uninephrectomy and kidney cortex mass resection. Each group was further assigned to 3 diet protocols--regular diet, regular diet with 10% fructose (F10), and 60% fructose-rich diet (F60). After 8 weeks of insulin administration, C-peptide, glycated hemoglobin level, serum urea nitrogen, creatinine clearance, and homeostasis model assessment of insulin resistance were evaluated. Static glucose insulin stimulation test of isolated pancreatic islets and histologic analysis of pancreatic tissue were performed.. The F10 diet increased the levels of insulin and C-peptide in all groups. Homeostasis model assessment of insulin resistance was increased in all animals fed with fructose. The elevated levels of creatinine and diminished creatinine clearance were detected in CKD 5/6 rats fed with 60% fructose-rich diet. The F10 diet resulted in high levels of serum insulin and C-peptide and glucose-stimulated insulin secretion. Fructose-rich diet increased the islet size and number, with irregular morphology and exocrine tissue fibrosis.. The fructose-rich diet accelerates the progression of CKD and affects the pancreatic islet function.

Topics: Animals; Body Weight; C-Peptide; Creatinine; Dietary Carbohydrates; Fructose; Glucose; Hypoglycemic Agents; In Vitro Techniques; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Kidney Failure, Chronic; Male; Rats, Wistar

Diabetic ketosis had been identified as a characteristic of type 1 diabetes mellitus (T1DM), but now emerging evidence has identified that they were diagnosed as T2DM after long time follow up. This case control study was aimed at comparing the clinical characteristic, β-cell function, and insulin resistance of ketosis and nonketotic onset T2DM and providing evidence for treatment selection. 140 cases of newly diagnosed T2DM patients were divided into ketosis (62 cases) and nonketotic onset group (78 cases). After correction of hyperglycemia and ketosis with insulin therapy, plasma C-peptide concentrations were measured at 0, 0.5, 1, 2, and 3 hours after 75 g glucose oral administration. Area under the curve (AUC) of C-peptide was calculated. Homoeostasis model assessment was used to estimate basal β-cell function (HOMA-β) and insulin resistance (HOMA-IR). Our results showed that ketosis onset group had higher prevalence of nonalcoholic fatty liver disease (NAFLD) than nonketotic group (P = 0.04). Ketosis onset group had increased plasma C-peptide levels at 0 h, 0.5 h, and 3 h and higher AUC(0-0.5), AUC₀₋₁, AUC₀₋₃ (P < 0.05). Moreover, this group also had higher HOMA-β and HOMA-IR than nonketotic group (P < 0.05). From these data, we concluded that ketosis onset T2DM had better islet β-cell function and more serious insulin resistance than nonketotic onset T2DM.

Topics: Adolescent; Adult; Aged; C-Peptide; Case-Control Studies; China; Diabetes Mellitus, Type 2; Diabetic Ketoacidosis; Fatty Liver; Female; Humans; Hyperglycemia; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Ketone Bodies; Male; Middle Aged; Non-alcoholic Fatty Liver Disease; Prevalence; Retrospective Studies; Young Adult

To investigate the clinical characteristics, metabolic status, insulin resistance and insulin secretory function of diabetic patients with early onset.. The study was undertaken in the West China Hospital of Sichuan University. Characteristics of 342 admitted diabetic patients with early onset (EOD group, diagnosed at age 15-45 years old) were reviewed and compared with 296 admitted patients with late onset (LOD group, diagnosed at age >45 years old). All of the participants had negative islet autoantibodies. Homeostasis model assessment 2 of insulin resistant (HOMA2-IR) and HOMA2 of insulin sencitivity (HOMA2-% S) were measured to estimate insulin resistance and insulin sensitivity. HOMA2 of beta-cell function (HOMA2-% beta) index was used to estimate beta-cell secretory function. We also compared clinical characteristics and metabolic status between the two groups.. EOD patients were more likely to have ketosis, ketoacidosis, insulin therapy and positive diabetic family history than LOD patients (P < 0.05). Levels of systolic blood pressure (SBP), diastolic blood pressure (DBP), body mass index (BMI), waist-to-hip ratio (WHR), fasting and postprandial insulin (Fins, PIns), fasting and postprandial plasma C-peptide (FCP, PCP) were significantly lower, and glycosylated hemoglobin A1c (HbA1), triglycerides (TG), fasting and postprandial blood glucose (FPG, PPG) were significantly higher in EOD patients than in LOD patients (P < 0.05). EOD patients had lower prevalence of hypertension, central obesity, hyperuricemia, metabolic syndrome (MS) and co-exist of three or more metabolic disorders than LOD patients (P < 0.05). EOD patients had decreased levels of HOMA2-% beta, deltaI30/deltaG30 and HOMA2-IR, increased HOMA2-%S, and increased proportions with FCP < 0.2 nmol/L and FIns < 2.9 microU/mL compared with LOD patient (P < 0.05). Linear regression analyses showed that HOMA2-%beta, deltaI30/deltaG30, positive diabetic family history were independent risk factors predicting early onset of diabetes.. Early onset diabetic patients are characterized with low prevalence of metabolic disorders, insulin resistance and severe insulin secretion dysfunction. Loss of beta-cell function may play a major role in the development of early onset diabetes in this population.

Topics: Adolescent; Adult; Blood Glucose; Body Mass Index; C-Peptide; China; Diabetes Mellitus, Type 2; Glycated Hemoglobin; Humans; Hypertension; Insulin; Insulin Resistance; Metabolic Syndrome; Middle Aged; Obesity, Abdominal; Prevalence; Risk Factors; Triglycerides; Waist-Hip Ratio; Young Adult

We examined whether waist circumference (WC) and waist-to-hip ratio (WHR) after breast cancer diagnosis are associated with all-cause or breast cancer-specific mortality and explored potential biological pathways mediating these relationships. Our analysis included 621 women diagnosed with local or regional breast cancer who participated in the Health, Eating, Activity, and Lifestyle study. At 30 (±4) months postdiagnosis, trained staff measured participants' waist and hip circumferences and obtained fasting serum samples for biomarker assays for assays of insulin, glucose, C-peptide, insulin growth factor-1 and binding protein-3, C-reactive protein (CRP), and adiponectin. We estimated multivariate hazard ratios (HR) and 95 % confidence intervals (CI) for death over ~9.5 years of follow-up. After adjustment for measured body mass index, treatment, comorbidities, race/ethnicity, diet quality, and postdiagnosis physical activity, WC was positively associated with all-cause mortality (HRq4:q1: 2.99, 95 % CI 1.14, 7.86) but its positive association with breast cancer-specific mortality was not statistically significant (HRq4:q1: 2.69, 95 % CI 0.69, 12.01). WHR was positively associated with all-cause mortality (HRq4:q1: 2.10, 95 % CI 1.08, 4.05) and breast cancer-specific mortality (HRq4:q1: 4.02, 95 % CI 1.31, 12.31). After adjustment for homeostatic model assessment (HOMA) score and C-reactive protein, risk estimates were attenuated and not statistically significant. In this diverse breast cancer survivor cohort, postdiagnosis WC and WHR were associated with all-cause mortality. Insulin resistance and inflammation may mediate the effects of central adiposity on mortality among breast cancer patients.

Topics: Adiponectin; Adiposity; Aged; Blood Glucose; Breast Neoplasms; C-Peptide; Feeding Behavior; Female; Humans; Insulin; Insulin Resistance; Middle Aged; Motor Activity; Obesity, Abdominal; Waist Circumference; Waist-Hip Ratio

Controlling meal-related glucose excursions continues to be a therapeutic challenge in diabetes mellitus. Mechanistic reasons for this need to be understood better to develop appropriate therapies. To investigate delayed gastric emptying effects on postprandial glucose turnover, insulin sensitivity, and β-cell responsivity and function, as a feasibility study prior to studying patients with type 1 diabetes, we used the triple tracer technique C-peptide and oral minimal model approach in healthy subjects. A single dose of 30 μg of pramlintide administered at the start of a mixed meal was used to delay gastric emptying rates. With delayed gastric emptying rates, peak rate of meal glucose appearance was delayed, and rate of endogenous glucose production (EGP) was lower. C-peptide and oral minimal models enabled the assessments of β-cell function, insulin sensitivity, and β-cell responsivity simultaneously. Delayed gastric emptying induced by pramlintide improved total insulin sensitivity and decreased total β-cell responsivity. However, β-cell function as measured by total disposition index did not change. The improved whole body insulin sensitivity coupled with lower rate of appearance of EGP with delayed gastric emptying provides experimental proof of the importance of evaluating pramlintide in artificial endocrine pancreas approaches to reduce postprandial blood glucose variability in patients with type 1 diabetes.

Topics: Adolescent; Adult; Algorithms; Blood Glucose; C-Peptide; Female; Food; Gastric Emptying; Glucagon; Glucose; Humans; Hyperglycemia; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin-Secreting Cells; Islet Amyloid Polypeptide; Kinetics; Male; Middle Aged; Young Adult

Highly prevalent maternal psychosocial complaints are accompanied by increases in glucocorticoid stress hormones, which may predispose the offspring for type 2 diabetes and cardiovascular disease later in adulthood. The aim of the current research is to study whether prenatal maternal psychosocial stress is associated with parameters of blood glucose metabolism in their children aged 5-6 years. The study design was a prospective birth cohort (the Amsterdam Born Children and their Development study, the Netherlands). Depressive symptoms, pregnancy-related anxiety, parenting daily hassles and job strain were recorded by questionnaire (gestational week 16). A cumulative score was also calculated. Possible sex differences in the associations were considered. The subjects were 1952 mother-child pairs. Outcome measures were fasting glucose (n=1952), C-peptide and insulin resistance (HOMA2-IR) (n=1478) in the children at the age of 5-6 years. The stress scales, single and cumulative, were not associated with glucose/C-peptide/insulin resistance (all P>0.05). We did not find evidence for sex differences. In conclusion, we did not find evidence for an association between psychosocial stress during early pregnancy and parameters of glucose metabolism in offspring at the age of 5-6 years. Differences emerging later in life or in response to a metabolic challenge should not be ruled out.

Topics: Adult; Blood Glucose; C-Peptide; Child; Child, Preschool; Fasting; Female; Gestational Age; Humans; Insulin Resistance; Male; Netherlands; Pregnancy; Pregnancy Complications; Prenatal Exposure Delayed Effects; Prospective Studies; Stress, Psychological

There is a paucity of literature describing metabolic and histological data in adult-onset autoimmune diabetes. This subgroup of diabetes mellitus affects at least 5% of clinically diagnosed type 2 diabetic patients (T2DM) and it is termed Latent Autoimmune Diabetes in Adults (LADA). We evaluated indexes of insulin secretion, metabolic assessment, and pancreatic pathology in clinically diagnosed T2DM patients with and without the presence of humoral islet autoimmunity (Ab). A total of 18 patients with at least 5-year duration of clinically diagnosed T2DM were evaluated in this study. In those subjects we assessed acute insulin responses to arginine, a glucose clamp study, whole-body fat mass and fat-free mass. We have also analyzed the pancreatic pathology of 15 T2DM and 43 control cadaveric donors, using pancreatic tissue obtained from all the T2DM organ donors available from the nPOD network through December 31, 2013. The presence of islet Ab correlated with severely impaired β-cell function as demonstrated by remarkably low acute insulin response to arginine (AIR) when compared to that of the Ab negative group. Glucose clamp studies indicated that both Ab positive and Ab negative patients exhibited peripheral insulin resistance in a similar fashion. Pathology data from T2DM donors with Ab or the autoimmune diabetes associated DR3/DR4 allelic class II combination showed reduction in beta cell mass as well as presence of autoimmune-associated pattern A pathology in subjects with either islet autoantibodies or the DR3/DR4 genotype. In conclusion, we provide compelling evidence indicating that islet Ab positive long-term T2DM patients exhibit profound impairment of insulin secretion as well as reduced beta cell mass seemingly determined by an immune-mediated injury of pancreatic β-cells. Deciphering the mechanisms underlying beta cell destruction in this subset of diabetic patients may lead to the development of novel immunologic therapies aimed at halting the disease progression in its early stage.

Topics: Adult; Aged; Alleles; Autoantibodies; Autoimmunity; Biomarkers; Blood Glucose; Body Composition; C-Peptide; Cell Size; Diabetes Mellitus, Type 2; Female; HLA-DR Antigens; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Middle Aged; Tissue Donors

The clinical implications of prediabetes for development of type 2 diabetes may differ for Asian ethnicity. We investigated various indices derived from a 2-h oral glucose tolerance test (OGTT) in people with prediabetes to predict their future risk of diabetes.. We recruited 406 consecutive subjects with prediabetes from 2005 to 2006 and followed them up every 3-6 months for up to 9 years. Prediabetes was defined as isolated impaired fasting glucose (IFG), isolated impaired glucose tolerance (IGT), combined glucose intolerance (CGI), or isolated elevated HbA1c (5.7-6.4%, 39-46 mmol/mol) without IFG or IGT. The rate of diabetes conversion was compared between prediabetes categories. The association of glycemic indices with development of diabetes was also investigated.. Eighty-one patients were diagnosed with diabetes during the 9-year follow-up (median 46.0 months). The rate of diabetes conversion was higher in subjects with CGI (31.9%), or isolated IGT (18.5%) than in those with isolated IFG (15.2%) or isolated elevated HbA1c (10.9%). Surrogate markers reflecting β-cell dysfunction were more closely associated with diabetes conversion than insulin resistance indices. Subjects with a 30-min postload glucose ≥ 165 mg/dL and a 30-min C-peptide < 5 ng/mL had 8.83 times greater risk (95% confidence interval 2.98-26.16) of developing diabetes than other prediabetic subjects.. In Asians, at least Koreans, β-cell dysfunction seems to be the major determinant for diabetes conversion. A combination of high glucose and low C-peptide levels at 30 min after OGTT may be a good predictor for diabetes conversion in this population.

Topics: Adult; Aged; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Disease Progression; Female; Follow-Up Studies; Glucose Intolerance; Glucose Tolerance Test; Health Status Indicators; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Prediabetic State; Risk

To validate the partial remission (PR) definition based on insulin dose-adjusted HbA1c (IDAA1c).. The IDAA1c was developed using data in 251 children from the European Hvidoere cohort. For validation, 129 children from a Danish cohort were followed from the onset of type 1 diabetes (T1D). Receiver operating characteristic curve (ROC) analysis was used to evaluate the predictive value of IDAA1c and age on partial C-peptide remission (stimulated C-peptide, SCP > 300 pmol/L).. PR (IDAA1c ≤ 9) in the Danish and Hvidoere cohorts occurred in 62 vs. 61% (3 months, p = 0.80), 47 vs. 44% (6 months, p = 0.57), 26 vs. 32% (9 months, p = 0.32) and 19 vs. 18% (12 months, p = 0.69). The effect of age on SCP was significantly higher in the Danish cohort compared with the Hvidoere cohort (p < 0.0001), likely due to higher attained Boost SCP, so the sensitivity and specificity of those in PR by IDAA1c ≤ 9, SCP > 300 pmol/L was 0.85 and 0.62 at 6 months and 0.62 vs. 0.38 at 12 months, respectively. IDAA1c with age significantly improved the ROC analyses and the AUC reached 0.89 ± 0.04 (age) vs. 0.94 ± 0.02 (age + IDAA1c) at 6 months (p < 0.0004) and 0.76 ± 0.04 (age) vs. 0.90 ± 0.03 (age + IDAA1c) at 12 months (p < 0.0001).. The diagnostic and prognostic power of the IDAA1c measure is kept but due to the higher Boost stimulation in the Danish cohort, the specificity of the formula is lower with the chosen limits for SCP (300 pmol/L) and IDAA1c ≤9, respectively.

Topics: Adolescent; Age Factors; C-Peptide; Child; Child, Preschool; Cohort Studies; Denmark; Diabetes Mellitus, Type 1; Diagnosis, Differential; Female; Glycated Hemoglobin; Humans; Hyperglycemia; Hypoglycemic Agents; Infant; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Prediabetic State; Remission Induction; Sensitivity and Specificity

Significant increase of the elderly in the demographic structure of a modern society is one of the main reasons for increase in the number of patients with diabetes type 2 and impaired glucose tolerance. The purpose of this research was to study impact of Pancragen (tetrapeptide Lys-Glu-Asp-Trp) on endocrine function of the pancreas of non-human primates, female rhesus monkeys, and to elucidate the possibil- ity of its use for correction age-related dysfunction of pancreatic islet apparatus. In old animals after the glucose administration (standard dose) in control period, a reduced glucose "disappearance" rate and a higher values of insulin and C-peptide peaks (5 and 15 min after the glucose injection) were observed in comparison with young animals in similar experiments. Pancragen administration (50 μg/animal per day during 10 days, intramuscularly) to old monkeys caused markedly increased the glucose "disappear- ance" rate, normalized the plasma insulin and C-peptide dynamics in response to glucose administration. The recovering effect of Pancragen on the function of the pancreas partially remained 3 weeks after discontinuation of the drug. Thus, Pancragen is a promising factor for restoring the age-related endocrine dysfunction of primates.

Topics: Aging; Animals; Blood Glucose; C-Peptide; Female; Glucose; Glucose Tolerance Test; Injections, Intramuscular; Insulin; Insulin Resistance; Islets of Langerhans; Kinetics; Macaca mulatta; Oligopeptides

Obesity is widely acknowledged as a critical risk factor for metabolic complications. Among obese subjects, there is a phenotype of metabolically healthy but obese (MHO) individuals that shows a favorable cardiometabolic risk profile. We aimed to evaluate the potential mechanisms underlying the metabolic profile of this subset, including alpha and beta cell function and entero-insular axis.. One hundred twenty-nine obese and 24 nonobese subjects were studied. Obese participants were defined as MHO or at-risk obese, according to the homeostasis model of assessment-insulin resistance (HOMA-IR) index (MHO: lower tertile of HOMA-IR, n = 43; at-risk: upper tertile of HOMA-IR index, n = 41). Insulin, glucagon, and incretin responses after a 120' oral glucose tolerance test (75-g OGTT) were investigated.. During OGTT, MHO individuals showed in comparison with at-risk subjects: lower fasting and afterloads plasma levels of glucose, insulin, and C-peptide; higher disposition index; lower fasting (P = 0.004) and at 30' (P = 0.01) plasma glucose-dependent insulinotropic polypeptide (GIP) levels; lower area under the curve (AUC) (0-30) for GIP (P = 0.008); higher glucagon-like peptide-1 (GLP-1) plasma levels at 90' (P = 0.02) and 120' (P = 0.02); lower glucagon plasma levels at baseline (P = 0.04) and at 30' (P = 0.03); and appropriate glucagon suppression after the oral glucose load.. MHO subjects show, as well as normal-weight individuals, a lower diabetogenic profile by virtue of higher disposition index and unaffected entero-insular axis. At-risk obese individuals present increased GIP levels that might play a role in determining increased glucagon secretion and inappropriate glucagon responses after glucose load, thus contributing to impaired glucose homeostasis.

Topics: Adult; Area Under Curve; Blood Glucose; C-Peptide; Fasting; Female; Gastric Inhibitory Polypeptide; Glucagon; Glucagon-Like Peptide 1; Glucagon-Secreting Cells; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Obesity

We investigated postprandial glucagon-like peptide-1 (GLP-1) responses in pregnant women with and without gestational diabetes mellitus (GDM) and again following delivery when normal glucose tolerance (NGT) was re-established.. Eleven women with GDM [plasma glucose (PG) concentration at 120 min after a 75-g oral glucose tolerance test (OGTT): 10.0 ± 0.9 mM (mean ± SD); age: 31 ± 6 years; body mass index (BMI): 31.6 ± 6.4 kg/m(2) ; haemoglobin A1c (HbA1c): 5.6 ± 0.5%] and eight pregnant women with NGT (PG(120 min), OGTT : 5.7 ± 0.7 mM; age: 28 ± 3 years; BMI: 29.7 ± 5.4 kg/m(2) ; HbA1c: 5.4 ± 0.3%) were investigated with a 4-h liquid meal test during third trimester (TT) and 3-4 months postpartum (PP). All patients with GDM re-established NGT following delivery.. Pregnancy was associated with low postprandial GLP-1 responses. Patients with GDM exhibited reduced postprandial GLP-1 responses compared to their PP levels [area under curve (AUC): 5.5 ± 1.3 vs. 8.4 ± 3.2 nM × min, p=0.005], but the difference among NGT women (7.3 ± 2.8 vs. 8.8 ± 2.0 nM × min, p=0.066) was not statistically significant. Pregnancy did not influence postprandial responses of the other incretin hormone glucose-dependent insulinotropic polypeptide (GIP) in any of the groups, but GDM patients were characterized by greater postprandial GIP responses during both TT and PP compared to NGT subjects.. Pregnancy is associated with reduced postprandial GLP-1 responses (most pronounced in patients with GDM) that normalize after delivery. In contrast, postprandial GIP responses seem unaffected by pregnancy but is increased in GDM patients.

Topics: Adult; Area Under Curve; Biomarkers; Blood Glucose; Body Mass Index; C-Peptide; Diabetes, Gestational; Female; Gastric Emptying; Gastric Inhibitory Polypeptide; Glucagon; Glucagon-Like Peptide 1; Glucose Tolerance Test; Glycated Hemoglobin; Homeostasis; Humans; Insulin; Insulin Resistance; Insulin Secretion; Postpartum Period; Postprandial Period; Pregnancy

Ectopic fat accumulation in liver and skeletal muscle may be an essential link between abdominal obesity, insulin resistance and increased risk of cardiovascular disease after menopause. We hypothesized that a diet containing a relatively high content of protein and unsaturated fat [mainly monounsaturated fatty acids (MUFAs)] but limited carbohydrates and saturated fat would reduce lipid content in liver and muscle and increase insulin sensitivity in postmenopausal women.. Ten healthy, nonsmoking postmenopausal women with a body mass index (BMI) >27 (28-35) kg m(-2) were included in the study.. Participants were instructed to consume an ad libitum Palaeolithic-type diet intended to provide approximately 30 energy percentage (E%) protein, 40 E% fat (mainly MUFAs) and 30 E% carbohydrate. Intramyocellular lipid (IMCL) levels in calf muscles and liver triglyceride levels were quantified using proton magnetic resonance spectroscopy ((1) H-MRS) before and 5 weeks after dietary intervention. Insulin sensitivity was estimated by homoeostasis model assessment (HOMA) indices and the euglycaemic hyperinsulinaemic clamp technique.. Mean energy intake decreased by 25% with a weight loss of 4.5 kg. BMI, waist and hip circumference, waist/hip ratio and abdominal sagittal diameter also decreased significantly, as did diastolic blood pressure (mean -7 mmHg), levels of fasting serum glucose, cholesterol, triglycerides, LDL/HDL cholesterol, apolipoprotein B (ApoB) and apolipoprotein A1 (ApoA1), urinary C-peptide and HOMA indices. Whole-body insulin sensitivity did not change. Liver triglyceride levels decreased by 49%, whereas IMCL levels in skeletal muscle were not significantly altered.. A modified Palaeolithic-type diet has strong and tissue-specific effects on ectopic lipid deposition in postmenopausal women.

Topics: Adipose Tissue; Apolipoproteins A; Apolipoproteins B; Biomarkers; Blood Glucose; Blood Pressure; Body Mass Index; C-Peptide; Cholesterol, HDL; Cholesterol, LDL; Diet; Dietary Carbohydrates; Dietary Fats; Dietary Proteins; Fatty Acids, Monounsaturated; Fatty Liver; Female; Follow-Up Studies; Glucose Clamp Technique; Humans; Insulin Resistance; Magnetic Resonance Spectroscopy; Middle Aged; Motor Activity; Muscle, Skeletal; Obesity, Abdominal; Postmenopause; Retrospective Studies; Triglycerides; Waist Circumference; Weight Loss

An overactive renin-angiotensin system (RAS) is known to contribute to type 2 diabetes mellitus (T2DM). Although ACE2 overexpression has been shown to be protective against the overactive RAS, a role for pancreatic ACE2, particularly in the islets of Langerhans, in regulating glycemia in response to elevated angiotensin II (Ang II) levels remains to be elucidated. This study examined the role of endogenous pancreatic ACE2 and the impact of elevated Ang II levels on the enzyme's ability to alleviate hyperglycemia in an Ang II infusion mouse model. Male C57bl/6J mice were infused with Ang II or saline for a period of 14 days. On the 7th day of infusion, either an adenovirus encoding human ACE2 (Ad-hACE2) or a control adenovirus (Ad-eGFP) was injected into the mouse pancreas. After an additional 7-8 days, glycemia and plasma insulin levels as well as RAS components expression and oxidative stress were assessed. Ang II-infused mice exhibited hyperglycemia, hyperinsulinemia, and impaired glucose-stimulated insulin secretion from pancreatic islets compared with control mice. This phenotype was associated with decreased ACE2 expression and activity, increased Ang II type 1 receptor (AT1R) expression, and increased oxidative stress in the mouse pancreas. Ad-hACE2 treatment restored pancreatic ACE2 expression and compensatory activity against Ang II-mediated impaired glycemia, thus improving β-cell function. Our data suggest that decreased pancreatic ACE2 is a link between overactive RAS and impaired glycemia in T2DM. Moreover, maintenance of a normal endogenous ACE2 compensatory activity in the pancreas appears critical to avoid β-cell dysfunction, supporting a therapeutic potential for ACE2 in controlling diabetes resulting from an overactive RAS.

Topics: Adaptor Proteins, Signal Transducing; Adenoviridae; Angiotensin II; Angiotensin-Converting Enzyme 2; Animals; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Genetic Therapy; Humans; Hyperglycemia; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Mice; Mice, Inbred C57BL; Peptidyl-Dipeptidase A; Renin-Angiotensin System; Vasoconstrictor Agents

Alloxan generates hydrogen peroxide in the body, and a small amount of alloxan administered to acatalasemic mice results in diabetes. D-α-Tocopherol (vitamin E) is an antioxidant which helps prevent excess oxidation in the body. In this study, we examined the effect of vitamin E on diabetes caused by alloxan administration in mice.. Mice were maintained on a vitamin E-deprived diet and supplemented diet, respectively, for 14 weeks. Alloxan was then intraperitoneally administered, and blood glucose, glucose tolerance and the insulin level in mouse blood were examined.. Hyperglycemia was observed in the mice maintained on the vitamin E-deprived diet. The incidence of hyperglycemia in the mice maintained on the vitamin E-deprived diet was significantly higher than that in the mice maintained on the supplemented diet. The abnormal glucose metabolism caused by alloxan administration was ameliorated by the vitamin E-supplemented diet.. It is deduced that vitamin E can prevent a decrease of insulin concentration in the blood in this mouse model.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Administration, Oral; Alloxan; alpha-Tocopherol; Animals; Antioxidants; Biomarkers; Blood Glucose; C-Peptide; Catalase; Deoxyguanosine; Diabetes Mellitus, Experimental; Glucose Tolerance Test; Hyperglycemia; Insulin; Insulin Resistance; Male; Mice; Mice, Inbred C3H; Oxidative Stress; Pancreas

Obesity is linked to both increased metabolic disturbances and increased adipose tissue macrophage infiltration. However, whether macrophage infiltration directly influences human metabolism is unclear. The aim of this study was to investigate if there are obesity-independent links between adipose tissue macrophages and metabolic disturbances.. Expression of macrophage markers in adipose tissue was analyzed by DNA microarrays in the SOS Sib Pair study and in patients with type 2 diabetes and a BMI-matched healthy control group.. The expression of macrophage markers in adipose tissue was increased in obesity and associated with several metabolic and anthropometric measurements. After adjustment for BMI, the expression remained associated with insulin sensitivity, serum levels of insulin, C-peptide, high density lipoprotein cholesterol (HDL-cholesterol) and triglycerides. In addition, the expression of most macrophage markers was significantly increased in patients with type 2 diabetes compared to the control group.. Our study shows that infiltration of macrophages in human adipose tissue, estimated by the expression of macrophage markers, is increased in subjects with obesity and diabetes and associated with insulin sensitivity and serum lipid levels independent of BMI. This indicates that adipose tissue macrophages may contribute to the development of insulin resistance and dyslipidemia.

Topics: Adipose Tissue; Body Mass Index; C-Peptide; Case-Control Studies; Cholesterol, HDL; Diabetes Mellitus, Type 2; Female; Gene Expression; Genetic Markers; Humans; Insulin; Insulin Resistance; Macrophages; Male; Obesity; Oligonucleotide Array Sequence Analysis; Triglycerides

To evaluate the association between glucagon-like peptide 1 (GLP-1) secretion and the long-term (>2 years) outcome of type 2 diabetes mellitus (T2DM) after Roux-en-Y gastric bypass (RYGBP).. Cross-sectional study in 18 T2DM morbidly obese subjects who underwent RYGBP but differed in the long-term outcome of T2DM (remission: G1, n = 6; relapse: G2, n = 6; lack of remission: G3: n = 6). Groups were matched for their sex, age, and body mass index. The GLP-1, glucose, C-peptide, and glucagon responses to a standardized test meal (STM) were evaluated. Insulin secretion and insulin sensitivity were estimated from the STM and by frequently sampling intravenous glucose tolerance test (FSIVGTT). Dual-energy X-ray absorptiometry was used to assess body composition.. Patients in G1 presented a lower area under the curve (AUC0-120) of glucose in response to the STM as compared with G2, and G3 (P < 0.01). In contrast, the AUC0-120 of GLP-1 (P = 0.884) and glucagon (P = 0.630) did not differ significantly among the 3 groups. Indices of insulin secretion adjusted by the prevailing insulin sensitivity derived from STM and FSIVGTT, demonstrated larger β-cell function in subjects in G1 as compared with G2 or G3 (Disposition Index-STM, P = 0.005; DI-FSIVGTT, P = 0.006). Body composition and inflammatory markers did not differ significantly among the 3 study groups.. Our data show that in subjects with T2DM an enhanced GLP-1 response to meal intake is not sufficient to maintain normal glucose tolerance in the long term after RYGBP. Our data suggest that β-cell function is a key determinant of the long-term remission of T2DM after this bariatric surgery technique.

Topics: Absorptiometry, Photon; Aged; Biomarkers; Blood Glucose; Body Composition; C-Peptide; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Female; Follow-Up Studies; Gastric Bypass; Glucagon; Glucagon-Like Peptide 1; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Obesity, Morbid; Treatment Outcome

Dietary protein restriction during pregnancy and lactation in rats impairs β-cell function and mass in neonates and leads to glucose intolerance in adult offspring. Maternal taurine (Tau) supplementation during pregnancy in rats restores β-cell function and mass in neonates, but its long-term effects are unclear. The prevention of postnatal catch-up growth has been suggested to improve glucose tolerance in adult offspring of low-protein (LP)-fed mothers. The objective of this study was to examine the relative contribution of β-cell dysfunction and insulin resistance to impaired glucose tolerance in 130-day-old rat offspring of LP-fed mothers and the effects of maternal Tau supplementation on β-cell function and insulin resistance in these offspring. Pregnant rats were fed i) control, ii) LP, and iii) LP+Tau diets during gestation and lactation. Offspring were given a control diet following weaning. A fourth group consisting of offspring of LP-fed mothers, maintained on a LP diet following weaning, was also studied (LP-all life). Insulin sensitivity in the offspring of LP-fed mothers was reduced in females but not in males. In both genders, LP exposure decreased β-cell function. Tau supplementation improved insulin sensitivity in females and β-cell function in males. The LP-all life diet improved β-cell function in males. We conclude that i) maternal Tau supplementation has persistent effects on improving glucose metabolism (β-cell function and insulin sensitivity) in adult rat offspring of LP-fed mothers and ii) increasing the amount of protein in the diet of offspring adapted to a LP diet after weaning may impair glucose metabolism (β-cell function) in a gender-specific manner.

Topics: Animals; C-Peptide; Diabetes Mellitus, Type 2; Diet, Protein-Restricted; Dietary Proteins; Dietary Supplements; Female; Insulin Resistance; Insulin-Secreting Cells; Lactation; Male; Maternal Nutritional Physiological Phenomena; Pregnancy; Pregnancy Complications; Protein Deficiency; Rats; Rats, Wistar; Sex Characteristics; Taurine; Weaning

There is controversy regarding whether a specific hepatitis C virus (HCV) genotype is associated with diabetes mellitus. This study aimed to investigate HCV genotype distribution in diabetics and its relation to some clinical and laboratory variables in HCV-positive diabetic versus non-diabetic Egyptians in East Delta.. The study included 100 HCV-positive patients of which 66 were diabetic in addition to 35 healthy adults as a control group. Clinical assessment, laboratory measurements of plasma glucose, insulin, C-peptide, C-reactive protein (CRP), tumour necrosis factor-α (TNF-α) and liver functions (alanine aminotransferase (ALT), aspartate aminotransferase (AST) and gamma-glutamyltransferase (GGT)) as well as HCV genotype determination were done, and AST/platelet ratio index (APRI) and Homoeostasis Model of Assessment-Insulin Resistance (HOMA-IR) were calculated.. The main results were the presence of HCV genotype 3, in 31.8% of the diabetic group and in 26.5% of the non-diabetic group, while the remainder of cases had genotype 4, the predominant genotype in Egypt. This is the first report of the presence of HCV genotype 3 in about 30% of an Egyptian cohort. However, there was no significant difference in genotype distribution between both groups. Further, there were significantly higher values of HOMA-IR, insulin and C-peptide in HCV-positive groups in comparison to the control group, while TNF-α was significantly higher in the HCV-positive diabetic group. However, there were no significant differences between both genotypes regarding these parameters.. Although this study reveals for the first time the presence of HCV genotype 3 in a significant percentage of a group of Egyptian patients, where the majority were diabetic, the association between diabetes and certain HCV genotypes could not be confirmed on the basis of our findings. Hence, taking into consideration the impact of such a finding on the treatment decisions of those patients, further studies are warranted to explore these findings to a greater extent.

Topics: Adult; Alanine Transaminase; Analysis of Variance; Aspartate Aminotransferases; Blood Glucose; C-Peptide; C-Reactive Protein; Diabetes Mellitus; Egypt; Female; gamma-Glutamyltransferase; Genotype; Hepacivirus; Hepatitis C; Homeostasis; Humans; Insulin Resistance; Male; Middle Aged; Platelet Count; Statistics, Nonparametric; Tumor Necrosis Factor-alpha

Causes of hyperglycemia in critically ill non-diabetic children may differ from those in adults. The objective of this study was to investigate the pathogenesis of critical illness hyperglycemia (CIH) in terms of insulin resistance and β-cell dysfunction. Critically ill children with blood glucose (BG) levels of >150 mg/dL (8.3 mmol/L) were enrolled in the study. Insulin sensitivity and β-cell function in the hyperglycemic and euglycemic periods were analyzed with BG/insulin and BG/C-peptide ratios, and utilizing homeostasis model assessment (HOMA). A total of 40 patients were enrolled in the study. BG/insulin and BG/C-peptide ratios were significantly higher in the hyperglycemic period. The HOMA-B and S scores for the hyperglycemic period revealed that out of all the patients who survived (n=30), 20 had β-cell dysfunction, while the remaining (n=11) had insulin resistance. β-cell dysfunction was significantly higher in the hyperglycemic period (p<0.001). As in adults, β-cell dysfunction may play a major role in the pathophysiology of CIH in children.

Topics: Adolescent; Blood Glucose; C-Peptide; Child; Child, Preschool; Critical Illness; Female; Humans; Hyperglycemia; Infant; Insulin Resistance; Insulin-Secreting Cells; Male

Evaluating insulin secretion ability and sensitivity is essential to establish an appropriate treatment for patients with type 2 diabetes. The serum C-peptide response (CPR) level is used to evaluate the quantity of endogenous insulin secretion. However, the serum CPR level alone cannot indicate insulin-secretion ability or insulin sensitivity, because plasma glucose levels influence endogenous insulin secretion and vice versa. The CPR index, a ratio of serum CPR level to plasma glucose concentration when measured simultaneously, was previously reported to be a useful marker to determine the necessity of insulin treatment in patients with type 2 diabetes, but the reasons are unknown. The aim of this study was to clarify which factors affect the CPR index in patients with type 2 diabetes. Totally, 121 subjects were included in this study; all participants were hospitalized for type 2 diabetes. On the day after admission, we calculated the CPR index from each patient's fasting blood sample and a blood sample taken 2 hours after breakfast (the postprandial sample). A detailed medical history was taken from each patient to establish the disease duration. The degree of diabetic retinopathy judged by an ophthalmologist was obtained from patients' medical records. An oral glucose tolerance test and a glucagon load test were performed after the fasting plasma glucose level decreased to 130 mg/dl, and indices of insulin secretion and sensitivity were calculated. Fasting and postprandial CPR indices were moderately correlated with total endogenous insulin secretion after oral glucose load and with the CPR level after glucagon load, insulin sensitivity, composite index, and the reciprocal index of homeostasis model assessment (HOMA-R-1). Furthermore, there was a weak but significant correlation between the postprandial CPR index and the duration of diabetes. The postprandial CPR index was inversely correlated with the degree of diabetic retinopathy, which is known to be associated with the duration of hyperglycemia. Our data clearly shows that the CPR index is a useful parameter to reflect the degree of impaired glucose tolerance.

Topics: Adult; Aged; Aged, 80 and over; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Humans; Insulin; Insulin Resistance; Insulin Secretion; Male; Middle Aged

We investigated characteristics associated with the efficacy of dipeptidyl peptidase-4 inhibitors (DPP4i) in Korean patients with type 2 diabetes. We reviewed medical records of 477 patients who had taken sitagliptin or vildagliptin longer than 40 weeks. Response to DPP4i was evaluated with HbA1c change after therapy (ΔHbA1c). The Student's t-test between good responders (GR: ΔHbA1c > 1.0%) and poor responders (PR: ΔHbA1c < 0.5%), a correlation analysis among clinical parameters, and a linear multivariate regression analysis were performed. The mean age was 60 yr, duration of diabetes 11 yr and HbA1c was 8.1%. Baseline fasting plasma glucose (FPG), HbA1c, C-peptide, and creatinine were significantly higher in the GR compared to the PR. Duration of diabetes, FPG, HbA1c, C-peptide and creatinine were significantly correlated with ΔHbA1c. In the multivariate analysis, age (r(2) = 0.006), duration of diabetes (r(2) = 0.019), HbA1c (r(2) = 0.296), and creatinine levels (r(2) = 0.024) were independent predictors for the response to DPP4i. Body mass index and insulin resistance were not associated with the response to DPP4i. In conclusion, better response to DPP4i would be expected in Korean patients with type 2 diabetes who have higher baseline HbA1c and creatinine levels with shorter duration of diabetes.

Topics: Adamantane; Blood Glucose; Body Mass Index; C-Peptide; Creatinine; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Glycated Hemoglobin; Humans; Insulin Resistance; Male; Middle Aged; Multivariate Analysis; Nitriles; Pyrazines; Pyrrolidines; Retrospective Studies; Sitagliptin Phosphate; Triazoles; Vildagliptin

To report Type 2 diabetes-related outcomes after the implantation of a duodenal-jejunal bypass liner device and to investigate the role of proximal gut exclusion from food in glucose homeostasis using the model of this device.. Sixteen patients with Type 2 diabetes and BMI <36 kg/m(2) were evaluated before and 1, 12 and 52 weeks after duodenal-jejunal bypass liner implantation and 26 weeks after explantation. Mixed-meal tolerance tests were conducted over a period of 120 min and glucose, insulin and C-peptide levels were measured. The Matsuda index and the homeostatic model of assessment of insulin resistance were used for the estimation of insulin sensitivity and insulin resistance. The insulin secretion rate was calculated using deconvolution of C-peptide levels.. Body weight decreased by 1.3 kg after 1 week and by 2.4 kg after 52 weeks (P < 0.001). One year after duodenal-jejunal bypass liner implantation, the mean (sem) HbA(1c) level decreased from 71.3 (2.4) mmol/mol (8.6[0.2]%) to 58.1 (4.4) mmol/mol (7.5 [0.4]%) and mean (sem) fasting glucose levels decreased from 203.3 (13.5) mg/dl to 155.1 (13.1) mg/dl (both P < 0.001). Insulin sensitivity improved by >50% as early as 1 week after implantation as measured by the Matsuda index and the homeostatic model of assessment of insulin resistance (P < 0.001), but there was a trend towards deterioration in all the above-mentioned variables 26 weeks after explantation. Fasting insulin levels, insulin area under the curve, fasting C-peptide, C-peptide area under the curve, fasting insulin and total insulin secretion rates did not change during the duodenal-jejunal bypass liner implantation period or after explantation.. The duodenal-jejunal bypass liner improves glycaemia in overweight and obese patients with Type 2 diabetes by rapidly improving insulin sensitivity. A reduction in hepatic glucose output is the most likely explanation for this improvement.

Topics: Area Under Curve; Blood Glucose; C-Peptide; Device Removal; Diabetes Mellitus, Type 2; Duodenum; Fasting; Female; Gastric Bypass; Glycated Hemoglobin; Homeostasis; Humans; Insulin; Insulin Resistance; Insulin Secretion; Jejunum; Male; Middle Aged; Obesity; Prospective Studies; Treatment Outcome; Weight Loss

The shortage of data concerning the character of changes of leptin concentration and its role information of insulin resistance under development of acute coronary events determined the appropriateness of the present study. The cardiac infarction patients with and without diabetes type II were examined. The identified hyperleptinemia, its relationship with basal and post-prandial hyperglycemia and with increase of C-peptide concentration and free fatty acids made possible to consider leptin both as one of the important components in the series of carbohydrate and lipid metabolism disorders and the additional marker of development of insulin resistance under cardiac infarction. These study results can be applied to patients with diabetes anamnesis and to patients without this concomitant pathology. The study results can be used as a foundation for new diagnostic and therapy tactics of metabolic disorders correction in patients with acute coronary vascular pathology.

Topics: Aged; Biomarkers; Blood Glucose; Body Mass Index; C-Peptide; Case-Control Studies; Diabetes Mellitus, Type 2; Female; Humans; Insulin; Insulin Resistance; Leptin; Male; Middle Aged; Myocardial Infarction

Insulin responses to oral and intravenous glucose markedly differ by ethnicity. This study examined whether ethnic differences in pancreatic insulin secretion, hepatic insulin extraction and clearance explain these disparate findings in 35 obese African-American and 41 Latina girls (Tanner Stages: IV-V; ages: 14-18; body mass index percentile: 85.9-99.8%).. Pancreatic insulin secretion, hepatic insulin extraction and clearance were estimated by C-peptide and insulin modeling during an oral glucose tolerance test. Insulin sensitivity (SI), acute insulin response to glucose (AIRG ) and disposition index were derived from a frequently sampled intravenous glucose tolerance test.. Compared to Latinas, obese African-American adolescents had lower pancreatic insulin secretion (21.3%; P < 0.01), glucose incremental area under the curve (IAUC) (41.7%, P = 0.02), C-peptide IAUC (25.1%, P < 0.01) and SI (33.7%; P < 0.01). There were no ethnic differences in hepatic insulin extraction and clearance (P's > 0.05).. Compensatory mechanisms to insulin resistance do not appear to explain the ethnic differences in insulin responses to oral and intravenous glucose in obese African-American and Latina girls.

Topics: Adolescent; Area Under Curve; Black or African American; Blood Glucose; Body Composition; Body Mass Index; C-Peptide; Female; Glucose Tolerance Test; Hispanic or Latino; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Obesity; United States

Quantifying the effect size of acute exercise on insulin sensitivity (SI(exercise)) and simultaneous measurement of glucose disappearance (R(d)), endogenous glucose production (EGP), and meal glucose appearance in the postprandial state has not been developed in humans. To do so, we studied 12 healthy subjects [5 men, age 37.1 ± 3.1 yr, body mass index 24.1 ± 1.1 kg/m², fat-free mass (FFM) 50.9 ± 3.9 kg] during moderate exercise at 50% V(O₂max) for 75 min, 120-195 min after a triple-tracer mixed meal consumed at time 0. Tracer infusion rates were adjusted to achieve constant tracer-to-tracee ratio and minimize non-steady-state errors. Glucose turnover was estimated by accounting for the nonstationary kinetics introduced by exercise. Insulin sensitivity index was calculated in each subject both in the absence [time (t) = 0-120 min, SI(rest)] and presence (t = 0-360 min, SI(exercise)) of physical activity. EGP at t = 0 min (13.4 ± 1.1 μM·kg FFM⁻¹·min⁻¹) fell at t = 120 min (2.4 ± 0.4 μM·kg FFM⁻¹·min⁻¹) and then rapidly rose almost eightfold at t = 180 min (18.2 ± 2.6 μM·kg FFM⁻¹·min⁻¹) before gradually falling at t = 360 min (10.6 ± 0.9 μM·kg FFM⁻¹·min⁻¹). R(d) rapidly peaked at t = 120 min at the start of exercise (89.5 ± 11.6 μM·kg FFM⁻¹·min⁻¹) and then gradually declined at t = 195 min (26.4 ± 3.3 μM·kg FFM⁻¹·min⁻¹) before returning to baseline at t = 360 min. SI(exercise) was significantly higher than SI(rest) (21.6 ± 3.7 vs. 12.5 ± 2.0 10⁻⁴ dl·kg⁻¹·min⁻¹ per μU/ml, P < 0.0005). Glucose turnover was estimated for the first time during exercise with the triple-tracer technique. Our results, applying state-of-the-art techniques, show that moderate exercise almost doubles postprandial insulin sensitivity index in healthy subjects.

Topics: Activities of Daily Living; Adult; Algorithms; Blood Glucose; C-Peptide; Carbon Radioisotopes; Deuterium; Feasibility Studies; Female; Glucagon; Gluconeogenesis; Glucose; Humans; Infusions, Intravenous; Insulin; Insulin Resistance; Male; Middle Aged; Models, Biological; Motor Activity; Postprandial Period; Tritium; Young Adult

The C-peptide index (CPI), a ratio of serum C-peptide to plasma glucose levels, is a readily measured index of β-cell function. The difference in the physiological features reflected by the index measured under fasting (F-CPI) or postprandial (PP-CPI) conditions has remained unclear, however.. We investigated the relationship of the two CPIs to indexes of insulin secretion measured with an oral glucose tolerance test (OGTT) or with hyperglycemic and hyperinsulinemic-euglycemic clamp analyses as well as to disposition indexes (indexes of insulin secretion adjusted for insulin sensitivity) calculated from OGTT- or clamp-based analyses. We also examined the relationship between glucose tolerance and the clamp-based disposition index.. The clamp-based disposition index declined progressively from normal glucose tolerance to impaired glucose tolerance to Type 2 diabetes, and it strongly correlated with the 2-h plasma glucose level during an OGTT. For patients with Type 2 diabetes, both F-CPI and PP-CPI correlated with indexes of insulin secretion including HOMA-β, the insulinogenic index, the ratio of the area under the insulin curve to that under the glucose curve during an OGTT, the serum C-peptide level after glucagon challenge, as well as early and total insulin secretion measured with a hyperglycemic clamp. PP-CPI, but not F-CPI, was significantly correlated with clamp-based and OGTT-based disposition indexes.. F-CPI was correlated only with unadjusted indexes of insulin secretion, whereas PP-CPI was correlated with such indexes as well as with those adjusted for insulin sensitivity. The better clinical utility of PP-CPI might be attributable to these physiological characteristics.

Topics: Adult; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Fasting; Female; Glucose; Glucose Clamp Technique; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Postprandial Period

Previously, we screened a proteoglycan for anti-hyperglycemic, named FYGL, from Ganoderma Lucidum. For further research of the antidiabetic mechanisms of FYGL in vivo, the glucose homeostasis, activities of insulin-sensitive enzymes, glucose transporter expression and pancreatic function were analyzed using db/db mice as diabetic models in the present work. FYGL not only lead to a reduction in glycated hemoglobin level, but also an increase in insulin and C-peptide level, whereas a decrease in glucagons level and showed a potential for the remediation of pancreatic islets. FYGL also increased the glucokinase activities, and simultaneously lowered the phosphoenol pyruvate carboxykinase activities, accompanied by a reduction in the expression of hepatic glucose transporter protein 2, while the expression of adipose and skeletal glucose transporter protein 4 was increased. Moreover, the antioxidant enzyme activities were also increased by FYGL treatment. Thus, FYGL was an effective antidiabetic agent by enhancing insulin secretion and decreasing hepatic glucose output along with increase of adipose and skeletal muscle glucose disposal in the late stage of diabetes. Furthermore, FYGL is beneficial against oxidative stress, thereby being helpful in preventing the diabetic complications.

Topics: Animals; Antioxidants; Biological Factors; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Disease Models, Animal; Glucokinase; Glucose; Glucose Transporter Type 2; Glucose Transporter Type 4; Glycated Hemoglobin; Hypoglycemic Agents; Hypolipidemic Agents; Insulin; Insulin Resistance; Islets of Langerhans; Liver; Male; Mice; Mice, Inbred C57BL; Muscle, Skeletal; Oxidative Stress; Phosphoenolpyruvate Carboxykinase (ATP); Proteoglycans; Reishi

Topics: Adult; Aged; Aged, 80 and over; Biomarkers; C-Peptide; Diabetes Mellitus, Type 2; Female; Humans; Insulin; Insulin Resistance; Kaplan-Meier Estimate; Male; Middle Aged; Predictive Value of Tests; Proportional Hazards Models; Prospective Studies; Radioimmunoassay; Risk Factors

The prevalence of adolescents' obesity and overweight has dramatically elevated in China. Obese children were likely to insulin resistance and dyslipidemia, which are risk factors of cardiovascular diseases. However there was no cut-off point of anthropometric values to predict the risk factors in Chinese adolescents. The present study was to investigate glycolipid metabolism status of adolescents in Shanghai and to explore the correlations between body mass index standard deviation score (BMI-SDS) and metabolic indices, determine the best cut-off value of BMI-SDS to predict dyslipidemia.. Fifteen schools in Shanghai's two districts were chosen by cluster sampling and primary screening was done in children aged 9-15 years old. After screening of bodyweight and height, overweight and obese adolescents and age-matched children with normal body weight were randomly recruited in the study. Anthropometric measurements, biochemical measurements of glycolipid profiles were done. SPSS19.0 was used to analyze the data. Receiver operating characteristic (ROC) curves were made and the best cut-off values of BMI-SDS to predict dyslipidemia were determined while the Youden indices were maximum.. Five hundred and thirty-eight adolescents were enrolled in this research, among which 283 have normal bodyweight, 115 were overweight and 140 were obese. No significant differences of the ages among 3 groups were found. There were significant differences of WC-SDS (p<0.001), triacylglycerol (p<0.05), high and low density lipoprotein cholesterol (p<0.01), fasting insulin (p<0.01) and C-peptide (p<0.001) among 3 groups. Significant difference of fasting glucose was only found between normal weight and overweight group. Significant difference of total cholesterol was found between obese and normal weight group. There was no significant difference of glycated hemoglobin among 3 groups. The same tendency was found in boys but not in girls. Only HDL-C reduced and TG increased while BMI elevated in girls. The best cut-off value of BMI-SDS was 1.22 to predict dyslipidemia in boys. The BMI cut-off was 21.67 in boys.. Overweight and obese youths had reduced insulin sensitivity and high prevalence of dyslipidemia.When BMI-SDS elevated up to 1.22 and BMI was higher than 21.67 in boys, dyslipidemia may happen.

Topics: Adolescent; Blood Glucose; Body Composition; Body Mass Index; C-Peptide; Child; China; Cholesterol, HDL; Cholesterol, LDL; Cross-Sectional Studies; Dyslipidemias; Female; Humans; Insulin; Insulin Resistance; Male; Obesity; Prevalence; Prognosis; Risk Factors; ROC Curve; Sex Factors; Triglycerides

To compare the difference in body mass index (BMI), waist-to-hip ratio (WHR), and glucose and lipid metabolism parameters between drug-naïve, first-episode schizophrenia patients and healthy controls matched for age, ethnicity and gender, we conducted a test including BMI, WHR, and fasting glucose and lipid metabolism parameters in both 70 drug-naïve, first-episode schizophrenia patients, having not a single day of cumulative exposure to antipsychotic medications and 44 normal healthy controls at baseline. Student's t tests (two tailed) were conducted to examine between group differences. We found that drug-naïve first-episode schizophrenia patients had higher insulin, insulin resistance and C-peptide levels, and had lower total cholesterol (TC), high density lipoprotein cholesterol (HDL-c) and apolipoproteinA1 levels. Simultaneously, drug-naïve, first-episode schizophrenia patients show a potential tendency of WHR enlargement, although there were no statistically significant differences between groups (mean=0.82, SD=0.06, for the patients versus mean=0.79, SD=0.06, for the health subjects). These results suggest that drug-naïve, first-episode schizophrenia patients do differ from healthy controls in their fasting glycometabolism parameters and lipid profiles, including fasting plasma levels of insulin, C-peptide, TC, HDL-c, and apolipoproteinA1, and patients are more insulin resistant before the onset of antipsychotic medication treatment.

Topics: Adolescent; Adult; Apolipoproteins A; Blood Glucose; Body Mass Index; C-Peptide; Chi-Square Distribution; Cholesterol, HDL; Fasting; Female; Humans; Insulin Resistance; Lipid Metabolism; Lipids; Male; Observation; Prospective Studies; Schizophrenia; Waist-Hip Ratio; Young Adult

The diabetes mellitus Incidence Cohort Registry (DiMelli) aims to characterize diabetes phenotypes by immunologic, metabolic, and genetic markers. We classified patients into three groups according to islet autoantibody status and examined whether patients with multiple diabetes-associated autoantibodies, one autoantibody, or without autoantibodies differed with respect to clinical, metabolic, and genetic parameters, including an insulin sensitivity (IS) score based on waist, HbA1c, and triglycerides. We also assessed whether metabolic markers predicted the immune status.. As of June 2012, 630 patients in Bavaria, Germany, aged <20 years diagnosed with any type of diabetes within the preceding 6 months were registered in DiMelli. We compared the clinical and laboratory parameters between islet autoantibody status defined patient groups. Parameters showing the strongest associations were included in principal component analysis. Receiver operating characteristic curves were used to assess the ability of the IS Score to predict islet autoantibody status.. Patients with multiple islet autoantibodies, one autoantibody, or without autoantibodies were significantly different in terms of BMI percentile, weight loss before diagnosis, fasting C-peptide (all, P<0.001), and IS Score (P=0.034). However, principal component analysis revealed no distinct patterns according to autoantibody status. At the optimal IS Score cut-off for predicting islet autoantibody positivity (single compared to none), the specificity was 52.0% and the sensitivity was 86.8%. With respect to prediction of multiple autoantibodies (compared to none), specificity and sensitivity were slightly lower and in combination inferior to those obtained using the BMI percentile and fasting C-peptide.. The DiMelli study indicated that patients with and without islet autoantibodies differed with respect to metabolic and genetic markers but there was considerable overlap of phenotypes, and autoantibody status could not be predicted by these parameters. Thus, our results suggest that refined diabetes classification may require both immune and metabolic phenotyping.

Topics: Adolescent; Autoantibodies; Body Mass Index; C-Peptide; Child; Child, Preschool; Cohort Studies; Diabetes Mellitus; Female; Humans; Incidence; Infant; Insulin Resistance; Islets of Langerhans; Male; Phenotype; Registries; Young Adult

Impairment of the incretin effect is one of the hallmarks of type 2 diabetes mellitus (T2DM). However, it is unknown whether this abnormality is specific to incretin-stimulated insulin secretion or a manifestation of generalized β-cell dysfunction. The aim of this study was to determine whether improved glycemic control restores the incretin effect.. Fifteen T2DM subjects were studied before and after 8 weeks of intensified treatment with insulin. The incretin effect was determined by comparing plasma insulin and C-peptide levels at clamped hyperglycemia from iv glucose, and iv glucose plus glucose ingestion.. Long-acting insulin, titrated to reduce fasting glucose to 7 mM, lowered hemoglobin A1c from 8.6% ± 0.2% to 7.1% ± 0.2% over 8 weeks. The incremental C-peptide responses and insulin secretion rates to iv glucose did not differ before and after insulin treatment (5.6 ± 1.0 and 6.0 ± 0.9 nmol/L·min and 0.75 ± 0.10 and 0.76 ± 0.11 pmol/min), but the C-peptide response to glucose ingestion was greater after treatment than before (10.9 ± 2.2 and 7.1 ± 0.9 nmol/L·min; P = .03) as were the insulin secretion rates (1.11 ± 0.22 and 0.67 ± 0.07 pmol/min; P = .04). The incretin effect computed from plasma C-peptide was 21.8% ± 6.5% before insulin treatment and increased 40.9% ± 3.9% after insulin treatment (P < .02).. Intensified insulin treatment to improve glycemic control led to a disproportionate improvement of insulin secretion in response to oral compared with iv glucose stimulation in patients with type 2 diabetes. This suggests that in T2DM the impaired incretin effect is independent of abnormal glucose-stimulated insulin secretion.

Topics: Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Drug Monitoring; Female; Glucose Clamp Technique; Humans; Hyperglycemia; Hypoglycemic Agents; Incretins; Insulin; Insulin Glargine; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Insulin, Long-Acting; Male; Middle Aged; Overweight

Insulin-resistance is commonly found in adrenal incidentaloma (AI) patients. However, little is known about beta-cell secretion in AI, because comparisons are difficult, since beta-cell-function varies with altered insulin-sensitivity.. To retrospectively analyze beta-cell function in non-diabetic AI, compared to healthy controls (CON).. AI (n=217, 34%males, 57 ± 1 years, body-mass-index:27.7 ± 0.3 kg/m(2)) and CON [n = 25, 32%males, 56 ± 1 years, 26.7 ± 0.8 kg/m(2)] with comparable anthropometry (p ≥ 0.31) underwent oral-glucose-tolerance-tests (OGTTs) with glucose, insulin, and C-peptide measurements. 1mg-dexamethasone-suppression-tests were performed in AI. AI were divided according to post-dexamethasone-suppression-test cortisol-thresholds of 1.8 and 5 µg/dL into 3 subgroups: pDexa<1.8 µg/dL, pDexa1.8-5 µg/dL and pDexa>5 µg/dL. Using mathematical modeling, whole-body insulin-sensitivity [Clamp-like-Index (CLIX)], insulinogenic Index, Disposition Index, Adaptation Index, and hepatic insulin extraction were calculated.. CLIX was lower in AI combined (4.9 ± 0.2 mg · kg(-1) · min(-1)), pDexa<1.8 µg/dL (4.9 ± 0.3) and pDexa1.8-5 µg/dL (4.7 ± 0.3, p<0.04 vs.CON:6.7 ± 0.4). Insulinogenic and Disposition Indexes were 35%-97% higher in AI and each subgroup (p<0.008 vs.CON), whereas C-peptide-derived Adaptation Index, compensating for insulin-resistance, was comparable between AI, subgroups, and CON. Mathematical estimation of insulin-derived (insulinogenic and Disposition) Indexes from associations to insulin-sensitivity in CON revealed that AI-subgroups had ~19%-32% higher insulin-secretion than expectable. These insulin-secretion-index differences negatively (r=-0.45, p<0.001) correlated with hepatic insulin extraction, which was 13-16% lower in AI and subgroups (p<0.003 vs.CON).. AI-patients show insulin-resistance, but adequately adapted insulin secretion with higher insulin concentrations during an OGTT, because of decreased hepatic insulin extraction; this finding affects all AI-patients, regardless of dexamethasone-suppression-test outcome.

Topics: Adrenal Gland Neoplasms; Blood Glucose; C-Peptide; Case-Control Studies; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Liver; Male; Middle Aged; Retrospective Studies; Risk Factors

The objective of this study was to assess the relationship between fasting proinsulin (PI) and age in general population and to determine whether there are differences regarding this association in obese and non-obese persons.. A random population-based sample (n=656) of Romanians (26-80 years) living in Bucharest, Romania was studied; 432 persons had diabetes and they were not analyzed in this paper. Circulating levels of fasting plasma glucose (FPG), fasting plasma insulin (FPI), fasting plasma proinsulin (FPP), fasting plasma C-peptide, HbA1c, lipid profile, creatinine, urea were measured. The homeostasis model assessment of insulin resistance (HOMA-IR), HOMA-B, and Quicki index were also calculated.. For all participants proinsulin was the highest in the third quartile of the age group (59-67 years), with a median proinsulin of 5.8 pmol/L. Subsequently, proinsulin increased with age, from 2.6 pmol/L for participants aged 20-51 years, to 4.7 pmol/L for participants aged 51-59 years; proinsulin levels decreased in the upper quartile 4.8 pmol/L for those aged over 67 years. In sex-specific analyses, proinsulin increased with age for both men and women, except for those in the upper quartile. The prevalence of the obesity was 30.4% (n=68); obesity prevalence did not increase with age (p=0.26). Fasting proinsulin levels significantly increased with body mass index (BMI) category from lean (n=67, 2.9 pmol/L) to overweight (n=89, 4.5 pmol/L) and obese (n=69, 6.63 pmol/L) (p<0.0001).. Our study has demonstrated a close association between age and elevated proinsulin and proinsulin/insulin ratio in general population.

Topics: Adult; Age Factors; Aged; Aged, 80 and over; Blood Glucose; Body Mass Index; C-Peptide; Female; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Obesity; Proinsulin

Osteocalcin, a protein synthesized by osteoblasts, and vitamin D status have independently been implicated in energy metabolism and glucose regulation. This study was conducted to simultaneously explore the relationships among osteocalcin, vitamin D status and indicators of glucose metabolism and adiposity in a mixed-ethnicity cohort of adult women.. Cross-sectional.. Aboriginal and white women (n=368) over 25 years of age (45.3±13.6 years) were studied for measures of osteocalcin and 25-hydroxy vitamin D [25(OH)D] plus glucose metabolism including glucose, insulin, C-peptide, hemoglobin A1c (HbA1c) and homeostatic model assessment of insulin resistance (HOMA-IR). Measures of adiposity included body mass index (BMI) plus total body fat and trunk fat from dual-energy X-ray absorptiometry.. Aboriginal women had higher BMI, fat and markers of dysglycemia. Osteocalcin was not different between groups, but 25(OH)D was lower in Aboriginal women. Osteocalcin was inversely related to all five parameters of glucose metabolism, whereas 25(OH)D was inversely related to insulin, C-peptide and HOMA-IR. After accounting for age, ethnicity or adiposity using regression analyses, glucose, HbA1c and HOMA-IR were inversely related to both osteocalcin and 25(OH)D. However, only 25(OH)D was inversely related to C-peptide, and neither osteocalcin nor 25(OH)D was related to insulin.. These data from a unique mixed Aboriginal and white population suggest that both vitamin D and osteocalcin are involved in glucose control.

Topics: Absorptiometry, Photon; Adult; Aged; American Indian or Alaska Native; Body Composition; Body Mass Index; C-Peptide; Canada; Cross-Sectional Studies; Female; Glucose; Homeostasis; Humans; Insulin Resistance; Middle Aged; Osteocalcin; Vitamin D; White People

Previous research on the association between fish consumption and incident type 2 diabetes has been inconclusive. In addition, few studies have investigated how fish consumption may be related to the metabolic abnormalities underlying diabetes. Therefore, we examined the association of fish consumption with measures of insulin sensitivity and beta-cell function in a multi-ethnic population.. We examined the cross-sectional association between fish consumption and measures of insulin sensitivity and secretion in 951 non-diabetic participants in the Insulin Resistance Atherosclerosis Study (IRAS). Fish consumption, categorized as <2 vs. ≥2 portions/week, was measured using a validated food frequency questionnaire. Insulin sensitivity (S(I)) and acute insulin response (AIR) were determined from frequently sampled intravenous glucose tolerance tests. Higher fish consumption was independently associated with lower S(I)-adjusted AIR (β = -0.13 [-0.25, -0.016], p = 0.03, comparing ≥2 vs. <2 portions/week). Fish consumption was positively associated with intact and split proinsulin/C-peptide ratios, however, these associations were confounded by ethnicity (multivariable-adjusted β = 0.073 [-0.014, 0.16] for intact proinsulin/C-peptide ratio, β = 0.031 [-0.065, 0.13] for split proinsulin/C-peptide ratio). We also observed a significant positive association between fish consumption and fasting blood glucose (multivariable-adjusted β = 2.27 [0.68, 3.86], p = 0.005). We found no association between fish consumption and S(I) (multivariable-adjusted β = -0.015 [-0.083, 0.053]) or fasting insulin (multivariable-adjusted β = 0.016 [-0.066, 0.10]).. Fish consumption was not associated with measures of insulin sensitivity in the multi-ethnic IRAS cohort. However, higher fish consumption may be associated with pancreatic beta-cell dysfunction.

Topics: Adult; Aged; Animals; Atherosclerosis; Blood Glucose; C-Peptide; Cohort Studies; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Diet; Female; Fishes; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Linear Models; Male; Meat; Middle Aged; Multivariate Analysis; Surveys and Questionnaires

Increased insulin resistance (IR) has been found in androgenetic alopecia in several studies. However, IR has not been investigated in alopecia areata (AA). We aimed to investigate IR in AA patients and the controls. Anthropometric and demographic data were obtained from 51 AA patients and 36 controls. We measured insulin, c-peptide and blood glucose and HOMA-IR. Demographic characteristics of the two groups were similar. AA group had higher insulin [12.5 ± 7.01 vs. 8.3 ± 3.9 µIU/mL, p = 0.001], c-peptide [2.7 ± 1.07 vs. 2. ± 0.6 ng/mL, p = 0.007] and HOMA-IR levels [2.8 ± 1.6 vs. 1.9 ± 0.9, p = .004] than the controls. Patient and control groups were also similar regarding lipid profiles. In this study, we found increased IR in AA patients for the first time in literature. Increased inflammatory cytokines and hypothalamic-pituitary-adrenal axis activation may be responsible for this finding. Further studies with larger sample sizes may give additional information for IR in AA.

Topics: Adolescent; Adult; Alopecia Areata; Blood Glucose; Blood Pressure; C-Peptide; Case-Control Studies; Female; Humans; Insulin; Insulin Resistance; Lipids; Male; Middle Aged; Young Adult

Procyanidins have positive effects on glucose metabolism in conditions involving slightly disrupted glucose homeostasis, but it is not clear how procyanidins interact with β-cells. In this work, we evaluate the effects of procyanidins on β-cell functionality under an insulin-resistance condition. After 13 weeks of cafeteria diet, female Wistar rats were treated with 25 mg of grape seed procyanidin extract (GSPE)/kg of body weight (BW) for 30 days. To determine the possible mechanisms of action of procyanidins, INS-1E cells were separately incubated in high-glucose, high-insulin and high-oleate media to reproduce the conditions the β-cells were subjected to during the cafeteria diet feeding. In vivo experiments showed that chronic GSPE treatment decreased insulin production, since C-peptide levels and insulin protein levels in plasma were lower than those of cafeteria-fed rats, as were insulin and Pdx1 mRNA levels in the pancreas. GSPE effects observed in vivo were reproduced in INS-1E cells cultured with high oleate for 3 days. GSPE treatment significantly reduces triglyceride content in β-cells treated with high oleate and in the pancreas of cafeteria-fed rats. Moreover, gene expression analysis of the pancreas of cafeteria-fed rats revealed that procyanidins up-regulated the expression of Cpt1a and down-regulated the expression of lipid synthesis-related genes such as Fasn and Srebf1. Procyanidin treatment counteracted the decrease of AMPK protein levels after cafeteria treatment. Procyanidins cause a lack of triglyceride accumulation in β-cells. This counteracts its negative effects on insulin production, allowing for healthy levels of insulin production under hyperlipidemic conditions.

Topics: Animals; Antioxidants; C-Peptide; Carnitine O-Palmitoyltransferase; Culture Media; Fatty Acid Synthase, Type I; Fatty Acids; Female; Glucose; Grape Seed Extract; Homeodomain Proteins; Insulin; Insulin Resistance; Insulin-Secreting Cells; Lipid Metabolism; Proanthocyanidins; Rats; Rats, Wistar; RNA, Messenger; Sterol Regulatory Element Binding Protein 1; Trans-Activators

Genetic background may interact with habitual dietary fat composition, and affect development of the metabolic syndrome (MetS). The phosphoenolpyruvate carboxykinase gene (PCK1) plays a significant role regulating glucose metabolism, and fatty acids are key metabolic regulators, which interact with transcription factors and influence glucose metabolism. We explored genetic variability at the PCK1 gene locus in relation to degree of insulin resistance and plasma fatty acid levels in MetS subjects. Moreover, we analyzed the PCK1 gene expression in the adipose tissue of a subgroup of MetS subjects according to the PCK1 genetic variants.. Insulin sensitivity, insulin secretion, glucose effectiveness, plasma concentrations of C-peptide, fatty acid composition and three PCK1 tag-single nucleotide polymorphisms (SNPs) were determined in 443 MetS participants in the LIPGENE cohort.. The rs2179706 SNP interacted with plasma concentration of n - 3 polyunsaturated fatty acids (n - 3 PUFA), which were significantly associated with plasma concentrations of fasting insulin, peptide C, and HOMA-IR. Among subjects with n - 3 PUFA levels above the population median, carriers of the C/C genotype exhibited lower plasma concentrations of fasting insulin (P = 0.036) and HOMA-IR (P = 0.019) as compared with C/C carriers with n - 3 PUFA below the median. Moreover, homozygous C/C subjects with n - 3 PUFA levels above the median showed lower plasma concentrations of peptide C as compared to individuals with the T-allele (P = 0.006). Subjects carrying the T-allele showed a lower gene PCK1 expression as compared with carriers of the C/C genotype (P = 0.015).. The PCK1 rs2179706 polymorphism interacts with plasma concentration of n - 3 PUFA levels modulating insulin resistance in MetS subjects.

Topics: Adipose Tissue; Adult; Aged; Alleles; Blood Glucose; Body Mass Index; C-Peptide; Cross-Sectional Studies; Dietary Fats; Fasting; Fatty Acids, Omega-3; Female; Gene-Environment Interaction; Genetic Loci; Genotype; Homozygote; Humans; Insulin; Insulin Resistance; Insulin Secretion; Intracellular Signaling Peptides and Proteins; Linear Models; Male; Metabolic Syndrome; Middle Aged; Phosphoenolpyruvate Carboxykinase (GTP); Polymorphism, Single Nucleotide; Randomized Controlled Trials as Topic

To compare indices of insulin secretion, insulin sensitivity (IS), and oral disposition index (oDI) during the liquid mixed-meal test in obese youth with clinically diagnosed type 2 diabetes mellitus (T2DM) and negative autoantibodies (Ab(-)) versus those with T2DM and positive autoantibodies (Ab(+)) to examine whether differences in β-cell function can be detected between the 2 groups.. Twenty-seven youth with Ab(-) and 15 youth with Ab(+) clinically diagnosed T2DM underwent a mixed-meal test (Boost; 55% carbohydrate, 25% protein, and 20% fat). Fasting and mixed-meal-derived insulin and C-peptide indices of IS, secretion (30-minute insulinogenic [ΔI(30)/ΔG(30)] and C-peptide [ΔC(30)/ΔG(30)]), and oDI were calculated.. Indices of insulin secretion were ~40%-50% lower in patients with Ab(+) T2DM compared with those with Ab(-) T2DM. After controlling for body mass index, ΔI(30)/ΔG(30), ΔC(30)/ΔG(30), C-peptide area under the curve (AUC)/glucose AUC, and insulin AUC/glucose AUC were significantly (P < .05) lower in the Ab(+) group compared with the Ab(-) group. Sensitivity indices were significantly higher in the Ab(+) group. The oDI, 1/fasting insulin × ΔI(30)/ΔG(30) (0.04 ± 0.02 vs 0.12 ± 0.02 mg/dL(-1); P = .005), and 1/fasting C-peptide × ΔC(30)/ΔG(30) (0.02 ± 0.009 vs 0.05 ± 0.006 mg/dL(-1); P = .018) were lower in the Ab(+) group. Receiver operating characteristic curve analyses revealed that fasting C-peptide <3.2 ng/mL had 87% sensitivity and 74% specificity and ΔC(30)/ΔG(30) <0.075 ng/mL per mg/dL had 93% sensitivity and 80% specificity for identifying youth with Ab(+) T2DM.. During a liquid mixed-meal test, indices of β-cell function were lower and IS was higher in patients with Ab(+) T2DM versus those with Ab(-) T2DM, with high sensitivity and specificity for fasting and stimulated C-peptide as markers of Ab(+) status. Indices of insulin secretion during this standardized mixed-meal test could be used to assess β-cell function in therapeutic trials of β-cell restoration in youth with T2DM.

Topics: Adolescent; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Humans; Insulin; Insulin Resistance; Insulin Secretion; Male; Meals; Obesity

We developed a simple and new insulin resistance index derived from a glucose clamp and a meal tolerance test (MTT) in Japanese patients with type 2 diabetes mellitus.. Fifteen patients [mean age: 53 years, fasting plasma glucose (FPG) 7.7 mmol/L, HbA1c 7.1% (54 mmol/mol), body mass index 26.8 kg/m(2)] underwent a MTT and a glucose clamp. Participants were given a test meal (450 kcal). Plasma glucose and insulin were measured at 0 (fasting), 30, 60, 120, and 180 min. Serum C-peptide immunoreactivity (CPR) was measured at 0 (fasting; F-CPR) and 120 min. Homeostasis model assessment of insulin resistance (HOMA-IR) and insulin sensitivity indices (ISI) were calculated from the MTT results. The glucose infusion rate (GIR) was measured during hyperinsulinemic-euglycemic glucose clamps.. The mean GIR in all patients was 5.8 mg·kg(-1)·min(-1). The index 20/(F-CPR × FPG) was correlated strongly with GIR (r = 0.83, P < 0.0005). HOMA-IR (r = -0.74, P < 0.005) and ISI (r = 0.66, P < 0.01) were also correlated with GIR. In 10 patients with mild insulin resistance (GIR 5.0-10.0 mg·kg(-1)·min(-1)), 20/(F-CPR × FPG) was very strongly correlated with GIR (r = 0.90, P < 0.0005), but not with HOMA-IR and ISI (r = -0.49, P = 0.15; r = 0.20, P = 0.56, respectively). In patients with mild insulin resistance, plasma adiponectin (r = 0.65, P < 0.05), but not BMI or waist circumstance, was correlated with GIR.. 20/(F-CPR × FPG) is a simple and effective index of insulin resistance, and performs better than HOMA-IR and ISI in Japanese patients with type 2 diabetes mellitus. Our results suggest that 20/(F-CPR × FPG) is a more effective index than HOMA-IR in Japanese patients with mild insulin resistance.

Topics: Adult; Aged; Asian People; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Fasting; Female; Humans; Insulin Resistance; Male; Middle Aged

The purpose of this investigation is to determine the role of osteopontin and adiponectin in the formation of arterial hypertension in adolescents with obesity. 67 adolescents with obesity have been examined. Two groups were composed taking into account the state of arterial pressure. The first group included adolescents with obesity and arterial hypertension, the second group - adolescents with obesity and without arterial hypertension. Arterial pressure was measured and serum content of osteopontin, insulin, C-peptid and adiponectin in blood has been determined. The result of the investigation has revealed that in adolescents without arterial pressure the growth of insulin and C-peptid in the serum of blood has been observed; in patients with obesity and arterial hypertension the increase of content of osteopontin and hypoadiponectinemia has been occurred. The revealed changes indicated about the pathogenic role of osteopontin and adiponectin in the formation of arterial hypertension in adolescents with obesity.

Topics: Adiponectin; Adolescent; Arterial Pressure; C-Peptide; Case-Control Studies; Female; Humans; Hypertension; Insulin; Insulin Resistance; Male; Obesity; Osteopontin

To assess the major determinants of glucose tolerance between age, genotype, and clinical status in cystic fibrosis (CF) patients, and study if defects of insulin secretion and insulin sensitivity were associated with the onset of CF-related diabetes (CFRD).. One hundred and nineteen patients, in stable clinical condition were studied. They were subdivided into 3 groups based on age, and 2 groups based on Schwachman-Kulczycki clinical score. All patients were genotyped, and subsequently divided into 3 groups. Ninety-four healthy normal-weight controls, comparable for sex and age were also studied. All subjects had baseline blood samples taken for glucose and insulin, C-peptide, and glycated hemoglobin. Homeostasis model assessment of insulin resistance (HOMA-IR), fasting glucose/insulin ratio (FGIR) were calculated as indices of IR and insulinogenic index as a marker of pancreatic β-cell function. All patients underwent an oral glucose tolerance test, and 57 underwent an IVGTT for the calculation of first-phase (FPIR) and acute insulin responses (AIR).. The F508del homozygous patients had an increased chance of developing impaired glucose tolerance (IGT) and significantly lower FPIR, decreased HOMA-IR, and insulinogenic index. Heterozygote F508del patients had an increased chance of having normal glucose tolerance. HOMA-IR, FGIR, and insulinogenic index did not change with age or clinical score. HOMAIR correlated with FPIR. FPIR correlated positively with insulinogenic index. AIR correlated negatively with FGIR, and positively with C-reactive protein. In multiple linear regression analyses, glucose tolerance was related to the agegroup, and to the HOMA-IR and insulinogenic indexes.. IGT and CFRD were related mainly to genotype, although, as expected, the prevalence increased with age. The data suggested a possible combined contribution of insulin deficiency, β-cell function, and reduced insulin sensitivity to the onset of CFRD; however, further studies are warranted to better elucidate this aspect.

Topics: Adolescent; Adult; Age Factors; Body Mass Index; C-Peptide; Child; Cystic Fibrosis; Female; Genotype; Glucose Tolerance Test; Homeostasis; Humans; Inflammation; Insulin; Insulin Resistance; Insulin-Secreting Cells; Lung; Male; Young Adult

No data is so far available on the relation between glucose values and insulin resistance and mortality, both at short- and long-term, in patients with acute heart failure syndromes (AHF). We prospectively assessed in 100 consecutive non-diabetic AHF patients whether acute glucose metabolism, as indicated by fasting glycemia and insulin resistance (HOMA index) was able to affect short- and long-term mortality. In the overall population, 51 patients showed admission glucose values >140 mg/dl. No significant difference was observed in admission and peak glycemia, insulin and C-peptide values and in HOMA-index between dead and survived patients. At multivariate logistic backward stepwise analysis the following variables were independent predictors for in-ICCU mortality (when adjusted for left ventricular ejection fraction): Fibrinogen (1 mg/dl increase) [OR (95% CI) 0.991 (0.984-0.997); p = 0.004]; NT-pro BNP (100 UI increase) [OR (95%CI) 1.005 (1.002-1.009); p = 0.004]; leukocyte count (1,000/μl increase) [OR (95%CI) 1.252 (1.070-1.464); p = 0.005]. eGFR was independently correlated with long-term mortality (HR 0.96, 95%CI 0.94-0.98, p < 0.001). In consecutive patients with acute heart failure without previously known diabetes, we documented, for the first time, that fasting glucose and insulin values and insulin resistance do not affect mortality at short- and long-term. Inflammatory activation (as indicated by the leukocyte count and the fibrinogen) and NT-pro BNP levels are independent predictors for early death while the eGFR affects the long-term mortality.

Topics: Acute Disease; Aged; Aged, 80 and over; Blood Glucose; C-Peptide; Diabetes Mellitus; Female; Glomerular Filtration Rate; Heart Failure; Humans; Hyperglycemia; Insulin; Insulin Resistance; Male; Middle Aged; Natriuretic Peptide, Brain; Prospective Studies

Postprandial glucose (PPG) is an independent predictor of cardiovascular events and death, regardless of diabetes status. Whereas changes in physical activity produce changes in insulin sensitivity, it is not clear whether changes in daily physical activity directly affect PPG in healthy free-living persons.. We used continuous glucose monitors to measure PPG and PPG excursions (ΔPPG, postmeal - premeal blood glucose) at 30-min increments after meals in healthy habitually active volunteers (n = 12, age = 29 ± 1 yr, body mass index = 23.6 ± 0.9 kg·m(-2), VO2max = 53.6 ± 3.0 mL·kg(-1)·min(-1)) during 3 d of habitual (≥10,000 steps per day) and reduced (<5000 steps per day) physical activity. Diets were standardized across monitoring periods, and fasting-state oral glucose tolerance tests (OGTT) were performed on the fourth day of each monitoring period.. During 3 d of reduced physical activity (12,956 ± 769 to 4319 ± 256 steps per day), PPG increased at 30 and 60 min after a meal (6.31 ± 0.19 to 6.68 ± 0.23 mmol·L(-1) and 5.75 ± 0.16 to 6.26 ± 0.28 mmol·L(-1), P < 0.05 relative to corresponding active time point), and ΔPPG increased by 42%, 97%, and 33% at 30, 60, and 90 min after a meal, respectively (P < 0.05). Insulin and C-peptide responses to the OGTT increased after 3 d of reduced activity (P < 0.05), and the glucose response to the OGTT did not change significantly.. Thus, despite evidence of compensatory increases in plasma insulin during an OGTT, ΔPPG assessed by continuous glucose monitoring systems increased markedly during 3 d of reduced physical activity in otherwise healthy free-living individuals. These data indicate that daily physical activity is an important mediator of glycemic control, even among healthy individuals, and reinforce the utility of physical activity in preventing pathologies associated with elevated PPG.

Topics: Adult; Blood Glucose; Body Mass Index; C-Peptide; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Male; Monitoring, Ambulatory; Motor Activity; Oxygen Consumption; Postprandial Period; Young Adult

Epidemiological evidence suggests that whole grain intake is associated with reduced risk of type 2 diabetes. However, studies of individual whole grains on the prevention of type 2 diabetes are lacking. The objective of the present study was to examine the effect of different whole grains on type 2 diabetes in an animal model of type 2 diabetes, the Goto-Kakisaki (GK) rat. GK rats were fed either a basal diet or a whole grain-containing diet for 5 months. Whole grain diets contained 65 % whole grain flours of wheat, barley, oats or maize. After 2 months of feeding, fasting plasma glucose concentrations were lower in the wheat, barley and oats groups, compared with the basal group, whereas glycated Hb was significantly greater in the wheat group compared with other groups. Feeding of whole barley and maize increased plasma C-peptide concentrations compared with whole wheat at 2 months. There was a trend in the improvement of insulin resistance with a consumption of barley and oats diets at 2 months (P = 0·06) compared with the basal diet. Oxidative stress markers, urinary thiobarbituric acid-reactive substances and 8-isoprostane, did not improve with whole grain intake at 2 months. At 5 months, whole grain diets did not differ from the basal diet in glycaemic control, insulin secretion, oxidative stress and preservation of pancreatic β-cell mass. These results suggest that the consumption of whole grains may offer modest benefit early in the development of type 2 diabetes, but this benefit is lost with further development of the disease.

Topics: Animals; Antioxidants; Biomarkers; C-Peptide; Diabetes Mellitus, Type 2; Dietary Fiber; Dinoprost; Disease Progression; Edible Grain; Food Handling; Functional Food; Glycated Hemoglobin; Hyperglycemia; Insulin Resistance; Insulin-Secreting Cells; Male; Oxidative Stress; Random Allocation; Rats; Rats, Mutant Strains; Rats, Wistar; Thiobarbituric Acid Reactive Substances

This study was designed to investigate the effect of aging on the glucose metabolism on cynomolgus (Macaca fascicularis) monkeys. A total of 33 cynomolgus monkeys in three aged groups were monitored for glucose levels, serum parameters in fasting state and somatometric measurements. Intravenous glucose tolerance test (IVGTT) and insulin tolerance test (ITT) were also performed. Aging associated changes lies in the less secretion of insulin and C-peptide during IVGTT in cynomolgus monkeys. It was also found that impaired insulin sensitivity occurred in female monkeys during aging based on HOMA-IR and K(ITT) value. In addition, triglyceride level also rose with the increase of age. Less insulin secretion and impaired insulin sensitivity in female were the characteristic during the aging of cynomolgus monkeys in this study. Body mass index, weight and waist hip rate may be the relevant factors in insulin resistance of cynomolgus monkeys.

Topics: Age Factors; Aging; Animals; Biomarkers; Blood Glucose; Body Mass Index; Body Weight; C-Peptide; Fasting; Female; Glucose Tolerance Test; Insulin; Insulin Resistance; Macaca fascicularis; Male; Models, Animal; Sex Factors; Time Factors; Triglycerides; Waist-Hip Ratio

Intravenous glucose tolerance tests have demonstrated lower whole-body insulin sensitivity (S(I)) among African Americans (AA) compared with European Americans (EA). Whole-body S(I) represents both insulin-stimulated glucose disposal, primarily by skeletal muscle, and insulin's suppression of endogenous glucose production (EGP) by liver. A mathematical model was recently introduced that allows for distinction between disposal and hepatic S(I). The purpose of this study was to examine specific indexes of S(I) among AA and EA women to determine whether lower whole-body S(I) in AA may be attributed to insulin action at muscle, liver, or both. Participants were 53 nondiabetic, premenopausal AA and EA women. Profiles of EGP and indexes of Disposal S(I) and Hepatic S(I) were calculated by mathematical modeling and incorporation of a stable isotope tracer ([6,6-(2)H(2)]glucose) into the intravenous glucose tolerance test. Body composition was assessed by dual-energy x-ray absorptiometry. After adjustment for percentage fat, both Disposal S(I) and Hepatic S(I) were lower among AA (P = .009 for both). Time profiles for serum insulin and EGP revealed higher peak insulin response and corresponding lower EGP among AA women compared with EA. Indexes from a recently introduced mathematical model suggest that lower whole-body S(I) among nondiabetic AA women is due to both hepatic and peripheral components. Despite lower Hepatic S(I), AA displayed lower EGP, resulting from higher postchallenge insulin levels. Future research is needed to determine the physiological basis of lower insulin sensitivity among AA and its implications for type 2 diabetes mellitus risk.

Topics: Absorptiometry, Photon; Adolescent; Adult; Algorithms; Black or African American; Blood Glucose; C-Peptide; Ethnicity; Female; Glucose; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Liver; United States; White People; Young Adult

The aim of the present study was to determine the effects of a cafeteria diet on the function and apoptosis of the pancreas, and the activity and expression of the insulin-degrading enzyme (IDE). Female Wistar rats were fed either with a cafeteria diet or a control diet for 17 weeks, and blood and tissues were then collected for analysis. The cafeteria diet-treated rats had higher plasma insulin and C-peptide levels (P<0·05), showing increased insulin secretion by the pancreas. Insulin protein and gene expression levels were higher in the pancreas of obese rats, as was its transcriptional controller, pancreatic duodenal homeobox 1 (P<0·05). Feeding a cafeteria diet down-regulated the gene expression of the anti-apoptotic marker B-cell/lymphoma 2 (BCL2), and up-regulated the protein levels of BCL2-associated X protein, a pro-apoptotic marker (P<0·05). The cafeteria diet caused lipid accumulation in the pancreas and modified the expression of key genes that control lipid metabolism. To assay whether insulin clearance was also modified, we checked the activity of the IDE, one of the enzymes responsible for insulin clearance. We found increased liver IDE activity (P<0·05) in the cafeteria diet-fed animals, which could, in part, be due to an up-regulation of its gene expression. Conversely, IDE gene expression was unmodified in the kidney and adipose tissue; although when the adipose tissue weight was considered, the insulin clearance potential was higher in the cafeteria diet-treated rats. In conclusion, treatment with a cafeteria diet for 17 weeks in rats mimicked a pre-diabetic state, with ectopic lipid accumulation in the pancreas, and increased the IDE-mediated insulin clearance capability.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; C-Peptide; Diet, High-Fat; Disease Models, Animal; Female; Gene Expression Regulation; Homeodomain Proteins; Hyperinsulinism; Insulin; Insulin Resistance; Insulysin; Liver; Organ Specificity; Pancreas; Prediabetic State; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Wistar; RNA, Messenger; Trans-Activators; Triglycerides

The purpose of the study was to compare the effects of maximal resistance training (MRT) vs. endurance resistance training (ERT) on improvements in insulin levels and glucose tolerance in overweight individuals at risk of developing type 2 diabetes. Eighteen participants with baseline values suggesting impaired glucose tolerance were randomly assigned to 1 of 2 groups. Group 1 engaged in supervised MRT (Bernstein inverted pyramid system: 5 × 3-4, 60-85% 1 repetition maximum [1RM]), 3 d·wk(-1) over 4 months, whereas members of group 2 acted as controls. Later, group 2 engaged in supervised ERT (3 × 12-15, 45-65% 1RM), 3 d·wk(-1) over a 4 month period with the 2 prebaselines as controls. Both interventions consisted of 8 exercises that included the entire body. Glucose (fasting and 2-hour test), insulin and C-peptide measures were assessed from pre to post in both groups. The MRT led to reduced blood levels of 2-hour glucose (p = 0.044) and fasting C-peptide (p = 0.023) and decreased insulin resistance (p = 0.040). The ERT caused a significant reduction in the blood levels of insulin (p = 0.023) and concomitant positive effects on % insulin sensitivity (p = 0.054) and beta-cell function (p = 0.020). The findings indicate that both MRT and ERT lead to decreased insulin resistance in people with a risk of developing type 2 diabetes; MRT led to a greater increase in glucose uptake capacity (in muscles), whereas ERT led to greater insulin sensitivity, supporting the recommendation of both MRT and ERT as primary intervention approaches for individuals at a risk of developing type 2 diabetes.

Topics: Adult; Aged; Analysis of Variance; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 1; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Overweight; Physical Endurance; Random Allocation; Resistance Training

Type 2 diabetes (T2D) is characterized by insulin resistance and pancreatic β-cell dysfunction, the latter possibly caused by a defect in insulin signaling in β-cells. We hypothesized that insulin's effect to potentiate glucose-stimulated insulin secretion (GSIS) would be diminished in insulin-resistant persons. To evaluate the effect of insulin to modulate GSIS in insulin-resistant compared with insulin-sensitive subjects, 10 participants with impaired glucose tolerance (IGT), 11 with T2D, and 8 healthy control subjects were studied on two occasions. The insulin secretory response was assessed by the administration of dextrose for 80 min following a 4-h clamp with either saline infusion (sham) or an isoglycemic-hyperinsulinemic clamp using B28-Asp-insulin (which can be distinguished immunologically from endogenous insulin) that raised insulin concentrations to high physiologic concentrations. Pre-exposure to insulin augmented GSIS in healthy persons. This effect was attenuated in insulin-resistant cohorts, both those with IGT and those with T2D. Insulin potentiates glucose-stimulated insulin secretion in insulin-resistant subjects to a lesser degree than in normal subjects. This is consistent with an effect of insulin to regulate β-cell function in humans in vivo with therapeutic implications.

Topics: Adult; Blood Glucose; C-Peptide; Calcium; Diabetes Mellitus, Type 2; Female; Glucose; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Middle Aged

We have previously investigated effects of moderate maternal zinc (Zn) restriction on growth and glucose homeostasis in offspring, but interaction between maternal Zn restriction and postnatal nutrition have not been studied.. Weight and serum Zn were lower in ZnD-IN than in ZnC-IN rats at wk 3, but ZnD-AN and ZnD-EN rats had greater weights than respective controls and higher insulin-like growth factor-1 (ZnD-AN) and leptin levels (ZnD-EN). Subsequently, both ZnD-AN and ZnD-EN pups were insulin resistant, and had evidence of elevated serum leptin and depressed insulin receptor phosphorylation with gender-specific differences up to 15 weeks.. Maternal Zn restriction interacted with postnatal nutritional status, resulting in divergent effects on weight gain and insulin resistance. Interaction between potential effects of fetal Zn restriction and food availability postnatally may be one factor responsible for later metabolic derangements.. Rats were fed Zn restricted (ZnD, 7 μg/g) or control (ZnC, 25 μg/g) diets ad libitum from 3 wk pre-conception to 3 wk post-parturition. Postnatally, litters were culled to 13 (IN, inadequate nutrition), 7 (AN, adequate nutrition), and 4 (EN, excess nutrition) pups/dam, respectively, and nursed by their original mothers. Postweaning, pups were fed rodent diet ad libitum. Tests to assess insulin resistance were performed subsequently.

Topics: Animals; Animals, Newborn; C-Peptide; Female; Glucose; Homeostasis; Insulin; Insulin Resistance; Insulin-Like Growth Factor I; Leptin; Male; Models, Animal; Nutritional Status; Pregnancy; Prenatal Exposure Delayed Effects; Rats; Rats, Sprague-Dawley; Sex Characteristics; Zinc

This study analysed the relationship of plasma testosterone with β-cell secretion, insulin sensitivity and other pituitary-target gland hormones in normoglycaemic adult men. The sample frame was the 'Offspring of individuals with diabetes study' database. A total of 358 offspring of individuals with type-2 diabetes (T2DM) and 287 individuals without known family history of T2DM were recruited for the study. Normoglycaemic men aged ≥18 years (maximum 55) were selected for this analysis. All participants underwent 75 g oral glucose tolerance test (OGTT); blood samples were collected at 0, 30, 60 and 120 min for plasma insulin and C-peptide. Total testosterone, cortisol, adrenocorticotropic hormone, thyroid stimulating hormone and thyroxine (T4) were measured in the fasting sample. A total of 164 men (age 28 ± 7.7 years) were included in analysis. Testosterone correlated negatively with BMI, waist to hip ratio (WHR), area under curve (AUC) of C-peptide and insulin (during OGTT) and was positively correlated with insulin sensitivity (r ~ 0.4). Cortisol and T4 positively correlated (weak) with testosterone (r ~ 0.2). In multivariate analysis, AUC C-peptide, BMI, WHR (negatively) and cortisol (positively) were related to testosterone. Concluding, testosterone correlated negatively with BMI and β-cell secretion. There was a positive association of testosterone with insulin sensitivity, cortisol and T4.

Topics: Adult; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Glucose Tolerance Test; Humans; Hydrocortisone; Hyperinsulinism; Insulin; Insulin Resistance; Male; Middle Aged; Testosterone; Thyrotropin; Thyroxine

The aim of this study was to assess the prevalence of diabetes and to study the effects of excess growth hormone (GH) on insulin sensitivity and β-cell function in Korean acromegalic patients. One hundred and eighty-four acromegalic patients were analyzed to assess the prevalence of diabetes, and 52 naïve acromegalic patients were enrolled in order to analyze insulin sensitivity and insulin secretion. Patients underwent a 75 g oral glucose tolerance test with measurements of GH, glucose, insulin, and C-peptide levels. The insulin sensitivity index and β-cell function index were calculated and compared according to glucose status. Changes in the insulin sensitivity index and β-cell function index were evaluated one to two months after surgery. Of the 184 patients, 17.4% were in the normal glucose tolerance (NGT) group, 45.1% were in the pre-diabetic group and 37.5% were in the diabetic group. The insulin sensitivity index (ISI(0,120)) was significantly higher and the HOMA-IR was lower in the NGT compared to the diabetic group (P = 0.001 and P = 0.037, respectively). The ISI(0,120) and disposition index were significantly improved after tumor resection. Our findings suggest that both insulin sensitivity and β-cell function are improved by tumor resection in acromegalic patients.

Topics: Acromegaly; Adult; Asian People; Blood Glucose; C-Peptide; Diabetes Mellitus; Female; Glucose Tolerance Test; Human Growth Hormone; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Middle Aged; Prediabetic State; Republic of Korea

Roux-en-Y gastric bypass (RYGB) surgery causes profound changes in secretion of gastrointestinal hormones and glucose metabolism. We present a detailed analysis of the early hormone changes after RYGB in response to three different oral test meals designed to provide this information without causing side effects (such as dumping).. We examined eight obese non-diabetic patients before and within 2 weeks after RYGB. On separate days, oral glucose tolerance tests (25 or 50 g glucose dissolved in 200 mL of water) and a liquid mixed meal test (200 mL 300 kcal) were performed. We measured fasting and postprandial glucose, insulin, C-peptide, glucagon, total and intact glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-2 (GLP-2), peptide YY(3-36) (PYY), cholecystokinin (CCK), total and active ghrelin, gastrin, somatostatin, pancreatic polypeptide (PP), amylin, leptin, free fatty acids (FFA), and registered postprandial dumping. Insulin sensitivity was measured by homeostasis model assessment of insulin resistance.. Fasting glucose, insulin, ghrelin, and PYY were significantly decreased and FFA was elevated postoperatively. Insulin sensitivity increased after surgery. The postprandial response increased for C-peptide, GLP-1, GLP-2, PYY, CCK, and glucagon (in response to the mixed meal) and decreased for total and active ghrelin, leptin, and gastrin, but were unchanged for GIP, amylin, PP, and somatostatin after surgery. Dumping symptoms did not differ before and after the operation or between the tests.. Within 2 weeks after RYGB, we found an increase in insulin secretion and insulin sensitivity. Responses of appetite-regulating intestinal hormones changed dramatically, all in the direction of reducing hunger.

Topics: Adult; Appetite; C-Peptide; Cholecystokinin; Confounding Factors, Epidemiologic; Female; Gastric Bypass; Gastric Inhibitory Polypeptide; Gastrins; Gastrointestinal Hormones; Ghrelin; Glucagon; Glucagon-Like Peptide 1; Glucagon-Like Peptide 2; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Islet Amyloid Polypeptide; Leptin; Male; Middle Aged; Obesity, Morbid; Pancreatic Polypeptide; Peptide YY; Postprandial Period; Somatostatin; Time Factors; Weight Loss

Gut hormones play a role in diabetes remission after a Roux-en-Y gastric bypass (RYGB). Our aim was to investigate differences in gut hormone secretion according to diabetes remission after surgery. Second, we aimed to identify differences in insulin secretion and sensitivity according to diabetes remission after RYGB.. Twenty-two severely obese patients with type 2 diabetes underwent RYGB. A meal tolerance test (MTT) was performed 12 months after RYGB. The secretions of active glucagon-like peptide-1 (active GLP-1), glucose-dependent insulinotropic peptide (GIP), peptide YY, C-peptide and insulin during the MTT test were calculated using total area under the curve values (AUC). Remission was defined as glycated haemoglobin (A(1C)) of <6.5% and a fasting glucose concentration of <126 mg/dL for 1 year or more without active pharmacological therapy.. Of the 22 patients, 16 (73%) had diabetes remission (remission group). The secretion CURVES of active GLP-1, GIP and peptide YY were not different between the groups. AUC of insulin and C-peptide were also not different. Homeostasis model assessment estimate of insulin resistance was significantly lower (1.26 ± 1.05 versus 2.37 ± 1.08, p = 0.006), and Matsuda index of insulin sensitivity was significantly higher in the remission group (10.5 ± 6.2 versus 5.8 ± 2.1, p = 0.039). The disposition index (functional reserve of beta cells) was significantly higher in the remission group compared with that in the non-remission group (5.34 ± 2.74 versus 1.83 ± 0.70, p < 0.001).. Remission of diabetes after RYGB is not associated with a difference in gut hormone secretion. Patients remaining diabetic had higher insulin resistance and decreased β cell functional reserve.

Topics: Adult; Blood Glucose; C-Peptide; Case-Control Studies; Diabetes Complications; Diabetes Mellitus, Type 2; Female; Gastric Bypass; Glucagon-Like Peptide 1; Glucose Tolerance Test; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Obesity; Prognosis; Prospective Studies; Remission Induction; Young Adult

Insulin is pivotal in regulating hepatic lipid synthesis, metabolism, and export.. We tested the hypothesis that intrahepatic insulin exposure is an important determinant of intrahepatocellular lipid (IHCL), taking into account regional adiposity and both glucoregulatory and antilipolytic insulin sensitivity.. We compared 21 European males with known nonalcoholic fatty liver disease (NAFLD) with 19 healthy male controls. Insulin sensitivity, secretion, and percentage hepatic extraction were derived from iv glucose tolerance test (IVGTT) glucose, insulin, and C-peptide concentrations. Intrahepatic insulin exposure was calculated as percentage hepatic insulin extraction multiplied by basal or IVGTT insulin secretion. IHCL was quantified by proton magnetic resonance spectroscopy. Total and regional adipose tissue was measured using whole body magnetic resonance imaging.. Percentage hepatic extraction of newly secreted insulin differed between cases with NAFLD and controls at borderline significance (median, 76 vs. 83%; P = 0.07). Cases had higher intrahepatic insulin exposure than controls, both in the basal (34 vs. 18 pmol; P = 0.0002) and glucose-stimulated states (58 vs. 24 pmol; P = 0.01). IHCL was significantly related to both basal (r(s) = 0.62; P < 0.0001) and IVGTT intrahepatic insulin exposure (r(s) = 0.47; P = 0.002). As predictors of IHCL, both basal and IVGTT intrahepatic insulin exposure were dependent on the waist-to-hip ratio and homeostasis model assessment insulin resistance, but not on magnetic resonance imaging fat measures or IVGTT insulin sensitivity.. Men with NAFLD have higher intrahepatic insulin exposure than controls. This correlates with IHCL, but the principal determinants of IHCL were fat distribution and hepatic rather than peripheral insulin resistance.

Topics: Adipose Tissue; Adult; Aged; Blood Glucose; C-Peptide; Cohort Studies; Fatty Liver; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Lipid Metabolism; Liver; Magnetic Resonance Imaging; Male; Middle Aged; Non-alcoholic Fatty Liver Disease; Young Adult

Insufficient sleep is associated with changes in glucose tolerance, insulin secretion, and insulin action. Despite widespread use of weight-loss diets for metabolic risk reduction, the effects of insufficient sleep on glucose regulation in overweight dieters are not known. To examine the consequences of recurrent sleep restriction on 24-h blood glucose control during diet-induced weight loss, 10 overweight and obese adults (3F/7M; mean (s.d.) age 41 (5) years; BMI 27.4 (2.0) kg/m(2)) completed two 14-day treatments with hypocaloric diet and 8.5- or 5.5-h nighttime sleep opportunity in random order 7 (3) months apart. Oral and intravenous glucose tolerance test (IVGTT) data, fasting lipids and free fatty acids (FFA), 24-h blood glucose, insulin, C-peptide, and counter-regulatory hormone measurements were collected after each treatment. Participants had comparable weight loss (1.0 (0.3) BMI units) during each treatment. Bedtime restriction reduced sleep by 131 (30) min/day. Recurrent sleep curtailment decreased 24-h serum insulin concentrations (i.e., enhanced 24-h insulin economy) without changes in oral glucose tolerance and 24-h glucose control. This was accompanied by a decline in fasting blood glucose, increased fasting FFA, which suppressed normally following glucose ingestion, and lower total and low-density lipoprotein cholesterol concentrations. Sleep-loss-related changes in counter-regulatory hormone secretion during the IVGTT limited the utility of the test in this study. In conclusion, sleep restriction enhanced 24-h insulin economy without compromising glucose homeostasis in overweight individuals placed on a balanced hypocaloric diet. The changes in fasting blood glucose, insulin, lipid and FFA concentrations in sleep-restricted dieters resembled the pattern of human metabolic adaptation to reduced carbohydrate availability.

Topics: Adult; Blood Glucose; C-Peptide; Diet, Reducing; Fasting; Fatty Acids, Nonesterified; Female; Glucose Tolerance Test; Humans; Insulin Resistance; Insulin-Secreting Cells; Lipids; Male; Obesity; Sedentary Behavior; Sleep Deprivation; Weight Loss

Insulin resistance (IR) is an independent risk factor for atherosclerosis or cardiovascular events and renal function impairment. The aim of this study was to investigate IR in children with primary nephrotic syndrome (NS).. One-hundred and nineteen primary NS patients with normal renal function and 125 normal controls were studied. Fasting blood glucose, fasting serum insulin, and fasting serum C-peptide were measured. The Homa index of insulin resistance (HOMA-IR), Islet B cell function, and insulin sensitivity index were calculated. Correlations were assessed between HOMA-IR, fasting serum C-peptide, blood pressure, blood lipids, renal function, coagulation, clinical disease type, pathology and the early therapeutic effectiveness of high-dose glucocorticoids.. There was no evidence of IR in the primary NS group. Although levels of fasting blood glucose, fasting serum insulin and fasting serum C-peptide were all within the normal ranges, fasting serum C-peptide was significantly higher compared to the controls. There was no disorder of carbohydrate metabolism in different hormone therapy efficacy and pathological diagnosis. Although IR was not detected, a significant increase in blood pressure, uric acid, blood lipids and coagulability was observed in the primary NS group.. A correlation observed between HOMA-IR, age, blood pressure, serum creatinine (Cr) and triglyceride may suggest that insulin sensitivity will emerge as renal disease progresses. Fasting serum C-peptide levels were increased in the primary NS group, suggesting that fasting serum C-peptide may be a protective factor.

Topics: Adolescent; Biomarkers; Blood Coagulation; Blood Glucose; Blood Pressure; C-Peptide; Case-Control Studies; Child; Child, Preschool; China; Cross-Sectional Studies; Disease Progression; Fasting; Female; Glomerular Filtration Rate; Glucocorticoids; Humans; Infant; Insulin; Insulin Resistance; Insulin-Secreting Cells; Kidney; Linear Models; Lipids; Male; Multivariate Analysis; Nephrotic Syndrome; Treatment Outcome

To correctly evaluate the glucose control system, it is crucial to account for both insulin sensitivity and secretion. The disposition index (DI) is the most widely accepted method to do so. The original paradigm (hyperbolic law) consists of the multiplicative product of indices related to insulin sensitivity and secretion, but more recently, an alternative formula has been proposed with the exponent α (power function law). Traditionally, curve-fitting approaches have been used to evaluate the DI in a population: the algorithmic implementations often introduce some critical issues, such as the assumption that one of the two indices is error free or the effects of the log transformation on the measurement errors. In this work, we review the commonly used approaches and show that they provide biased estimates. Then we propose a novel nonlinear total least square (NLTLS) approach, which does not need to use the approximations built in the previously proposed alternatives, and show its superiority. All of the traditional fit procedures, including NLTLS, account only for uncertainty affecting insulin sensitivity and secretion indices when they are estimated from noisy data. Thus, they fail when part of the observed variability is due to inherent differences in DI values between individuals. To handle this inevitable source of variability, we propose a nonlinear mixed-effects approach that describes the DI using population hyperparameters such as the population typical values and covariance matrix. On simulated data, this novel technique is much more reliable than the curve-fitting approaches, and it proves robust even when no or small population variability is present in the DI values. Applying this new approach to the analysis of real IVGTT data suggests a value of α significantly smaller than 1, supporting the importance of testing the power function law as an alternative to the simpler hyperbolic law.

Topics: Adult; Aged; Aging; Algorithms; Blood Glucose; C-Peptide; Computer Simulation; Glucose Tolerance Test; Homeostasis; Humans; Hyperglycemia; Hypoglycemia; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Least-Squares Analysis; Middle Aged; Models, Biological; Nonlinear Dynamics; Young Adult

It remains unsettled whether dietary patterns play a role in insulin resistance. We assessed the association of major dietary patterns with C-peptide concentrations in a Japanese working population.. A cross-sectional study was conducted in 456 municipal employees (270 men and 186 women) 21 to 67 y old who participated in a health survey at the time of their periodic checkup. The dietary patterns were derived by using the principal component analysis of the consumption of 52 food and beverage items, which was assessed by a validated brief dietary history questionnaire. Multiple regression analysis was used to estimate the means of C-peptide concentrations across tertiles of each dietary pattern score with the adjustment of potential confounders, including age, body mass index, physical activity, smoking, alcohol drinking, and energy intake.. We identified three dietary patterns: healthy, animal food, and Westernized breakfast patterns. The Westernized breakfast pattern was characterized by high intakes of bread, confectionaries, and milk and yogurt but low intakes of rice and alcohol and was inversely associated with C-peptide concentrations in women but not in men. The multivariable-adjusted means of C-peptide concentrations were 1.03 ng/mL (95% confidence interval 0.95-1.12), 0.95 ng/mL (95% confidence interval 0.88-1.03), and 0.89 ng/mL (95% confidence interval 0.82-0.97) for the lowest through the highest tertiles of the Westernized breakfast pattern score (P for trend = 0.015) in women. Other dietary patterns were not appreciably associated with C-peptide concentrations. In a subgroup, similar associations were observed between dietary patterns and the homeostasis model assessment of insulin resistance.. The Westernized breakfast pattern may be associated with a lower insulin resistance in Japanese women.

Topics: Adult; Aged; Animals; Breakfast; C-Peptide; Confidence Intervals; Cross-Sectional Studies; Diet; Feeding Behavior; Female; Health Surveys; Humans; Insulin Resistance; Japan; Male; Middle Aged; Multivariate Analysis; Principal Component Analysis; Sex Factors; Surveys and Questionnaires; Young Adult

Our group has reported a high incidence of reactive hypoglycemia following Roux-en-Y gastric bypass (RYGB) with specific interest in postprandial insulin and the ratio of 1- to 2-h serum glucose levels. The purpose of this study is to compare the 6-month response to oral glucose challenge in patients undergoing RYGB, duodenal switch (DS), and vertical sleeve gastrectomy (VSG).. Thirty-eight patients meeting the NIH criteria for bariatric surgery who have reached the 6-month postoperative mark are the basis of this report. Preoperatively and at 6 months follow-up, patients underwent blood draw to determine levels of fasting glucose, fasting insulin, HbA1c, C peptide, and 2 h oral liquid glucose challenge test (OGTT). HOMA-IR and 1 to 2 h ratios of glucose and fasting to 1 h ratio of insulin were calculated.. All patients underwent a successful laparoscopic bariatric procedure (VSG =13, DS =13, and RYGB = 12). All operations reduced BMI, HgbA1c, fasting glucose, and fasting insulin. HOMA IR and glucose tolerance improved with all procedures. In response to OGTT at 6 months, there was a 20-fold increase in insulin at 1 h in RYGB, which was not seen in DS. At 6 months, 1-h insulin was markedly lower in DS (p < .05), yet HbA1C was also lower in DS (p < .05). This resulted in 1- to 2-h glucose ratio of 1.9 for RYGB, 1.8 for VSG, and 1.3 for DS (p < .05).. All operations improve insulin sensitivity and decrease HgbA1c. Six-month weight loss was substantial in all groups between 22-29% excess body weight. RYGB results in marked rise in glucose following challenge with corresponding rise in 1-h insulin. VSG has a similar response to RYGB. In comparison, at 6 months following surgery, DS causes a much lower rise in 1-h insulin, with this difference being statistically significant at p < .05. As a result, DS results in a less abrupt reduction in blood glucose. Although 1-h insulin is lower, DS patients had the lowest HbA1C at 6 months (p < .05). We believe that these findings have important implications for the choice of bariatric procedure for both diabetic and non-diabetic patients.

Topics: Adult; Blood Glucose; Body Mass Index; C-Peptide; Duodenum; Female; Follow-Up Studies; Gastric Bypass; Gastroplasty; Glucose Tolerance Test; Glycated Hemoglobin; Homeostasis; Humans; Hypoglycemia; Insulin Resistance; Male; Obesity, Morbid; Prospective Studies; Treatment Outcome; Weight Loss

The dynamic response to insulin is highly potentiated after meal ingestion, and this meal-induced insulin sensitization (MIS) in healthy subjects is dependent on cholinergic mechanisms. The main objective of this study was to test the hypothesis that the reduced response to insulin observed in moderately overweight subjects, in comparison with control lean subjects, is due to MIS impairment and not to a reduction in the direct hypoglycemic action of insulin. Both lean and overweight male subjects were recruited. Insulin sensitivity (IS) was assessed by the rapid insulin sensitivity test (RIST) performed after a 24 h fast, as well as after a standardized meal. Fasting glucose disposal was similar between lean and overweight subjects. Following the meal, glucose disposal increased more extensively in lean than overweight subjects. The insulin profiles, in both fasted and fed states, were superimposable, suggesting that the absence of a factor other than insulin is responsible for the decreased postprandial insulin sensitivity observed in overweight subjects. Our data suggest that in overweight subjects, MIS contribution is decreased, which is responsible for the postprandial impaired IS observed and is suggested to be the cause, not effect, of mild adiposity.

Topics: Adult; Blood Glucose; C-Peptide; Energy Metabolism; Fasting; Glucose; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Overweight; Postprandial Period

Large for gestational age (LAG) neonates who had been exposed to an intrauterine environment of either diabetes or maternal obesity are at increased risk of developing the metabolic syndrome. This can be explained by exposure to high glucose and insulin levels in utero which alter fetal adaptation and programming.. The aim of the study was to evaluate the onset of preclinical atherosclerosis in utero.. We measured umbilical artery wall thickness (ruWT) in the third trimester by obstetric ultrasound and umbilical artery intima-media thickness (uIMT) in pathologic specimens of umbilical cords obtained shortly after delivery and investigated the relation between these measurements and serum insulin level and C-peptide level in cord blood and assessed insulin resistance with the homeostasis model assessment of insulin resistance (HOMA-IR) in infants of diabetic mothers (IDMs), i.e. the study group, which was divided into a large for gestational age group (LGA)-IDM group and an appropriate for gestational age group (AGA)-IDM group and compared with a control group.. The LGA-IDM group had significantly higher insulin (p < 0.001), C-peptide (p = 0.018) and HOMA-IR levels (p < 0.001) compared with the AGA-IDM and control groups. The LGA-IDM group had significantly larger ruWT (p = 0.013) and uIMT (p < 0.001) compared with the AGA-IDM and the control groups. The LGA-IDM group had increased uIMT and ruWT that correlated with the severity of maternal hyperglycemia.. Measurement of ruWT in the third trimester is feasible, reproducible and strongly correlated with pathological serum insulin, C-peptide in cord blood and HOMA-IR levels.

Topics: Adult; Atherosclerosis; C-Peptide; Case-Control Studies; Chi-Square Distribution; Diabetes, Gestational; Diabetic Angiopathies; Female; Fetal Blood; Gestational Age; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Predictive Value of Tests; Pregnancy; Pregnancy Trimester, Third; Prospective Studies; Tunica Intima; Tunica Media; Turkey; Ultrasonography; Umbilical Arteries

Two groups of breast cancer patients (53±2 years) in clinical remission receiving no specific therapy were examined: group 1, with BRCA1 gene mutations (N=11) and group 2, without mutations of this kind (N=11). The two groups did not differ by insulinemia and glycemia, insulin resistance index, blood levels of thyrotropic hormone, sex hormone-binding globulin, insulin-like growth factor-1, triglycerides, or lipoproteins. In group 1, blood estradiol level was higher. Intensive glucose-induced generation of reactive oxygen species in these patients was associated with a decrease of cholesterolemia, of the C-peptide/insulin proportion, and a trend to higher urinary excretion of 4-hydroxyestrone, one of the most genotoxic catecholestrogens. BRCA1 gene mutations in breast cancer patients were associated with signs of estrogenization and a pro-genotoxic shift in the estrogen and glucose system, which could modulate the disease course and requires correction.

Topics: Blood Glucose; BRCA1 Protein; Breast Neoplasms; C-Peptide; Endocrine System; Estradiol; Female; Humans; Hydroxyestrones; Insulin; Insulin Resistance; Insulin-Like Growth Factor I; Lipoproteins; Middle Aged; Mutation; Reactive Oxygen Species; Sex Hormone-Binding Globulin; Thyrotropin; Triglycerides

To ascertain to which extent the use of HbA(1c) and oral glucose tolerance test (OGTT) for diagnosis of glucose tolerance could identify individuals with different pathogenetic mechanisms and cardiovascular risk profile.. A total of 844 subjects (44% men; age 49.5 ± 11 years; BMI 29 ± 5 kg/m(2)) participated in this study. Parameters of β-cell function were derived from deconvolution of the plasma C-peptide concentration after a 75-g OGTT and insulin sensitivity assessed by homeostasis model assessment of insulin resistance (IR). Cardiovascular risk profile was based on determination of plasma lipids and measurements of body weight, waist circumference, and blood pressure. Glucose regulation categories by OGTT and HbA(1c) were compared with respect to insulin action, insulin secretion, and cardiovascular risk profile.. OGTT results showed 42% of the subjects had prediabetes and 15% had type 2 diabetes mellitus (T2DM), whereas the corresponding figures based on HbA(1c) were 38 and 11%, with a respective concordance rate of 54 and 44%. Subjects meeting both diagnostic criteria for prediabetes presented greater IR and impairment of insulin secretion and had a worse cardiovascular risk profile than those with normal glucose tolerance at both diagnostic methods. In a logistic regression analyses adjusted for age, sex, and BMI, prediabetic subjects, and even more T2DM subjects by OGTT, had greater chance to have IR and impaired insulin secretion.. HbA(1c) identifies a smaller proportion of prediabetic individuals and even a smaller proportion of T2DM individuals than OGTT, with no difference in IR, insulin secretion, and cardiovascular risk profile. Subjects fulfilling both diagnostic methods for prediabetes or T2DM are characterized by a worse metabolic profile.

Topics: Adult; C-Peptide; Cardiovascular Diseases; Diabetes Mellitus, Type 2; Female; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Insulin Resistance; Male; Middle Aged; Prediabetic State

Low birthweight (BW) is associated with increased risk of type 2 diabetes. We compared glucose metabolism in adult BW-discordant monozygotic (MZ) twins, thereby controlling for genetic factors and rearing environment.. Among 77,885 twins in the Danish Twin Registry, 155 of the most BW-discordant MZ twin pairs (median BW difference 0.5 kg) were assessed using a 2 h oral glucose tolerance test with sampling of plasma (p-)glucose, insulin, C-peptide, glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1. HOMA for beta cell function (HOMA-β) and insulin resistance (HOMA-IR), and also insulin sensitivity index (BIGTT-SI) and acute insulin response (BIGTT-AIR), were calculated. Subgroup analyses were performed in those with: (1) double verification of BW difference; (2) difference in BW >0.5 kg; and (3) no overt metabolic disease (type 2 diabetes, hyperlipidaemia or thyroid disease).. No intra-pair differences in p-glucose, insulin, C-peptide, incretin hormones, HOMA-β, HOMA-IR or BIGTT-SI were identified. p-Glucose at 120 min was higher in the twins with the highest BW without metabolic disease, and BIGTT-AIR was higher in those with the highest BW although not in pairs with a BW difference of >0.5 kg.. BW-discordant MZ twins provide no evidence for a detrimental effect of low BW on glucose metabolism in adulthood once genetic factors and rearing environment are controlled for.

Topics: Adult; Aged; Analysis of Variance; Birth Weight; Blood Glucose; C-Peptide; Denmark; Diabetes Mellitus, Type 2; Disease Susceptibility; Female; Glucagon-Like Peptide 1; Glucose Intolerance; Glucose Tolerance Test; Humans; Infant, Low Birth Weight; Infant, Newborn; Insulin Resistance; Logistic Models; Male; Middle Aged; Risk Factors; Surveys and Questionnaires; Twins, Monozygotic

Few studies have explored the epidemiology of beta cell loss in youth with diabetes. This report describes the evolution and major determinants of beta cell function, assessed by fasting C-peptide (FCP), in the SEARCH for Diabetes in Youth study.. Participants were 1,277 youth with diabetes (948 positive for diabetes autoantibodies [DAs] and 329 negative for DAs), diagnosed when aged <20 years, who were followed from a median of 8 months post diagnosis, for approximately 30 months. We modelled the relationship between rate of change in log FCP and determinants of interest using repeated measures general linear models.. Among DA-positive youth, there was a progressive decline in beta cell function of 4% per month, independent of demographics (age, sex, race/ethnicity), genetic susceptibility to autoimmunity (HLA risk), HbA(1c) and BMI z score, or presence of insulin resistance. Among DA-negative youth, there was marked heterogeneity in beta cell loss, reflecting an aetiologically mixed group. This group likely includes youths with undetected autoimmunity (whose decline is similar to that of DA-positive youth) and youth with non-autoimmune, insulin-resistant diabetes, with limited decline (~0.7% per month).. SEARCH provides unique estimates of beta cell function decline in a large sample of youth with diabetes, indicating that autoimmunity is the major contributor. These data contribute to a better understanding of clinical evolution of beta cell function in youth with diabetes, provide strong support for the aetiological classification of diabetes type and may inform tertiary prevention efforts targeted at high-risk groups.

Topics: Adolescent; Age of Onset; Autoantibodies; Biomarkers; Body Mass Index; C-Peptide; Child; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Disease Progression; Fasting; Female; Glycated Hemoglobin; Humans; Insulin Resistance; Insulin-Secreting Cells; Male; Predictive Value of Tests; Risk Factors; United States

Plasma C-peptide reflects the insulin-secretory activity of pancreatic β-cells which modulates fetal growth. Cord blood C-peptide levels were measured in women with gestational diabetes mellitus (GDM) and in women with normal glucose tolerance (NGT). Forty-one women underwent a 75-g oral glucose tolerance test (18 GDM, 23 NGT). Cord blood C-peptide (p = 0.09) and glucose levels (p = 0.08) from newborns of GDM women tended to be higher than those from NGT women. In the entire group, cord blood C-peptide correlated with maternal insulin, fasting C-peptide, insulin sensitivity, interleukin-6, weight and body mass index measured at screening (ρ from 0.34 to 0.48, all p < 0.05) and tended to correlate with offspring weight (ρ = 0.28, p = 0.08). Newborns of GDM women tended to have elevated cord blood C-peptide which correlated with maternal insulin, insulin sensitivity and anthropometric measures at diagnosis and with offspring characteristics. This suggests that insulin-secretory activity of the newborn is related to maternal metabolic parameters.

Topics: Adult; Body Mass Index; C-Peptide; Diabetes, Gestational; Female; Fetal Blood; Glucose Tolerance Test; Humans; Insulin Resistance; Interleukin-6; Metabolome; Pregnancy; Pregnancy Outcome; Quebec; Regression Analysis

Hyperglycemia following major trauma is a well know phenomenon related to stress-induced systemic reaction. Reports on glucose level management in patients with head trauma have been published, but the development of insulin resistance in trauma patients without head injury has not been extensively studied. The aim of this study was therefore to investigate the prognostic role of acute insulin-resistance, assessed by the HOMA model, in patients with severe trauma without head injury.. All patients consecutively admitted to the Intensive Care Unit (ICU) of a tertiary referral center (Careggi Teaching Hospital, Florence, IT) for major trauma without head injury (Jan-Dec 2010) were enrolled. Patients with a previous diagnosis of diabetes mellitus requiring insulin therapy or metabolism alteration were excluded from the analysis. Patients were divided into "insulin resistant" and "non-insulin resistant" based on the Homeostasis Model Assessment index (HOMA IR). Results are expressed as medians.. Out of 175 trauma patients admitted to the ICU during the study period, a total of 54 patients without head trauma were considered for the study, 37 of whom met the inclusion criteria. In total, 23 patients (62.2%) resulted insulin resistant, whereas 14 patients (37.8%) were non-insulin resistant. Groups were comparable in demographic, clinical/laboratory characteristics, and severity of injury. Insulin resistant patients had a significantly higher BMI (P=0.0416), C-reactive protein (P=0.0265), and leukocytes count (0.0301), compared to non-insulin resistant patients. Also ICU length of stay was longer in insulin resistant patients (P=0.0381).. Our data suggest that admission insulin resistance might be used as an early outcome predictor.

Topics: Adult; Body Mass Index; C-Peptide; C-Reactive Protein; Female; Humans; Hyperglycemia; Infections; Insulin Resistance; Intensive Care Units; Length of Stay; Leukocyte Count; Logistic Models; Male; Middle Aged; Pilot Projects; Prognosis; Prospective Studies; Respiration, Artificial; Wounds and Injuries

The association of fatty acid composition with insulin resistance and type 2 diabetes has been reported in Western populations, but there is limited evidence of this association among the Japanese, whose populace consume large amounts of fish. To test the hypothesis that high palmitic, palmitoleic, and dihomo-γ-linolenic acids and low levels of linoleic and n-3 fatty acids are associated with higher insulin resistance among the Japanese, the authors investigated the relationship between serum fatty acid composition and serum C-peptide concentrations in 437 Japanese employees aged 21 to 67 years who participated in a workplace health examination. Serum cholesterol ester and phospholipid fatty acid compositions were measured by gas-liquid chromatography. Desaturase activity was estimated by fatty acid product-to-precursor ratios. A multiple regression was used to assess the association between fatty acid and C-peptide concentrations. C-peptide concentrations were associated inversely with linoleic acid levels in cholesterol ester and phospholipid (P for trend = .01 and .02, respectively) and positively with stearic and palmitoleic acids in cholesterol ester (P for trend =.02 and .006, respectively) and dihomo-γ-linolenic acid in cholesterol ester and phospholipid (P for trend < .0001 for both). C-peptide concentrations were not associated with n-3 polyunsaturated fatty acids. C-peptide concentrations significantly increased as δ-9-desaturase (16:1 n-7/16:0) and δ-6-desaturase (18:3 n-6/18:2 n-6) increased (P for trend = .01 and .03, respectively) and δ-5-desaturase (20:4 n-6/20:3 n-6) decreased (P for trend = .004). In conclusion, a fatty acid pattern with high levels of serum stearic, palmitoleic, or dihomo-γ-linolenic acids; δ-9-desaturase (16:1 n-7/16:0) or δ-6-desaturase (18:3 n-6/18:2 n-6) activities; and low levels of serum linoleic acid or δ-5-desaturase (20:4 n-6/20:3 n-6) activity might be associated with higher insulin resistance in Japanese adults.

Topics: 8,11,14-Eicosatrienoic Acid; Adult; Aged; Asian People; C-Peptide; Cholesterol Esters; Chromatography, Gas; Cross-Sectional Studies; Delta-5 Fatty Acid Desaturase; Fatty Acid Desaturases; Fatty Acids, Monounsaturated; Fatty Acids, Omega-3; Female; Humans; Insulin Resistance; Linoleic Acid; Linoleoyl-CoA Desaturase; Male; Middle Aged; Multivariate Analysis; Phospholipids; Regression Analysis; Stearic Acids; Stearoyl-CoA Desaturase; Young Adult

The aim of investigation was to study the impact of insulin resistance in patients with HCV infection. 130 patients were investigated: 20 with acute hepatitis C; 38 with chronic hepatitis C; 72 with cirrhosis. The study demonstrated, that the serum level of C-peptide and Insulin in patients with liver cirrhosis is higher, than in patients with acute and chronic HCV infection. This is necessary the monitoring of patients with insulin resistance, which will contribute to the prevention of complications and can improve patients' quality of life.

Topics: Adolescent; Adult; Aged; Blood Glucose; C-Peptide; Female; Hepatitis C, Chronic; Humans; Insulin; Insulin Resistance; Liver Cirrhosis; Male; Middle Aged

Poor fetal growth, also known as intrauterine growth restriction (IUGR), is a worldwide health concern. IUGR is commonly associated with both an increased risk in perinatal mortality and a higher prevalence of developing chronic metabolic diseases later in life. Obesity, type 2 diabetes or metabolic syndrome could result from noxious "metabolic programming." In order to better understand early alterations involved in metabolic programming, we modeled IUGR rat pups through either prenatal exposure to synthetic glucocorticoid (dams infused with dexamethasone 100 µg/kg/day, DEX) or prenatal undernutrition (dams feeding restricted to 30% of ad libitum intake, UN). Physiological (glucose and insulin tolerance), morphometric (automated tissue image analysis) and transcriptomic (quantitative PCR) approaches were combined during early life of these IUGR pups with a special focus on their endocrine pancreas and adipose tissue development. In the absence of catch-up growth before weaning, DEX and UN IUGR pups both presented basal hyperglycaemia, decreased glucose tolerance, and pancreatic islet atrophy. Other early metabolic defects were model-specific: DEX pups presented decreased insulin sensitivity whereas UN pups exhibited lowered glucose-induced insulin secretion and more marked alterations in gene expression of pancreatic islet and adipose tissue development regulators. In conclusion, these results show that before any catch-up growth, IUGR rats present early physiologic, morphologic and transcriptomic defects, which can be considered as initial mechanistic basis of metabolic programming.

Topics: Adipose Tissue; Analysis of Variance; Animals; Blood Glucose; Blotting, Western; Body Weights and Measures; C-Peptide; Corticosterone; Dexamethasone; DNA Primers; Female; Fetal Growth Retardation; Gene Expression Profiling; Insulin; Insulin Resistance; Islets of Langerhans; Leptin; Malnutrition; Pregnancy; Prenatal Exposure Delayed Effects; Radioimmunoassay; Rats; Rats, Sprague-Dawley; Real-Time Polymerase Chain Reaction

To evaluate the one year effect of modified Roux-en-Y gastric bypass (RYGP) in the treatment of non-obese type 2 diabetes and to investigate the reasonable indications for surgery.. Totally 72 patients diagnosed as type 2 diabetes underwent RYGP from May 2009 to June 2010. There were 45 male and 27 female patients, with an average age of (47 ± 10) years. Preoperative body mass index (BMI) of the patients was 18.69 to 31.22 kg/m(2), average (26 ± 4) kg/m(2). The follow-up data included fasting plasma glucose (FPG), 2 h plasma glucose after oral glucose challenge (2hPG), weight, BMI and medication usage in 1, 3, 6 and 12 months postoperative; hemoglobin A1c (HbA1c), fasting C-peptide (C-P), fasting serum insulin (Fins) and homeostasis model assessment of insulin resistance index (HOMA-IR) in 6 and 12 months postoperative, respectively.. Compared with the preoperative, FPG, 2hPG, weight and BMI in 1, 3, 6 and 12 months after surgery were improved (t = 7.014 to 10.254, P = 0.000), while HbA1c, C-P and HOMA-IR in 6 and 12 months after surgery were improved (t = 1.782 to 7.789, P = 0.000 to 0.103) and there was no significant difference in Fins (P > 0.05). The rates of complete remission in 1, 3, 6 and 12 months after surgery were gradually improved to 22.2%, 27.8%, 36.1% and 60.6%, respectively, and the rate of remission in 1 year was 94.3%. The complete remission of 1 year after surgery was associated with normal C-P, insulin antibody and oral antidiabetic drugs (χ(2) = 11.730, P = 0.003; χ(2) = 7.131, P = 0.028;χ(2) = 6.149, P = 0.046).. Modified RYGP is safely and effectively in the treatment of no-obese type 2 diabetes patients. The function of islet cells is significantly improved after operation. Especially for the patients of whom C-P is normal, insulin antibody is negative before surgery, the rate of complete remission after 1 year is better.

Topics: Adult; Blood Glucose; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Female; Follow-Up Studies; Gastric Bypass; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Obesity; Weight Loss

Insulin resistance, characterized by hyperinsulinemia and normal or elevated serum glucose, is an established precursor to diabetes and cardiovascular disease. Despite fasting serum C-peptide levels being an accurate and stable marker of endogenous insulin production used in patients with diabetes, it is unknown whether C-peptide could serve as a marker of insulin resistance and predict outcomes in patients without diabetes.. This is a retrospective cohort study using data from the NHANES-3 (1988-1994) survey with mortality follow-up through December 31, 2006. Participants included 5153 subjects, 40 to 74 years of age with fasting glucose ≥ 70 mg/dL, without diabetes by history or laboratory testing. Receiver-operating-curve analysis compared fasting C-peptide against known insulin resistance measures such as fasting plasma glucose, serum insulin, HOMA-IR, quantitative-insulin-sensitivity-check-index, and metabolic syndrome for the prediction of cardiovascular and overall death. Subjects were then stratified by quartiles of C-peptide levels. Cox proportional-hazards modeling compared hazards of cardiovascular and overall death amongst C-peptide quartiles and adjusted for potential confounders of cardiovascular and diabetes risk. Fasting serum C-peptide levels predicted cardiovascular and overall death better than other studied measures (AUC=0.62 and 0.60 respectively vs the rest, with AUC ≤ 0.58 and ≤ 0.57 respectively, P<0.001). When compared with the lowest C-peptide quartile, subjects in the highest quartile had significantly higher adjusted hazard ratios (HR) of cardiovascular death (HR=1.60, 95%CI 1.07 to 2.39) and overall mortality (HR=1.72, 95%CI 1.34 to 2.21) after controlling for confounders.. C-peptide levels significantly related to hazards of cardiovascular and overall death in nondiabetic adults and was a better predictor of these outcomes than serum insulin and/or glucose derived measures.

Topics: Adult; Aged; Blood Glucose; C-Peptide; Cardiovascular Diseases; Cohort Studies; Diabetes Mellitus; Fasting; Female; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Mortality; Nutrition Surveys; Predictive Value of Tests; Proportional Hazards Models; Retrospective Studies; Risk Factors; ROC Curve

Mammalian target of rapamycin (mTOR) is an important mediator for cross talk between nutritional signals and metabolic signals of insulin by downregulating insulin receptor substrate proteins. Therefore, mTOR inhibition could become a therapeutic strategy in insulin-resistant states, including insulin resistance induced by burn. We tested this hypothesis in the rat model of 30% TBSA full thickness burn, using the mTOR inhibitor rapamycin. Rapamycin (0.4 mg/kg, i.p.) was injected 2 h before euglycemic-hyperinsulinemic glucose clamps at 4 days after burn. IRS-1, phospho-serine³⁰⁷, phospho-tyrosine of IRS-1 and phospho-mTOR in muscle tissue were determined by immunoprecipitation and Western blot analysis or immunohistochemistry. Plasma TNF-α, insulin and C-peptide were determined before and after euglycemic-hyperinsulinemic glucose clamps. Our data showed that TNF-α, insulin and C-peptide significantly increased in the early stage after burn (P < 0.01). The infused rates of total 10% glucose (GIR, mg/kg min) significantly decreased at 4 days after burn. The level of IRS-1 serine³⁰⁷ phosphorylation in muscle in vivo significantly increased after burn (P < 0.01), while insulin-induced tyrosine phosphorylation of IRS-1 significantly decreased (P < 0.01). Inhibition of mTOR by rapamycin inhibited the phosphorylation of mTOR, reduced serine³⁰⁷ phosphorylation, elevated tyrosine phosphorylation and partly prevented the decrease of GIR after burn. However, TNF-α, insulin and C-peptide were not decreased by rapamycin treatment postburn. Taken together, these results indicate that the mTOR pathway is an important modulator of the signals involved in the acute regulation of insulin-stimulated glucose metabolism, and at least, partly contributes to burn-induced insulin resistance. mTOR inhibition may become a therapeutic strategy in insulin-resistant states after burn.

Topics: Animals; Anti-Bacterial Agents; Blotting, Western; Burns; C-Peptide; Disease Models, Animal; Glucose Clamp Technique; Immunohistochemistry; Insulin; Insulin Receptor Substrate Proteins; Insulin Resistance; Muscle, Skeletal; Phosphorylation; Phosphoserine; Phosphotyrosine; Rats; Rats, Sprague-Dawley; Serine; Sirolimus; TOR Serine-Threonine Kinases; Tumor Necrosis Factor-alpha

Insulin sensitivity (SI) is useful in the diagnosis, screening and treatment of diabetes. However, most current tests cannot provide an accurate, immediate or real-time estimate. The DISTq method does not require insulin or C-peptide assays like most SI tests, thus enabling real-time, low-cost SI estimation. The method uses a posteriori parameter estimations in the absence of insulin or C-peptide assays to simulate accurate, patient-specific, insulin concentrations that enable SI identification. Mathematical functions for the a posteriori parameter estimates were generated using data from 46 fully sampled DIST tests (glucose, insulin and C-peptide). SI values found using the DISTq from the 46 test pilot cohort and a second independent 218 test cohort correlated R=0.890 and R=0.825, respectively, to the fully sampled (including insulin and C-peptide assays) DIST SI metrics. When the a posteriori insulin estimation functions were derived using the second cohort, correlations for the pilot and second cohorts reduced to 0.765 and 0.818, respectively. These results show accurate SI estimation is possible in the absence of insulin or C-peptide assays using the proposed method. Such estimates may only need to be generated once and then used repeatedly in the future for isolated cohorts. The reduced correlation using the second cohort was due to this cohort's bias towards low SI insulin resistant subjects, limiting the data set's ability to generalise over a wider range. All the correlations remain high enough for the DISTq to be a useful test for a number of clinical applications. The unique real-time results can be generated within minutes of testing as no insulin and C-peptide assays are required and may enable new clinical applications.

Topics: Blood Glucose; C-Peptide; Cohort Studies; Computer Simulation; Diabetes Mellitus, Type 2; Female; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Models, Biological; Pilot Projects

The aim of the presented study is to evaluate metabolic features in adolescents with polycystic ovary syndrome (PCOS) in comparison with age- and BMI-matched subjects. Forty-three adolescents with PCOS according to ESHRE criteria were prospectively evaluated and compared with 48 control subjects. Blood sampling was done in the early follicular phase of menstrual cycle, between 1st and 5th day, for plasma glucose, total and high-density lipoprotein (HDL)-cholesterol, triglycerides, insulin and C peptide. The diagnosis of metabolic syndrome was done according to IDF adolescent criteria. Adolescents with PCOS have increased low-density lipoprotein (LDL)-cholesterol (p < 0.002), decreased HDL-cholesterol (p <0.0007) and increased C peptide levels (p < 0.02) in comparison with healthy adolescents. Total cholesterol, triglycerides, fasting blood glucose, fasting insulin, HOMA-IR, waist-to-hip ratio, systolic and diastolic blood pressure did not differ between the groups. There was no difference when we compared the prevalence of adolescents with at least one feature of metabolic syndrome between PCOS (17 from 43) and healthy controls (27 from 48). In conclusion, adolescents with PCOS have less favourable blood lipid profiles with higher LDL-cholesterol and lower levels of HDL-cholesterol and are more insulin resistant than their healthy counterparts having higher fasting C peptide levels.

Topics: Adolescent; Adult; Body Mass Index; C-Peptide; Cholesterol, HDL; Cholesterol, LDL; Czech Republic; Female; Follicular Phase; Humans; Hypercholesterolemia; Insulin Resistance; Metabolic Syndrome; Obesity; Polycystic Ovary Syndrome; Prevalence; Prospective Studies; Young Adult

The aim of this analysis was to evaluate glucagon and c-peptide concentrations in two scenarios: euglycemic hyperinsulinemia and hyperglycemic hyperinsulinemia. We postulated that worsening obesity and insulin resistance will be reflected as an up-regulated (less suppressible) islet secretion profile.. Eighty-two [34 obese with normal glucose tolerance (NGT), 30 obese with impaired glucose tolerance (IGT), and 18 nonobese with NGT] subjects underwent a euglycemic-hyperinsulinemic clamp (EHC) and a hyperglycemic clamp. C-peptide and glucagon were evaluated at basal and steady-state (SS) conditions.. Basal glucagon was significantly elevated in obese insulin-resistant and obese IGT subjects as was basal c-peptide. SS glucagon and c-peptide levels during the EHC were lower in the lean and obese insulin-sensitive subjects compared with the obese insulin-resistant subjects with NGT or IGT. Fasting glucagon was the only significant determinant (β = 0.66, P < 0.001) of SS glucagon during the EHC (R(2) = 0.57). In a longitudinal follow-up of a subsample, those who converted from normal to IGT significantly increased their fasting glucagon concentration in comparison with those who remained with NGT.. Islet up-regulation manifesting as basal elevated glucagon and c-peptide secretion that determines the suppressive effects of hyperinsulinemia appears early in the course of deteriorating glucose tolerance.

Topics: Adolescent; Analysis of Variance; Area Under Curve; Blood Glucose; C-Peptide; Glucagon; Glucagon-Secreting Cells; Glucose Clamp Technique; Humans; Insulin; Insulin Resistance; Obesity; Regression Analysis; Up-Regulation; Young Adult

Islet autoimmunity has long been recognized in the pathogenesis of type 1 diabetes and is becoming increasingly acknowledged as a component in the pathogenesis of type 2 diabetes. Islet reactive T cells and autoantibodies have been demonstrated in type 1 diabetes, whereas islet autoimmunity in type 2 diabetes has been limited to islet autoantibodies. In this study, we investigated whether islet reactive T cells might also be present in type 2 diabetic patients and how islet reactive T cells correlate with β-cell function.. Adult phenotypic type 2 diabetic patients (n = 36) were screened for islet reactive T-cell responses using cellular immunoblotting and five islet autoantibodies (islet cell antibody, GADA, insulin autoantibody, insulinoma-associated protein-2 autoantibody, and zinc transporter autoantibody).. We identified four subgroups of adult phenotypic type 2 diabetic patients based on their immunological status (Ab(-)T(-), Ab(+)T(-), Ab(-)T(+), and Ab(+)T(+)). The Ab(-)T(+) type 2 diabetic patients demonstrated T-cell responses similar to those of the Ab(+)T(+) type 2 diabetic patients. Data were adjusted for BMI, insulin resistance, and duration of diabetes. Significant differences (P < 0.02) were observed among groups for fasting and glucagon-stimulated C-peptide responses. T-cell responses to islet proteins were also demonstrated to fluctuate less than autoantibody responses.. We have identified a group of adult autoimmune phenotypic type 2 diabetic patients who are Ab(-)T(+) and thus would not be detected using autoantibody testing alone. We conclude that islet autoimmunity may be more prevalent in adult phenotypic type 2 diabetic patients than previously estimated.

Topics: Adult; Aged; Autoantibodies; C-Peptide; Diabetes Mellitus, Type 2; Haplotypes; Humans; Immunoblotting; Insulin Resistance; Middle Aged; T-Lymphocytes

Increased postprandial glucose-dependent insulinotropic polypeptide (GIP) and glucagon responses and reduced postprandial glucagon-like peptide-1 (GLP-1) responses have been observed in some patients with type 2 diabetes mellitus. The causality of these pathophysiological traits is unknown. We aimed to determine the impact of insulin resistance and reduced glucose tolerance on postprandial GIP, GLP-1, and glucagon responses in healthy subjects.. A 4-h 2200 KJ-liquid meal test was performed in 10 healthy Caucasian males without family history of diabetes [age, 24 ± 3 yr (mean ± sd); body mass index, 24 ± 2 kg/m(2); fasting plasma glucose, 4.9 ± 0.3 mm; hemoglobin A(1)c, 5.4 ± 0.1%] before and after intervention using high-calorie diet, relative physical inactivity, and administration of prednisolone (37.5 mg/d) for 12 d.. The intervention resulted in insulin resistance according to the homeostatic model assessment [1.1 ± 0.3 vs. 2.3 (mean ± SEM) ± 1.3; P = 0.02] and increased postprandial glucose excursions [area under curve (AUC), 51 ± 28 vs. 161 ± 32 mm · 4 h; P = 0.045], fasting plasma insulin (36 ± 3 vs. 61 ± 6 pm; P = 0.02), and postprandial insulin responses (AUC, 22 ± 6 vs. 43 ± 13 nm · 4 h; P = 0.03). This disruption of glucose homeostasis had no impact on postprandial GLP-1 responses (AUC, 1.5 ± 0.7 vs. 2.0 ± 0.5 nm · 4 h; P = 0.56), but resulted in exaggerated postprandial GIP (6.2 ± 1.0 vs. 10.0 ± 1.3 nm · 4 h; P = 0.003) and glucagon responses (1.6 ± 1.5 vs. 2.4 ± 3.2; P = 0.007).. These data suggest that increased postprandial GIP and glucagon responses may occur as a consequence of insulin resistance and/or reduced glucose tolerance. Our data suggest that acute disruption of glucose homeostasis does not result in reduced postprandial GLP-1 responses as observed in some individuals with type 2 diabetes mellitus.

Topics: Adult; Area Under Curve; Blood Glucose; C-Peptide; Diet; Energy Intake; Fasting; Gastric Inhibitory Polypeptide; Glucagon; Glucagon-Like Peptide 1; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Motor Activity; Postprandial Period; Prednisolone; Young Adult

This study investigated the relationship of obesity, insulin resistance, inflammation and angiogenesis with cancer progression and survival in a colorectal cancer cohort.. Clinical and pathological data, along with anthropometric and follow-up data, were collected from 344 consecutive colorectal cancer patients. Serum samples at diagnosis were analysed by immunoassay for adiponectin, C-reactive protein (CRP), vascular endothelial growth factor-A (VEGF-A), angiopoietin-2 (Ang-2), insulin-like growth factor-1 (IGF-1), insulin and C-peptide.. Serum Ang-2 and VEGF-A levels increased with tumour T stage (P=0.007 and P=0.025, respectively) and N stage (P=0.02 and P=0.03, respectively), and correlated with CRP levels (r=0.43, P<0.001 and r=0.23, P<0.001, respectively). Angiopoietin-2 correlated with C-peptide (r=0.14, P=0.007) and VEGF-A with IGF-1 in males (r=0.25, P=0.001). Kaplan-Meier analysis showed that patients with high serum levels of CRP and Ang-2 had significantly reduced survival (both P≤0.001). After adjusting for tumour stage and age, Ang-2 remained a significant predictor of survival. The CRP levels were inversely associated with survival in American Joint Committee on Cancer stage II patients (P=0.038), suggesting that CRP could be used to support treatment decisions in this subgroup. Serum markers and anthropometric measures of obesity correlated with each other, but not with survival.. Our study supports the concept that obesity-related inflammation, rather than obesity itself, is associated with colorectal cancer progression and survival. The study confirms serum Ang-2 as a predictive marker for outcome of colorectal cancer.

Topics: Adenocarcinoma; Adult; Aged; Aged, 80 and over; Angiopoietin-2; Biomarkers; Body Mass Index; C-Peptide; C-Reactive Protein; Colorectal Neoplasms; Enzyme-Linked Immunosorbent Assay; Female; Humans; Insulin; Insulin Resistance; Insulin-Like Growth Factor I; Male; Middle Aged; Obesity; Prospective Studies; Survival Rate; Treatment Outcome; Vascular Endothelial Growth Factor A

To examine the association between serum C-peptide, a marker of insulin secretion, measured 3 years after a breast cancer diagnosis, and death resulting from all causes and breast cancer.. This was a prospective, observational study of 604 women enrolled onto the Health, Eating, Activity, and Lifestyle (HEAL) Study who were diagnosed with local or regional breast cancer between 1995 and 1998 and observed until death or December 31, 2006, whichever came first. The hazard ratio (HR) for all deaths and deaths owing to breast cancer and 95% CIs for the HR were estimated using multivariable stratified Cox regression analyses.. Among women without type 2 diabetes, fasting C-peptide levels were associated with an increased risk of death resulting from all causes and from breast cancer. A 1-ng/mL increase in C-peptide was associated with a 31% increased risk of any death (HR = 1.31; 95% CI, 1.06 to 1.63; P = .013) and a 35% increased risk of death as a result of breast cancer (HR = 1.35; 95% CI, 1.02 to 1.87, P = .048). Associations between C-peptide levels and death as a result of breast cancer were stronger in certain subgroups, including women with type 2 diabetes, women with a body mass index less than 25 kg/m(2), women diagnosed with a higher stage of disease, and women whose tumors were estrogen receptor positive.. Treatment strategies to reduce C-peptide levels in patients with breast cancer, including dietary-induced weight loss, physical activity, and/or use of insulin-lowering medications, should be explored.

Topics: Breast Neoplasms; C-Peptide; Diabetes Mellitus, Type 2; Fasting; Female; Humans; Insulin; Insulin Resistance; Insulin Secretion; Life Style; Middle Aged; Motor Activity; Prognosis; Prospective Studies; Risk Factors

Intronic variants of TCF7L2 are confirmed genetic risk factors for type 2 diabetes and are associated to alterations in beta cell function in nondiabetic individuals.. The objective of the study was to test whether TCF7L2 variability may affect β-cell function also in patients with type 2 diabetes.. This was a cross-sectional association study.. The study was conducted at a university hospital referral center for diabetes.. Patients included 464 (315 males and 149 females) glutamic acid decarboxylase-negative patients [age: median 59 yr (interquartile range: 52-65); body mass index: 29.3 kg/m(2) (26.5-32.9); fasting plasma glucose: 7.0 mmol/liter (6.1-8.0)] with newly diagnosed type 2 diabetes.. Interventions included frequently sampled oral glucose tolerance test and euglycemic insulin clamp.. β-Cell function (derivative control and proportional control); insulin sensitivity; genotypes of the following TCF7L2 single-nucleotide polymorphisms: rs7901695, rs7903146, rs11196205, and rs12255372.. Both rs7901695 and rs7903146 diabetes risk alleles were associated with reduced proportional control of β-cell function (P = 0.019 and P = 0.022, respectively). Two low-frequency haplotypes were associated with extreme (best and worst) phenotypes of β-cell function (P < 0.01). No associations between TCF7L2 genotypes and insulin sensitivity were detected.. TCF7L2 diabetes risk variants, either as single-nucleotide polymorphisms or as haplotypes, detrimentally influence β-cell function and might play a role in determining the metabolic phenotype of patients with newly diagnosed type 2 diabetes.

Topics: Aged; Alleles; Blood Glucose; Body Mass Index; C-Peptide; Cohort Studies; Cross-Sectional Studies; Databases, Factual; Diabetes Mellitus, Type 2; Female; Genetic Variation; Glucose Tolerance Test; Haplotypes; Humans; Hypoglycemic Agents; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Models, Biological; Pancreatic Function Tests; Polymorphism, Single Nucleotide; Risk Factors; Transcription Factor 7-Like 2 Protein

To investigate the relationship between insulin resistance (IR) and subsequent gestational hypertension (GH) or preeclampsia (PE) in normoglycemic and in gestational diabetic pregnant women. Furthermore, we tested whether this association was independent of the prepregnancy body mass index (BMI).. Each participant underwent a 75-gram oral glucose tolerance test (OGTT) according to World Health Organization recommendation criteria with determination of serum glucose and C-peptide concentrations. IR was determined as a C-peptide-to-glucose ratio at the fasting (FCGR) state and at 2 h (2CGR) after load.. A total of 2,954 women were included with a singleton pregnancy, delivery at term, no chronic hypertension, and data on both glucose and C-peptide. Of these women, 183 (6.2%) developed GH and 49 (1.7%) PE. Gestational diabetes mellitus (GDM) was diagnosed in 6.0% of the participants. The FCGR and 2CGR were significantly higher in all women with GH, irrespective of their BMI, compared to the normotensive group; however, the PE and the normotensive groups had similar FCGR and 2CGR values.. The present study suggests that IR at the OGTT is associated with the later development of GH; on the other hand, it is not associated with PE. These relationships are independent of the maternal BMI.

Topics: Adult; Blood Glucose; Body Mass Index; C-Peptide; Diabetes, Gestational; Fasting; Female; Glucose Tolerance Test; Humans; Hypertension, Pregnancy-Induced; Insulin Resistance; Pre-Eclampsia; Pregnancy

After initiation of treatment in Type 1 diabetes, a period with lower insulin requirement often follows, reflecting increased insulin sensitivity and improved insulin secretion. We explored if efficiency of proinsulin processing is associated with the remission phenomenon.. Seventy-eight patients with new-onset Type 1 diabetes were followed prospectively for 3 years. Daily insulin dosage, HbA(1c) , plasma glucose, proinsulin, C-peptide, glucagon concentrations and islet antibodies were determined at diagnosis and after 3, 6, 9, 12, 18, 24, 30 and 36 months. We studied remission, defined as an insulin dose ≤ 0.3 U kg(-1) 24 h(-1) and HbA(1c) within the normal range, in relation to the above-mentioned variables.. A rise and subsequent decline in plasma proinsulin and C-peptide concentrations was observed. Forty-five per cent of the patients experienced remission at one or more times, characterized by higher proinsulin and C-peptide levels, and lower proinsulin/C-peptide ratios, indicating more efficient proinsulin processing, compared with those not in remission. Non-remission also tended to be associated with higher glucagon values. Patients entering remission were more often men, had higher BMI at diagnosis, but did not differ at baseline with respect to islet antibody titres compared with patients with no remission.. Remissions after diagnosis of Type 1 diabetes were associated with lower proinsulin/C-peptide ratios, suggesting more efficient proinsulin processing, and tended to have lower glucagon release than non-remissions. This indicates that, in remission, the residual islets maintain a secretion of insulin and glucagon of benefit for control of hepatic glucose production.

Topics: Adolescent; Adult; Biomarkers; C-Peptide; Diabetes Mellitus, Type 1; Disease Progression; Fasting; Female; Glucagon; Glycated Hemoglobin; Humans; Insulin Resistance; Male; Proinsulin; Prospective Studies; Reference Values; Remission Induction; Young Adult

We evaluated the relationship between insulin resistance (IR) and insulin secretion with the metabolic syndrome (MS) in 885 subjects (377 men/508 women, age 49±11 years, BMI 29±5.2kgm(-2)) at risk of diabetes enrolled in the genetics, pathophysiology and evolution of type 2 diabetes (GENFIEV) study.. All subjects underwent a 75-g oral glucose tolerance test (OGTT) for the estimation of plasma levels of glucose and C-peptide, as well as fasting insulin and lipid profile. IR was arbitrarily defined as HOMA-IR value above the 75th centile of normal glucose tolerance (NGT) subjects. Overall MS prevalence (National Cholesterol Treatment Panel-Adult Treatment Panel (NCEP-ATPIII) criteria) was 33%, 19% in subjects with NGT, 42% in impaired fasting glucose (IFG), 34% in impaired glucose tolerance (IGT), 74% in IFG+IGT subjects, and 56% in newly diagnosed diabetic patients. Prevalence was slightly higher with IDF criteria. MS prevalence was >50% in subjects with 2h glucose >7.8mmoll(-1), independently of fasting plasma glucose. IR prevalence was higher in subjects with MS than in those without (63% vs. 23%; p<0.0001) and increased from 54% to 73% and 88% in the presence of three, four or five traits, respectively. IR occurred in 42% of subjects with non-diabetic alterations of glucose homeostasis, being the highest in those with IFG+IGT (IFG+IGT 53%, IFG 45%, IGT 38%; p<0.0001). Individuals with MS were more IR irrespective of glucose tolerance (p<0.0001) with no difference in insulinogenic index. Hypertriglyceridaemia (OR: 3.38; Confidence Interval, CI: 2.294.99), abdominal obesity (3.26; CI: 2.18-4.89), hyperglycaemia (3.02; CI: 1.80-5.07) and hypertension (1.69; CI: 1.12-2.55) were all associated with IR.. These results show that in subjects with altered glucose tolerance (in particular IFG+IGT) MS prevalence is high and is generally associated to IR. Some combinations of traits of MS may significantly contribute to identify subjects with IR.

Topics: Adult; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucose Intolerance; Glucose Tolerance Test; Humans; Hyperglycemia; Hypertension; Insulin Resistance; Italy; Logistic Models; Male; Metabolic Syndrome; Middle Aged; Prediabetic State; Prevalence; Risk Factors

Topics: Antipsychotic Agents; Blood Glucose; C-Peptide; Cholesterol; Cooperative Behavior; Diabetes Mellitus, Type 2; Health Promotion; Humans; Hyperlipidemias; Insulin; Insulin Resistance; Interdisciplinary Communication; Metabolic Syndrome; Mind-Body Relations, Metaphysical; Patient Admission; Patient Care Team; Psychotic Disorders; State Medicine; Triglycerides; Weight Gain

Intrauterine exposure to elevated glucose concentrations may be a mediating factor in prenatal programming of offspring diabetes risk. However, studies examining the effects of maternal glucose concentration on measures of insulin sensitivity and β-cell response in prepubertal children are limited.. We tested the hypothesis that maternal gestational glucose concentration would be inversely associated with children's insulin sensitivity independent of adiposity and positively associated with children's β-cell response independent of adiposity and insulin sensitivity.. This was a cross-sectional study of 21 children aged 5-10 yr in a clinical research setting.. Children's insulin sensitivity index and basal, static, dynamic, and total β-cell response to glucose were determined by mathematical modeling using insulin, glucose, and C-peptide values after a liquid meal tolerance test. Children's percent body fat was determined by dual-energy x-ray absorptiometry. Maternal gestational glucose concentration for the target pregnancy was determined after a 50-g, 1-h oral glucose challenge test at 24-28 wk gestation.. Maternal glucose concentration was significantly, inversely associated with children's insulin sensitivity, independent of percent fat and ethnicity (P <0.05). A significant, positive association was observed for maternal glucose concentration with static β-cell response, independent of percent fat and insulin sensitivity (P < 0.05).. Maternal gestational glucose concentration was significantly associated with offspring insulin sensitivity and β-cell response independent of adiposity. These results suggest that maternal glucose may program the fetus both at the pancreas and at the level of insulin target tissues such as skeletal muscle and liver.

Topics: Absorptiometry, Photon; Adiposity; Adult; Blood Glucose; Body Composition; Body Mass Index; C-Peptide; Child; Child, Preschool; Data Interpretation, Statistical; Female; Follow-Up Studies; Glucose Tolerance Test; Humans; Hyperglycemia; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Pancreatic Function Tests; Pregnancy; Pregnancy Complications

To observe the relationship between inflammatory response and the constituents of islet β cell secretion during stress hyperglycemia (SHG) in critically ill patients, in order to study the impact of inflammatory response on insulin resistance and the secretion function of islet β cells.. According to the state of inflammatory response, 45 critical patients with SHG were divided into two groups: stress and the convalescence period. Twenty five healthy individuals were enrolled as control group. The blood levels of tumour necrosis factor β (TNF-β), blood glucose (BG), and insulin components including proinsulin (PI), immunoreactive insulin (IRI), true insulin (TI), C-peptide (C-P) were measured respectively. The levels of BG, TNF-β, insulin components, insulin resistance index (HOMA-IR) and the secretion index (HOMA-β) were compared among groups. The relationship between TNF-β and BG, insulin components, HOMA-IR, HOMA-β were analyzed.. (1)There was no difference in concentrations of TI among stress period, convalescence stage and control group [3.68 (1.57, 7.70), 3.42 (2.41, 7.40), 1.46 (0.35, 4.90) mU/L, all P >0.05], whereas the concentration of BG [(10.04 ± 2.43) mmol/L], TNF-β [13.70 (11.77, 20.00) ng/L], PI [6.20 (3.22, 9.27) pmol/L], IRI [13.45 (9.88, 19.88) mU/L] and C-P [3.01 (2.37, 4.00) μg/L]in stress period were significantly higher than those in the convalescence stage[BG: (6.09 ± 0.84) mmol/L, TNF-β: 11.58 (8.80, 13.22) ng/L,PI: 1.54 (0.36, 11.82) pmol/L, IRI: 10.80 (5.35, 12.60) mU/L, C-P: 2.42 (1.17, 3.56) μg/L] and control group [BG: (4.87 ± 0.56) mmol/L,TNF-β: 9.27 (7.48, 12.16) ng/L, PI: 2.20 (1.88, 4.54) pmol/L, IRI: 5.50 (4.00, 8.00) mU/L, C-P: 1.15 (0.87, 1.76) μg/L, P <0.05 or P <0.01]. (2)The HOMA-IR [5.17 (3.41, 11.51)] in stress period was significantly higher than that in the convalescence[3.24 (1.51, 6.95)] and control group [1.14 (0.81, 1.79), P <0.05 and P<0.01]. The HOMA-β [10.80 (3.72, 31.40)] of isletβ cell in stress period was significantly lower than that in the convalescence [28.42 (6.46, 125.01)] and control group [21.94 (7.77, 62.01), P <0.01 and P <0.05]. (3)There were positive correlations between the concentration of TNF-β and PI, IRI, C-P and HOMA-IR ( r 1=0.292, r 2=0.344, r 3=0.397, r 4=0.324, P <0.05 or P <0.01). There were negative correlation between concentration of TNF-β and HOMA-β ( r =-0.235 , P <0.05) .. The severer the inflammatory response, the higher PI, IRI and C-P, while the secretion of TI is relatively deficient.Inflammatory response could affect insulin resistance and the secretion function of islet βcell during SHG in critically ill patients.

Topics: Adult; Aged; Blood Glucose; C-Peptide; Case-Control Studies; Critical Illness; Female; Humans; Hyperglycemia; Inflammation; Insulin; Insulin Resistance; Islets of Langerhans; Lymphotoxin-alpha; Male; Middle Aged; Young Adult

In the postprandial state, insulin regulates metabolic and cardiovascular responses. In insulin resistance, the insulin action is impaired at both levels. However, postprandial hemodynamic responses are poorly characterized in this setting.. We investigated fasting and postprandial cardiac and vascular hemodynamic responses in subjects with and without insulin resistance.. Sixty-six atherosclerosis-free, healthy volunteers were studied in a fasted state and ≤180 min after ingestion of a mixed meal. The insulin sensitivity index was determined by using a minimal model analysis; hemodynamic response was monitored by using continuous impedance cardiography that allowed a reliable beat-to-beat noninvasive evaluation of stroke volume, cardiac contractility, and several derived variables.. Subjects were divided into insulin-resistant (IR; n = 33) and insulin-sensitive (IS; n = 33) groups. After fasting, IR subjects had significantly higher values of systolic and diastolic blood pressures and the systemic vascular resistance index (SVRI) than did IS subjects. In the postprandial state, acute vasodilatation was comparable and synchronous (at 30 min) in IR and IS subjects (P = 0.209), but subsequent vascular tone recovery (30-180 min) was significantly impaired in IR subjects (P = 0.018), even after adjustment for age and sex (P = 0.031). Hemodynamic dysregulation was directly correlated with metabolic disturbances in the postprandial state. In basal and postprandial states, hemodynamic variables related to cardiac function were not significantly different in IR and IS subjects.. IR subjects had a worse fasting vascular performance than did IS subjects. In the postprandial phase, insulin resistance was associated with a shorter duration of vasodilatation in the absence of an altered cardiac performance. Peripheral hemodynamic alterations in fasting and postprandial states may have a negative effect on cardiovascular performance in IR patients.

Topics: Adult; Blood Glucose; Blood Pressure; C-Peptide; Cardiography, Impedance; Cardiovascular Diseases; Cross-Sectional Studies; Eating; Female; Hemodynamics; Humans; Insulin; Insulin Resistance; Kinetics; Male; Middle Aged; Postprandial Period; Vascular Resistance; Vasodilation

Recent studies on the pathogenesis of type 1 diabetes (T1DM) show that autoimmune activity in human pancreatic 1-cells is accompanied by abnormalities of fatty tissue metabolism, which is the underlying process in type 2 diabetes.The aim of the study was to determine the correlation between C-peptide concentration, indicating residual insulin secretion, and free fatty acids (FFA) level in children with T1DM.. We recruited 178 diabetic patients (mean age 10.8 years; M/F 99/79). In all individuals the fasting C-peptide by a radioimmunological method and FFA serum levels using an enzymatic colorimetric method were measured at the onset and after 6 months of the diabetes duration.. Thirty four (19.1%) of the patients had the C-peptide level above the lower limit of normal range (>0.28 pmol/ml) at both time points. FFA level at onset was significantly higher as compared to the level after 6 months of follow-up (38.4+29.4 vs. 28.9 ± 23.1 mg/dl; p=0.0003). However, both values were positively correlated (r=0.31; p=0.0008). Interestingly, a negative correlation was found between FFA and C-peptide measurements at onset (r=-0.19; p=0.01) and at 6th month of the disease (r=-0.18; p=0.02). Moreover, when the C-peptide level was treated as a binominal variable(above and below 0.28 pmol/ml) higher levels of FFA were observed in children with C-peptide deficiency at onset of diabetes (41.1 vs. 29.9 mg/dl; p=0.03) and a similar trend was noticed at 6th month of the disease (31.0 vs. 23.7 mg/dl; p=0.1). No relation of FFA with age at onset, gender,insulin requirement and HbA1c were revealed.. The obtained results, which link the FFA level with residual insulin secretion in T1DM,may serve as further evidence supporting the contribution of fatty tissue metabolism in the patho-genesis of T1DM.

Topics: Adolescent; Blood Glucose; C-Peptide; Child; Child, Preschool; Diabetes Mellitus, Type 1; Fatty Acids, Nonesterified; Female; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Insulin Secretion; Male; Risk Factors

Cystic fibrosis (CF)-related diabetes is a leading complication of CF and is associated with pulmonary and nutritional deterioration, years before an evident hyperglycemia, possibly because of insulin deficiency and resistance.. To evaluate glucose tolerance, insulin secretion, and insulin sensitivity by a widely applicable method suitable for accurate and prospective measurements in a CF population.. A total of 165 CF subjects (80 females) aged 17±5 years and 18 age- and sex-matched healthy controls (CON) received an oral glucose tolerance test with glucose, insulin and C-peptide determinations. Insulin sensitivity was defined on the basis of glucose and insulin concentrations using the oral glucose insulin sensitivity index, whereas β-cell function was determined on the basis of a model relating insulin secretion (C-peptide profile) to glucose concentration.. Fifteen percent of CF patients had glucose intolerance and 6% had diabetes without fasting hyperglycemia and 3% had diabetes with fasting hyperglycemia. β-cell function was reduced in CF patients compared with CON (70.0±4.1 vs 117.9±11.6  pmol/min per m(2) per mM, P<0.001) and decreased significantly with age by -2.7  pmol/min per m(2) per mM per year (confidence interval (CI) -4.5 to -0.82), i.e. almost 4% yearly. The early insulin secretion index was also reduced. Insulin sensitivity was similar to CON. CF patients who attained glucose tolerance comparable to CON had lower β-cell function and higher insulin sensitivity.. The major alteration in insulin secretion and insulin sensitivity of CF patients is slowly declining β-cell function, consisting of delayed and reduced responsiveness to hyperglycemia, that in CF patients with normal glucose tolerance may be compensated by an increased insulin sensitivity.

Topics: Adolescent; Adult; C-Peptide; Cystic Fibrosis; Diabetes Mellitus; Female; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Male

Hyperglycaemia in acutely ill patients is well described and correcting this hyperglycaemia improves outcomes. It has been generally attributed to endogenous factors, specifically decreased secretion of insulin or increased secretion of anti-insulin hormones, and cytokines, or both. Norepinephrine is the most commonly used vasopressor in critically ill patients. When titrated, it has anecdotally been found to cause wide swings in blood glucose levels. We tested the hypothesis that norepinephrine, a plausible exogenous, iatrogenic cause of hyperglycaemia, causes resistance to insulin action with the hyperinsulinaemic-euglycaemic clamp method.. Hyperinsulinaemic-euglycaemic (about 100 mg dL(-1) ) clamps were performed before and during infusion of norepinephrine, in doses of 110 ng kg(-1) min(-1) , which raised mean arterial pressure from 82 ± 7 to 94 ± 8 mmHg (p < 0.01) in 11 healthy adults.. The glucose infusion rate required to maintain euglycaemia during the clamps, a marker of whole-body insulin sensitivity, decreased from 11.2 ± 3.7 mg kg(-1) min(-1) at baseline to 9.0 ± 2.6 mg kg(-1) min(-1) (p = 0.015) during the norepinephrine infusion. Steady-state insulin and C-peptide levels did not significantly change. Cortisol levels showed diurnal variation in the beginning and were also different at steady state.. Infusion of pressor doses of norepinephrine causes resistance to insulin action in humans.

Topics: Adult; C-Peptide; Female; Glucose Clamp Technique; Humans; Hydrocortisone; Hyperglycemia; Insulin; Insulin Resistance; Male; Norepinephrine; Vasoconstrictor Agents

Weight-loss independent mechanisms may play an important role in the improvement of glucose homeostasis after Roux-en-Y gastric bypass (RYGB). The objective of this analysis was to determine whether RYGB causes greater improvement in glucostatic parameters as compared with laparoscopic adjustable gastric banding (LAGB) or low calorie diet (LCD) after equivalent weight loss and independent of enteral nutrient passage. Study 1 recruited participants without type 2 diabetes mellitus (T2DM) who underwent LAGB (n = 8) or RYGB (n = 9). Study 2 recruited subjects with T2DM who underwent LCD (n = 7) or RYGB (n = 7). Insulin-supplemented frequently-sampled intravenous glucose tolerance test (fsIVGTT) was performed before and after equivalent weight reduction. MINMOD analysis of insulin sensitivity (Si), acute insulin response to glucose (AIRg) and C-peptide (ACPRg) response to glucose, and insulin secretion normalized to the degree of insulin resistance (disposition index (DI)) were analyzed. Weight loss was comparable in all groups (7.8 ± 0.4%). In Study 1, significant improvement of Si, ACPRg, and DI were observed only after LAGB. In Study 2, Si, ACPRg, and plasma adiponectin increased significantly in the RYGB-DM group but not in LCD. DI improved in both T2DM groups, but the absolute increase was greater after RYGB (258.2 ± 86.6 vs. 55.9 ± 19.9; P < 0.05). Antidiabetic medications were discontinued after RYGB contrasting with 55% reduction in the number of medications after LCD. No intervention affected fasting glucagon-like peptide (GLP)-1, peptide YY (PYY) or ghrelin levels. In conclusion, RYGB produced greater improvement in Si and DI compared with diet at equivalent weight loss in T2DM subjects. Such a beneficial effect was not observed in nondiabetic subjects at this early time-point.

Topics: Adiponectin; Adult; Blood Glucose; C-Peptide; Caloric Restriction; Diabetes Mellitus, Type 2; Diet, Reducing; Female; Gastric Bypass; Ghrelin; Glucagon-Like Peptide 1; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Laparoscopy; Male; Middle Aged; Obesity; Peptide YY; Weight Loss

The aim of this study was to evaluate the relationship between vitiligo and insulin resistance (IR). A total of 96 subjects were included in the study; 57 patients with vitiligo and 39 subjects in an age and a body mass index-matched control group. In fasting blood samples, insulin, C-peptide, glucose, total cholesterol, triglyceride, low-density lipoprotein-cholesterol (LDL-C) and high-density lipoprotein-cholesterol (HDL-C) were measured. IR was calculated with the homeostasis model assessment-IR (HOMA-IR) method. Comparison of the vitiligo and the control groups revealed that patients with vitiligo had higher IR (2.3 vs. 2.0, p < 0.01), higher insulin and C-peptide levels (p < 0.001, p < 0.001, respectively), higher LDL/HDL ratio and lower HDL-C levels (p < 0.01, p < 0.0001, respectively). Systolic blood pressures of patients with vitiligo were also higher compared with control subjects (p < 0.01). Further experimental and clinical studies are needed to elucidate the molecular mechanisms underlying this association.

Topics: Adult; Biomarkers; Blood Glucose; Blood Pressure; Body Mass Index; C-Peptide; Case-Control Studies; Chi-Square Distribution; Fasting; Female; Humans; Insulin; Insulin Resistance; Lipids; Male; Middle Aged; Turkey; Vitiligo; Waist Circumference; Young Adult

The atypical antipsychotics (AAPs) have been associated with increased risk of type-2 diabetes. Evidence suggests direct, drug-related effects independent of weight gain and although mechanisms underlying this phenomenon are unclear, it has been suggested that the heterogeneous receptor binding profile of the AAPs may influence receptors implicated in glucose metabolism. This study aimed to clarify weight gain-independent mechanisms of AAP-induced changes in insulin secretion by deconstructing their binding profile with representative antagonists. Healthy rats were pretreated with a single subcutaneous dose of darifenacin 6 mg/kg (n=10), a selective M(3) muscarinic antagonist; ketanserin 2mg/kg (n=10), a 5HT(2A) antagonist; raclopride 0.3mg/kg (n=11) a selective D(2)/D(3) antagonist; terfenadine 20mg/kg (n=9) a selective H(1) antagonist; or, vehicle (n=11). Hyperglycemic clamps were employed following injection, providing an index of secretory capacity of pancreatic β-cells. Acute treatment with darifenacin and ketanserin significantly decreased insulin response to glucose challenge as compared to controls, which was confirmed in the darifenacin group by reduced C-peptide levels. Treatment with raclopride resulted in an increased insulin response and a strong tendency to increased C-peptide levels. H(1) blockade did not result in effects on insulin or C-peptide. Results suggest that the effects of antipsychotics on glucose dysregulation may be related to direct inhibitory effects of muscarinic (M(3)) and serotonergic (5HT(2)) antagonism on insulin secretion. Based on the expression of D(2)-like receptors in β-cells, which mediate inhibition of insulin secretion, we propose that prolonged D(2) blockade with antipsychotics may predispose to depletion of insulin stores and an eventual defect in pancreatic compensation.

Topics: Animals; Antipsychotic Agents; Blood Glucose; C-Peptide; Disease Models, Animal; Glucose; Hyperglycemia; Insulin; Insulin Resistance; Male; Protein Binding; Radioimmunoassay; Random Allocation; Rats; Rats, Sprague-Dawley; Receptor, Muscarinic M3; Receptor, Serotonin, 5-HT2A; Receptors, Dopamine D2; Receptors, Histamine

This study aimed to investigate the impairment of pancreatic endocrine function and the associated risk factors after acute pancreatitis (AP).. Fifty-nine patients were subjected to tests of pancreatic function after an attack of pancreatitis. The mean time after the event was 3.5 years. Pancreatic endocrine function was evaluated by fasting blood glucose (FBG), glycosylated hemoglobin, fasting blood insulin, and C-peptide. Homeostasis model assessment was used to evaluate insulin resistance and islet β-cell function. Pancreatic exocrine function was evaluated by fecal elastase 1. Factors that could influence endocrine function were also investigated.. Nineteen patients (32%) were found to have elevated FBG, whereas 5 (8%) had abnormal glycosylated hemoglobin levels. The levels of FBG, fasting blood insulin, and C-peptide were higher in patients than in controls (P < 0.01). The islet β-cell function of patients was lower than that of controls (P < 0.01), whereas insulin resistance index was higher among patients (P < 0.01). Obesity, hyperlipidemia, and diabetes-related symptoms were found to be associated with endocrine insufficiency. Pancreatic exocrine functional impairment was found at the same time.. Endocrine functional impairment with insulin resistance was found in patients after AP. Obesity, hyperlipidemia, and diabetes-related symptoms increased the likelihood of developing functional impairment after AP.

Topics: Acute Disease; Aged; Analysis of Variance; Biomarkers; Blood Glucose; C-Peptide; Case-Control Studies; China; Fasting; Female; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Islets of Langerhans; Logistic Models; Male; Middle Aged; Pancreatic Function Tests; Pancreatitis; Predictive Value of Tests; Recovery of Function; Retrospective Studies; Risk Assessment; Risk Factors; Severity of Illness Index; Time Factors

Continuous glucose monitoring devices measure interstitial glucose and are commonly used to investigate hypoglycemia. The relationship between interstitial glucose and blood glucose is not completely understood, particularly at low blood glucose concentrations. Interstitial glucose during hypoglycemia is generally lower than blood glucose in young subjects without diabetes and those with type 1 diabetes, but the effect of insulin resistance and obesity in type 2 diabetes on this relationship has not been examined previously. We studied the relationship between blood and interstitial glucose during experimental hypoglycemia in subjects with type 2 diabetes treated with insulin or sulfonylureas and matched controls without diabetes.. Twenty subjects with type 2 diabetes (10 sulfonylurea-treated and 10 insulin-treated) and 10 controls without diabetes of similar age and weight underwent stepped hyperinsulinemic hypoglycemic clamps. We compared blood and interstitial glucose at different levels of hypoglycemia using random effects modeling.. Interstitial glucose was significantly higher than blood glucose at all levels of hypoglycemia (P<0.001), and this difference increased as glucose fell. For every 1 mmol/L drop in blood glucose, the difference increased by 0.32 mmol/L (P<0.001). This difference was not affected by presence of type 2 diabetes or by modality of treatment (P=0.10).. In older subjects with or without type 2 diabetes, interstitial glucose is significantly higher than blood glucose, and this difference increases with increasing severity of hypoglycemia. Continuous glucose monitors may underestimate hypoglycemia in this group, and this should be taken into account when interpreting results obtained using this technology.

Topics: Aged; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Extracellular Fluid; Humans; Hypoglycemia; Hypoglycemic Agents; Insulin; Insulin Resistance; Middle Aged; Severity of Illness Index; Sulfonylurea Compounds

Laparoscopic ileal interposition associated with a sleeve gastrectomy (LII-SG) is a safe and effective operation for the treatment of type 2 diabetic (T2DM) patients with BMI below 35. The aim of this study was to evaluate insulin sensitivity (IS) and β-cell function using the euglycemic hyperinsulinemic clamp (EHC) with the intravenous glucose tolerance test (IVGTT).. This was a prospective study of 24 T2DM patients submitted to a 3-hour EHC-IVGTT before and 1 month after LII-SG. Mean BMI was 29.0, mean age was 54.8 years and mean duration of T2DM was 10.2 years; insulin therapy was used by 62.5% of the patients.. Mean BMI decreased from 29.0 to 25.8 (p < 0.001). Mean fasting plasma glucose and mean postprandial glucose were 202 and 251.3 mg/dl and dropped to 127.7 and 131.8 mg/dl (p < 0.001), respectively. Mean preoperative IS was 1.4 mmol·min(-1)·nmol(-1) and increased to 2.2 mmol· min(-1)·nmol(-1) postoperatively (p < 0.001). Mean C-peptide AUC was 488 pmol·nmol(-1) and increased to 777 pmol· nmol(-1) (p = 0.37). The disposition index increased from 9.4 to 36.4 postoperatively (p = 0.01).. According to the clamp technique, II-SG significantly improved IS and β-cell function as early as 30 days postoperatively in a T2DM population with a BMI of 21.9-33.8.

Topics: Adult; Area Under Curve; Bariatric Surgery; Blood Glucose; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Female; Gastrectomy; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Ileum; Insulin; Insulin Resistance; Insulin-Secreting Cells; Laparoscopy; Male; Middle Aged; Obesity; Postoperative Period; Preoperative Period; Prospective Studies; Weight Loss

Associations of proinsulin-to-insulin ratios with incident type 2 diabetes have been inconsistent. The use of C-peptide as the denominator in the ratio may allow for better prediction because C-peptide concentration is not affected by hepatic insulin clearance. The objective of this paper was to compare fasting intact and split proinsulin-to-insulin ratios (PI/I, SPI/I) with intact and split proinsulin-to-C-peptide ratios (PI/C-pep, SPI/C-pep) in the prediction of type 2 diabetes.. Prospective data on 818 multi-ethnic adults without diabetes at baseline from the Insulin Resistance Atherosclerosis Study (IRAS) were used. Insulin sensitivity (S(I)) and acute insulin response (AIR) were determined from frequently sampled intravenous glucose tolerance tests, and fasting intact and split proinsulin were measured using specific two-site monoclonal antibody-based immunoradiometric assays. Associations of proinsulin ratios with type 2 diabetes were determined using logistic regression and differences in prediction were assessed by comparing areas under the receiver operating characteristic curve (AROCs).. In logistic regression analyses, PI/C-pep and SPI/C-pep were more strongly associated with incident type 2 diabetes (n = 128) than PI/I and SPI/I, and were significantly better predictors of diabetes in AROC analyses (PI/C-pep = 0.662 vs PI/I = 0.603, p = 0.02; SPI/C-pep = 0.690 vs SPI/I = 0.631, p = 0.01). Both PI/C-pep and SPI/C-pep were associated with type 2 diabetes after adjustment for age, sex, ethnicity, waist circumference, impaired glucose tolerance, lipids and S(I). Both PI/C-pep and SPI/C-pep were significantly associated with incident type 2 diabetes in models that included AIR.. Proinsulin-to-C-peptide ratios were stronger predictors of diabetes in comparison with proinsulin-to-insulin ratios. These findings support the use of C-peptide as the denominator for proinsulin ratios, to more accurately reflect the degree of disproportional hyperproinsulinaemia.

Topics: Atherosclerosis; C-Peptide; Fasting; Female; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Prediabetic State; Predictive Value of Tests; Proinsulin; Prospective Studies; ROC Curve; Waist Circumference

Some type 1 diabetic patients do not require insulin at diagnosis of diabetes, and they progress to insulin dependence only after several years (latent autoimmune diabetes in adults). However, not all patients with latent autoimmune diabetes in adults progress to insulin dependence. We compared the characteristics of patients with high glutamic acid decarboxylase antibodies (GADA) titres (≥10 U/mL) to those of patients with low titres and examined other factors possibly associated with the progression to insulin dependence.. We began registering diabetic patients in 1993 and have since followed them prospectively. Among these patients, we analysed clinical characteristics and progression to insulin dependence in those followed for more than 5 years.. Patients with high GADA titres were younger and had lower body mass index, shorter disease durations and lower serum C-peptide (s-CPR) levels than the patients with low GADA titre and GADA negative type 2 diabetes. Frequencies of other islet-related autoantibodies were significantly higher in patients with high GADA titre than in those with low GADA titres. Disease protective HLA class II genotypes were less frequent in patients with high titre. The positive predictive value of being GADA positive was only 42.7%. The positive predictive value increased to 78.6% when the cut-off was set at the relatively high level of 10 U/mL. Combining GADA with other islet-related autoantibodies or HLA class II genotype increased positive predictive value but decreased sensitivity.. Our results suggest that latent autoimmune diabetes in adults constitutes a heterogeneous group and that the majority of patients with high GADA titres (≥10 U/mL) will ultimately develop type 1 diabetes while those with low titres include patients with type 1 and type 2 diabetes.

Topics: Adult; Aged; Autoantibodies; C-Peptide; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Female; Glutamate Decarboxylase; Humans; Insulin; Insulin Resistance; Islets of Langerhans; Male; Middle Aged; Predictive Value of Tests; Prospective Studies; Sensitivity and Specificity

Our study was carried out to ascertain the role of valproic acid for inducing metabolic disorders like hyperinsulinemia, insulin resistance and metabolic syndrome. Seventy-nine subjects were enrolled into the study. They were divided in 3 groups: 26 patients with epilepsy on VPA monotherapy and 28 patients with epilepsy on CBZ monotherapy and 25 healthy controls. Blood samples for fasting insulin, glucose, C-peptide, TG and HDL were collected. We compared insulin, C-peptide, C-peptide/insulin ratio, HOMA-IR, BMI, central obesity and metabolic syndrome in patients treated with VPA, patients treated with CBZ and in healthy controls. VPA treatment was associated with insulin resistance (30.8%) in opposite to CBZ treatment (7.1%). Metabolic syndrome existed in 34,6%, 14,3% and 12% among VPA, CBZ and control groups, respectively. There was no difference in C peptide/insulin ratio between study groups. Interestingly lean VPA treated patients showed high frequency of insulin resistance and metabolic syndrome compared to lean CBZ treated patients and controls. Therefore we suppose that obesity should not be an obligatory factor for VPA induced metabolic disturbances. VPA treatment is associated with insulin resistance and metabolic syndrome. This metabolic disorders were not connected with diminished hepatic insulin extraction. Although VPA treated patients showed central obesity predominance, we suggest that VPA can induce such metabolic and endocrine changes without obesity.

Topics: Adult; Blood Glucose; Body Mass Index; C-Peptide; Carbamazepine; Cholesterol, HDL; Epilepsy; Female; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Male; Metabolic Syndrome; Middle Aged; Obesity; Triglycerides; Valproic Acid

Numerous tests have been developed to estimate insulin sensitivity (SI). However, most of the established tests are either too expensive for widespread application or do not yield reliable results. The dynamic insulin sensitivity and secretion test (DISST) uses assays of glucose, insulin, and C-peptide from nine samples to quantify SI and endogenous insulin secretion (UN) at a comparatively low cost. The quick dynamic insulin sensitivity test has shown that the DISST SI values are robust to significant assay omissions.. Eight DISST-based variations of the nine-sample assay regimen are proposed to investigate the effects of assay omission within the DISST-based framework. SI and UN were identified using the fully-sampled DISST and data from 218 nine-sample tests undertaken in 74 female individuals with elevated diabetes risk. This same data was then used with appropriate assay omissions to identify SI and UN with the eight DISST-based assay variations.. Median intraprocedure proportional difference between SI values from fully-sampled DISST and the DISST-based variants was in the range of -17.9 to 7.8%. Correlations were in the range of r = 0.71 to 0.92 with the highest correlations between variants with the greatest commonality with the nine-sample DISST. Metrics of UN correlated relatively well between tests when C-peptide was assayed (r = 0.72 to 1) but were sometimes not well estimated when samples were not assayed for C-peptide (r = -0.14 to 0.75).. The DISST-based spectrum offers a series of tests with very distinct compromises of information yield, accuracy, assay cost, and clinical intensity. Thus, the spectrum of tests has the potential to enable researchers to better allocate funds by selecting an optimal test configuration for their particular application.

Topics: Blood Chemical Analysis; Blood Glucose; C-Peptide; Female; Humans; Insulin; Insulin Resistance; Reproducibility of Results

The progress of metabolic syndrome (MetS) continues with the onset of type-2 diabetes mellitus (Type-2 DM) along with linkage to other disorders such as neurodegenerative, especially Alzheimer's disease (AD), via oxidative stress and low grade systemic inflammatory process. Type-2 DM and AD are health disorders of priority research. The treatment for an individual suffering with Type- 2 DM and/or AD requires monitoring by clinicians. The aim of this study was to investigate the role of C-peptide and its correlation to insulin resistance, body mass index (BMI), β cell function, insulin sensitivity, lipid profile and hemoglobin A1c (HbA1c). The study was designed to include 96 Type-2 DM individuals from India. 58.3% males and 41.7% females were selected and fasting blood samples were collected for estimation of fasting C-peptide, fasting blood sugar (FBS), postprandial blood sugar (PPBS), HbA1c and lipid profile. Analysis was done on Hitachi912 and Elecsys 2010 using Roche reagents and standard controls. Anthropometries to calculate BMI and β cell function, insulin sensitivity, and insulin resistance were obtained. The statistical tool ANOVA, followed by calculation of p-value and r � value were applied for investigating correlation of C-peptide levels to those of high density lipoprotein-C (HDL-C), low density lipoprotein-C (LDL-C), triglycerides (TGL), HbA1c, β cell function, insulin sensitivity and insulin resistance. Highly significant positive correlations were observed in different quantiles of C-peptide levels to the studied parameters of MetS, BMI and % β cell function. Lower HDL-C level was found to be significantly related to higher C-peptide levels. Similarly, TGL and C-peptide levels displayed a significant positive correlation. A significant negative correlation was observed between C-peptide quantiles and % sensitivity. Thus, insulin resistance showed a positive correlation until the fourth quantile. No significant correlation was observed between C-peptide and HbA1c levels. This study demonstrates that assessment of C-peptide levels is a useful tool to monitor the progress of MetS among patients suffering from Type-2 DM and AD, as these disorders are intertwined to each other by common metabolic pathways. Assessment of C-peptide levels, along with HDL-C levels, in patients can be used to monitor insulin resistance.

Topics: Adult; Aged; Aged, 80 and over; Alzheimer Disease; Biomarkers; Body Mass Index; C-Peptide; Cholesterol, HDL; Diabetes Mellitus, Type 2; Female; Humans; Insulin Resistance; Male; Metabolic Syndrome; Middle Aged; Prospective Studies; Young Adult

Transoral gastroplasty (TOGA) recently emerged as a new, feasible and relatively safe technique for the surgical treatment of obesity. However, so far there are no data on the effects on insulin sensitivity in the literature. Our aim is to evaluate the effect of TOGA on insulin sensitivity and secretion.. Nine glucose normo-tolerant obese subjects (age:41+/-6 years; BMI:42.49+/-1.03 kg/m(2)) were studied. Fat-free mass (FM) and fat mass (FM) were assessed by bioelectrical impedance; plasma glucose, insulin, and C-peptide were measured during an oral glucose tolerance test (OGTT) before and 3 months after the operation. Insulin sensitivity was calculated using the oral-glucose insulin-sensitivity index, and insulin secretion by C-peptide deconvolution. Three months after surgery, a significant (P=0.008) reduction of BMI to 35.65+/-0.65 kg/m(2), with a decrease of FM and FFM from 57.22+/-2.19 to 41.46+/-3.02 kg (P=0.008) and from 59.52+/-1.36 to 56.67+/-1.10 kg (P=0.048) respectively, was observed. Insulinemia was significantly reduced at fast and at 120 min after OGTT; in contrast, no significant change in glucose concentration was observed. Insulin sensitivity significantly increased (348.45+/-20.08 vs. 421.18+/-20.84 ml/min/m(2), P=0.038) and the incremental area of insulin secretion rate (total ISR) significantly decreased (from 235.05+/-27.50 to 124.77+/-14.50 nmol/min/m(2), P=0.021). Total ISR correlated with weight, BMI and FM (r=0.522, P=0.028; r=0.541, P=0.020; r=0.463, P=0.049, respectively). BMI represented the most powerful predictor of ISR decrease (R(2)=0.541, P=0.020).. Transoral gastroplasty allows a significant weight loss 3 months after the intervention as well as an amelioration of insulin sensitivity with subsequent reduction of the insulin secretion.

Topics: Adiposity; Adult; Blood Glucose; Body Composition; Body Mass Index; C-Peptide; Electric Impedance; Energy Intake; Female; Gastroplasty; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Male; Middle Aged; Obesity; Treatment Outcome; Weight Loss

Recently, vaspin was identified as a novel adipokine with insulin-sensitizing effects that might be implicated in endogenous glucose regulation. Our objective was to evaluate the impact of acute weight loss and metabolic changes on serum vaspin concentrations in morbidly obese subjects following laparoscopic Roux-en-Y gastric bypass (RYGB) surgery.. Longitudinal, clinical intervention study in 33 morbidly obese subjects before and 12 months after RYGB was conducted. Fasting serum concentrations of vaspin were measured by a commercially available ELISA and correlated with BMI, parameters of insulin sensitivity, and other biochemical measurements. Fasting insulin sensitivity was estimated using the homeostasis model assessment (HOMA) of insulin resistance.. RYGB-induced weight loss resulted in a reduction of circulating vaspin, leptin, insulin, and C-peptide levels as well as of BMI, HbA1c, and HOMA (p < 0.0001, respectively). Changes in serum vaspin concentrations correlated positively with those in HOMA, insulin, C-peptide, HbA1c, and leptin (p < 0.05, respectively) levels. The association between percent change of vaspin and HOMA remained significant even after the adjustment for RYGB-induced changes in BMI.. Following RYGB surgery, changes in serum vaspin concentrations correlate significantly with the reduction of circulating leptin, insulin, and C-peptide levels and with the amelioration of insulin sensitivity. However, further studies have to elucidate whether vaspin is only a biomarker for body-weight-related changes of insulin sensitivity or whether it is implicated in the regulation of human glucose homeostasis.

Topics: Adult; Biomarkers; Blood Glucose; C-Peptide; Female; Gastric Bypass; Homeostasis; Humans; Insulin; Insulin Resistance; Leptin; Male; Menopause; Obesity, Morbid; Serpins; Weight Loss

To describe the clinical experience and the pharmacokinetics of U-500 regular insulin in severely insulin-resistant obese type 2 diabetic patients.. Patients requiring >200 units of insulin with A1C levels >8.0% were switched to U-500 regular insulin. For the pharmacokinetic study, fasting subjects received 100 units of U-500 regular insulin subcutaneously, and samples drawn before and every 30-60 min for glucose, insulin, and C-peptides until glucose fell below 100 mg/dl.. U-500 regular insulin doses were adjusted using the same approach as for adjusting NPH insulin doses. Mean values at baseline and at minimum A1C levels were, respectively, A1C 9.9 and 7.1%, 3.2 and 3.3 units/kg, and weight 98.6 and 102.8 kg. Pharmacokinetically, insulin concentrations rose briskly by 30 min and remained elevated for at least 7 h.. Uncontrolled severely insulin-resistant obese type 2 diabetic patients can be satisfactorily controlled with U-500 regular insulin.

Topics: Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Fasting; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Male; Obesity

Adults with type 2 diabetes mellitus (T2DM) have broad impairments in beta-cell function, including severe attenuation of the first-phase insulin response to glucose, and reduced beta-cell mass. In adolescents with T2DM, there is some evidence that beta-cell dysfunction may be less severe. Our objective was to determine beta-cell sensitivity to glucose and maximal insulin secretory capacity (AIR(max)) in teenagers with T2DM.. Fifteen adolescents with T2DM [11 F/4 M, age 18.4 +/- 0.3 yr, body mass index (BMI) 39.8 +/- 2.2 kg/m(2)] and 10 non-diabetic control subjects (7 F/3 M, age 17.4 +/- 0.5 yr, BMI 41.5 +/- 2.2 kg/m(2)) were studied. T2DM subjects had a mean duration of diabetes of 48.8 +/- 6.4 months, were treated with conventional therapies, and had good metabolic control [hemoglobin A1c (HbA1c) 6.7 +/- 1.2%]. Insulin and C-peptide were determined before and after a graded glucose infusion and after intravenous arginine at a whole blood glucose level of >or=22 mM.. The insulin response to increasing plasma glucose concentrations was blunted in the diabetic compared with control subjects (34.8 +/- 11.9 vs. 280.5 +/- 57.8 pmol/mmol; p < 0.0001), and AIR(max) was also significantly reduced in the diabetic group (1868 +/- 330 vs. 4445 +/- 606; p = 0.0005).. Even adolescents with well-controlled T2DM have severe impairments of insulin secretion. These data support beta-cell dysfunction as central in the pathogenesis of T2DM in young people, and indicate that these abnormalities can develop over a period of just several years.

Topics: Adolescent; Arginine; Blood Glucose; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Fasting; Female; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male

Adiponectin is a peptide hormone secreted from the adipose tissue, affecting the proliferation and insulin sensitivity in different cell types. The levels of adiponectin have been found to be decreased in hyperinsulinemia and insulin resistant states, such as obesity. The previous studies have suggested that plasma adiponectin levels are decreased in patients with endometrial and breast cancer. In our study, the relationship among serum adiponectin levels, demographic features and histopathological variables was evaluated in gastric cancer patients. Forty consecutive patients with gastric cancer who underwent gastrectomy with standard lymph node dissection were included and 43 healthy controls were included in this study. The serum levels of glucose, insulin, C-peptide, HbA1c and adiponectin were measured in both groups. We analyzed the correlation among these parameters and patients' demographic features, such as age, gender, body mass index (BMI) and histopathological variables such as tumor localization, stage, nodal status, histological grade, vascular and lymphatic invasion. The mean age was 60.05+9.72 in patients, while it was 38.6+12.73 in controls. The mean serum adiponectin levels were 12.62+7.9 and 10.07+6.72 ng/ml, respectively, in groups. There was no different in terms of adiponectin, C-peptide, HOMA-R level in both groups. On the other hand, BMI, glucose and insulin levels were significantly different in gastric cancer patients in comparison with the controls. There was no correlation among the levels of adiponectin, BMI, insulin and c-peptide levels in patient group (P>0.05). The adiponectin levels of woman were significantly lower than male patients (P=0.002). No relations were detected among tumor stage, tumor localization, nodal status, lymphatic and vascular invasion, and the levels of serum adiponectin (P>0.05). Interestingly, a positive correlation was found between tumor grade and plasma adiponectin levels (r=0.372; P=0.018). Our results suggest that plasma adiponectin levels were similar in both patients with gastric cancer and the controls. In addition, no correlation was found between adiponectin levels and demographic features and histopathological variables of patients. But, in undifferentiated tumors, plasma adiponectin level was significantly higher than well-differentiated grade tumors.

Topics: Adiponectin; Adult; Aged; Blood Glucose; Body Mass Index; C-Peptide; Case-Control Studies; Female; Gastrectomy; Gastric Mucosa; Humans; Insulin; Insulin Resistance; Lymph Node Excision; Male; Middle Aged; Neoplasm Invasiveness; Neoplasm Staging; Obesity; Prognosis; Risk Factors; Stomach Neoplasms; Survival Rate

OBJECTIVE Using the clamp technique, youths with a clinical diagnosis of type 2 diabetes (CDx-type 2 diabetes) and positive pancreatic autoantibodies (Ab(+)) were shown to have severe impairment in insulin secretion and less insulin resistance than their peers with negative antibodies (Ab(-)). In this study, we investigated whether oral glucose tolerance test (OGTT)-derived indexes of insulin secretion and sensitivity could distinguish between these two groups. RESEARCH DESIGN AND METHODS A total of 25 Ab(-), 11 Ab(+) CDx-type 2 diabetic, and 21 obese control youths had an OGTT. Fasting and OGTT-derived indexes of insulin sensitivity (including the Matsuda index, homeostasis model assessment [HOMA] of insulin resistance, quantitative insulin sensitivity check index, and glucose-to-insulin ratio) and insulin secretion (HOMA of insulin secretion and 30-min insulogenic and C-peptide indexes) were used. Glucagon and glucagon-like peptide (GLP)-1 responses were assessed. RESULTS Fasting C-peptide and C-peptide-to-glucose ratio, and C-peptide area under the curve (AUC) were significantly lower in the Ab(+) CDx-type 2 diabetic patients. Other OGTT-derived surrogate indexes of insulin sensitivity and secretion were not different between the Ab(+) versus Ab(-) patients. GLP-1 during the OGTT was highest in the Ab(+) youths compared with the other two groups, but this difference disappeared after adjusting for BMI. Ab(+) and Ab(-) CDx-type 2 diabetes had relative hyperglucagonemia compared with control subjects. CONCLUSIONS The clinical measures of fasting and OGTT-derived surrogate indexes of insulin sensitivity and secretion, except for fasting C-peptide and C-peptide AUC, are less sensitive tools to distinguish metabolic/pathopysiological differences, detected by the clamp, between Ab(+) and Ab(-) CDx-type 2 diabetic youths. This underscores the importance of using more sensitive methods and the importance of determining antibody status in obese youths with CDx-type 2 diabetes.

Topics: Adolescent; Autoantibodies; Blood Glucose; C-Peptide; Case-Control Studies; Diabetes Mellitus, Type 2; Fasting; Female; Glucose Tolerance Test; Glycemic Index; Humans; Immunoassay; Insulin; Insulin Resistance; Male; Phenotype

Relatives of type 1 diabetic patients are at enhanced risk of developing diabetes. We investigated the mode of onset of hyperglycemia and how insulin sensitivity and beta-cell function contribute to the progression to the disease.. In 328 islet cell autoantibody-positive, nondiabetic relatives from the observational arms of the Diabetes Prevention Trial-1 Study (median age 11 years [interquartile range 8], sequential OGTTs (2,143 in total) were performed at baseline, every 6 months, and 2.7 years [2.7] later, when 115 subjects became diabetic. Beta-cell glucose sensitivity (slope of the insulin-secretion/plasma glucose dose-response function) and insulin sensitivity were obtained by mathematical modeling of the OGTT glucose/C-peptide responses.. In progressors, baseline insulin sensitivity, fasting insulin secretion, and total postglucose insulin output were similar to those of nonprogressors, whereas beta-cell glucose sensitivity was impaired (median 48 pmol/min per m2 per mmol/l [interquartile range 36] vs. 87 pmol/min per m2 per mmol/l [67]; P < 0.0001) and predicted incident diabetes (P < 0.0001) independently of sex, age, BMI, and clinical risk. In progressors, 2-h glucose levels changed little until 0.78 years before diagnosis, when they started to rise rapidly (approximately 13 mmol x l(-1) x year(-1)); glucose sensitivity began to decline significantly (P < 0.0001) earlier (1.45 years before diagnosis) than the plasma glucose surge. During this anticipation phase, both insulin secretion and insulin sensitivity were essentially stable.. In high-risk relatives, beta-cell glucose sensitivity is impaired and is a strong predictor of diabetes progression. The time trajectories of plasma glucose are frequently biphasic, with a slow linear increase followed by a rapid surge, and are anticipated by a further deterioration of beta-cell glucose sensitivity.

Topics: Adolescent; Blood Glucose; C-Peptide; Child; Child, Preschool; Diabetes Mellitus, Type 1; Disease Progression; Female; Follow-Up Studies; Glucose Intolerance; Glucose Tolerance Test; Humans; Hyperglycemia; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Kaplan-Meier Estimate; Male; Models, Biological; Predictive Value of Tests; Risk Factors

Topics: Adult; C-Peptide; Female; Humans; Insulin Resistance; Male; Middle Aged; S100 Proteins; Schizophrenia

Insulin and glucose may influence cancer mortality via their proliferative and anti-apoptotic properties. Using longitudinal data from the nationally representative Third National Health and Nutrition Examination Survey (NHANES III; 1988-1994), with an average follow-up of 8.5 years to death, we evaluated markers of glucose and insulin metabolism, with cancer mortality, ascertained using death certificates or the National Death Index. Plasma glucose, insulin, C-peptide, and lipid concentrations were measured. Anthropometrics, lifestyle, medical, and demographic information was obtained during in-person interviews. After adjusting for age, race, sex, smoking status, physical activity, and body mass index, for every 50 mg/dl increase in plasma glucose, there was a 22% increased risk of overall cancer mortality. Insulin resistance was associated with a 41% (95% confidence interval (CI) (1.07-1.87; p = 0.01) increased risk of overall cancer mortality. These associations were stronger after excluding lung cancer deaths for insulin-resistant individuals (HR: 1.67; 95% CI: 1.15-2.42; p = 0.01), specifically among those with lower levels of physical activity (HR: 2.06; 95% CI: 1.4-3.0; p = 0.0001). Similar associations were observed for other blood markers of glucose and insulin, albeit not statistically significant. In conclusion, hyperglycemia and insulin resistance may be 'high-risk' conditions for cancer mortality. Managing these conditions may be effective cancer control tools.

Topics: Adult; Aged; Aged, 80 and over; Biomarkers; Blood Glucose; Body Mass Index; C-Peptide; Female; Glucose; Health Surveys; Humans; Insulin; Insulin Resistance; Life Style; Lipids; Longitudinal Studies; Male; Middle Aged; Neoplasms; Nutrition Surveys; Survival Rate; Time Factors; United States; Young Adult

The metabolic syndrome (MS) has become an epidemiological problem in Western countries. We developed a diet-induced obese rat model that mimics all the symptoms of MS in humans, but whose insulin resistance, hyperphagia and hyperleptinemia are caused by nutrition rather than genetic modifications.. Spontaneously hypertensive rats (SHR) were allowed for 12 weeks to choose between a cafeteria diet (CD, 20.3 kJ/g) and standard rat chow (11.7 kJ/g). Controls received rat chow.. Body weight (BW) exceeded control levels when SHR were fed with CD. The increase in BW was attributed to enhanced energy intake. The abundance of abdominal fat as well as the plasma levels of leptin and triglycerides increased concomitant with glucose, insulin and C-peptide. This prediabetic condition was further confirmed by a markedly increased insulin response following glucose challenge and by impaired glucose utilization after insulin tolerance tests.. Increases in food intake and BW despite hyperleptinemia indicate leptin resistance following CD feeding. CD-fed SHR feature leptin and insulin resistance, hypertension and obesity, thus mimicking the situation of MS patients. As such, our model is more suitable than the genetically modified rat models used to study human MS.

Topics: Abdominal Fat; Animals; Biomarkers; Blood Glucose; Blood Pressure; Body Weight; C-Peptide; Diet; Disease Models, Animal; Energy Intake; Heart Rate; Hyperphagia; Insulin; Insulin Resistance; Leptin; Male; Metabolic Syndrome; Obesity; Rats; Rats, Inbred SHR; Rats, Sprague-Dawley; Triglycerides

Hyperinsulinaemia is detected in horses with insulin resistance (IR) and has previously been attributed to increased pancreatic insulin secretion. Connecting peptide (C-peptide) can be measured to assess pancreatic function because it is secreted in equimolar amounts with insulin and does not undergo hepatic clearance.. A human double antibody radioimmunoassay (RIA) detects C-peptide in equine serum and concentrations would reflect responses to different stimuli and conditions.. A validation procedure was performed to assess the RIA. Six mature mares were selected and somatostatin administered i.v. as a primed continuous rate infusion, followed by 50 nmol human C-peptide i.v. Insulin and C-peptide concentrations were measured in horses (n = 6) undergoing an insulin-modified frequently sampled i.v. glucose tolerance test, and in horses with insulin resistance (n = 10) or normal insulin sensitivity (n = 20).. A human RIA was validated for use with equine sera. Endogenous C-peptide secretion was suppressed by somatostatin and median (range) clearance rate was 0.83 (0.15-1.61) ml/min/kg bwt. Mean + or - s.d. C-peptide-to-insulin ratio significantly (P = 0.004) decreased during the glucose tolerance test from 3.60 + or - 1.95 prior to infusion to 1.03 + or - 0.18 during the first 20 min following dextrose administration. Median C-peptide and insulin concentrations were 1.5- and 9.5-fold higher, respectively in horses with IR, compared with healthy horses.. Endogenous C-peptide secretion decreases in response to somatostatin and increases after dextrose infusion. Results suggest that relative insulin clearance decreases as pancreatic secretion increases in response to dextrose infusion. Hyperinsulinaemia in insulin resistant horses may be associated with both increased insulin secretion and decreased insulin clearance.. Both C-peptide and insulin concentrations should be measured to assess pancreatic secretion and insulin clearance in horses.

Topics: Animals; C-Peptide; Female; Glucose; Hormones; Horses; Insulin; Insulin Resistance; Pancreas; Reproducibility of Results; Somatostatin

We used homeostasis model assessment to investigate insulin sensitivity and secretion after a simultaneous pancreas-kidney transplant or kidney transplant alone. In that model, fasting plasma glucose and C-peptide levels are used to evaluate insulin sensitivity and beta-cell function.. Factors (eg, age, sex, race, delayed kidney allograft function) were correlated with homeostasis model assessment of beta-cell function and homeostasis model assessment of insulin sensitivity values after simultaneous pancreas-kidney transplant (n=89) or kidney transplant alone (n=68), and the results were compared with those in healthy subjects (n=49).. Homeostasis model assessment of beta-cell function values were similar in patients who underwent kidney transplant alone or a simultaneous pancreas-kidney transplant, and were higher than homeostasis model assessment of beta cell function values in healthy subjects. The homeostasis model assessment of insulin sensitivity showed intermediate values for patients who underwent a simultaneous pancreas-kidney transplant and correlated with prednisone dosages (in those who underwent kidney transplant alone) and tacrolimus levels (in patients who underwent a simultaneous pancreas-kidney transplant). Homeostasis model assessment of beta-cell function values correlated with prednisone dosages in both groups and with tacrolimus levels in only those who underwent a simultaneous pancreas-kidney transplant. The body mass index of subjects who underwent kidney transplant alone correlated with both homeostasis model assessment of beta-cell function results and homeostasis model assessment of insulin sensitivity results. A family history of diabetes in subjects who underwent a simultaneous pancreas-kidney transplant correlated with homeostasis model assessment of beta-cell function results and homeostasis model assessment of insulin sensitivity results.. Immunosuppressive regimen and body mass index were linked with reduced insulin sensitivity after kidney transplant. A family history of diabetes was linked with higher values of insulin secretion and lower insulin sensitivity in patients who underwent a simultaneous pancreas-kidney transplant.

Topics: Adult; Blood Glucose; Body Mass Index; C-Peptide; Case-Control Studies; Diabetes Mellitus; Female; Homeostasis; Humans; Immunosuppressive Agents; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Kidney Transplantation; Male; Models, Biological; Pancreas Transplantation; Pedigree; Prednisone; Tacrolimus

It is commonly thought that hyperglycaemia results from insufficient compensation of insulin secretion for insulin resistance. To verify this hypothesis, we assessed beta cell function and insulin sensitivity (IS) in a large cohort of volunteers with normal glucose tolerance (NGT) or impaired glucose regulation (IGR), i.e. impaired glucose tolerance or impaired fasting glucose.. In men and women with NGT (n=1,123) or IGR(n=156) (age 44 +/- 8 years, BMI 25+/-4 kg/m2, mean +/- SD)we measured: (1) IS by clamp; (2) insulin secretion rates(ISR) and beta cell glucose sensitivity (=slope of the insulin secretion/plasma glucose dose-response) by C-peptide deconvolution and OGTT modelling; and (3) acute insulin response to intravenous glucose.. After controlling for centre, sex, age and BMI, fasting and total ISR were inversely related to IS in both groups,whereas beta cell glucose sensitivity was not. Acute insulin response was reciprocally related to IS in both groups, but the relationships were incompatible with inadequate compensation and significance was lost after controlling for fasting ISR. InIGR vs NGT, IS was impaired (92 [75] vs 133 [86] micromol min(-1)[kg fat-free mass](-1) [nmol/l](-1), median [interquartile range],p<0.0001) as was beta cell glucose sensitivity (69 [46] vs 119[83] pmol min(-1) m(-2) [nmol/l](-1), p<0.0001), whereas fasting and total ISR were increased (35% and 25%, respectively, p<0.0001). In fully adjusted models, beta cell glucose sensitivity was the strongest determinant of OGTT glucose levels.. Insulin resistance normally upregulates the secretory tone, with no evidence of defective compensation in IGR. In contrast, beta cell glucose sensitivity is independent of insulin resistance, but a key determinant of glucose tolerance. This suggests that hyperglycaemia results from an intrinsic beta cell defect rather than from inadequate compensation for insulin resistance.

Topics: Adult; Blood Glucose; C-Peptide; Fasting; Female; Glucose Intolerance; Glucose Tolerance Test; Humans; Hyperglycemia; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Patch-Clamp Techniques

A novel mutation of insulin receptor gene (INSR gene) was identified in a three generation family with phenotypical variety. Proband was a 12-year-old Japanese girl with type A insulin resistance. She showed diabetes mellitus with severe acanthosis nigricans and hyperinsulinemia without obesity. Using direct sequencing, a heterozygous nonsense mutation causing premature termination at amino acid 331 in the alpha subunit of INSR gene (R331X) was identified. Her father, 40 years old, was not obese but showed impaired glucose tolerance. Her paternal grandmother, 66 years old, has been suffered from diabetes mellitus for 15 years. Interestingly, they had the same mutation. One case of leprechaunism bearing homozygous mutation at codon 331 was identified. These findings led to the hypothesis that R331X may contribute to the variation of DM in the general population in Japan. An extensive search was done in 272 participants in a group medical examination that included 92 healthy cases of normoglycemia and 180 cases already diagnosed type 2 DM or detected hyperglycemia. The search, however, failed to detect any R331X mutation in this local population. In addition, the proband showed low level C-peptide/insulin molar ratio, indicating that this ratio is considered to be a useful index for identifying patients with genetic insulin resistance. In conclusion, a nonsense mutation causing premature termination after amino acid 331 in the alpha subunit of the insulin receptor was identified in Japanese diabetes patients. Further investigations are called for to address the molecular mechanism.

Topics: Acridine Orange; Adult; Aged; C-Peptide; Child; Codon, Nonsense; Diabetes Mellitus, Type 2; Female; Humans; Insulin; Insulin Resistance; Male; Protein Subunits; Receptor, Insulin

Insulin sensitivity (IS) is measured by the euglycemic-hyperinsulinemic clamp under a nonphysiological condition. Daily C-peptide urinary excretion may be a physiological index of IS, because C-peptide is co-secreted with insulin as a function of nutrient intake and IS. The amount of (2)H(2)O released from glycolytic glucose metabolism after [6,6-(2)H(2)]-glucose ingestion was recently proposed as a physiological measure of IS. We compared these IS surrogates to the gold standard (euglycemic-hyperinsulinemic clamp). Thirty (15 male/15 female) sedentary, nondiabetic participants (27.2 +/- 4.0 (s.d.) kg/m(2), 35 +/- 12 years) were admitted for 3 days to our in-patient unit. After a 10-h fast, they received 60 g of glucose and 15 g of [6,6-(2)H(2)]-glucose. Before glucose ingestion and hourly thereafter for 4 h, plasma glucose and insulin concentrations, and plasma deuterium enrichment were determined. Plasma (2)H(2)O production divided by insulin response was used as the glycolytic index. On day 2, subjects spent 23 h in a metabolic chamber (eucaloric diet, 50% carbohydrate, 30% fat). Urinary C-peptide excretion was divided by energy intake yielding the C-peptide to energy intake ratio (CPEP/EI). After leaving the chamber (day 3, 10-h fast), IS was measured by a 2-h clamp (120 mU/m(2)/min). Average IS (clamp) was 7.3 +/- 2.6 mg glucose/kg estimated metabolic body size/min (range: 3.6-13.2). These values were inversely correlated with CPEP/EI (r = -0.62; P < 0.01) and positively with the glycolytic rate (r = 0.60; P < 0.01). In nondiabetic subjects, two novel estimates of IS--daily urinary C-peptide urinary excretion and glycolytic rate during an oral glucose tolerance test --were related to IS by a clamp.

Topics: Adolescent; Adult; Biomarkers; C-Peptide; Deuterium; Diet; Energy Intake; Fasting; Female; Glucose; Glucose Clamp Technique; Glucose Tolerance Test; Glycolysis; Humans; Insulin; Insulin Resistance; Isotope Labeling; Male; Middle Aged; Sedentary Behavior; Water; Young Adult

The present study aimed to establish hyperinsulinemic euglycemic step clamping with tracer glucose infusion and labeled glucose infusate (step hot-GINF HEC) for assessment of acute insulin resistance in anesthetized pigs and to arrange for combination with invasive investigative methods. Tracer enrichment was measured during D-[6,6-(2)H(2)]glucose infusion before and after surgical instrumentation (n = 8). Insulin dose-response characteristics were determined by two step hot-GINF HEC procedures, with accordingly labeled glucose infusates performed at a total of six insulin infusion rates ranging from 0.2 to 2.0 mU kg(-1) min(-1) (n = 8). Finally, three-step hot-GINF HEC (0.4, 1.2, and 2.0 mU kg(-1) min(-1)) was performed subsequent to major surgical trauma (n = 8). Tracer enrichment, basal glucose kinetics, and circulating levels of C-peptide, cortisol, glucagon, and catecholamines were not influenced by surgical instrumentation. Mean intraindividual coefficient of variance levels for glucose infusion rates and repeatedly measured insulin, glucose, and tracer enrichment indicated stable clamping conditions. Basal and maximal insulin-stimulated glucose utilization was twice as high as in humans at approximately 5.5 and 21 mg kg(-1) min(-1). Surgical trauma elicited pronounced peripheral and moderate hepatic insulin unresponsiveness (45% lower whole body glucose disposal and 19% less suppressed endogenous glucose release) and apparently diminished metabolic insulin clearance. Step hot-GINF HEC seems suitable for assessment of acute insulin resistance in anesthetized pigs, and combination with invasive investigative methods requiring surgical instrumentation can be accomplished without the premises for utilization of the technique being altered, but attention must be paid to alterations in metabolic insulin clearance.

Topics: Animals; C-Peptide; Chromatography, Liquid; Dose-Response Relationship, Drug; Glucagon; Glucose; Glucose Clamp Technique; Hydrocortisone; Insulin; Insulin Resistance; Kinetics; Liver; Male; Swine; Tandem Mass Spectrometry

Classic 21-hydroxylase deficiency (21HD) presents some traits of the metabolic syndrome.. To characterize discrete alterations of lipid and carbohydrate metabolism in children and young adults with classic 21HD, which could predict early atherogenesis.. Twenty-seven Caucasian patients with classic 21HD (4-31 years); 27 sex-, age- and BMI-matched controls. Clinical parameters, hormonal status and genotype were assessed in all patients. Lipid parameters, including relative (%) and absolute (mg/dl) small-dense low-density lipoproteins subfractions (sd-LDL) were measured in patients and controls. Oral glucose tolerance tests were performed in both groups.. sd-LDL (%) was significantly higher in patients than controls (39.7 +/- 5.9 vs. 35.5 +/- 5.7%; p = 0.008). The same applies for absolute sd-LDL (mg/dl) (42.6 +/- 11.9 vs. 36.4 +/- 7.5; p = 0.029). HDL-cholesterol was lower in patients (p = 0.032). Fasting glucose and insulin were significantly higher in patients. Similar differences were noticed for HOMA-IR (p = 0.001), IRI (p = 0.001) and HOMA-B (p = 0.002). IRI correlated directly and significantly with the total hydrocortisone dose and the duration of treatment. Fasting glucose correlated with absolute sd-LDL. No obvious differences were seen between clinical forms or genotype groups.. Substitution therapy should be adapted particularly at young ages to prevent early atherogenesis and cardiovascular risk in later life.

Topics: Adolescent; Adrenal Hyperplasia, Congenital; Adult; Blood Glucose; C-Peptide; Carbohydrate Metabolism; Child; Child, Preschool; Cholesterol, HDL; Cholesterol, LDL; Cross-Sectional Studies; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Lipid Metabolism; Male; Statistics, Nonparametric; Steroid 21-Hydroxylase; Triglycerides; Young Adult

The loss of incretin effect in patients with type 2 diabetes mellitus may be secondary to impaired glucose homeostasis. We investigated whether reduced glucose tolerance and insulin resistance induced by steroid treatment, relative physical inactivity, and high-calorie diet in healthy young males would impair the incretin effect.. The incretin effect was measured using 75 g oral glucose tolerance test (OGTT) and isoglycemic iv glucose infusion (IIGI) in 10 healthy Caucasian normal glucose-tolerant male subjects without any family history of diabetes [age 24 + or - 3 yr (mean + or - sd); body mass index 23 + or - 2 kg/m(2); glycosylated hemoglobin 5.4 + or - 0.1%] before and at the end of a 12-d period with oral administration of prednisolone (37.5 mg once daily), high-calorie diet, and relative physical inactivity.. The 12-d intervention period resulted in significant increases in body weight [79 + or - 5 vs. 80 + or - 6 kg (mean + or - sd), P = 0.03] and fasting plasma glucose (5.1 + or - 0.1 vs. 5.6 + or - 0.2 mm, P = 0.016), whereas insulin sensitivity (Matsuda index 17.6 + or - 1.7 vs. 9.2 + or - 1.0, P = 0.0001) decreased. Glucose tolerance [as assessed by the 120-min plasma glucose value after OGTT (4.9 + or - 1.1 vs. 7.8 + or - 2.5 mm, P < 0.0001) and area under curve (AUC) (152 + or - 45 vs. 384 + or - 53 mm.4 h, P = 0.002)] during the OGTT deteriorated. Also, the incretin effect [incretin effect (percent) = 100% x (AUC(insulin,OGTT) - AUC(insulin,IIGI))/AUC(insulin,OGTT))] deteriorated (72 + or - 5 vs. 43 + or - 7%, P = 0.002). An increase in glucose-dependent insulinotropic polypeptide response during OGTT, but no significant changes in glucagon-like peptide-1 or glucagon responses, was observed after glucose homeostatic dysregulation.. Impairment of the incretin effect can be elicited by a short period of reduced glucose tolerance and insulin resistance in healthy male subjects not disposed for type 2 diabetes.

Topics: Adult; Area Under Curve; Blood Glucose; Body Weight; C-Peptide; Diet; Glucagon; Glucagon-Like Peptide 1; Glucose Tolerance Test; Humans; Incretins; Insulin; Insulin Resistance; Male; Motor Activity; Prednisolone

The high incidence of insulin resistance, type 2 diabetes, and metabolic syndrome in Western societies and their impact on quality of life emphasize the importance of identifying underlying susceptibility loci for metabolic diseases. The polycystic ovary syndrome (PCOS) susceptibility locus D19S884 allele 8 (A8) is associated with measures of insulin resistance, beta-cell dysfunction, and other metabolic phenotypes in PCOS families. We now investigate the role of D19S884 A8 in pregnancy.. Using the multiethnic Hyperglycemia and Adverse Pregnancy Outcome cohort, we assessed the associations of D19S884 A8 with measures of maternal glycemia and fetal size.. We tested for association of maternal D19S884 A8 with maternal outcomes (fasting, 1-h, and 2-h plasma glucose, and fasting and 1-h C-peptide from an oral glucose tolerance test) and fetal and maternal D19S884 A8 with fetal outcomes (birth weight, length, head circumference, sum of skin folds, fat mass, cord C-peptide, and 2-h neonatal plasma glucose).. We analyzed 4424 Caucasian mothers and 3347 offspring of northern European ancestry, 1957 Thai mothers and 2089 offspring from Bangkok, 1208 Afro-Caribbean mothers and 1209 offspring from Barbados, and 774 Hispanic mothers and 762 offspring from Bellflower, California.. After adjusting for confounding variables and multiple testing, neither maternal nor fetal D19S884 A8 showed significant evidence for association with any of the outcomes tested.. The PCOS susceptibility locus, D19S884 A8, is not a major factor contributing to glycemia during pregnancy or fetal size in a general obstetric population.

Topics: Alleles; Birth Weight; Blood Glucose; C-Peptide; Female; Fetal Development; Genetic Association Studies; Genetic Predisposition to Disease; Genotype; Humans; Insulin Resistance; Polycystic Ovary Syndrome; Pregnancy; Pregnancy Outcome

Insertion of a transjugular intrahepatic porto-systemic shunt (TIPS) increases body cell mass (BCM) in patients with liver cirrhosis. The responsible mechanism is unidentified, but may involve changes in insulin sensitivity and glucose metabolism. Eleven patients with liver cirrhosis were examined before and 6 mo after a TIPS procedure with bioimpedance analyses, 2-h oral glucose tolerance tests, and two-step hyperinsulinemic euglycemic clamp with tracer-determined endogenous glucose production. After TIPS, BCM increased by 4.8 kg [confidence interval (CI): 2.7-7.3]. Fasting (f)-insulin increased from 123 +/- 81 to 193 +/- 124 pmol/l (P = 0.03), whereas f-glucose was unchanged (6.0 +/- 0.8 vs. 6.2 +/- 1.0 mmol/l). Glucose and insulin oral glucose tolerance test area under the curve increased by 14% (CI: 7-22%) and 53% (CI: 14-90%), respectively, P < 0.05. The C-peptide-to-insulin ratio decreased by 21% (CI: 8-35%, P = 0.01). Insulin sensitivity based on glucose infusion rate (4.69 +/- 1.82 vs. 4.85 +/- 2.37 mg.kg(-1).min(-1)) and glucose tracer-based rate of disappearance were unchanged (5.01 +/- 1.61 vs. 4.97 +/- 2.13 mg.kg(-1).min(-1)). Despite a further increase in peripheral hyperinsulinemia, f-endogenous glucose production did not change between study days (2.01 +/- 0.42 vs. 2.42 +/- 0.58 mg.kg(-1).min(-1)) and was suppressed equally by insulin (1.1 +/- 0.1 vs. 1.0 +/- 0.1 mg.kg(-1).min(-1)). Insulin clearance, growth hormone, cortisol, and glucagon levels were unchanged. BCM improvement did not correlate with the measured variables. After TIPS, BCM rose, despite enhanced hyperinsulinemia and aggravated glucose intolerance, but unchanged peripheral and hepatic insulin sensitivity. This apparent discrepancy may be ascribed to shunt-related decreased insulin exposure to the liver cells. However, the anabolic effect of TIPS seems not to be related to improvements in insulin sensitivity and remains mechanistically unexplained.

Topics: Body Composition; C-Peptide; Diabetes Mellitus; Energy Metabolism; Fatty Acids, Nonesterified; Female; Glucagon; Glucose; Glucose Clamp Technique; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin Resistance; Liver; Liver Cirrhosis; Male; Middle Aged; Portasystemic Shunt, Transjugular Intrahepatic; Predictive Value of Tests; Rest

The aim of this study is to investigate the effect of body size on insulin-mediated, whole-body glucose uptake (M-value) in morbidly obese (MO) subjects, who have large amounts of fat mass. Furthermore, we aimed at verifying which surrogate insulin-sensitivity index can better substitute the euglycemic clamp values and whether the insulin secretion/insulin resistance index is meaningful also in MO subjects.. The study design is cross-sectional, case-control study of insulin sensitivity--assessed by different methods--and insulin secretion.. One-hundred and sixty-eight subjects ca. 39 years old, with a body mass index (BMI) between 17 and 64 kg m⁻², underwent euglycemic hyperinsulinemic clamp and oral glucose tolerance test (OGTT) with surrogate measures of insulin sensitivity together with body composition by ³H₂O dilution. Insulin secretion rate (ISR) was measured at fast and after OGTT by C-peptide deconvolution.. The population was divided into quartiles of BMI. In the fourth quartile, the best insulin-sensitivity variable between M/I/kg(FFM) and M/I/kg(bw) was the latter, as shown by area under the receiver-operator characteristic (ROC) curve (0.85 vs 0.89). The best index to identify insulin-resistant individuals (lowest distribution quartile: M/I/kg(bw)≤ 29.3 μmol min⁻¹ kg⁻¹ nmol l⁻¹) were Matsuda index and oral glucose insulin sensitivity (OGIS), whereas fasting insulin concentration, QUICKI, and HOMA failed (ROC analysis). M-value declined exponentially as the BMI increased, whereas ISR linearly increased. The insulin secretion/insulin resistance index well applied to MO.. In MO subjects, in which the fat mass is highly represented, fat-free mass cannot be considered the only determinant of insulin sensitivity, thus M-value should be normalized by total body weight. The best surrogates of insulin sensitivity measured by euglycemic clamp are Matsuda index and OGIS. BMI directly affects both insulin sensitivity and ISR and the insulin secretion/insulin resistance index is a valid model to correlate ISR with insulin sensitivity also in MO.

Topics: Adult; Area Under Curve; Blood Glucose; Body Mass Index; Body Size; Body Weight; C-Peptide; Case-Control Studies; Cross-Sectional Studies; Fasting; Female; Glucose; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Male; Obesity, Morbid

Prohormone convertase 1 is involved in maturation of peptides. Rare mutations in gene PCSK1, encoding this enzyme, cause childhood obesity and abnormal glucose homeostasis with elevated proinsulin concentrations. Common single nucleotide polymorphisms (SNPs) within this gene, rs6232 and rs6235, are associated with obesity. We studied whether these SNPs influence the prediabetic traits insulin resistance, beta-cell dysfunction, or glucose intolerance.. We genotyped 1498 German subjects for SNPs rs6232 and rs6235 within PCSK1. The subjects were metabolically characterized by oral glucose tolerance test with glucose, insulin, proinsulin, and C-peptide measurements. A subgroup of 512 subjects underwent a hyperinsulinemic-euglycemic clamp.. The minor allele frequencies were 25.8% for SNP rs6235 and 6.0% for rs6232. After adjustment for sex and age, we found no association of SNPs rs6235 and rs6232 with BMI or other weight-related traits (all p >or= 0.07). Both minor alleles, adjusted for sex, age, BMI and insulin sensitivity were associated with elevated AUCproinsulin and AUCproinsulin/AUCinsulin (rs6235: p(additive) model or= 0.08). The minor allele of SNP rs6232 was additionally associated with 15% higher OGTT-derived and 19% higher clamp-derived insulin sensitivity (pdom

Topics: Body Composition; C-Peptide; Genotype; Glucose; Glucose Clamp Technique; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Obesity; Polymorphism, Single Nucleotide; Proinsulin; Risk Factors; White People

Peroxisome proliferator-activated receptor (PPAR)-gamma and PPAR-alpha agonists individually reduce intra-organ triglyceride content and improve insulin sensitivity. However, the precise effects of combined PPAR-gamma and PPAR-alpha therapy on intra-organ triglyceride content and insulin sensitivity in subjects with Type 2 diabetes have not yet been determined.. Diet-controlled Type 2 subjects (n = 9) were studied before and after 16 weeks of combined PPAR-gamma [pioglitazone (PIO), 45 mg daily] and PPAR-alpha [bezafibrate (BEZA), modified release 400 mg daily] agonist therapy. Glucose metabolism and endogenous glucose production were measured following a standard liquid test meal. Liver and muscle triglyceride levels were measured by (1)H magnetic resonance spectroscopy.. Combined PIO and BEZA therapy reduced mean fasting (7.5 +/- 0.5 vs. 6.5 +/- 0.2 mmol/l, P = 0.04) and peak postprandial plasma glucose (15.3 +/- 1.1 vs. 11.7 +/- 0.6 mmol/l, P = 0.007). No significant change in hepatic or muscle triglyceride content was observed. Postprandial suppression of endogenous glucose production remained similar on both study days. Both subcutaneous and visceral fat content increased following therapy.. Combined PIO and BEZA therapy in Type 2 diabetes does not decrease intrahepatic triglyceride content or postprandial endogenous glucose production. This study demonstrates an unexpected adverse interaction of PPAR-alpha with PPAR-gamma agonist therapy.

Topics: Abdominal Muscles; Adult; Aged; Bezafibrate; Blood Glucose; Body Weight; C-Peptide; Diabetes Mellitus, Type 2; Glucagon; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Hypolipidemic Agents; Insulin; Insulin Resistance; Liver; Middle Aged; Pioglitazone; PPAR alpha; PPAR gamma; Thiazolidinediones; Triglycerides

Glucose is a more efficient substrate for ATP production than free fatty acid (FFA). Insulin resistance (IR) results in higher FFA concentrations and impaired myocardial glucose use, potentially worsening ischemia. We hypothesized that metabolic manipulation with a hyperinsulinemic euglycemic clamp (HEC) would affect a greater improvement in left ventricular (LV) performance during dobutamine stress echo (DSE) in subjects with IR.. 24 subjects with normal LV function and coronary disease (CAD) awaiting revascularization underwent 2 DSEs. Prior to one DSEs they underwent an HEC, where a primed infusion of insulin (rate 43 mU/m 2/min) was co-administered with 20% dextrose at variable rates to maintain euglycemia. At steady-state the DSE was performed and images of the LV were acquired with tissue Doppler at each stage for offline analysis. Segmental peak systolic velocities (Vs) were recorded, as well as LV ejection fraction (EF). Subjects were then divided into two groups based on their insulin sensitivity during the HEC.. HEC changed the metabolic environment, suppressing FFAs and thereby increasing glucose use. This resulted in improved LV performance at peak stress, measured by EF (IS group mean difference 5.3 (95% CI 2.5-8) %, p = 0.002; IR group mean difference 8.7 (95% CI 5.8-11.6) %, p < 0.0001) and peak V s in ischemic segments (IS group mean improvement 0.7(95% CI 0.07-1.58) cm/s, p = 0.07; IR group mean improvement 1.0 (95% CI 0.54-1.5) cm/s, p < 0.0001) , that was greater in the subjects with IR.. Increased myocardial glucose use induced by HEC improves LV function under stress in subjects with CAD and IR. Cardiac metabolic manipulation in subjects with IR is a promising target for future therapy.

Topics: Aged; Blood Glucose; C-Peptide; Coronary Artery Disease; Echocardiography, Doppler, Color; Echocardiography, Stress; Fatty Acids, Nonesterified; Female; Glucose Clamp Technique; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Male; Middle Aged; Myocardium; Stroke Volume; Time Factors; Ventricular Dysfunction, Left; Ventricular Function, Left

Several studies have shown an association between psoriasis and atherosclerotic risk factors. In this study, we aimed to evaluate endothelial function by flow-mediated dilation (FMD) and insulin resistance by Homeostasis model assessment-insulin resistance (HOMA-IR).. We examined 75 consecutive psoriasis patients and 50 healthy controls. All subjects underwent transthoracic echocardiography and brachial artery imaging for detecting FMD. Fasting blood samples were drawn from all subjects for measuring insulin, C-peptide, fasting blood glucose. HOMA-IR was calculated.. Baseline characteristics of both groups were similar. Twenty-four psoriatic patients had arthritis. Insulin [9.3 (4.0-208.1) vs. 8.2 (2.3-16.5) mcIU/ml, P = 0.016] and C-peptide [2.5 (0.9-20.0) vs. 2.0 (0.9-3.7) ng/ml, P = 0.009] levels were significantly higher in patients with psoriasis than in controls. HOMA-IR [2.1 (0.8-68.9) vs. 1.8 (0.6-8.6), P = 0.036] was significantly higher in patients with psoriasis than in controls. FMD was reduced in patients with psoriasis compared with healthy controls (5.6 +/- 1.9% vs. 10.9 +/- 1.9%, P < 0.001).. This study demonstrated a significant impairment in endothelial function and increased insulin resistance in patients with psoriasis. This is a comprehensive study for identifying atherosclerotic risk factors in psoriasis. We suggest that psoriatic patients should be paid attention for atherosclerosis and its risk factors.

Topics: Adult; Atherosclerosis; Blood Glucose; Brachial Artery; C-Peptide; Echocardiography; Endothelium, Vascular; Female; Homeostasis; Humans; Insulin; Insulin Resistance; Lipids; Male; Middle Aged; Psoriasis; Regional Blood Flow; Risk Factors

Dynamic insulin sensitivity (SI) tests often utilise model-based parameter estimation. This research analyses the impact of expanding the typically used two-compartment model of insulin and C-peptide kinetics to incorporate a hepatic third compartment. The proposed model requires only four C-peptide assays to simulate endogenous insulin production (uen), greatly reducing the cost and clinical burden. Sixteen subjects participated in 46 dynamic insulin sensitivity tests (DIST). Population kinetic parameters are identified for the new compartment. Results are assessed by model error versus measured data and repeatability of the identified SI. The median C-peptide error was 0% (IQR: -7.3, 6.7)%. Median insulin error was 7% (IQR: -28.7, 6.3)%. Strong correlation (r=0.92) existed between the SI values of the new model and those from the original two-compartment model. Repeatability in SI was similar between models (new model inter/intra-dose variability 3.6/12.3% original model -8.5/11.3%). When frequent C-peptide samples may be available, the added hepatic compartment does not offer significant diagnostic, repeatability improvement over the two-compartment model. However, a novel and successful three-compartment modelling strategy was developed which provided accurate estimation of endogenous insulin production and the subsequent SI identification from sparse C-peptide data.

Topics: Algorithms; Blood Glucose; C-Peptide; Computer Simulation; Diabetes Mellitus, Type 2; Diagnostic Techniques, Endocrine; Extracellular Fluid; Glucose; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Liver; Models, Biological; Prediabetic State

Despite existing epidemiologic data concerning the increased incidence of breast cancer in diabetes type 2, the association between insulin resistance and breast carcinogenesis is not yet well defined. In this cross-sectional study, we examined the homeostatic model assessment values of insulin resistance (HOMA-IR) among 82 patients with malignant breast tumor, 48 subjects with benign breast mass, and 838 healthy Iranian women. One hundred and thirty (n = 130) surgical inpatients of Tehran Central Cancer Institute (Tehran, Iran) were evaluated preoperatively. Healthy subjects were nondiabetic, nonhypertensive women aged 20-77 years from four different locations in Tehran. Age and central obesity-adjusted HOMA-IR values were 3.6 [95% confidence interval (CI), 2.8-4.4], 2.3 (1.7-2.9), and 1.7(1.6-1.8) correspondingly in subjects with malignant breast tumor, those with benign breast mass, and healthy subjects. The interaction effect of age on the association between breast mass (malignant/ benign /no breast mass) with HOMA-IR values was significant [F(54) = 10, P < 0.001, partial eta squared = 0.03]. The interaction of central obesity on this association was also significant [F(54) = 37, P < 0.001, partial eta squared = 0.11]. We conclude that the noted linkage between insulin resistance and breast cancer may indicate an underlying pathology of mammary carcinogenesis.

Topics: Adult; Age Factors; Aged; Blood Glucose; Breast Neoplasms; C-Peptide; Cross-Sectional Studies; Female; Humans; Insulin; Insulin Resistance; Iran; Middle Aged; Obesity; Risk Factors

Topics: Autoimmune Diseases; C-Peptide; Diabetes Mellitus, Type 1; Factitious Disorders; Humans; Hypoglycemia; Insulin Antibodies; Insulin Resistance; Insulin-Secreting Cells

Obesity is associated with insulin resistance and the resulting hyperinsulinemia has been attributed to an increase of insulin secretion and a reduction of insulin clearance. The present study was intended to further characterize the relative contribution of secretion and clearance especially in the postprandial state. In relation to WHO body weight classes 291 subjects were divided in 5 subgroups Basal insulin concentrations rose stepwise and significantly with increasing BMI. This was paralleled by C-peptide concentrations and insulin secretion, while the reduction of insulin clearance was less stringent in relation to BMI. Basal glucose was unchanged in the BMI25 group and 8% higher in the obese groups (BMI 30, 35, 40) compared to normal weight (NW). Although postprandial insulin concentrations were significantly higher in the overweight and obese groups compared to NW the correlation was not as tight as in the basal state. Furthermore, the present data demonstrate for the first time that insulin secretion only increased in the overweight group without further augmentation in the obese groups. Further hyperinsulinemia of the latter was due to weight-dependent reduction of insulin clearance. The postprandial glucose response was 38-82% higher with increasing weight compared to NW. In summary basal hyperinsulinemia is mainly due to weight related increase of insulin secretion with moderate contribution of reduced insulin clearance. Postprandially, hyperinsulinemia of overweight is predominantly due to secretion while further postprandial hyperinsulinemia of obese subjects is mainly due to reduced clearance. Thus, postprandial insulin secretion cannot respond adequately to the challenge of weight-dependent insulin resistance already in non-diabetic obese subjects.

Topics: Adult; Blood Glucose; Body Mass Index; Body Weight; C-Peptide; Female; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Insulin Secretion; Male; Obesity

First-degree relatives (FDR) of patients with type 2 diabetes mellitus are at increased risk of developing type 2 diabetes mellitus. We studied if endothelial dysfunction of the resistance vessels is present and may coexist with metabolic insulin resistance in FDR. Male FDR (n = 13; 26 +/- 1 years; body mass index, 25 +/- 1 kg m(2) [mean +/- SEM]) and matched control subjects (CON) (n = 22; 25 +/- 1 years; body mass index, 24 +/- 1 kg m(2)) were studied by hyperinsulinemic (40 mU min(-1)m(-2)) isoglycemic clamp combined with brachial arterial and deep venous catheterization of the forearm. Forearm blood flow (FBF) was measured by venous occlusion plethysmography upon stimulation with systemic hyperinsulinemia (291 +/- 11 pmol/L, pooled data from both groups) and upon intraarterial infusion of adenosine (ADN) and acetylcholine (ACH) +/- hyperinsulinemia. Forearm blood flow response to ADN and ACH was less in FDR vs CON (P < .05); systemic hyperinsulinemia added to the FBF effect of ADN in CON (P < .05) but not in FDR. In addition, FDR demonstrated impaired FBF to hyperinsulinemia (2.1 +/- 0.2 vs 4.0 +/- 0.6 mL 100 mL(-1) min(-1)) in FDR and CON, respectively (P < .05). Both M-value (5.0 +/- 0.7 vs 7.0 +/- 0.5 mg min(-1) kg(-1)) and forearm glucose clearance (0.6 +/- 0.1 vs 1.4 +/- 0.4 mL 100 mL(-1)min(-1)) were diminished in FDR compared with CON (all P < .05). FDR demonstrated endothelial dysfunction of the resistance vessels in addition to impaired insulin-stimulated increase in bulk flow. Moreover, FDR demonstrated whole-body insulin resistance as well as decreased basal and insulin-stimulated forearm glucose uptake. It remains to be established whether FDR also demonstrate impaired insulin-stimulated microvascular function.

Topics: Acetylcholine; Adenosine; Adult; Blood Gas Analysis; Blood Glucose; C-Peptide; C-Reactive Protein; Cholesterol; Diabetes Mellitus, Type 2; Endothelium, Vascular; Family; Glucose Clamp Technique; Homocysteine; Humans; Insulin; Insulin Resistance; Male; Plethysmography; Potassium; Statistics, Nonparametric; Vascular Resistance; Vasodilator Agents

Chronic hepatitis C virus infection is associated with insulin resistance (IR), and both host and viral factors are important in its development. The association and the predictors of IR in chronic hepatitis B virus (CHBV) infection remain unclear.. A total of 69 CHBV-infected subjects were examined to study the relationship between histological findings and anthropometric and biochemical data, including IR determined by the homeostasis model assessment (HOMA-IR). To assess the influence of CHBV infection on IR independent of any effect of hepatic fibrosis, overweight, or sex we also compared fasting serum insulin, C-peptide, HOMA-IR, HOMA-beta (measure of beta-cell function) and C-peptide-insulin ratio (to distinguish impaired insulin degradation (low ratio) from insulin hypersecretion (normal ratio)) levels between the subset of 14 male normal weight (body mass index, BMI<23) CHBV patients with stage 0 or 1 hepatic fibrosis and 50 male normal weight healthy controls matched by age and anthropometry (BMI and waist circumference).. A total of 31 (44.9%) CHBV-infected patients were overweight (BMI>23 kg/m(2)) and 18 (26.1%) were obese (BMI>25 kg/m(2)). IR was seen in 34 (49.3%) patients. BMI (Spearman's coefficient=-0.436; P<0.001) and serum triglyceride levels (Spearman's coefficient=-0.307; P=0.010) were univariate predictors of IR. In multiple linear regression analysis, only BMI (P<0.001) was an independent predictor of HOMA-IR. The subgroup of CHBV-infected patients and the controls had comparable levels of all markers of IR, including fasting glucose, insulin, C-peptide, and HOMA-IR.. IR in CHBV-infected patients is a reflection of the host metabolic profile and CHBV infection is not in itself correlated with IR.

Topics: Adult; Blood Glucose; Body Mass Index; C-Peptide; Female; Glucose Tolerance Test; Hepatitis C, Chronic; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Liver; Male

Serum gamma-glutamyltranspeptidase level is often increased in patients with chronic hepatitis C, and we aimed to identify factors associated with this phenomenon in patients completely abstinent from alcohol (teetotaller).. 71 teetotaller patients have been identified by personal history, questioning of relatives, CAGE questionnaire administration and unscheduled alcoholemia measurements.. 39 patients (55%) had elevated (>50IU/L) gamma-glutamyltranspeptidase level. Body mass index, insulin and C-peptide level, insulin resistance, piecemeal necrosis score > or =3, fibrosis score > or =2 and steatosis score > or =1 were significantly higher in these patients than in those (n=32) with normal gamma-glutamyltranspeptidase. At multiple linear regression analysis gamma-glutamyltranspeptidase level was associated with C-peptide level, insulin resistance and histopathologic grading. At multiple logistic regression analysis, C-peptide level (OR=2.13) and piecemeal necrosis score > or =3 (OR=4.59) were the only factors independently associated with elevated gamma-glutamyltranspeptidase. Sustained virological response during pegylated interferon plus ribavirine treatment was achieved by 97% and 49% patients with normal and elevated gamma-glutamyltranspeptidase, respectively (p=0.0001).. Serum gamma-glutamyltranspeptidase level is often elevated in chronic hepatitis C and is associated with metabolic and inflammatory factors; this phenomenon may contribute to explain and to predict resistance to treatment in this subgroup of patients.

Topics: Adult; C-Peptide; Enoxacin; Female; gamma-Glutamyltransferase; Hepacivirus; Hepatitis C, Chronic; Humans; Insulin; Insulin Resistance; Liver; Male; Middle Aged; Temperance

We aimed to establish the prevalence and characteristics of latent autoimmune diabetes in adults (LADA) and compare it with type 2 diabetes in 1370 Korean patients. The prevalence of LADA was 5.1%. Low C-peptide level and absence of metabolic syndrome were variables independently associated with the diagnosis of LADA.

Topics: Adult; Age of Onset; Aged; C-Peptide; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Female; Humans; Insulin Resistance; Korea; Male; Metabolic Syndrome; Middle Aged; Prevalence

The acute hypermetabolic response post-burn is associated with insulin resistance and hyperglycemia, significantly contributing to adverse outcome of these patients.. The aim of the study was to examine the persistence of abnormalities of various clinical parameters commonly utilized to assess the degree of insulin resistance in severely burned children for up to 3 yr after the burn injury.. A total of 194 severely burned pediatric patients, admitted to our institute between 2002 and 2007, were enrolled in this prospective study and compared to a cohort of 95 nonburned, noninjured children.. Urinary cortisol, epinephrine, and norepinephrine, serum cytokines, and resting energy requirements were determined at admission and 1, 2, 6, 9, 12, 18, 24, and 36 months post-burn. A 75-g oral glucose tolerance test was performed at similar time points; serum glucose, insulin, and C-peptide were measured; and insulin sensitivity indices, such as ISI Matsuda, homeostasis model assessment, quantitative insulin sensitivity check index, and ISI Cederholm, were calculated. Statistical analysis was performed by ANOVA with Bonferroni correction with significance accepted at P < 0.05.. Urinary cortisol and catecholamines, serum IL-7, IL-10, IL-12, macrophage inflammatory protein-1b, monocyte chemoattractant protein-1, and resting energy requirements were significantly increased for up to 36 months post-burn (P < 0.05). Glucose values were significantly augmented for 6 months post-burn (P < 0.05), associated with significant increases in serum C-peptide and insulin that remained significantly increased for 36 months compared to nonburned children (P < 0.05). Insulin sensitivity indices, ISI Matsuda, ISI quantitative insulin sensitivity check index, and homeostasis model assessment were abnormal throughout the whole study period, indicating peripheral and whole body insulin resistance. The insulinogenic index displayed physiological values, indicating normal pancreatic beta-cell function.. A severe burn is associated with stress-induced insulin resistance that persists not only during the acute phase but also for up to 3 yr post-burn.

Topics: Adolescent; Area Under Curve; Blood Glucose; Body Height; Burns; C-Peptide; Calorimetry, Indirect; Catecholamines; Child; Child, Preschool; Cohort Studies; Cytokines; Female; Glucose Tolerance Test; Glycated Hemoglobin; Growth; Hormones; Humans; Hydrocortisone; Infant; Infant, Newborn; Insulin; Insulin Resistance; Male; Prospective Studies

Recently novel type 2 diabetes risk loci were identified and reported to associate with beta-cell dysfunction. We assessed whether the risk alleles in TCF7L2, CDKAL1, HHEX, SLC30A8, IGF2BP2, CDKN2A/2B, JAZF1, and WFS1 reduce insulin secretion in an additive manner and whether their impact is influenced by insulin sensitivity.. We genotyped 1397 nondiabetic subjects for the aforementioned risk alleles and performed risk allele summation. Participants underwent an oral glucose tolerance test and in a subgroup also an iv glucose tolerance test with C-peptide and insulin measurements. In our cohort, only polymorphisms in SLC30A8, HHEX, TCF7L2, and CDKAL1 influenced insulin secretion. So we tested only these polymorphisms and, in a separate analysis, all above-mentioned polymorphisms.. We observed a 28% decline in insulin secretion with increment of risk alleles (P

Topics: Adult; Alleles; Body Composition; Body Mass Index; C-Peptide; Cohort Studies; Diabetes Mellitus, Type 2; Female; Gene Frequency; Genotype; Germany; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Polymorphism, Single Nucleotide; Risk

Obstructive sleep apnea syndrome (OSAS) is associated with obesity and insulin resistance. Visfatin is an insulin-mimicking adipokine, which is considered a link between obesity and insulin resistance. Aim of this study was to evaluate levels of plasma visfatin in patients with severe OSAS and examine their potential correlation with sleep characteristics and several biochemical parameters.. Nondiabetic patients with severe OSAS (Apnea Hypopnea Index > 30/h, n = 32) and healthy controls (Apnea Hypopnea Index < 5/h, n = 12), examined with polysomnography, underwent a biochemical analysis to estimate fasting levels of visfatin, glucose, insulin, C-peptide, and lipid profile.. The two groups were matched for age and body mass index (BMI). OSAS patients had significantly higher fasting insulin levels (p = 0.045), but no difference was shown in visfatin between patients and controls (p = 0.585). In OSAS patients, visfatin levels correlated positively with sleep latency (r = 0.539, p = 0.01) and triglyceride levels (r = 0.584, p = 0.036) and negatively with total sleep time, percentage of stage 2 and REM sleep, and LDL-cholesterol levels (r = -0.659 and p = 0.001; r = -0.496 and p = 0.019; r = -0.577 and p = 0.005; r = -0.804 and p = 0.003, respectively). No association was found, however, between visfatin levels and HOMA index or indices of nocturnal hypoxia.. In patients with severe OSAS, visfatin levels are associated with characteristics of sleep architecture. However, there is no correlation between visfatin and insulin resistance or nocturnal hypoxia.

Topics: Blood Glucose; Body Mass Index; C-Peptide; Cholesterol, HDL; Cholesterol, LDL; Female; Humans; Insulin Resistance; Male; Middle Aged; Nicotinamide Phosphoribosyltransferase; Polysomnography; Sleep Apnea, Obstructive; Sleep Stages; Sleep, REM; Statistics as Topic; Triglycerides

Severe obesity is associated with type 2 diabetes mellitus, and both resolve with weight loss after bariatric operations. Intestinal hormones have been identified which are stimulated by rapid nutrient delivery to the lower small bowel after certain weight-loss operations. These incretins stimulate secretion and hypertrophy of the pancreatic beta cells. Surgical procedures are now being performed to treat diabetes in adults of lesser weight, and the importance of ruling out latent autoimmune diabetes in the adult (a variety of type 1) is suggested, before experimenting with these procedures.

Topics: Adult; Bariatric Surgery; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Glucagon-Like Peptide 1; Humans; Insulin Resistance; Obesity; Weight Loss

Recent epidemiologic studies have identified obesity as a risk factor for benign prostatic hyperplasia (BPH). We examined whether adiponectin, leptin, and C-peptide were associated with incident, symptomatic BPH and whether these factors mediate the relationship between obesity and BPH risk.. Data are from Prostate Cancer Prevention Trial placebo arm participants who were free of BPH at baseline. Incident BPH (n = 698) was defined as treatment, two International Prostate Symptom Score (IPSS) values > 14, or an increase of >or=5 in IPSS from baseline documented on at least two occasions plus at least one score >or=12. Controls (n = 709) were selected from men reporting no BPH treatment or IPSS > 7 during the 7-year trial. Baseline serum was analyzed for adiponectin, C-peptide, and leptin concentrations.. Neither C-peptide nor leptin was associated with BPH risk. The odds ratio [95% CI] contrasting highest to lowest quartiles of adiponectin was 0.65[0.47, 0.87] P(trend) = 0.004. Findings differed between levels of physical activity: there was a strong inverse association between adiponectin and BPH among moderately/very active men OR = 0.43 [0.29, 0.63], and no association among sedentary/minimally active men OR = 0.92 [0.65, 1.30] P(interaction) = 0.005. Adiponectin concentrations explained only a moderate amount of the relationship between obesity and BPH risk.. High adiponectin concentrations were associated with reduced risk of incident, symptomatic BPH. This association was limited to moderately/very active men; suggesting the relationship between obesity and BPH involves a complex interaction between factors affecting glucose uptake and insulin sensitivity. However, adiponectin is likely not the only mechanism through which obesity affects BPH risk.

Topics: Adiponectin; Aged; C-Peptide; Case-Control Studies; Disease Progression; Humans; Insulin Resistance; Leptin; Male; Middle Aged; Obesity; Prostatic Hyperplasia; Prostatic Neoplasms; Risk Factors; Washington

To assess the effect of growth hormone (GH) treatment on body composition and insulin resistance, and the interdependence of these factors, in short children born small for gestational age (SGA) and children with growth hormone deficiency (GHD).. In this longitudinal study we describe the relationship between changes in fasting hormone levels, and forearm cross-sectional fat/muscle area in 54 short children with GHD and 37 short children born SGA during the first 12 months of GH treatment. Mean GH dose was 31.4 microg/kg/day for GHD and 53.2 microg/kg/day for SGA. HOMA2-IR was calculated as a steady-state fasting measure of insulin resistance.. At baseline the SGA group displayed higher fasting glucose, insulin, C-peptide serum levels and higher HOMA2-IR (p < 0.01) than GHD patients despite similar low muscle mass and less fat mass. Both groups had low muscle mass for height, and mean changes in muscle, fat, insulin, C-peptide and HOMA2-IR during GH treatment were also similar. HOMA2-IR correlated positively with IGF-1 changes in both groups. In the SGA group, but not in the GHD group, the increase in fasting serum insulin, C-peptide and HOMA2-IR correlated negatively with increase in muscle mass (R(2) = 0.32, p < 0.001) and decrease in fat mass (R(2) = 0.12, p = 0.034).. In SGA, unlike in GHD, the insulin resistance caused by GH treatment appears to be diminished by the GH-induced increase in muscle mass and decrease in fat mass.

Topics: Body Composition; C-Peptide; Child; Growth Disorders; Human Growth Hormone; Humans; Infant, Newborn; Infant, Small for Gestational Age; Insulin Resistance; Muscle, Skeletal

Little is known about how lactating women accommodate for their increased glucose demands during fasting to avoid maternal hypoglycemia. The objective of this study was to determine whether lactating women conserve plasma glucose by reducing maternal glucose utilization by increasing utilization of FFA and ketone bodies and/or increasing gluconeogenesis and mammary gland hexoneogenesis. Six healthy exclusively breastfeeding women and six nonlactating controls were studied during 42 h of fasting and 6 h of refeeding. Glucose and protein kinetic parameters were measured using stable isotopes and GCMS and energy expenditure and substrate oxidation using indirect calorimetry. After 42 h of fasting, milk production decreased by 16% but remained within normal range. Glucose, insulin, and C-peptide concentrations decreased with the duration of fasting in both groups but were lower (P < 0.05) in lactating women. Glucagon, FFA, and beta-hydroxybutyrate concentrations increased with fasting time (P < 0.001) and were higher (P < 0.0001) in lactating women during both fasting and refeeding. During 42 h of fasting, gluconeogenesis was higher in lactating women compared with nonlactating controls (7.7 +/- 0.4 vs. 6.5 +/- 0.2 micromol kg(-1) min(-1), P < 0.05), whereas glycogenolysis was suppressed to similar values (0.4 +/- 0.1 vs. 0.9 +/- 0.2 micromol kg(-1) min(-1), respectively). Mammary hexoneogenesis did not increase with the duration of fasting. Carbohydrate oxidation was lower and fat and protein oxidations higher (P < 0.05) in lactating women. In summary, lactating women are at risk for hypoglycemia if fasting is extended beyond 30 h. The extra glucose demands of extended fasting during lactation appear to be compensated by increasing gluconeogenesis associated with ketosis, decreasing carbohydrate oxidation, and increasing protein and FFA oxidations.

Topics: Adult; Algorithms; Blood Glucose; C-Peptide; Calorimetry, Indirect; Diet; Fasting; Fatty Acids, Nonesterified; Female; Glucagon; Gluconeogenesis; Glucose; Hexoses; Humans; Insulin; Insulin Resistance; Isotope Labeling; Ketone Bodies; Kinetics; Lactates; Lactation; Milk, Human; Oxidation-Reduction

Studies have pointed to insulin resistance as a pathogenic factor in fatty liver. Although pancreatic B-cell function is believed to be involved, its role is unclear. This study was undertaken to test whether fasting C-peptide, an index of fasting B-cell function, was related to intra-hepatic fat (IHF) content in non-diabetic humans.. We assessed, retrospectively, fasting plasma C-peptide concentration in 31 patients with fatty liver and 62 individuals without fatty liver. The IHF content was measured by proton magnetic resonance spectroscopy ((1)H-MRS), while insulin sensitivity was estimated based on fasting plasma glucose and insulin with the homestasis model assessment (HOMA) 2 method.. Age, sex and body mass index (BMI) were not different between groups. Patients with fatty liver had higher fasting insulin (P < 0.01), C-peptide (P < 0.005) and lower insulin sensitivity (HOMA2-%S). Fasting insulin alone explained 14% of the IHF content variability (P < 0.001); inclusion of fasting C-peptide in multivariate regression explained up to 32% (P < 0.001). A subgroup analysis was performed by matching 1 : 1 for HOMA2-%S. These data were analysed by conditional logistic regression which showed that, when HOMA2-%S was matched between groups, fasting C-peptide remained the only significant predictor of fatty liver.. Non-diabetic individuals with fatty liver are characterized by increased fasting plasma C-peptide concentration, irrespective of their insulin resistant state.

Topics: Adult; B-Lymphocytes; Blood Glucose; C-Peptide; Fasting; Fatty Liver; Female; Humans; Insulin Resistance; Magnetic Resonance Spectroscopy; Male; Reference Values; Retrospective Studies

Digenic causes of human disease are rarely reported. Insulin via its receptor, which is encoded by INSR, plays a key role in both metabolic and growth signaling pathways. Heterozygous INSR mutations are the most common cause of monogenic insulin resistance. However, growth retardation is only reported with homozygous or compound heterozygous mutations. We describe a novel translocation [t(7,19)(p15.2;p13.2)] cosegregating with insulin resistance and pre- and postnatal growth deficiency. Chromosome translocations present a unique opportunity to identify modifying loci; therefore, our objective was to determine the mutational mechanism resulting in this complex phenotype.. Breakpoint mapping was performed by fluorescence in situ hybridization (FISH) on patient chromosomes. Sequencing and gene expression studies of disrupted and adjacent genes were performed on patient-derived tissues. RESULTS Affected individuals had increased insulin, C-peptide, insulin-to-C-peptide ratio, and adiponectin levels consistent with an insulin receptoropathy. FISH mapping established that the translocation breakpoints disrupt INSR on chromosome 19p15.2 and CHN2 on chromosome 7p13.2. Sequencing demonstrated INSR haploinsufficiency accounting for elevated insulin levels and dysglycemia. CHN2 encoding beta-2 chimerin was shown to be expressed in insulin-sensitive tissues, and its disruption was shown to result in decreased gene expression in patient-derived adipose tissue.. We present a likely digenic cause of insulin resistance and growth deficiency resulting from the combined heterozygous disruption of INSR and CHN2, implicating CHN2 for the first time as a key element of proximal insulin signaling in vivo.

Topics: Adult; Age of Onset; Antigens, CD; Biomarkers; Blood Glucose; C-Peptide; Chromosome Mapping; Chromosomes, Human, Pair 19; Chromosomes, Human, Pair 7; Diabetes Mellitus; DNA-Binding Proteins; Female; Fetal Growth Retardation; Gene Expression Regulation; Growth Disorders; Haplotypes; Humans; In Situ Hybridization, Fluorescence; Insulin; Insulin Resistance; Male; Pregnancy; Receptor, Insulin; Receptors, Steroid; Receptors, Thyroid Hormone; Sequence Analysis, DNA; Signal Transduction; Translocation, Genetic

Waist and hip circumferences are largely influenced by Fat Mass and several other determinants. To evaluate the specific effects of a preferential fat distribution, we corrected the waist and hip circumferences for all their determinants. We then examined the association between fat distribution and several cardio-metabolic parameters in a clinically healthy population.. In a subgroup of 625 females (F) and 490 males (M) from the RISC (Relationship between Insulin Sensitivity and Cardiovascular Disease) study, we evaluated insulin sensitivity by hyperinsulinaemic euglycaemic clamp and intima-media thickness (IMT) of the common (CCA) and internal (ICA) carotid artery by ultrasound imaging. Waist and hip circumferences were adjusted for age, height, fat and fat-free mass; in males, waist was also adjusted by hip and vice versa.. Both F and M with enlarged waist showed significantly increased plasma insulin, C-peptide, total cholesterol, non-high density lipoprotein-cholesterol, low density lipoprotein cholesterol and triglycerides, when compared with subjects with a smaller waist circumference. Males also showed lower glucose uptake and higher heart rate and ICA-IMT. A larger hip in both females and males was linked to a significantly greater inhibition of free fatty acids during the clamp test.. Adjustment of waist circumference for its determinants permits the detection of early impairment of cardiovascular function and of glucose and lipid metabolism in a clinically healthy population, in particular in normal body weight subjects. Enlarged hip adjusted values are associated with greater insulin sensitivity.

Topics: Adult; C-Peptide; Carotid Artery, Common; Cholesterol; Female; Glucose; Heart Rate; Humans; Insulin; Insulin Resistance; Lipids; Male; Middle Aged; Triglycerides; Tunica Intima; Tunica Media; Ultrasonography; Waist Circumference; Waist-Hip Ratio; White People

So far, high prevalence of metabolic symptoms accompanying diffuse idiopathic skeletal hyperostosis (DISH) appears not definitely elucidated because of their possible origin from other disorders such as diabetes and/or body mass differences. From such reasons this study was aimed to compare non-diabetic DISH patients to a group of age and BMI matched controls in order to distinguish the influence of DISH proper on metabolic parameters free of additional metabolic effects caused by diabetes and/or body weight differences.. Both groups of patients were subjected to oral glucose tolerance test (OGTT) and fasting serum levels of glucose, insulin, C-peptide, growth hormone, insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 3 (IGF-BP3) were assayed. Fasting serum total cholesterol, HDL cholesterol, triglycerides, non-esterified fatty acids (NEFA) and uric acid were determined as well. The indices of insulin sensitivity and insulin secretion were calculated.. With the exception of decreased NEFA serum level and decreased insulinogenic index and insulin/C-peptide ratio in DISH patients any other significant differences in serum parameters and indices of insulin sensitivity were not found.. The data obtained suggest impaired beta-cell pancreatic stimulation and increased insulin hepatic extraction in DISH. It is assumed that the above mentioned conditions, if persisting for a long time, might lead to decreased ability of insulin to maintain normal serum glucose level and consequently to insulin resistance which is highly prevalent in symptomatic DISH patients.

Topics: Blood Glucose; C-Peptide; Fatty Acids, Nonesterified; Female; Glucose Tolerance Test; Human Growth Hormone; Humans; Hyperostosis, Diffuse Idiopathic Skeletal; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Like Growth Factor Binding Protein 3; Insulin-Like Growth Factor I; Insulin-Secreting Cells; Lipids; Male; Metabolic Syndrome; Middle Aged

Model-based insulin sensitivity testing via the intravenous glucose tolerance test (IVGTT) or similar is clinically very intensive due to the need for frequent sampling to accurately capture the dynamics of insulin secretion and clearance. The goal of this study was to significantly reduce the number of samples required in intravenous glucose tolerance test protocols to accurately identify C-peptide and insulin secretion characteristics.. Frequently sampled IVGTT data from 12 subjects [5 normal glucose-tolerant (NGT) and 7 type 2 diabetes mellitus (T2DM)] were analyzed to calculate insulin and C-peptide secretion using a well-accepted C-peptide model. Samples were reduced in a series of steps based on the critical IVGTT profile points required for the accurate estimation of C-peptide secretion. The full data set of 23 measurements was reduced to sets with six or four measurements. The peak secretion rate and total secreted C-peptide during 10 and 20 minutes postglucose input and during the total test time were calculated. Results were compared to those from the full data set using the Wilcoxon rank sum to assess any differences.. In each case, the calculated secretion metrics were largely unchanged, within expected assay variation, and not significantly different from results obtained using the full 23 measurement data set (P < 0.05).. Peak and total C-peptide and insulin secretory characteristics can be estimated accurately in an IVGTT from as few as four systematically chosen samples, providing an opportunity to minimize sampling, cost, and burden.

Topics: Adult; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Glucose Tolerance Test; Humans; Insulin; Insulin Infusion Systems; Insulin Resistance; Insulin Secretion; Time Factors

Type 1 diabetes mellitus (T1DM) is characterized by a selective destruction of pancreatic beta cells. Recent data suggest a role of insulin resistance (IR) along with the deficient insulin reserve.. Fifty-eight consecutive patients of T1DM, with low C-peptide levels were included. Patients with an obvious secondary cause like steroid therapy, fibrocalculous pancreatic disease, chronic infections or comorbid illness were excluded. A clinical assessment for the presence of obesity was made based on anthropometric data. Clinical markers of IR and the insulin dose required to achieve a stable glycemic control calculated in terms of body weight were also studied.. There were 30 males and 28 females with a mean age of 16.5 +/- 2.3 (5-39) years. The mean body mass index (BMI) was 19.21 +/- 3.7 and the waist circumference was 67 +/- 5.2 cms. Nineteen ( 32.75%) and six (10.34%) patients were overweight (BMI > 23) and obese (BMI > 27) respectively while 16 (27.58%) had abdominal obesity. The body fat percentage was high (> 25%) in 34 (58.62%), mean 28.33 +/- 11.4%. Acanthosis nigricans was found in 14 (24.13%) cases, hypertension in two (3.4%) but none of the girls had clinical polycystic ovarian syndrome (PCOS). The insulin dose required was 1.11 +/- 0.41 u/kg (0.3-2.9) at an glycated haemoglobin A1C (A1C) of 7.56 +/- 1.04% (4.9-9.3), it was more than 0.6 u/kg/day in 38 (65.51%) patients.. The study concludes that IR is present in a large number of Indian T1DM patients along with a high body fat percentage.

Topics: Adolescent; Adult; Blood Glucose; Body Composition; Body Mass Index; C-Peptide; Child; Child, Preschool; Diabetes Mellitus, Type 1; Female; Humans; Hypoglycemic Agents; India; Insulin; Insulin Resistance; Male; Obesity; Overweight; Waist Circumference; Young Adult

Polycystic ovary syndrome (PCOS) has been linked to a high risk of type 2 diabetes mellitus. Disturbances in the secretion of the incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) have been observed in states with impaired glucose regulation. This paper considers the secretion of GIP and GLP-1 after oral glucose load in a group of lean, glucose-tolerant PCOS women in comparison with age- and body mass index (BMI)-matched healthy women.. Case control.. PCOS (n=21, 25.8+/-4.1 years, BMI 21.6+/-1.7 kg/m(2)) and control healthy women (CT, n=13, 28.5+/-7.2 years, BMI 20.3+/-2.5 kg/m(2)) underwent oral glucose tolerance test (OGTT) with blood sampling for glucose, insulin, C-peptide, total GIP, and active GLP-1. Insulin sensitivity was determined both at fasting and during the test.. Repeated measures ANOVA.. Glucose levels and insulin sensitivity did not differ between PCOS and CT. PCOS had significantly higher levels of C-peptide (P<0.05) and tended to have higher insulin levels. The levels of total GIP were significantly higher in PCOS than in CT (P<0.001). Active GLP-1 levels exhibited a significantly different time-dependent pattern in PCOS (P<0.002 for PCOS versus time interaction). GLP-1 concentrations were similar in PCOS and CT in the early phase of OGTT and then reached significantly lower levels in PCOS than in CT at 180 min (P<0.05).. Increased total GIP and lower late phase active GLP-1 concentrations during OGTT characterize PCOS women with higher C-peptide secretion in comparison with healthy controls, and may be the early markers of a pre-diabetic state.

Topics: Adult; Blood Glucose; C-Peptide; Case-Control Studies; Female; Gastric Inhibitory Polypeptide; Glucagon-Like Peptide 1; Glucose Tolerance Test; Humans; Incretins; Insulin; Insulin Resistance; Polycystic Ovary Syndrome; Time Factors

There is evidence that androgens are regulators of insulin resistance (IR), and may be involved in the regulation of resistin, a cytokine that has been related with IR. Earlier studies found that androgen receptor length polymorphisms CAGn and GGNn and the aromatase polymorphism TTTAn may influence receptor or enzyme activity and serum concentrations of androgens. This study was designed to determine whether polymorphism length was related to serum resistin concentration and to other variables related with IR. In 1,580 persons chosen randomly from the general population of the Canary Islands (Spain), we measured polymorphism length, waist circumference, waist/hip ratio, BMI, and serum glucose concentration. In smaller subgroups, we also measured C-peptide (n = 677), resistin (n = 583), and leptin concentration (n = 754) and estimated IR (homeostasis model assessment-IR (HOMA2-IR)). In men, polymorphism length correlated with resistin concentration (CAGn, r = 0.13, P = 0.031; TTTAn, r = 0.15, P = 0.005; GGNn, r = -0.15, P = 0.026), and the correlations were confirmed in multivariate regression models. The length of CAGn and TTTAn correlated inversely with C-peptide (r = -0.13, P = 0.016 and r = -0.21, P < 0.001, respectively) and with estimated IR (r = -0.12, P = 0.032 and r = -0.19, P = 0.001, respectively). In men, length of the CAGn, GGNn, and TTTAn was associated with serum resistin concentration. These results support the hypothesis that androgens may be involved in the regulation of resistin. Resistin may be a link between IR and androgens.

Topics: Adolescent; Adult; Aged; Anthropometry; Aromatase; Blood Glucose; C-Peptide; Cohort Studies; Cross-Sectional Studies; Female; Humans; Insulin Resistance; Leptin; Male; Microsatellite Repeats; Middle Aged; Polymorphism, Genetic; Receptors, Androgen; Resistin; Young Adult

There is virtually no information on the metabolic impact of dietary fructose intake in adolescents despite their high fructose consumption, particularly via sweetened beverages.. To determine the short-term metabolic effects of dietary fructose intake in obese adolescents.. Six volunteers (3 M/3 F; 15.2 +/- 0.5 yr; 35 +/- 2 kg/m2; 39 +/- 2% body fat) were studied twice following 7 d of isocaloric, isonitrogenous high carbohydrate (60% CHO; 25% fat) diets with fructose accounting for 6% and 24% of total energy intake, respectively (random order). Insulin sensitivity and secretion were analyzed by the stable labeled intravenous glucose tolerance test and glucose and lipid kinetics using GCMS.. A fourfold increase in dietary fructose intake did not affect insulin sensitivity or secretion, glucose kinetics, lipolysis or glucose, insulin, C-peptide, triglycerides, HDL- and LDL-cholesterol concentrations.. In the short term, when energy intake is constant, dietary fructose per se is not a contributor to insulin resistance and hypersecretion in obese adolescents.

Topics: Adolescent; Blood Glucose; C-Peptide; Dietary Carbohydrates; Energy Intake; Female; Fructose; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Lipid Metabolism; Male; Obesity

The relationship between insulin resistance (IR) and essential hypertension (HTN) is controversial. The aim of this study was to determine the association of IR estimated by homeostasis model assessment of insulin resistance (HOMA-IR) and HTN in a large sample of Iranian diabetic and non-diabetic population. A total of 2047 diabetic and non-diabetic individuals with or without HTN, aged 30-75 yrs, who were referred to a university general hospital between November 2004 and April 2007 were included in this study. Demographic data and anthropometric characteristics of participants were recorded. Fasting blood samples were collected, and fasting plasma glucose (FPG), serum creatinine, lipids, insulin, C-peptide and HbA1c were measured. HOMA-IR and HOMA derived Beta-cell function (HOMA-B) were also calculated. Age, sex and waist girth adjusted HOMA-IR values were compared between hypertensive and normotensive subjects. Hypertensive patients had significantly higher HOMA-IR than age-, sex-, and waist girth-adjusted normotensive individuals in both non-diabetic (2.163 +/- 0.08 and 1.75 +/- 0.03, p < 0.001) and diabetic (3.40 +/- 0.10 and 3.07 +/- 0.09, p < 0.05) groups. Multivariate logistic regression analysis showed that after adjustment for age, sex, waist girth, BMI, triglyceride, total cholesterol, FPG, and C-peptide, HOMA-IR was a significant independent predictor of HTN in all subjects (odds ratio = 1.117, CI 95% = 1.026-1.216, p < 0.05) and in diabetic and non-diabetic subjects separately (odds ratio = 1.102, CI 95% = 1.009-1.203, p < 0.05 and odds ratio = 1.328, CI 95% = 1.116-1.580, p < 0.01, respectively). In conclusion, this study showed that IR is associated with HTN in Iranian diabetic and non-diabetic subjects.

Topics: Adult; Aged; Anthropometry; Blood Glucose; Blood Pressure; C-Peptide; Comorbidity; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Female; Glucose Tolerance Test; Homeostasis; Humans; Hypertension; Insulin; Insulin Resistance; Iran; Logistic Models; Male; Middle Aged; Models, Biological; Predictive Value of Tests

Reliable assays are critically needed to monitor graft potency in islet transplantation (IT). We tested a quantitative in vivo islet potency assay (QIVIPA) based on human C-peptide (hCP) measurements in normoglycemic nude mice after IT under the kidney capsule. QIVIPA was initially tested by transplanting incremental doses of human islets. hCP levels in mice were correlated with the number of transplanted islet equivalents (r(2) = 0.6, P<0.01). We subsequently evaluated QIVIPA in eight islet preparations transplanted in type 1 diabetic patients. Conversely to standard criteria including islet mass, viability, purity, adenosine triphosphate content, or glucose stimulated insulin secretion, hCP in mice receiving 1% of the final islet product was correlated to primary graft function (hCP increase) after IT (r(2)=0.85, P<0.01). QIVIPA appears as a reliable test to monitor islet graft potency, applicable to validate new methods to produce primary islets or other human insulin secreting cells.

Topics: Animals; C-Peptide; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 1; Gene Expression Regulation; Graft Survival; Humans; Insulin; Insulin Resistance; Islets of Langerhans; Islets of Langerhans Transplantation; Mice; Mice, Nude; Radioimmunoassay; Time Factors

Some atypical antipsychotics have been linked to an increased propensity for weight gain and metabolic disturbances, including type II diabetes. The objective of this study was to investigate an animal model to help understand the mechanisms underlying this phenomenon. Female, Sprague-Dawley rats were treated with olanzapine (2.0 or 7.5 mg/kg, via osmotic mini-pump) for 4 weeks, followed by the hyperinsulinemic/euglycemic and hyperglycemic clamp procedures to assess insulin sensitivity and secretion in vivo. Changes in body weight, visceral fat, food intake and locomotor activity were also assessed. Hepatic glucose production (R(A)) was increased in the hyperinsulinemic/euglycemic clamp for both treatment groups compared to control rats, while the high-dose olanzapine group had decreased peripheral glucose utilization (R(D)). No changes in insulin secretion were detected in the hyperglycemic clamp. Olanzapine did not change body weight or food intake, but did result in significant accumulation of visceral fat and decreases in locomotor activity. Like others, we found that a rodent model for antipsychotic-related weight gain per se is not tenable. However, chronic treatment with olanzapine was found to confer both hepatic and peripheral insulin resistance independent of weight gain, indicating a direct effect on glucose dysregulation.

Topics: Animals; Antipsychotic Agents; Benzodiazepines; Blood Glucose; Body Weight; C-Peptide; Diabetes Mellitus, Experimental; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Administration Schedule; Female; Hyperinsulinism; Insulin Resistance; Locomotion; Olanzapine; Rats; Rats, Sprague-Dawley

Obesity represents a risk factor for insulin resistance, type 2 diabetes mellitus, and atherosclerosis. In addition, for any given amount of total body fat, an excess of visceral fat or fat accumulation in the liver and skeletal muscle augments the risk. Conversely, even in obesity, a metabolically benign fat distribution phenotype may exist.. In 314 subjects, we measured total body, visceral, and subcutaneous fat with magnetic resonance (MR) tomography and fat in the liver and skeletal muscle with proton MR spectroscopy. Insulin sensitivity was estimated from oral glucose tolerance test results. Subjects were divided into 4 groups: normal weight (body mass index [BMI] [calculated as weight in kilograms divided by height in meters squared], < 25.0), overweight (BMI, 25.0-29.9), obese-insulin sensitive (IS) (BMI, > or = 30.0 and placement in the upper quartile of insulin sensitivity), and obese-insulin resistant (IR) (BMI, > or = 30.0 and placement in the lower 3 quartiles of insulin sensitivity).. Total body and visceral fat were higher in the overweight and obese groups compared with the normal-weight group (P < .05); however, no differences were observed between the obese groups. In contrast, ectopic fat in skeletal muscle (P < .001) and particularly the liver (4.3% +/- 0.6% vs 9.5% +/- 0.8%) and the intima-media thickness of the common carotid artery (0.54 +/- 0.02 vs 0.59 +/- 0.01 mm) were lower and insulin sensitivity was higher (17.4 +/- 0.9 vs 7.3 +/- 0.3 arbitrary units) in the obese-IS vs the obese-IR group (P < .05). Unexpectedly, the obese-IS group had almost identical insulin sensitivity and the intima-media thickness was not statistically different compared with the normal-weight group (18.2 +/- 0.9 AU and 0.51 +/- 0.02 mm, respectively).. A metabolically benign obesity that is not accompanied by insulin resistance and early atherosclerosis exists in humans. Furthermore, ectopic fat in the liver may be more important than visceral fat in the determination of such a beneficial phenotype in obesity.

Topics: Adiponectin; Adipose Tissue; Adolescent; Adult; Aged; Blood Glucose; Body Mass Index; C-Peptide; Carotid Artery, Common; Fatty Acids, Nonesterified; Fatty Liver; Female; Humans; Insulin; Insulin Resistance; Liver; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Male; Middle Aged; Muscle, Skeletal; Obesity; Tunica Intima; Tunica Media; Ultrasonography

We examined the reproducibility of the oral glucose tolerance test (OGTT) in overweight children and evaluated distinguishing characteristics between those with concordant vs. discordant results.. Sixty overweight youth (8-17 yr old) completed two OGTTs (interval between tests 1-25 d). Insulin sensitivity was assessed by the surrogate measures of fasting glucose to insulin ratio, whole-body insulin sensitivity index, and homeostasis model assessment of insulin resistance, and insulin secretion by the insulinogenic index with calculation of the glucose disposition index (GDI).. Of the 10 subjects with impaired glucose tolerance (IGT) during the first OGTT only three (30%) had IGT during the second OGTT. The percent positive agreement between the first and second OGTT was low for both impaired fasting glucose and IGT (22.2 and 27.3%, respectively). Fasting blood glucose had higher reproducibility, compared with the 2-h glucose. Youth with discordant OGTTs, compared with those with concordant results, were more insulin resistant (glucose/insulin 2.7+/-1.4 vs. 4.1+/-1.8, P=0.006, whole-body insulin sensitivity index of 1.3+/-0.6 vs. 2.2+/-1.1, P=0.003, and homeostasis model assessment of insulin resistance 10.6+/-8.1 vs. 5.7+/-2.8, P=0.001), had a lower GDI (0.45+/-0.58 vs. 1.02+/-1.0, P=0.03), and had higher low-density lipoprotein cholesterol (117.7+/-36.6 vs. 89.9+/-20.1, P=0.0005) without differences in physical characteristics.. Our results show poor reproducibility of the OGTT in obese youth, in particular for the 2-h plasma glucose. Obese youth who have discordant OGTT results are more insulin resistant with higher risk of developing type 2 diabetes mellitus, as evidenced by a lower GDI. The implications of this remain to be determined in clinical and research settings.

Topics: Administration, Oral; Adolescent; Blood Glucose; Body Mass Index; C-Peptide; Child; Fasting; Female; Glucose; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Male; Obesity; Overweight; Puberty; Reproducibility of Results

A hundred and seventy-nine patients with osteoarthrosis (OA) (mean age 50.48+/-5.81 years) were examined for metabolic syndrome (MS) from the International Diabetic Federation (IDF) criteria in the groups with normal and increased fasting C-peptide levels. The blood level of immunoreactive insulin was determined and the insulin resistance indices (Cari, HOMA-IR, ISI, and QUICKI) were calculated. The results were analyzed using the correlation analysis and methods of multivariate statistics. HyperC-peptidemia was found in 84.36% of patients with OA, hyperinsulinemia in 82.12%. As C-peptidemia increased, metabolic disturbances progressed in terms of levels and absolute values. At the same time four fifths of the OA patients with normal laboratory C-peptide levels were diagnosed as having MS from the 2005 IDF criteria. The level of C-peptide and the HOMA-IR and QUICKI indices were more closely correlated with the severity of polyosteoarthritis than insulin. The relationship of insulin resistance to the course of osteoarthritis has been confirmed. It is suggested that hyperC-peptidemia and hyperinsulinemia shows an inflammation-adaptive role in the pathogenesis of OA, the latter associated with obesity in particular.

Topics: C-Peptide; Female; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Osteoarthritis

We sought to determine whether pioglitazone and metformin alter NEFA-induced insulin resistance in type 2 diabetes and, if so, the mechanism whereby this is effected.. Euglycaemic-hyperinsulinaemic clamps (glucose approximately 5.3 mmol/l, insulin approximately 200 pmol/l) were performed in the presence of Intralipid-heparin (IL/H) or glycerol before and after 4 months of treatment with pioglitazone (n = 11) or metformin (n = 9) in diabetic participants. Hormone secretion was inhibited with somatostatin in all participants.. Pioglitazone increased insulin-stimulated glucose disappearance (p < 0.01) and increased insulin-induced suppression of glucose production (p < 0.01), gluconeogenesis (p < 0.05) and glycogenolysis (p < 0.05) during IL/H. However, glucose disappearance remained lower (p < 0.05) whereas glucose production (p < 0.01), gluconeogenesis (p < 0.05) and glycogenolysis (p < 0.05) were higher on the IL/H study day than on the glycerol study day, indicating persistence of NEFA-induced insulin resistance. Metformin increased (p < 0.001) glucose disappearance during IL/H to rates present during glycerol treatment, indicating protection against NEFA-induced insulin resistance in extrahepatic tissues. However, glucose production and gluconeogenesis (but not glycogenolysis) were higher (p < 0.01) during IL/H than during glycerol treatment with metformin, indicating persistence of NEFA-induced hepatic insulin resistance.. We conclude that pioglitazone improves both the hepatic and the extrahepatic action of insulin but does not prevent NEFA-induced insulin resistance. In contrast, whereas metformin prevents NEFA-induced extrahepatic insulin resistance, it does not protect against NEFA-induced hepatic insulin resistance.

Topics: Blood Glucose; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Fat Emulsions, Intravenous; Fatty Acids, Nonesterified; Female; Glucagon; Gluconeogenesis; Glucose; Glucose Clamp Technique; Glycerol; Heparin; Humans; Insulin; Insulin Resistance; Male; Metformin; Middle Aged; Pioglitazone; Thiazolidinediones

The newer atypical antipsychotics, as a class, have been associated with an increased risk of weight gain and metabolic abnormalities. The mechanisms underlying this phenomenon are currently unclear, but there are data to suggest the possibility of an immediate (as opposed to chronic) effect of these drugs. The aim of the present study was to assess the acute effects of olanzapine on specific measures of insulin sensitivity and secretion. Healthy animals were tested in either the hyperinsulinemic-euglycemic or the hyperglycemic clamp. After reaching steady state in the hyperinsulinemic-euglycemic clamp, rats were injected with olanzapine (3 mg/kg sc) and monitored for an additional 130 minutes. In the hyperglycemic clamp, olanzapine was injected approximately 90 minutes before receiving a glucose bolus, and hyperglycemia was maintained via exogenous glucose infusion for an additional 90 minutes. Insulin and C-peptide levels were monitored throughout this clamp.Acute administration of olanzapine significantly lowered the glucose infusion rate due to an increase in hepatic glucose production and a decrease in glucose utilization. Olanzapine pretreatment induced hyperglycemia and markedly decreased plasma insulin and C-peptide in response to the glucose challenge. These findings indicate that olanzapine can directly induce metabolic changes that occur rapidly and well in advance of the changes that might be anticipated as a result of its weight-gain liability. We present novel findings highlighting an olanzapine-induced deficit in beta-cell functioning.

Topics: Animals; Antipsychotic Agents; Benzodiazepines; C-Peptide; Disease Models, Animal; Glucose; Glucose Clamp Technique; Hyperglycemia; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Olanzapine; Rats; Rats, Sprague-Dawley; Time Factors

The liver is the main source and insulin the main regulator of IGF binding protein 1 (IGFBP-1) in humans. Here we examined how serum IGFBP-1 concentrations are related to directly measured hepatic insulin sensitivity and liver fat content in humans.. We measured fasting serum (fS) IGFBP-1 concentrations and liver fat content by proton magnetic resonance spectroscopy in 113 nondiabetic subjects. In addition, hepatic insulin sensitivity was measured using the euglycemic hyperinsulinemic clamp (insulin 0.3 mU/kg.min) technique in combination with the infusion of [3-(3)H]glucose in 78 subjects.. fS-IGFBP-1 concentrations were inversely related to liver fat content (r = -0.38, P < 0.0001). Of circulating parameters, fS-IGFBP-1 was better correlated to hepatic insulin sensitivity (r = 0.48, P < 0.0001) than fS-insulin (r = -0.42, P = 0.0001), fS-C-peptide (r = -0.41, P = 0.0002), fS-triglyceride (r = -0.33, P = 0.003), or fS-high-density lipoprotein cholesterol (r = 0.30, P = 0.007). In multiple linear regression analyses, body mass index (P < 0.0001) and fS-IGFBP-1 (P = 0.008), but neither age nor gender, were independently associated with hepatic insulin sensitivity (P < 0.0001 for ANOVA). Neither fS-insulin nor fS-C-peptide were independent determinants of hepatic insulin sensitivity after adjusting for age, gender, and body mass index.. fS-IGFBP-1 is inversely correlated with liver fat and is an obesity-independent and liver-specific circulating marker of hepatic insulin sensitivity.

Topics: Adolescent; Adult; Aging; Biomarkers; Blood Glucose; Body Composition; Body Mass Index; C-Peptide; Female; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin-Like Growth Factor Binding Protein 1; Lipid Metabolism; Lipids; Liver; Magnetic Resonance Spectroscopy; Male; Middle Aged; Sex Characteristics; Waist Circumference

During the last 10 years we have experienced an increasing number of referrals due to hyperferritinemia. This is probably due to increased awareness of hereditary hemochromatosis, and the availability of a genetic test for this condition. Most of these referred patients were over-weight middle-aged men with elevated ferritin levels, but without the hemochromatosis-predisposing gene mutations. We evaluated the relationship between hyperferritinemia and the metabolic syndrome in 40 patients.. Forty consecutive patients referred for hyperferritinemia were investigated. The examination programme included medical history, clinical investigation and venous blood samples drawn after an overnight fast. This resulted in 34 patients with unexplained hyperferritinemia, which were further examined. Liver biopsy was successfully performed in 29 subjects. Liver iron stores were assessed morphologically, and by quantitative phlebotomy in 16 patients.. The majority of the patients had markers of the metabolic syndrome, and 18 patients (52%) fulfilled the IDF-criteria for the metabolic syndrome. Mean body mass index was elevated (28.8+/-4.2), mean diastolic blood pressure was 88.5+/-10.5 mmHg, and mean fasting insulin C-peptide 1498+/-539 pmol/l. Liver histology showed steatosis and nuclear glycogen inclusions in most patients (19 out of 29). Only four patients had increased iron stores by histology, of which two could be explained by alcohol consumption. Fourteen of 16 patients normalized ferritin levels after phlebotomy of a cumulative blood amount corresponding to normal iron stores. Ferritin levels were significantly related to insulin C-peptide level (p<0.002) and age (p<0.002).. The present results suggest that liver steatosis and insulin resistance but not increased iron load is frequently seen in patients referred for suspected hemochromatosis on the basis of hyperferritinemia. The ferritin level seems to be positively associated to insulin resistance.

Topics: Adult; Aged; Alanine Transaminase; Blood Sedimentation; C-Peptide; C-Reactive Protein; Fatty Liver; Female; Ferritins; Humans; Insulin Resistance; Iron Metabolism Disorders; Iron Overload; Lipids; Male; Metabolic Syndrome; Middle Aged; Thyrotropin

The aim of present study was to identify the visceral adipose tissue genes differentially expressed in a well-characterized rat model of high-fat diet (HFD)-induced obesity. Male Sprague-Dawley rats were fed either the HFD (17 g lard + 3 g corn oil/100 g) or the normal diet (5 g corn oil/100 g) for 9 weeks. The HFD rats weighed 55% more and accumulated 85% to 133% greater visceral fats than did the normal-diet rats (P < .05). Animals given the HFD for 9 weeks acquired dyslipidemia, fatty liver, insulin resistance, and hyperleptinemia along with the overexpression of several obesity-related genes, such as leptin, tumor necrosis factor alpha, resistin, peroxisome proliferator-activated receptor gamma2, CCAAT/enhancer-binding protein alpha, and sterol regulatory element-binding protein-1c, in the epididymal adipose tissue. The differential gene expression profile obtained from the cDNA microarray analysis followed by the real-time polymerase chain reaction confirmation led to a recruitment of several uncharacterized adipose tissue genes responding to the HFD. We report herein, for the first time, that a series of genes which might be implicated in the insulin-stimulated glucose transporter 4 translocation, such as protein phosphatase 2 (formerly 2A), cell division cycle 42-interacting protein 4, syntaxin 6, linker of T-cell receptor pathways 10, as well as the genes which might be involved in cancer development, such as heat shock 10-kd protein 1, and ras-related C3 botulinum toxin substrate 1, were differentially expressed in the epididymal adipose tissue of rats rendered obese by an HFD.

Topics: Animals; Body Weight; C-Peptide; Dietary Fats; Epididymis; Gene Expression Profiling; Gene Expression Regulation; Glucose; Insulin; Insulin Resistance; Intra-Abdominal Fat; Leptin; Lipids; Liver; Male; Obesity; Oligonucleotide Array Sequence Analysis; Rats; Rats, Sprague-Dawley

Obstructive sleep apnea syndrome (OSAS) is associated with autonomic dysfunction and metabolic abnormalities including obesity, dyslipidemia, and insulin resistance. Heart rate recovery at 1min after exercise termination (HRR-1) is a marker of vagal tone. We hypothesized that patients with more severe OSAS would have a lower HRR-1, either due to the co-existing metabolic abnormalities or OSAS.. Sixty-three patients with untreated OSAS (49.2+/-9.8years) without glucose- or lipid-lowering or negatively chronotropic drugs underwent cardiopulmonary exercise testing including HRR-1 measurement and assessment of several metabolic parameters. Patients with severe OSAS (apnea-hypopnea index [AHI]>30h(-1); n=32) were compared to patients with mild to moderate OSAS (AHI 5-30h(-1); n=31).. Patients with severe OSAS were more likely to be male (25 vs. 3%; p=0.01) and to have hypertension (72 vs. 39%; p=0.01); they also had higher fasting glucose (5.4+/-0.5 vs. 5.1+/-0.4mmol/l; p=0.016) and C-peptide [905 (651-1353) vs. 749 (597-919)pmol/l; p=0.028] levels compared to patients with mild to moderate OSAS. The groups did not differ with respect to peak heart rate (p=0.2) or peak oxygen consumption (p=0.9), but HRR-1 was significantly lower in patients with severe OSAS compared to patients with mild and moderate OSAS [20 (15-25) vs. 24 (18-34)bpm; p=0.022]. Higher AHI (p=0.01) and lower peak heart rate (p=0.02), but not body mass index or insulin resistance, were independently associated with lower HRR-1.. The severity of OSAS expressed as higher AHI is independently associated with lower HRR-1, a measure of autonomic dysfunction.

Topics: Adult; Aged; Autonomic Nervous System; Blood Glucose; Blood Pressure; Body Composition; Body Mass Index; C-Peptide; Electrocardiography; Exercise Test; Female; Heart Rate; Humans; Hypertension; Insulin Resistance; Male; Middle Aged; Polysomnography; Retrospective Studies; Risk Factors; Sex Factors; Sleep Apnea, Obstructive; Vagus Nerve

Mononuclear cells (MNCs) are the primary cell type involved in the pro-inflammatory state of obesity-linked insulin-resistance, and atherosclerosis. Increased serum levels of MMP-9 are reported in insulin-resistant type 2 diabetic patients. Here we demonstrate insulin facilitating human monocytic THP-1 cell chemotaxis via prolonged Erk1/2-dependent induction of MMP-9. In vivo, significantly increased serum levels of MMP-9 were found in obesity-induced hyperinsulinemic C57BL/J6 mice, which were diminished by treatment with the anti-diabetic PPARgamma-ligand pioglitazone. In line with this, pioglitazone inhibited Erk1/2-phosphorylation and subsequent insulin-dependent MMP-9 synthesis in THP-1 cells. Thus, insulin increases MMP-9 gelatinolytic activity in monocytic cells, which results in accelerated chemotaxis. Hyperinsulinemia is associated with enhanced MMP-9 serum levels, potentially facilitating monocyte migration to and infiltration of adipose tissue and the arterial wall, thereby contributing to the increased cardiovascular risk in obese, hyperinsulinemic patients.

Topics: Animals; C-Peptide; Cell Line; Cell Movement; Chemotaxis, Leukocyte; Diet; Dietary Fats; Endothelium, Vascular; Humans; Hyperinsulinism; Hypoglycemic Agents; Inflammation; Insulin; Insulin Resistance; Leukocytes, Mononuclear; Male; Matrix Metalloproteinase 9; Mice; Mice, Inbred C57BL; Monocytes; Muscle, Smooth, Vascular; Obesity; Pioglitazone; Thiazolidinediones

This retrospective study was designed to identify metabolic and immune predictors of early islet allograft failure.. We measured several metabolic and immunological markers at the time of pretransplant and several time points posttransplantation in 17 patients with long-term functioning graft (long fx) and 20 patients with short-term functioning graft (short fx).. The short fx group showed higher insulin resistance, altered proinsulin processing, lower soluble interleukin-2 receptor (sIL-2r) (marker of T-cell activation), and higher soluble FasL (marker of apoptosis) during the entire follow-up, particularly at time of failure.. Patients who experienced an early failure of islet allograft showed specific metabolic and immunological signs long before islet failure.

Topics: Adult; Annexin A5; C-Peptide; Fas Ligand Protein; Graft Rejection; Graft Survival; Humans; Insulin; Insulin Resistance; Islets of Langerhans Transplantation; Postoperative Complications; Retrospective Studies; Time Factors

Obesity is associated with insulin resistance and hyperinsulinemia, which is considered to be a core component in the pathophysiology of obesity-related comorbidities. As yet it is unknown whether insulin resistance and hyperinsulinemia already develop during weight gain within the normal range. In 10 healthy male subjects the effect of intentional weight gain by 2 BMI points was examined on insulin. C-peptide and glucose levels following a meal, 75 g of glucose, and a two-step hyperglycemic clamp increased plasma glucose by 1.38 and 2.75 mmol/l, respectively. Baseline insulin, C-peptide, and glucose concentrations were significantly higher after weight gain from 21.8 to 23.8 kg/m(2) BMI within 4(1/2) mo. Calculations of insulin secretion and clearance indicate that reduced insulin clearance contributes more to post-weight gain basal hyperinsulinemia than insulin secretion. Following oral or intravenous stimulation insulin concentrations were significantly higher post-weight gain during all three test conditions, whereas C-peptide and glucose levels did not differ. Calculations of insulin secretion and clearance demonstrated that higher stimulated insulin concentrations are entirely due to clearance but not secretion. Despite significantly higher insulin levels, the rate of intravenous glucose required to maintain the defined elevation of glucose levels was either identical (1.38 mmol/l) or even significantly lower (2.75 mmol/l) following weight gain. The present study demonstrates for the first time that insulin resistance already develops during weight gain within the normal range of body weight. The associated basal and stimulated hyperinsulinemia is the result of differentiated changes of insulin secretion and clearance, respectively.

Topics: Adult; Blood Glucose; Body Mass Index; C-Peptide; Glucose; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Insulin Secretion; Kinetics; Male; Weight Gain

Much evidence demonstrates that elevated free fatty acids (FFAs) are associated with insulin resistance. However, it is not clear whether different FFAs can cause different degrees of peripheral insulin resistance. This study aimed to investigate the effects of short-term elevation of FFAs on hepatic and peripheral insulin action, and determine whether FFAs with different degrees of saturation have differential effects on hepatic insulin resistance.. Intralipid+heparin (IH, polyunsaturated fatty acids), oleate (OLE), lard oil+heparin (LOH), and saline (SAL) were separately infused intravenously for 7 hours in normal Wistar rats. During the last 2 hours of the fat/saline infusion, a hyperinsulinemic-euglycemic clamping was performed with [6-3H] glucose tracer. Plasma glucose was measured using the glucose oxygenase method. Plasma insulin and C-peptide were determined by radioimmunoassays. Plasma FFAs were measured using a colorimetric method.. Compared with infusion of SAL, plasma FFA levels were significantly elevated by infusions of IH, OLE, and LOH (P<0.001). All three fat infusions caused remarkably higher hepatic glucose production (HGP) than SAL (P<0.001). OLE and LOH infusions induced much higher HGP than IH (P<0.01). Glucose utilization (GU) was decreased with all three fat infusions relative to SAL (P<0.001), but GU did not differ among the three types of fat infusions.. Short-term elevation of FFAs can induce hepatic and peripheral insulin resistance. Polyunsaturated fatty acids induced less hepatic insulin resistance than monounsaturated or saturated fatty acids. However, IH, OLE, and LOH infusions induced similar peripheral insulin resistance.

Topics: Animals; Anticoagulants; Blood Glucose; C-Peptide; Dietary Fats; Fat Emulsions, Intravenous; Fatty Acids, Nonesterified; Fatty Acids, Unsaturated; Female; Glucose Clamp Technique; Heparin; Hyperinsulinism; Insulin; Insulin Resistance; Liver; Oleic Acid; Rats; Rats, Wistar

To validate a test for independent assessment of insulin secretion and insulin sensitivity during the same occasion for metabolic studies in clinical practice, i.e. combined glucagon-stimulated C-peptide test and insulin tolerance test (GITT).. We measured C-peptide response to 0.5 mg of intravenous glucagon followed 30 min later by administration of 0.05 U kg(-1) insulin (insulin tolerance test, ITT). Ten subjects with normal glucose tolerance participated on different days in an ITT, glucagon-C-peptide test, ITT followed by glucagon-C-peptide test and glucagon-C-peptide test followed by ITT to establish whether and how the tests could be combined. The test was then repeated in nine patients with type 2 diabetes to investigate its reproducibility. In 20 subjects with varying degrees of glucose tolerance, the test was compared with the Botnia clamp (an intravenous glucose tolerance test combined with a euglycaemic hyperinsulinemic clamp).. When ITT preceded the glucagon test, C-peptide response was blunted. Therefore, we first administered glucagon and then insulin (GITT). The K(ITT) from the GITT was reproducible (CV = 13 %) and correlated strongly with the glucose disposal rate from the Botnia clamp (r = 0.87, r(2) = 0.75, P < 0.001). The C-peptide response to glucagon was reproducible (CV = 13 %). The disposition index, providing a measure of beta-cell function adjusted for insulin sensitivity, calculated from the GITT showed good discrimination between individuals with varying degrees of glucose tolerance.. The GITT provides simple, reproducible and independent estimates of insulin sensitivity and secretion on the same occasion for metabolic studies in individuals with normal and abnormal glucose tolerance.

Topics: Adult; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucagon; Glucose Clamp Technique; Glucose Tolerance Test; Hormones; Humans; Insulin; Insulin Resistance; Insulin Secretion; Male; Middle Aged; Reproducibility of Results

The aim of this study was to define the metabolic abnormalities underlying the prediabetic status of isolated impaired fasting glucose (IFG), isolated impaired glucose tolerance (IGT), and combined IFG/IGT in obese youth.. We used state-of-the-art techniques (hyperinsulinemic-euglycemic and hyperglycemic clamps), applying a model of glucose-stimulated insulin secretion to the glucose and C-peptide concentration, in 40 normal glucose tolerance (NGT), 17 IFG, 23 IGT, and 11 IFG/IGT obese adolescents. Percent fat (by dual-energy x-ray absorptiometry), age, gender and ethnicity were comparable among groups.. Peripheral insulin sensitivity was similar between the IFG and NGT groups. In contrast, the IGT and IFG/IGT groups showed marked reductions in peripheral insulin sensitivity (P < 0.002). Basal hepatic insulin resistance index (basal hepatic glucose production x fasting plasma insulin) was significantly increased in IFG, IGT, and IFG/IGT (P < 0.009) compared with NGT. Glucose sensitivity of first-phase insulin secretion was progressively lower in IFG, IGT, and IFG/IGT compared with NGT. Glucose sensitivity of second-phase secretion showed a statistically significant defect only in the IFG/IGT group. In a multivariate regression analysis, glucose sensitivity of first-phase secretion and basal insulin secretion rate were significant independent predictors of FPG (total r(2) = 25.9%).. IFG, in obese adolescents, is linked primarily to alterations in glucose sensitivity of first-phase insulin secretion and liver insulin sensitivity. The IGT group is affected by a more severe degree of peripheral insulin resistance and reduction in first-phase secretion. IFG/IGT is hallmarked by a profound insulin resistance and by a new additional defect in second-phase insulin secretion.

Topics: Adolescent; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Male; Obesity; Phenotype

To evaluate haemoglobin A1c (HbA1c), fasting glucose, serum C-peptide and insulin resistance in relation to serum uric acid levels in a nationally representative sample of men and women.. Using data from 14,664 participants aged 20 yrs and older in The US Third National Health and Nutrition Examination Survey (1988-1994), we examined the relation between the levels of HbA1c, other biomarkers and serum uric acid levels using multivariate linear regressions stratified by gender.. The serum uric acid levels increased with increasing serum HbA1c levels up to the category of 6-6.9%, and thereafter decreased with further increasing HbA1c levels (a bell-shaped relation). Compared with a HbA1c level of < 5%, the multivariate differences among women were 26.8 micromol/l for HbA1c of 6-6.9% and -25.6 micromol/l (95% CI -42.8, -8.3) for HbA1c > or = 9%. The corresponding multivariate differences among men were 8.3 micromol/l (95% CI -3.0, 19.6) and -64.8 micromol/l (95% CI -46.0, -84.5), which were both significantly different from those among women (P-values for interaction by sex <0.001). Fasting glucose levels also showed a bell-shaped relation with serum uric acid levels. Individuals with diabetes showed lower serum uric acid levels and the association was larger among men (P-value for interaction, 0.007). Serum uric acid levels increased linearly with increasing fasting serum C-peptide levels, serum insulin levels or insulin resistance (multivariate P-values for trend, <0.001).. Individuals with moderately elevated HbA1c levels (i.e. pre-diabetes) may be at a higher risk of hyperuricaemia and gout, particularly in women, whereas individuals with diabetes or highly elevated HbA1c levels may be at a lower risk of these conditions, particularly in men.

Topics: Adult; Biomarkers; Blood Glucose; C-Peptide; Diet; Fasting; Female; Glycated Hemoglobin; Gout; Health Surveys; Humans; Insulin; Insulin Resistance; Linear Models; Male; Middle Aged; Risk; United States; Uric Acid

Interleukin-12 (IL-12) has been identified as a pro-inflammatory cytokine which is thought to contribute to the development of atherosclerosis. However, to date, the various associations between factors related to the course of type 2 diabetes, like metabolic compensation, beta cell secretory dysfunction, insulin resistance and IL-12 serum levels, remain unclear. Our study involved 41 patients with type 2 diabetes, 19 patients with coronary artery disease (CAD), and 19 healthy controls. We measured serum levels of fasting glucose, HbA(1)c, 1,5-anhydro-d-glucitol, and lipids. In addition, serum levels of C-peptide, insulin, proinsulin and IL-12 were assayed. HOMA(IR) score was calculated. The serum concentrations of IL-12 were higher in diabetics than in either patients with CAD or healthy controls, and were correlated with BMI, C-peptide, insulin, HOMA(IR), proinsulin and HDL serum levels. Multiple regression analysis revealed that the IL-12 serum level in type 2 diabetics primarily is dependent upon fasting proinsulin concentration. Our results demonstrate that elevated IL-12 serum levels in type 2 diabetics treated with sulphonylureas are induced especially by peripheral insulin resistance and beta cells dysfunction, as expressed by fasting serum proinsulin levels. This finding gives us hope that treatment to decrease peripheral insulin resistance and to avoid excessive proinsulin secretion might be successful in the prevention of IL-12-induced atherosclerosis.

Topics: Adult; Aged; Aged, 80 and over; Blood Glucose; C-Peptide; Coronary Artery Disease; Deoxyglucose; Diabetes Mellitus, Type 2; Female; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin-Secreting Cells; Interleukin-12; Lipoproteins, HDL; Male; Middle Aged; Multivariate Analysis; Proinsulin; Regression Analysis; Sulfonylurea Compounds

The objective of the study was to examine the association in humans between maternal psychosocial stress exposure during pregnancy and measures of glucose-insulin metabolism in the adult offspring.. Healthy young adults whose mothers experienced major stressful life events during their pregnancy (n = 36, prenatal stress, PS group, mean age 25 +/- 5.14 [SD] years) and a comparison group (n = 22, CG, mean age 24 +/- 3.7 [SD] years) underwent an oral glucose tolerance test.. Glucose levels were not significantly different across the groups; however, prenatally stressed subjects showed significantly elevated 2-hour insulin (P = .01) and C-peptide levels (P = .03). These differences were independent of other major risk factors for insulin resistance, including birth phenotype (birthweight, length of gestation), a family history of diabetes, gestational diabetes, body mass index, proinflammatory state, and smoking.. Higher insulin responses reflect relative insulin resistance in these prenatally stressed young adults. This study is the first to provide evidence for a link in humans between prenatal psychosocial stress exposure and alterations in glucose-insulin metabolic function.

Topics: Adiponectin; Adult; Blood Glucose; C-Peptide; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Leptin; Male; Pregnancy; Pregnancy Complications; Prenatal Exposure Delayed Effects; Stress, Psychological; Surveys and Questionnaires

Obesity and insulin resistance are highly correlated with metabolic disturbances. Both the excess and lack of adipose tissue can lead to severe insulin resistance and diabetes. Adipose tissue plays an active role in energy homeostasis, hormone secretion, and other proteins that affect insulin sensitivity, appetite, energy balance, and lipid metabolism. Rats with streptozotocin-induced diabetes during the neonatal period develop the classic diabetic picture of hyperglycemia, hypoinsulinemia, and insulin resistance in adulthood. Low body weight and reduced epididymal (EP) fat mass were also seen in this model. The aim of this study was to investigate the glucose homeostasis and metabolic repercussions on the adipose tissue following chronic treatment with antidiabetic drugs in these animals. In the 4th week post birth, diabetic animals started an 8-week treatment with pioglitazone, metformin, or insulin. Animals were then killed, EP fat pads were excised, and blood samples were collected for biological and biochemical assays. Pioglitazone and insulin treatments, but not metformin, reduced hyperglycemia, polydipsia, and polyphagia. Although all antidiabetic therapies improved insulin sensitivity, this was particularly noteworthy in the pioglitazone-treated rats. Furthermore, a recovery of adipose mass and insulin levels were observed in pioglitazone- and insulin-, but not metformin-treated animals. Treatments with insulin or pioglitazone were able to correct significantly, but not completely, the metabolic abnormalities, parallel to full recovery of adipose mass, indicating that not only the low insulin levels but also the lack of adipose tissue might play a significant role on the pathophysiology of this particular diabetes model.

Topics: Adipose Tissue; Animals; C-Peptide; Diabetes Mellitus, Experimental; Fatty Acids, Nonesterified; Glucose; Glucose Tolerance Test; Glucose Transporter Type 4; Glycerides; Insulin Resistance; Lipolysis; Male; Pioglitazone; Rats; Rats, Wistar; RNA, Messenger; Streptozocin; Thiazolidinediones

To study fasting biologically active serum ghrelin (RIA) and resistin (ELISA) levels in different trimesters of pregnancy (HP, n=45, 15 in each) and in gestational diabetes mellitus (GDM, n=30) compared to non-pregnant healthy women (NP, n=40) in correlation with TNF-alpha, soluble (s)TNF-receptor (R)-1, -2, leptin (ELISA), C-peptide (Cp, RIA) and Cp/blood glucose ratio (bg).. Cross-sectional case control study.. Acylated ghrelin levels were significantly increased (p<0.0001) in the 2nd (377+/-38pg/ml, X+/-S.D.) and decreased in the 3rd trimester (252+/-36) and in GDM (226+/-21) compared to NP controls (309+/-20) and HP women in the 1st trimester (314+/-41). Serum resistin levels were higher in the 1st (8.5+/-2.6ng/ml), 2nd (10.2+/-2.1) and 3rd (13.1+/-3.6) trimesters of pregnancy and in GDM (15.7+/-3.5) than in NP controls (6.5+/-2.3). Significant (p<0.01) negative linear correlations were found among fasting serum ghrelin and body mass index (BMI), the fasting C-peptide (Cp) level, C-peptide/blood glucose (Cp/bg) ratio, TNF-alpha, soluble (s)TNFR-2, leptin and resistin concentrations in both, HP and GDM groups. Significant positive correlations were observed between serum acylated ghrelin and adiponectin, and between BMI and fasting Cp, Cp/bg, TNF-alpha, sTNFR-1, -2 and leptin levels in both pregnant groups.. Increased fasting serum acylated ghrelin concentrations in the 2nd trimester may associate with weight gain during pregnancy. Hyperresistinemia may also be associated with the pregnancy-induced insulin resistance. A negative regulatory feed-back mechanism between resistin, TNF-alpha and ghrelin may be hypothesized.

Topics: Blood Glucose; C-Peptide; Case-Control Studies; Cross-Sectional Studies; Diabetes, Gestational; Female; Ghrelin; Humans; Insulin Resistance; Leptin; Multivariate Analysis; Peptide Hormones; Pregnancy; Pregnancy Trimesters; Receptors, Tumor Necrosis Factor; Resistin; Tumor Necrosis Factor-alpha

Low birth weight is associated with an increased risk of metabolic and cardiovascular diseases in adulthood. The development of insulin resistance (IR) seems to play a pivotal role; no data on the oxidant-antioxidant status are available in this risk group.. This study is an assessment of oxidant-antioxidant status in prepubertal children born small for gestational age (SGA) in comparison to healthy controls and the relationship to IR.. This cross-sectional study compares indexes of IR and oxidant-antioxidant status in three different groups (SGA+, SGA-, controls), with analysis by post hoc and Pearson correlation.. The study was conducted in the Academic Department of Pediatrics.. A total of 19 SGA+ and 16 SGA- children were compared with 13 controls.. No intervention was used.. Indexes of IR (glucose to insulin ratio, homeostasis model assessment of IR) were evaluated, and markers of oxidative stress (lag phase, malonildialdehyde, vitamin E) were measured.. Homeostasis model assessment of IR was significantly higher in SGA+ than SGA- children (1.32+/-0.9 vs. 0.69+/-0.47; P=0.03) and controls (0.71+/-0.37; P=0.04). Glucose to insulin ratio was significantly lower in SGA+ than SGA- children (12.41+/-5.01 vs. 26.54+/-17.18; P=0.02) and controls (26.96+/-20.70; P=0.04). Lag phase was significantly shorter in SGA+ than SGA- children (24.3+/-4.38 vs. 35.59+/-11.29 min; P=0.003) and controls (45.28+/-7.69 min; P=0.0001) and in SGA- than controls (P=0.01). Malonildialdehyde was significantly higher in SGA+ than SGA- children (0.79+/-0.3 vs. 0.6+/-0.1 nmol/mg; P=0.03) and controls (0.36+/-0.04 nmol/mg; P=0.0001) and in SGA- children than controls (P=0.02). Vitamin E was significantly reduced in SGA+ children than controls (27.54+/-7.9 vs. 43.23+/-11.32 micromol/liter; P=0.002).. Oxidative stress is present in both SGA+ and SGA- children, with a continuous alteration in relation to IR. Therefore, catch-up growth might exert the greatest influence in the development of future diseases.

Topics: Blood Glucose; Body Composition; Body Height; C-Peptide; Child; Child, Preschool; Electric Impedance; Female; Humans; Infant, Newborn; Infant, Small for Gestational Age; Insulin Resistance; Lipid Peroxidation; Lipoproteins, LDL; Male; Oxidative Stress; Reference Values; White People

Obesity is strongly associated with hyperinsulinemia and insulin resistance, both primary risk factors for type 2 diabetes. It has been thought that increased fasting free fatty acids (FFA) may be responsible for the development of insulin resistance during obesity, causing an increase in plasma glucose levels, which would then signal for compensatory hyperinsulinemia. But when obesity is induced by fat feeding in the dog model, there is development of insulin resistance and a marked increase in fasting insulin despite constant fasting FFA and glucose. We examined the 24-h plasma profiles of FFA, glucose, and other hormones to observe any potential longitudinal postprandial or nocturnal alterations that could lead to both insulin resistance and compensatory hyperinsulinemia induced by a high-fat diet in eight normal dogs. We found that after 6 wk of a high-fat, hypercaloric diet, there was development of significant insulin resistance and hyperinsulinemia as well as accumulation of both subcutaneous and visceral fat without a change in either fasting glucose or postprandial glucose. Moreover, although there was no change in fasting FFA, there was a highly significant increase in the nocturnal levels of FFA that occurred as a result of fat feeding. Thus enhanced nocturnal FFA, but not glucose, may be responsible for development of insulin resistance and fasting hyperinsulinemia in the fat-fed dog model.

Topics: Animals; Blood Glucose; Body Composition; C-Peptide; Circadian Rhythm; Diet; Dogs; Fasting; Fatty Acids, Nonesterified; Glucagon-Like Peptide 1; Glycerol; Hormones; Hyperinsulinism; Insulin; Insulin Resistance; Male; Triglycerides

Obesity and type 2 diabetes are worldwide health issues. The present paper investigates prenatal and postnatal pathways to obesity, identifying different metabolic outcomes with different effects on insulin sensitivity and different underlying mechanisms involving key components of insulin receptor signaling pathways. Pregnant Wistar rats either were fed chow ad libitum or were undernourished throughout pregnancy, generating either control or intrauterine growth restricted (IUGR) offspring. Male offspring were fed either standard chow or a high-fat diet from weaning. At 260 d of age, whole-body insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamp, and other metabolic parameters were measured. As expected, high-fat feeding caused diet-induced obesity (DIO) and insulin resistance. Importantly, the insulin sensitivity of IUGR offspring was similar to that of control offspring, despite fasting insulin hypersecretion and increased adiposity, irrespective of postnatal nutrition. Real-time PCR and Western blot analyses of key markers of insulin sensitivity and metabolic regulation showed that IUGR offspring had increased hepatic levels of atypical protein kinase C zeta (PKC zeta) and increased expression of fatty acid synthase mRNA. In contrast, DIO led to decreased expression of fatty acid synthase mRNA and hepatic steatosis. The decrease in hepatic PKC zeta with DIO may explain, at least in part, the insulin resistance. Our data suggest that the mechanisms of obesity induced by prenatal events are fundamentally different from those of obesity induced by postnatal high-fat nutrition. The origin of insulin hypersecretion in IUGR offspring may be independent of the mechanistic events that trigger the insulin resistance commonly observed in DIO.

Topics: Animal Feed; Animals; Blood Glucose; C-Peptide; Caloric Restriction; Diabetes, Gestational; Dietary Fats; Female; Fetal Growth Retardation; Fetal Nutrition Disorders; Glucose Clamp Technique; Glycogen; Hyperinsulinism; Insulin; Insulin Resistance; Insulin Secretion; Lipid Metabolism; Liver; Male; Muscle, Skeletal; Obesity; Phosphoenolpyruvate Carboxykinase (GTP); Pregnancy; Prenatal Exposure Delayed Effects; Rats; Rats, Wistar

Factors related to insulin resistance have been implicated in prostate cancer development, however, few analytical studies support such an association. We performed a case control study on 392 prostate cancer cases and 392 matched controls nested in a prospective cohort in Northern Sweden. Plasma concentrations of C-peptide, leptin, glycated haemoglobin (HbA1c) and fasting and post-load glucose were analysed and homeostatic model assessment of insulin resistance (HOMA-IR) was calculated. Conditional logistic regression analyses were used to calculate odds ratios (OR) of prostate cancer. High levels of C-peptide, HOMA-IR, leptin and HbA1c were associated with significant decreases in risk of prostate cancer, with ORs for top vs. bottom quartile for C-peptide of 0.59 (95% Confidence Interval [CI], 0.40-0.89; p(trend) = 0.008), HOMA-IR 0.60 (95% CI, 0.38-0.94; p(trend) = 0.03), leptin 0.55 (95% CI, 0.36-0.84; p(trend) = 0.006) and HbA1c 0.56 (95% CI, 0.35-0.91; p(trend) = 0.02). All studied factors were strongly inversely related to risk among men less than 59 years of age at blood sampling, but not among older men, with a significant heterogeneity between the groups for leptin (p(heterogeneity) = 0.006) and fasting glucose (p(heterogeneity) = 0.03). C-peptide and HOMA-IR were strongly inversely related to non-aggressive cancer but were non-significantly positively related to risk of aggressive disease (p(heterogeneity) = 0.007 and 0.01, respectively). Our data suggest that androgens, which are inversely associated with insulin resistance, are important in the early prostate cancer development, whereas insulin resistance related factors may be important for tumour progression.

Topics: Blood Glucose; Body Mass Index; C-Peptide; Case-Control Studies; Fasting; Glycated Hemoglobin; Homeostasis; Humans; Insulin; Insulin Resistance; Leptin; Logistic Models; Lymphatic Metastasis; Male; Odds Ratio; Prospective Studies; Prostate-Specific Antigen; Prostatic Neoplasms; Risk Factors; Sweden

Anthropometric markers of obesity are simple means that may be used as markers of cardiovascular risk and insulin resistance. We compare body mass index, waist circumference and waist hip ratio as tools to screen for insulin resistance in 81 overweight Indigenous Australians using ROC curve analysis. Body mass index and waist circumference emerged as better predictors of insulin resistance compared with waist hip ratio.

Topics: Adult; Aged; Aged, 80 and over; Anthropometry; Australia; Biomarkers; Blood Glucose; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Humans; Insulin Resistance; Middle Aged; Obesity; Predictive Value of Tests; Risk Factors; ROC Curve; Waist-Hip Ratio

To determine the contribution of hepatic insulin resistance to the pathogenesis of impaired fasting glucose (IFG).. Endogenous glucose production (EGP) and glucose disposal were measured in 31 subjects with IFG and 28 subjects with normal fasting glucose (NFG) after an overnight fast and during a clamp when endogenous secretion was inhibited with somatostatin and insulin infused at rates that approximated portal insulin concentrations present in IFG subjects after an overnight fast (approximately 80 pmol/l, "preprandial") or within 30 min of eating (approximately 300 pmol/l, "prandial").. Despite higher (P < 0.001) insulin and C-peptide concentrations and visceral fat (P < 0.05), fasting EGP and glucose disposal did not differ between IFG and NFG subjects, implying hepatic and extrahepatic insulin resistance. This was confirmed during preprandial insulin infusion when glucose disposal was lower (P < 0.05) and EGP higher (P < 0.05) in IFG than in NFG subjects. Higher EGP was due to increased (P < 0.05) rates of gluconeogenesis in IFG. EGP was comparably suppressed in IFG and NFG groups during prandial insulin infusion, indicating that hepatic insulin resistance was mild. Glucose disposal remained lower (P < 0.01) in IFG than in NFG subjects.. Hepatic and extrahepatic insulin resistance contribute to fasting hyperglycemia in IFG with the former being due at least in part to impaired insulin-induced suppression of gluconeogenesis. However, since hepatic insulin resistance is mild and near-maximal suppression of EGP occurs at portal insulin concentrations typically present in IFG subjects within 30 min of eating, extrahepatic (but not hepatic) insulin resistance coupled with accompanying defects in insulin secretion is the primary cause of postprandial hyperglycemia.

Topics: Adipose Tissue; Blood Glucose; Body Mass Index; C-Peptide; Fasting; Female; Glucagon; Gluconeogenesis; Glucose Intolerance; Humans; Hyperglycemia; Insulin Resistance; Liver; Male; Middle Aged; Reference Values

Impaired pancreatic beta cell function and insulin sensitivity are fundamental factors in the pathogenesis of type 2 diabetes; however, the predominant defect appears differ among ethnic groups. We conducted a cross-sectional study to evaluate the contribution of impaired beta cell function and insulin sensitivity at different stages of the deterioration of glucose tolerance in Thais. The study involved 420 urban Thais of both sexes, 43-84 years old. A 75-g oral glucose tolerance test was performed on all of the subjects. Indices of insulin resistance and beta cell function were calculated with the use of a homeostasis model assessment. The subjects were classified as having normal glucose tolerance (NGT), isolated impaired fasting glucose (IFG), isolated impaired glucose tolerance (IGT), combined IFG and IGT, or type 2 diabetes mellitus according to the American Diabetes Association (ADA) criteria. There were no differences between groups with regard to gender and age. The percentage of obesity was significantly greatest in the diabetic group. Fasting serum insulin and C-peptide levels progressively increased from the NGT to the diabetic subjects. Serum C-peptide was more strongly associated with newly diagnosed diabetes than insulin, and was an independent factor associated with newly diagnosed diabetic subjects. The insulin resistance index progressively increased when the glucose tolerance stage changed from NGT through diabetic subjects. Beta cell function did not change significantly in any other group compared to the NGT group. An increase in fasting serum C-peptide may be a risk factor for type 2 diabetes. Obesity and insulin resistance are the predominant features in the deterioration of glucose tolerance in Thais.

Topics: Adult; Aged; Aged, 80 and over; Blood Glucose; C-Peptide; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Female; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Middle Aged; Obesity; Prediabetic State; Thailand

Insulin resistance and obesity play an important role in the pathogenesis of polycystic ovary syndrome (PCOS). It is known that experimentally induced insulin resistance diminishes the stimulatory effect of insulin on leptin secretion. It is not yet known whether the long-term insulin resistance as found in PCOS patients alters the leptin response to hypo- and hyperglycaemia.. We induced hyper- and hypoglycaemia by glucose clamp technique in 7 patients with PCOS and 20 healthy controls. After a plasma glucose level of 8.8 mmol/l was reached, the plasma glucose level was reduced stepwise to 6.8, 4.8 and 2.8 mmol/l.. The PCOS patients required lower glucose infusion rates to reach the glycaemic targets (P < 0.05). Serum insulin and C-peptide concentrations increased significantly during the clamp compared with the baseline in both groups (P < 0.001 for insulin, and P < 0.001, P < 0.005 for C-peptide control and PCOS, respectively) and increased significantly more in PCOS patients compared with the control group (both P < 0.05). Basal leptin levels were significantly higher in the PCOS group than in the control group (P = 0.005). In the controls, the leptin concentration increased significantly during the clamp (P < 0.001 for each glycaemic target), whereas in the PCOS group, leptin secretion increased only during hypoglycaemia (P = 0.04).. Compared with the healthy controls, the response of leptin secretion to hyper- and hypoglycaemia was diminished in PCOS patients. Changes in leptin secretion seem not to be caused by hyper- and hypoglycaemia, but rather by hyperinsulinaemia. Reduced insulin sensitivity seems to be responsible for the diminished leptin response, which might contribute to the obesity found in PCOS patients.

Topics: Adult; Blood Glucose; C-Peptide; Female; Humans; Hyperglycemia; Hypoglycemia; Insulin; Insulin Resistance; Leptin; Polycystic Ovary Syndrome

To determine the clinical and laboratory parameters and the progression to insulin requirement in two groups of LADA patients separated according to GADA titers, and to evaluate the benefit of early insulinization in patients at high risk of premature beta-cell failure (high GADA titers).. Among the diabetic adults seen at our service and screened for GADA at diagnosis, 54 were diagnosed with LADA and classified as having low (> 1 U/ml and < 17.2 U/ml) or high (> 17.2 U/ml) GADA titers. Fifty-four patients with type 2 diabetes (GADA-) were selected for comparison. In addition, 24 patients who had GADA titers > 20 U/ml and who were not initially insulinized were compared to 16 patients who were insulinized at diagnosis.. Insulin resistance was higher in the GADA- group, followed by patients with low GADA titers. BMI and the frequency of arterial hypertension, elevated triglycerides and reduced HDL cholesterol were lower in the high GADA+ group, with no difference between the GADA- or low GADA+ groups. The high GADA+ group showed a greater reduction and lower levels of C-peptide and required insulin earlier during follow-up. Patients with GADA titers > 20 U/ml and insulinized early presented no significant variation in C-peptide levels, had better glycemic control and required a lower insulin dose than patients who were insulinized later.. We agree that patients with LADA should be differentiated on the basis of GADA titers and that patients with GADA titers > 20 U/ml benefit from early insulinization.

Topics: Adult; Analysis of Variance; Autoantibodies; Autoimmune Diseases; Biomarkers; Body Mass Index; C-Peptide; Diabetes Mellitus; Diabetes Mellitus, Type 2; Diagnosis, Differential; Female; Follow-Up Studies; Glutamate Decarboxylase; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Male; Statistics, Nonparametric

Korean type 2 diabetics differ from Western diabetics in showing non-obese but centrally obese anthropometry and relatively more insulin secretory defects than insulin resistance. We assessed insulin secretion based on fasting serum C-peptide level and insulin resistance using the short insulin tolerance test (Kitt; rate constant for plasma glucose disappearance) in 1601 type 2 diabetic Korean patients (831 men and 770 women). Insulin secretory defects were catergorized as severe (C-peptide<1.10 ng/ml), moderate (C-peptide 1.10-1.69 ng/ml), and mild to non-secretory defect (C-peptide> or=1.70 ng/ml). Groups with a Kitt value of less than 2.5%/min were considered insulin-resistant, while those with a Kitt value > or =2.5%/min were considered insulin-sensitive. Overall, 42.5% of patients had a BMI>or =25.0 kg/m(2), and 70.2% had a BMI> or =23.0 kg/m(2); 45.2% (41.7% of men and 58.3% of women) were abdominally obese (waist> or =90 cm in men and 80 cm in women); mean fasting serum C-peptide level was 1.93+/-0.90 ng/ml, and the mean Kitt value was 2.03+/-0.96%/min. Accordingly, 13, 33, and 54% of patients showed a severe, moderate, and mild to non-secretory defect, respectively; 70.6% were insulin-resistant; and 29.4% were insulin-sensitive. Obese type 2 diabetes is recently increasing in Korea, indicating a shift from insulin secretory defects to insulin resistance.

Topics: Adult; Aged; Anthropometry; Blood Glucose; Body Mass Index; Body Size; Body Weight; C-Peptide; Diabetes Mellitus, Type 2; Fasting; Female; Humans; Insulin; Insulin Resistance; Korea; Male; Middle Aged

To investigate the contribution of HCV infection to insulin resistance in chronic haemodialysis patients.. The study was performed with 55 patients who were on regular haemodialysis therapy three times per week. Of the 55 patients, 34 (20 females and 14 males with an average age of 40.9 years) were anti-HCV (+) and were defined as the HCV (+) group. The remaining 21 patients (8 females and 11 males with an average age of 50 years) were negative for HCV and other viral markers and were defined as the HCV (-) group. BMI of all patients were below 27. Insulin resistance (IR) was calculated according to the HOMA formula and patients were called HOMA-IR (+) if their HOMA scores were higher than 2.5. All of the HOMA-IR (+) patients in both groups were called the HOMA-IR (+) subgroup. None of the patients had a history of drug use or any diseases that were related to insulin resistance except uremia. In both groups and the healthy control group, insulin and glucose levels were studied at three different venous serum samples taken at 5- minute intervals after 12 hours of fasting. Other individual variables were studied at venous serum samples taken after 12 hours of fasting.. HOMA scores were (3)2.5 in 22 of 34 HCV (+) patients (64.7%) and 7 of 21HCV (-) patients (33.33%) (p=0.024). Insulin levels of HCV (+) group (13.32 +/- 9.44mIU/mL) were significantly higher than HCV (-) (9.07 +/- 7.39mIU/mL) and the control groups (6.40 +/- 4.94mIU/ mL) (p=0.039 and p=0.021 respectively). HCV (+) patients were younger (40.94 +/- 17.06 and 52.62 +/- 20.64 years, respectively) and had longer dialysis duration (7.18 +/- 3.61 and 2.91 +/- 2.69 years, respectively). Significant positive correlations of HOMA score with insulin (r=0.934, p=0.000) and fasting glucose levels (r=0.379, p=0.043) were found in the HOMA- IR (+) subgroup. Also, a significant positive correlation was found between ALT and insulin levels in the HOMA IR (+) subgroup. C-peptide levels of both HCV (+) and (-) groups were significantly higher than the control group (p < 0.001). There were not any significant correlations between HOMA score and some of the other individual variables including levels of triglyceride, ferritin, ALT, iPTH and Mg in any of the groups.. In chronic haemodialysis patients; HCV infection is related to a high prevalence of insulin resistance, higher insulin and glucose levels.

Topics: Adult; C-Peptide; Female; Hepatitis C; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Kidney Failure, Chronic; Male; Middle Aged; Renal Dialysis

To verify whether a diabetes family history might be a risk factor for the development, in adult age, of metabolic disorders, leptin, anthropometric and endocrine parameters were analysed in 95 babies with grandparents affected by type 2 diabetes (DF) and in 95 matched babies without diabetes family history (NDF). A sexual dimorphism for leptin was present in the NDF group (males: 6.7+/-4.1 ng/ml; females: 12.3+/-6.5; p < 0.0001) but not in the DF group (males: 9.0+/-5.5; females: 10.8+/-6.4), due to the significant increase in DF male leptin level, compared to that of NDF males (p < 0.05). In DF males only, leptin was positively correlated with body length, PI, C-peptide, IGF-1 and IGF1BP3. These results suggest that the increase in DF male leptin could be a compensatory mechanism for reduced insulin sensitivity in a pre-clinical alteration of glucose metabolism.

Topics: Birth Weight; Body Height; C-Peptide; Case-Control Studies; Diabetes Mellitus, Type 2; Female; Fetal Blood; Genetic Predisposition to Disease; Humans; Infant, Newborn; Insulin; Insulin Resistance; Insulin-Like Growth Factor Binding Protein 3; Insulin-Like Growth Factor I; Italy; Leptin; Male; Sex Characteristics

American women are five times more likely to be at risk for breast cancer than women from Asian countries. Epidemiologic studies have linked energy balance to an increased risk of breast cancer, yet few studies have investigated potential mediators of this association with Chinese women. We examined the above association by blood levels of insulin-like growth factors (IGFs), binding proteins, and C-peptide in the Shanghai Breast Cancer Study (SBCS), a case-control study conducted among 1,459 breast cancer cases and 1,556 healthy Chinese women from 1996 and 1998.. In-person surveys were used to collect data on energy intake, anthropometric measures, exercise/sport activity, and occupational activity. The present analyses consisted of 397 cases and 397 controls whose blood samples were measured for levels of IGFs, insulin growth-factor binding protein 3 (IGFBP-3), C-peptide, and the relationship with physical activity status, total energy intake, and body fat distribution.. Body mass index (BMI) and waist-to-hip ratio (WHR) were significantly positively correlated with IGFBP-3 and C-peptide. Adult exercise/sport activity was significantly negatively correlated with insulin-like growth factor 1 (IGF-I). C-peptide levels increased with increasing quartiles of WHR (p for trend<0.01). Additional analyses were performed to evaluate whether the association of energy balance measures with breast cancer risk changed after adjustment for IGFs, IGFBP-3, and C-peptide biomarkers. The associations attenuated, but none of them changed substantially.. Insulin resistance biomarkers may partially explain the association between positive energy balance and breast cancer risk, but future studies are needed to identify the underlying complex biological mechanisms of action for breast cancer prevention.

Topics: Adult; Asian People; Biomarkers; Body Mass Index; Breast Neoplasms; C-Peptide; Case-Control Studies; China; Energy Intake; Energy Metabolism; Exercise; Female; Humans; Insulin Resistance; Insulin-Like Growth Factor Binding Protein 3; Insulin-Like Growth Factor I; Insulin-Like Growth Factor II; Middle Aged; Motor Activity; Risk Assessment; Risk Factors; Waist-Hip Ratio

[corrected] Oxidative stress plays a critical role in the pathogenesis of various diseases. Recent reports indicate that obesity may induce systemic oxidative stress. The aim of the study was to potentiate oxidative stress as a factor which may aggravate peripheral insulin sensitivity and insulinsecretory response in obesity in this way to potentiate development of diabetes. The aim of the study was also to establish whether insulin-secretory response after glucagonstimulated insulin secretion is susceptible to prooxidant/antioxidant homeostasis status, as well as to determine the extent of these changes.. A mathematical model of glucose/insulin interactions and C-peptide was used to indicate the degree of insulin resistance and to assess their possible relationship with altered antioxidant/prooxidant homeostasis. The study included 24 obese healthy and 16 obese newly diagnozed non-insulin dependent diabetic patients (NIDDM) as well as 20 control healthy subjects, matched in age.. Total plasma antioxidative capacity, erythrocyte and plasma reduced glutathione level were significantly decreased in obese diabetic patients, but also in obese healthy subjects, compared to the values in controls. The plasma lipid peroxidation products and protein carbonyl groups were significantly higher in obese diabetics, more than in obese healthy subjects, compared to the control healthy subjects. The increase of erythrocyte lipid peroxidation at basal state was shown to be more pronounced in obese daibetics, but the apparent difference was obtained in both the obese healthy subjects and obese diabetics, compared to the control values, after exposing of erythrocytes to oxidative stress induced by H2O2. Positive correlation was found between the malondialdehyde (MDA) level and index of insulin sensitivity (FIRI).. Increased oxidative stress together with the decreased antioxidative defence seems to contribute to decreased insulin sensitivity and impaired insulin secretory response in obese diabetics, and may be hypothesized to favour the development of diabetes during obesity.

Topics: Adult; Antioxidants; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucagon; Humans; Insulin; Insulin Resistance; Insulin Secretion; Lipid Peroxidation; Male; Malondialdehyde; Middle Aged; Obesity; Oxidative Stress

Recent data suggest that circulating retinol-binding protein (RBP) might be involved in the pathogenesis of insulin resistance. Moreover, protein C inhibitor (PCI), which specifically binds retinoic acid, was found to be increased in myocardial infarction survivors who are also insulin resistant.. The objective of this study was to investigate the association of insulin resistance with RBP factors and PCI active antigen.. This was a clinical study.. Nondiabetic humans with high (IS; n = 20, 14 females, six males, aged 47.2 +/- 1.9 yr, body mass index 26 +/- 1 kg/m(2)) and low (IR; n = 20, 14 females, six males, aged 45.5 +/- 1.7 yr, body mass index 28 +/- 1 kg/m(2)) insulin-stimulated glucose-disposal (M) participated in this study.. M was measured by 2-h hyperinsulinemic (40 mU.min(-1).m(-2))-isoglycemic clamp tests. Measurements of RBP were performed using a nephelometric method and validated using quantitative Western blotting.. M (80-120 min) was higher in IS (10.9 +/- 0.6 mg.min(-1).kg(-1)) than IR (4.0 +/- 0.2; P < 10(-12)). Fasting plasma RBP concentrations were comparable between IS and IR measured by both nephelometry (IS: 4.4 +/- 0.3; IR: 4.6 +/- 0.3 mg/dl, P = 0.6) and quantitative Western blot (IS 7.9 +/- 0.5, IR 8.3 +/- 0.6 mg/dl; P = 0.6). Fasting plasma PCI active antigen was similar in both groups. Plasma RBP and PCI were not significantly related to M. RBP was positively correlated with uric acid (r = 0.488, P = 0.003), triglycerides (r = 0.592, P < 0.001), prealbumin (r = 0.63, P < 0.0001), and vitamin A (r = 0.75, P < 10(-6)).. Our data demonstrate that healthy, insulin-resistant humans do not show altered plasma retinol binding factors, such as RBP and PCI. Both do not significantly correlate with insulin sensitivity. Thus, our findings do not support the hypothesis of insulin sensitivity modulation by proteins involved in retinol transport.

Topics: Aging; Blood Glucose; Blotting, Western; Body Mass Index; Body Weight; C-Peptide; Enzyme-Linked Immunosorbent Assay; Fatty Acids, Nonesterified; Female; Gas Chromatography-Mass Spectrometry; Glucose Clamp Technique; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Protein C Inhibitor; Retinol-Binding Proteins, Plasma; Sex Characteristics; Vitamin A

Primary aldosteronism (PA) is the most common secondary cause of hypertension and recently has been implicated as a cause of impaired glucose tolerance. We investigated the glucose insulin sensitivity and insulin secretion in patients with idiopathic primary aldosteronism.. Thirty PA patients and 60 essential hypertensive (EH) patients as controls were included, matched (1: 2) by their body mass index (BMI) (29.9 +/- 4.3 versus 29.8 +/- 5.8 m/kg), age (53.7 +/- 9.4 versus 59.9 +/- 8.6 years old) and gender (male/female: 8/22 versus 17/43). In all patients, we measured insulin, total cholesterol, triglycerides, C-peptide and fasting glucose levels. Homeostasis model assessment for insulin resistance (HOMA-IR) and HOMA of pancreatic beta-cell function (HOMA-betaF) indexes were calculated. We also evaluated the response to spironolactone in 19 PA patients.. PA patients had higher levels of glucose (5.2 +/- 0.7 versus 4.9 +/- 0.7 mmol/l; P = 0.017). Insulin levels (10.7 +/- 6.5 versus 11.5 +/- 5.8 uUI/ml, P = 0.525) and HOMA-IR (2.51 +/- 1.59 versus 2.45 +/- 1.29 uUI/ml x mmol/l, P = 0.854) were similar in both groups. HOMA-betaF index (138.9 +/- 89.8 versus 179.8 +/- 100.2%, P = 0.049) and C-peptide (0.83 +/- 0.63 versus 1.56 +/- 0.84 ng/dl, P = 0.0001) were lower in PA patients. Potassium was normal in both groups. Negative correlations between serum aldosterone/plasma renin activity (SA/PRA) ratio and HOMA-betaF, and between C-peptide and SA levels were found in all patients. After the spironolactone treatment, we found an increase of C-peptide and insulin levels without changes in HOMA-IR or HOMA-betaF.. Our results showed differences in glucose metabolism between PA patients and those with hypertension suggesting that these findings could probably be determined by a lower beta-cell function influenced by aldosterone. These findings highlight the importance of aldosterone in glucose metabolism.

Topics: Aged; Aldosterone; Blood Glucose; C-Peptide; Case-Control Studies; Cholesterol; Female; Humans; Hyperaldosteronism; Hypertension; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Middle Aged; Mineralocorticoid Receptor Antagonists; Renin; Spironolactone; Triglycerides

Hyperinsulinemic hypoglycemia is newly recognized as a rare but important complication after Roux-en-Y gastric bypass (GB). The etiology of the syndrome and metabolic characteristics remain incompletely understood. Recent studies suggest that levels of incretin hormones are increased after GB and may promote excessive beta-cell function and/or growth.. We performed a cross-sectional analysis of metabolic variables, in both the fasting state and after a liquid mixed-meal challenge, in four subject groups: 1) with clinically significant hypoglycemia [neuroglycopenia (NG)] after GB surgery, 2) with no symptoms of hypoglycemia at similar duration after GB surgery, 3) without GB similar to preoperative body mass index of the surgical cohorts, and 4) without GB similar to current body mass index of the surgical cohorts.. Insulin and C-peptide after the liquid mixed meal were both higher relative to the glucose level achieved in persons after GB with NG compared with asymptomatic individuals. Glucagon, glucagon-like peptide 1, and glucose-dependent insulinotropic peptide levels were higher in both post-GB surgical groups compared with both overweight and morbidly obese persons, and glucagon-like peptide 1 was markedly higher in the group with NG. Insulin resistance, assessed by homeostasis model assessment of insulin resistance, the composite insulin sensitivity index, or adiponectin, was similar in both post-GB groups. Dumping score was also higher in both GB groups but did not discriminate between asymptomatic and symptomatic patients. Notably, the frequency of asymptomatic hypoglycemia after a liquid mixed meal was high in post-GB patients.. A robust insulin secretory response was associated with postprandial hypoglycemia in patients after GB presenting with NG. Increased incretin levels may contribute to the increased insulin secretory response.

Topics: Adult; Aged; Blood Glucose; Body Mass Index; C-Peptide; Eating; Female; Food; Gastric Bypass; Gastric Inhibitory Polypeptide; Glucagon; Glucagon-Like Peptide 1; Humans; Hypoglycemia; Incretins; Insulin; Insulin Resistance; Male; Middle Aged; Obesity; Obesity, Morbid; Postoperative Complications

The prevalence of childhood obesity has increased dramatically in the United States. Early presentation of type 2 diabetes has been observed in children and adolescents, especially in the Hispanic population. The genetic contribution of glucose homeostasis related to childhood obesity is poorly understood. The objective of this study was to localize quantitative trait loci influencing fasting serum glucose levels in Hispanic children participating in the Viva La Familia Study.. Subjects were 1030 children ascertained through an overweight child from 319 Hispanic families. Fasting serum glucose levels were measured enzymatically, and genetic linkage analyses were conducted using SOLAR software.. Fasting glucose was heritable, with a heritability of 0.62 +/- 0.08 (P < 0.01). Genome-wide scan mapped fasting serum glucose to markers D13S158-D13S173 on chromosome 13q (LOD score of 4.6). A strong positional candidate gene is insulin receptor substrate 2, regulator of glucose homeostasis and a candidate gene for obesity. This region was reported previously to be linked to obesity- and diabetes-related phenotypes.. A quantitative trait locus on chromosome 13q contributes to the variation in fasting serum glucose levels in Hispanic children at high risk for obesity.

Topics: Adolescent; Algorithms; Blood Glucose; Body Mass Index; C-Peptide; Child; Chromosomes, Human, Pair 13; Cohort Studies; Fasting; Female; Genotype; Glucose Tolerance Test; Hispanic or Latino; Humans; Insulin; Insulin Resistance; Lipids; Male; Overweight; Phenotype; Quantitative Trait Loci

Increased C-reactive protein (CRP) concentration and insulin resistance (IR) are associated with increased rates of adverse cardiovascular events. We sought to examine the relationship of CRP with surrogate measures of IR among nondiabetic adults in the US.. We conducted analyses using data from the National Health and Nutrition Examination Survey 1999-2002. We analyzed a nationally representative sample of 2514 men and nonpregnant women age > or = 20 years who were non-Hispanic white, non-Hispanic black, or Mexican American.. After adjustment for age, sex, race/ethnicity, smoking status, systolic blood pressure, and serum concentrations of HDL cholesterol, LDL cholesterol, and triglyceride, CRP was significantly associated with 10 IR measures (all P values <0.01). The strength of the association attenuated after further adjustment for waist circumference (change in adjusted regression coefficients ranging from 60.0% to 75.1%). The association of CRP with each IR surrogate was similar (standardized regression coefficient ranges from 0.06 to 0.09). The association of CRP (>3 vs <1 mg/L) with the homeostasis model for assessment of IR (> or = 75th vs <75th percentile) was statistically significant among people with a body mass index > or = 30 kg/m(2) (odds ratio, 2.6; 95% CI, 1.3-5.1) or with a body mass index <25 kg/m(2) (odds ratio, 2.5; 95% CI, 1.5-4.2).. CRP was significantly associated with the surrogate measures of IR among nondiabetic adults. Obesity may play an important role in the association of CRP with IR in this nationally representative sample.

Topics: Adult; Black People; Blood Glucose; Body Mass Index; C-Peptide; C-Reactive Protein; Cholesterol, HDL; Cholesterol, LDL; Fasting; Female; Health Surveys; Homeostasis; Humans; Insulin; Insulin Resistance; Logistic Models; Male; Mexican Americans; Middle Aged; Obesity; Smoking; Triglycerides; United States; White People

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Diabetic Ketoacidosis; Fasting; Humans; Insulin Resistance

People with obesity and/or the metabolic syndrome have an increased risk for developing diabetes and cardiovascular disease and may have low adiponectin levels. The obesity associated with Prader-Willi syndrome (PWS) would be expected to have similar complications. However, it was recently reported that, despite their adiposity, people with PWS have reduced visceral fat and are less likely to develop diabetes mellitus or the metabolic syndrome compared with people with simple obesity.. To determine if plasma adiponectin levels and other variables relevant to diabetes and cardiovascular risk are different in a cohort of PWS subjects with known genetic subtypes compared with age-, sex- and weight-matched control subjects.. Fasting plasma glucose, C-peptide, triglycerides, leptin and cholesterol levels were similar in PWS and obese subjects. Our 20 PWS subjects (mean age = 27.7 years) had higher percent body fat (54.1 vs 48.5%) determined by DEXA measurements and lower percent lean mass (45.9 vs 51.5%) compared with 14 obese controls (mean age = 26.9 year). Plasma adiponectin levels were significantly higher in PWS (15.5 +/- 8.2 microg/ml) than in obese controls (7.5 +/- 2.7 microg/ml). A significant positive correlation was found with insulin sensitivity in PWS subjects (r = 0.75, P = 0.0003) but not in obese controls (r = 0.36, P = 0.20).. Our study confirmed an earlier observation of higher adiponectin levels in PWS subjects and less insulin resistance proportionate to their obesity status than found in subjects with simple obesity. Furthermore, no differences were seen in PWS subjects with the chromosome 15 deletion or maternal disomy 15. The reported excessive visceral adiposity in subjects with simple obesity compared with PWS may be associated with decreased production and lower circulating levels of adiponectin.

Topics: Adiponectin; Adolescent; Adult; Biomarkers; Blood Glucose; Body Composition; Body Fat Distribution; C-Peptide; Humans; Insulin; Insulin Resistance; Leptin; Obesity; Prader-Willi Syndrome; Statistics, Nonparametric; Triglycerides

Women of Asian and South Asian descent are at increased risk of developing gestational diabetes mellitus compared with Caucasians, despite lower body mass index (BMI). Nevertheless, there has been limited study of insulin action during pregnancy in these ethnic groups.. The objective of the study was to compare insulin sensitivity in pregnancy in Asian, South Asian, and Caucasian subjects and to determine whether the impact of obesity on insulin action is modified by ethnicity.. A cross-sectional study was performed in outpatients undergoing oral glucose tolerance testing in late pregnancy. Participants were stratified into three groups: 1) Caucasian (n = 116); 2) South Asian (n = 31); and 3) Asian (n = 28).. Insulin sensitivity was measured using the oral glucose tolerance test (IS(OGTT)) index of M. Matsuda and R. DeFronzo, previously validated in pregnancy.. There were no significant ethnic differences in insulin sensitivity despite variation in prepregnancy BMI (Caucasians, 25.2 kg/m(2); South Asians, 23.3 kg/m(2); Asians, 21.4 kg/m(2); overall P = 0.0001). On multiple linear regression analysis, the strongest independent determinants of IS(OGTT) were gestational diabetes mellitus (t = -5.71; P < 0.0001) and BMI (t = -5.43; P < 0.0001). Importantly, both Asian (t = -2.87; P = 0.0047) and South Asian (t = -2.46; P = 0.015) ethnicity also emerged as negative, independent determinants of IS(OGTT). Furthermore, Asian ethnicity significantly modified the association of prepregnancy BMI with IS(OGTT) (interaction term, t = -2.29; P = 0.0231).. Asian and South Asian ethnicity are both independently associated with increased insulin resistance in late pregnancy. Prepregnancy BMI has a much greater effect on insulin resistance in pregnancy in Asian women than in Caucasians. Ethnicity thus emerges as a factor that modulates the effect of obesity on insulin resistance in pregnancy.

Topics: Adult; Asia, Southeastern; Asian; Biomarkers; Body Mass Index; C-Peptide; Cross-Sectional Studies; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Liver; Obesity; Pregnancy; Pregnancy Complications; Proinsulin; United States; White People

Type 2 diabetes mellitus (T2DM) is estimated to account for 10-45% of incident pediatric diabetes cases.. Our objective was to characterize the metabolic defects underlying T2DM in adolescents and young adults.. We conducted a cross-sectional study of islet function and insulin sensitivity in 16 adolescents with T2DM and 13 obese (OB) and 13 lean (LN) age-matched nondiabetic subjects at a University Medical Center.. We provided oral and iv glucose tolerance tests.. We measured insulin and glucagon levels, insulin sensitivity, acute insulin responses to iv glucose, and the ratio of proinsulin to immunoreactive insulin.. The diabetic subjects had elevated fasting insulin levels and significantly reduced insulin sensitivity (P < 0.05). The acute insulin response to iv glucose was comparable in the T2DM and LN groups (P < 0.05 for the OB vs. LN and T2DM), but insulin secretion adjusted for insulin resistance, the disposition index, was severely impaired in the diabetic subjects (P < 0.05 for the T2DM vs. LN and OB). The ratio of proinsulin to immunoreactive insulin did not differ among the three groups in the basal or stimulated state. Plasma glucagon levels were comparable before and after ingestion of glucose.. These findings demonstrate that diabetic adolescents have significant insulin resistance, even compared with subjects of similar obesity and body fatness, and impaired insulin secretion relative to their degree of insulin resistance. However, the adolescent diabetic subjects retained a first-phase insulin response to glucose that was comparable to lean controls and did not have hyperproinsulinemia or hyperglucagonemia.

Topics: Adolescent; Adult; Blood Glucose; Body Mass Index; C-Peptide; Diabetes Complications; Female; Glucose Intolerance; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Insulin Resistance; Insulin-Secreting Cells; Male; Obesity; Pancreatic Function Tests

To describe the outcome of 35 patients with type 2 diabetes prospectively followed for 6 years after the addition of a thiazolidinedione (TZD) to a failing regimen of a sulphonylurea and metformin -- triple oral therapy.. Study patients were assessed for the need for the addition of insulin to their regimen, and follow-up clinical and laboratory findings were analysed.. At a mean follow-up of 72 +/- 1.5 months (range 53-80), 18 (51%) of patients remained well controlled on triple oral therapy with a mean glycosylated haemoglobin (HbA1c) value of 6.9 +/- 0.2% (upper limit of normal 6.2%). In 17 other patients, triple oral therapy failed and the use of insulin was necessary after a mean duration of 38 (range 18-68) months. The mean HbA1c in these patients was 8.0 +/- 0.3%. The group that was maintained on triple oral therapy gained 15.2 +/- 1.9 lbs over the 6-year study which was significantly higher than the baseline weight. Alternatively, the group that failed and had insulin added to their therapy gained 20.2 +/- 4.5 lbs over the same period which was also significantly different from baseline but not from the triple oral therapy group. Although after 3 years a trend towards weight loss occurred in the triple oral therapy group, the insulin-added group continued to gain weight. Stimulated C-peptide levels increased significantly in the triple therapy group from 3.6 +/- 0.9 to 4.3 +/- 1.2 ng/ml and had not increased or decreased non-significantly from 3.7 +/- 0.8 to 3.2 +/- 0.6 ng/ml at the time of insulin initiation in the insulin-requiring group.. When used late in the course of type 2 diabetes, TZDs result in improved and prolonged glycaemic control which persisted for a median time of 6 years. Weight gain with TZDs peaks and then plateaus (and even trends downwards) at 3 years, although the addition of insulin to a failing oral therapy regimen results in a further and continuing weight gain in spite of inferior glycaemic control. Continuing glycaemic control with triple oral therapy is dependent on preservation or augmentation of endogenous insulin production.

Topics: Administration, Oral; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Follow-Up Studies; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Injections; Insulin; Insulin Resistance; Long-Term Care; Metformin; Middle Aged; Sulfonylurea Compounds; Thiazolidinediones; Treatment Failure; Treatment Outcome; Weight Gain

Pancreatitis and exocrine pancreatitic insufficiency have been described as extraintestinal manifestations of inflammatory bowel disease. In this study, we investigated whether the endocrine pancreatic function is also disturbed in patients with inflammatory bowel disease.. Seventeen patients with Crohn's disease and 13 healthy volunteers participated in the study. We analyzed the plasma insulin response in a 75-g oral glucose tolerance test. Glucose and insulin levels were determined at time 0 (fasting levels) and 30, 60, 90, 120, 180, 240, and 300 min after glucose uptake. Insulin resistance and beta cell function (BCF) were analyzed by calculating respective indices.. Fasting and oral glucose-tolerance test glucose levels appeared to be similar in patients with Crohn's disease and in the controls. Impaired fasting glucose, impaired glucose tolerance, and/or overt diabetes mellitus were not observed in the volunteers. Insulin as well as the index for BCF were significantly increased in patients with Crohn's disease. In addition, insulin resistance was shown to be significantly elevated in Crohn's disease.. Patients with Crohn's disease reveal an increased insulin secretion caused by an enhanced BCF, which may be induced by an up-regulated enteropancreatic axis. This hypersecretion may override the insulin resistance given by the chronic inflammatory state.

Topics: Adult; Blood Glucose; C-Peptide; Crohn Disease; Female; Glucose Tolerance Test; Homeostasis; Humans; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Male; Middle Aged

Former gestational diabetes (fGDM) constitutes a risk condition for the development of Type 2 diabetes. Former gestational diabetes is often characterized by obesity and hyperglycaemia, which may be concomitant and independent risk factors.. To assess insulin sensitivity and beta-cell function in fGDM uncomplicated by obesity and hyperglycaemia, we studied 24 lean fGDM women and 23 control women matched for age (30.7 +/- 0.7 years, whole cohort), body mass index (22.2 +/- 0.3 kg m(-2)), and indistinguishable for plasma glucose both at fasting and at 120 min. Several insulin sensitivity and beta-cell function indices were computed: homeostasis model assessment insulin resistance index (HOMA-R), insulin sensitivity index derived from an oral glucose tolerance test (OGIS), insulinogenic index, other empirical indices of insulin secretion and beta-cell function, and indices obtained using a beta-cell model.. Though the majority of indices, and in particular insulin sensitivity (HOMA-R: 1.35 +/- 0.13 vs. 1.65 +/- 0.14; OGIS: 492.7 +/- 6.3 vs. 496.4 +/- 9.4 mL min(-1) m(-2)), were not significantly different in the two groups, the beta-cell glucose sensitivity obtained by modelling analysis was lower in fGDM (108 +/- 14 vs. 165 +/- 22 pmol min(-1) m(-2) mM(-1), P = 0.031).. Impairment of beta-cell glucose sensitivity may be an intrinsic risk factor in fGDM independently of obesity and hyperglycaemia. Furthermore, we have shown that modelling analysis, in contrast to the empirical parameters, may be able to detect early beta-cell alterations in fGDM women.

Topics: Adult; Blood Glucose; C-Peptide; Diabetes, Gestational; Dose-Response Relationship, Drug; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Islets of Langerhans; Models, Biological; Pregnancy; Thinness

Circulating adiponectin (ADP) level in diabetic patients was mainly studied from a viewpoint of insulin action, with little being known about the regulation by pancreatic beta-cell function. We thus investigated the relationship between the serum ADP concentration and pancreatic beta-cell function in non-obese [body mass index (BMI) <30 kg/m(2)] diabetic patients. Serum ADP was measured in 239 type 2 diabetic patients, 61 type 1 diabetic patients and 159 non-obese and non-diabetic subjects with enzyme-linked immunosorbent assay. Serum ADP was analyzed separately by gender. In both males and females, the ADP level increased in conjugation with beta-cell dysfunction, estimated by fasting serum C-peptide, and showed marked increase in type 1 diabetic patients. Multivariate analysis in type 2 diabetic patients showed that the fasting serum C-peptide was extracted as an independent and significantly negative modulator for serum ADP in addition to BMI. The ADP level was not associated with the daily dose of injected insulin in the multivariate analysis using insulin treated patients with types 1 and 2 diabetes. These results indicate that pancreatic beta-cell function is one of a significant negative modulator for the circulating ADP level in non-obese diabetic patients and support the presence of an adipoinsular axis.

Topics: Adiponectin; Adiposity; Blood Glucose; Body Mass Index; C-Peptide; Diabetes Mellitus; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Fasting; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin-Secreting Cells; Male; Obesity; Regression Analysis; Sex Characteristics; Statistics as Topic

We examined whether insulin-resistant lipodystrophic HIV-infected patients with known high fasting prehepatic insulin secretion rates (FISRs) displayed alterations in first-phase prehepatic insulin response to intravenous glucose (ISREG0-10 min).. Eighteen normoglycaemic lipodystrophic HIV-infected (LIPO) patients and 25 normoglycaemic nonlipodystrophic HIV-infected patients (controls) were included in the study. The prehepatic insulin secretion rate was estimated by deconvolution of C-peptide concentrations, and insulin sensitivity (SIRd) was estimated by the glucose clamp technique. The disposition index (Di=ISREG0-10 min x SIRd) was calculated to estimate the beta-cell response relative to insulin sensitivity.. FISR was increased by 69% (P<0.001), whereas median Di was decreased by 75% (P<0.01), primarily as a result of a reduction of SI(Rd) by 60% (P<0.001) in LIPO patients compared with controls. Three LIPO groups were identified arbitrarily according to their FISR and ISREG0-10 min values relative to those of controls. Four LIPO patients displayed high FISR [+3 standard deviations (SD), P<0.001], high ISREG0-10 min (+3 SD, P<0.001) and low SIRd (P<0.01), suggesting an intact B-cell capacity to compensate insulin resistance; six LIPO patients exhibited high FISR (+3SD, P<0.001), low ISREG0-10min (-1 SD, P=0.01), and low SIRd (P<0.01), suggesting depletion of readily releasable insulin stores; the remaining eight LIPO patients and controls displayed identical FISR and ISREG0-10 min. Increased concentrations of the nonglucose insulin secretagogues triglyceride (+124%), alanine (+35%) and glucagon (+88%), and also lactate (+96%) and tumour necrosis factor (TNF)-alpha (+62%) were observed in the 10 LIPO patients with aberrations in FISR and ISREG0-10 min compared with the remaining HIV-infected patients (all P<0.05).. Plasma triglyceride, alanine, glucagon, lactate and TNF-alpha may be associated with alterations in the first-phase prehepatic insulin secretion response to intravenous glucose in normoglycaemic lipodystrophic HIV-infected patients.

Topics: Adult; Alanine; C-Peptide; Case-Control Studies; Glucagon; Glucose; Glucose Clamp Technique; HIV-1; HIV-Associated Lipodystrophy Syndrome; Humans; Infusions, Intravenous; Insulin; Insulin Resistance; Insulin Secretion; Insulin-Secreting Cells; Lactates; Male; Middle Aged; Stimulation, Chemical; Triglycerides; Tumor Necrosis Factor-alpha

Low birth weight is associated with insulin resistance and type 2 diabetes in adults. The fetal programming hypothesis has shown that insulin resistance and its associated metabolic disturbances result from a poor gestational environment, for which low birth weight is a surrogate. An at-home questionnaire survey was performed on 660 middle school students (12-15 years) in Seoul, Korea, and 152 cases were randomly selected based on their birth weight. Subjects were divided into three groups according to birth weight. We recorded their birth weight and measured their current anthropometric data, blood pressure, lipid profile, HOMA-IR, and HOMA-beta, and compared these parameters among the groups. The relation of birth weight to physiological characteristics in adolescence was examined. Systolic blood pressure, lipid profiles, and fasting plasma glucose, HOMA-beta were not significantly different among the groups, but diastolic blood pressure was lower in the third tertile. Insulin, C-peptide, and HOMA-IR were higher in the lower birth weight tertile. After adjustment for confounding factors, birth weight was inversely related to diastolic blood pressure, insulin, C-peptide, and HOMA-IR. We conclude that low birth weight may predict the risk of the insulin resistance and its progression over age, and that adequate gestational nutrition is therefore necessary to prevent low birth weight.

Topics: Adolescent; Birth Weight; Blood Pressure; C-Peptide; Child; Female; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Insulin-Secreting Cells; Korea; Male

The purpose of this study was to explore the initial pathogenic mechanisms of diabetes associated with hepatitis C virus (HCV) infection.. Insulin resistance, proinflammatory cytokines, and beta-cell function were evaluated in a case-control study. A total of 28 consecutive nondiabetic patients with chronic hepatitis C were included in the study (anti-HCV+). Fourteen patients with chronic hepatitis other than HCV infection served as the control group (anti-HCV-). Both groups were closely matched by the main clinical variables associated with insulin resistance and the degree of liver fibrosis. In addition, there were no differences between groups regarding hepatic insulin extraction measured by calculating the ratio between C-peptide and insulin. Serum levels of proinflammatory cytokines (tumor necrosis factor [TNF]-alpha, soluble TNF receptor [sTNFR] 1, soluble TNFR2, and interleukin-6) were measured by enzyme-linked immunosorbent assay. Insulin resistance (homeostasis model assessment [HOMA] of insulin resistance [HOMA-IR]) and insulin secretion at baseline (HOMA-beta) and after various stimulus (oral glucose tolerance test, standard food intake, and intravenous glucagon) were determined by previously validated mathematic indexes.. HOMA-IR was higher in anti-HCV+ than in anti-HCV- patients (4.35 +/- 2.27 vs. 2.58 +/- 1.74; P = 0.01). All the proinflammatory cytokines analyzed were significantly higher in anti-HCV+ patients than in anti-HCV- patients. In addition, sTNFR1 and sTNFR2 were directly correlated to HOMA-IR. HOMA-beta as well as insulin and C-peptide responses after the intravenous glucagon test were significantly higher in anti-HCV+ patients than in anti-HC- patients.. Insulin resistance mediated by proinflammatory cytokines, but not a deficit in insulin secretion, could be the primary pathogenic mechanism involved in the development of diabetes associated with HCV infection.

Topics: Adult; Area Under Curve; C-Peptide; Case-Control Studies; Cytokines; Female; Hepatitis C, Chronic; Humans; Inflammation; Insulin; Insulin Resistance; Insulin Secretion; Male; Middle Aged; Receptors, Tumor Necrosis Factor, Type I; Receptors, Tumor Necrosis Factor, Type II

We recently reported that, in contrast to the standard GH (SGH) replacement dose titrated to normalize serum IGF-I levels, 12-month treatment with a fixed low GH dose (LGH) (0.1 mg/day) decreased fasting glucose levels and improved insulin sensitivity with little effect on body composition in severely GH-deficient adults. In this study, we have subsequently examined the effects after 6 months of discontinuation of these variable GH doses (LGH: n = 8; fixed dose 0.10 mg/day and SGH: n = 8; mean dose 0.50 mg/day) on glucose metabolism, body composition and other surrogate cardiovascular risk markers.. Fasting insulin sensitivity using the homeostasis model assessment, and body composition using dual-energy X-ray absorptiometry scans were assessed at baseline, after 12 months of therapy (month 12) and after 6 months following discontinuation of therapy (month 18).. At month 12, the LGH decreased fasting glucose levels and improved insulin sensitivity without altering body composition, whereas the SGH improved body composition without modifying insulin sensitivity. Six months after discontinuation of the LGH treatment (month 18), fasting glucose levels remained decreased and the enhanced insulin sensitivity persisted. In contrast, after discontinuation of SGH treatment (month 18), body composition reverted to baseline without changes in either fasting glucose levels or insulin sensitivity. CONCLUSION In contrast to the SGH, the LGH induces effects on fasting glucose levels and insulin sensitivity, which persist after 6 months of discontinuation of therapy. The exact molecular mechanisms are unclear but may involve the modulation of hepatic and muscle insulin sensitivity, possibly by altering insulin and IGF-I receptor responsiveness and/or density.

Topics: Adult; Analysis of Variance; Blood Glucose; C-Peptide; Drug Administration Schedule; Fasting; Fatty Acids, Nonesterified; Female; Follow-Up Studies; Growth Hormone; Hormone Replacement Therapy; Human Growth Hormone; Humans; Insulin; Insulin Resistance; Insulin-Like Growth Factor Binding Protein 1; Insulin-Like Growth Factor Binding Protein 3; Insulin-Like Growth Factor I; Insulin-Like Growth Factor II; Male; Middle Aged; Time Factors; Withholding Treatment

We aimed to investigate whether the insulin precursors, intact (IP) and 32-33 split proinsulin (SP), which are elevated in states of insulin resistance and predict type 2 diabetes, would be elevated in human immunodeficiency virus (HIV)-infected patients with lipodystrophy (LIPO).. Forty-three normoglycaemic HIV-infected patients [18 LIPO and 18 without lipodystrophy (NONLIPO) receiving antiretroviral drugs, and seven patients naïve to antiretroviral drugs (NAIVE)] were examined. Insulin precursors were measured during fasting, during an intravenous glucose tolerance test and during a hyperinsulinaemic-euglycaemic clamp, respectively. Insulin secretion rates (ISR) were determined by deconvolution of C-peptide concentrations. Disposition index (DI) was calculated as insulin sensitivity (Si(RD)) multiplied by the first-phase insulin response to intravenous glucose.. LIPO exhibited increased fasting IP and SP (P < 0.05), a higher proportion of elevated fasting IP (3.1 pmol L(-1), 66% vs. 33% and 28%, P < 0.05) and SP (7.2 pmol L(-1), 50%, 11% and 0%, P < 0.01), reduced Si(RD) (> 50%, P < 0.001) and increased ISR (P < 0.001) compared with NONLIPO and NAIVE. Fasting SP and IP correlated positively with ISR (P < 0.001) and inversely and hyperbolically with Si(RD) (P < 0.001). Fasting SP/insulin ratio correlated inversely with Si(RD) (P < 0.05). Incremental IP + SP/insulin ratio after an intravenous glucose bolus correlated inversely with DI (P < 0.01), but did not differ between study groups.. Proinsulin appeared to be increased in HIV-lipodystrophy, but no more than caused by the increased ISR. Nevertheless, the inverse correlations between SP/insulin ratio versus Si(RD) and incremental total proinsulin/insulin ratio versus DI may argue for a subtle beta-cell dysfunction in those patients with insulin resistance and low DI.

Topics: Adult; Antiretroviral Therapy, Highly Active; Blood Glucose; Body Composition; C-Peptide; Fasting; Glucose Tolerance Test; HIV Infections; HIV-1; HIV-Associated Lipodystrophy Syndrome; Humans; Hyperlipidemias; Insulin; Insulin Resistance; Male; Middle Aged; Proinsulin

Neuronal apoptosis has been demonstrated to be a significant factor in neurological deficiencies associated with diabetes, and these deficiencies are exaggerated following ischemia. Diabetic rats have an increased basal level of apoptosis compared to non-diabetics and it has been previously demonstrated that infarct volumes were greater in diabetic animals following middle cerebral artery occlusion (MCAO) when compared to non-diabetics. In this study, we evaluated both the acute and chronic effects of insulin and/or C-peptide on CNS necrosis and apoptosis in non-diabetic and streptozotocin-induced diabetic rats following MCAO with reperfusion. Two brain areas, the sensori-motor cortex (layers-5 and 6) and the CA1 and CA3 sectors (pyramidal cell layers) of the hippocampus, were analyzed for apoptosis using TUNEL and Caspase-3 immunoreactivity. The chronic administration of a low maintenance concentration of insulin (2 U/kg), or the acute administration of insulin (2 U/kg) with or without C-peptide, did not alter the lesion volume or basal levels of apoptosis or the apoptotic levels in animals subjected to 2-h MCAO followed by 24-h reperfusion. However, both the acute or chronic administration of a high concentration of insulin (12 U/kg) significantly decreased lesion volume and apoptosis subsequent to 2-h MCAO followed by 24-h reperfusion. High dose insulin treatment also decreased the basal level of apoptosis. We conclude that in diabetic rats subjected to ischemia and reperfusion chronic insulin treatment decreased the basal apoptotic level, and both acute and chronic insulin decreased the MCAO-induced lesion volume and apoptosis. Maintenance insulin concentrations with or without C-peptide were without effect.

Topics: Animals; Apoptosis; Blood Glucose; Brain Ischemia; C-Peptide; Caspase 3; Caspases; Diabetes Mellitus, Experimental; Hypoglycemic Agents; In Situ Nick-End Labeling; Infarction, Middle Cerebral Artery; Insulin; Insulin Resistance; Male; Necrosis; Rats; Rats, Wistar; Reperfusion Injury

The present study was designed to examine the relationship between Pro12Ala polymorphism of the peroxisome proliferator-activated receptor-gamma gene (PPAR-gamma) and clinical and hormonal characteristics in women with polycystic ovary syndrome (PCOS).. One hundred patients with PCOS and 100 healthy subjects were included in the study. Serum levels of sex steroids were measured. Insulin resistance was evaluated by homeostasis model assessment (HOMA). The responses of glucose and insulin to an oral glucose tolerance test were analyzed by calculating the respective area under the curve (AUC) by the trapezoidal method. We used the restriction fragment length polymorphism technique and polymerase chain reaction to examine Pro12Ala polymorphism in exon 2 of PPAR-gamma.. Pro12Ala polymorphism of PPAR-gamma was significantly elevated in control subjects (22%) compared with PCOS subjects (15%). All of the Pro12Ala polymorphisms of PPAR-gamma were heterozygous. When PCOS subjects with the Pro allele and the Ala allele of PPAR-gamma were compared, the latter had lower free testosterone, androstenedione, dehydroepiandrosterone sulfate, insulin and C-peptide levels, as well as lower luteinizing hormone/follicle-stimulating hormone ratio, HOMA insulin resistance index, AUCinsulin, Ferriman-Gallwey score, acne, body mass index and waist-to-hip ratio.. We suggest that Pro12Ala polymorphism of the PPAR-gamma gene may be a modifier of insulin resistance in women with PCOS.

Topics: Adult; Alanine; Androstenedione; Blood Glucose; C-Peptide; Dehydroepiandrosterone Sulfate; Female; Follicle Stimulating Hormone; Glucose Tolerance Test; Heterozygote; Homeostasis; Humans; Insulin; Insulin Resistance; Luteinizing Hormone; Polycystic Ovary Syndrome; Polymerase Chain Reaction; Polymorphism, Genetic; Polymorphism, Restriction Fragment Length; PPAR gamma; Proline; Testosterone

This study compared the effects of endogenous (portal) insulin secretion versus peripheral insulin administration with subcutaneous or inhaled human insulin [INH; Exubera, insulin human (rDNA origin) inhalation powder] on glucose disposal in fasted dogs. In the control group, glucose was infused into the portal vein (Endo; n = 6). In two other groups, glucose was infused portally, whereas insulin was administered peripherally by inhalation (n = 13) or s.c. injection (n = 6) with somatostatin and basal glucagon. In the Endo group, over the first 3 h, the arterial insulin concentration was twice that of the peripheral groups, whereas hepatic sinusoidal insulin levels were half as much. Although net hepatic glucose uptake was greatest in the Endo group, the peripheral groups demonstrated larger increases in nonhepatic glucose uptake so that total glucose disposal was greater in the latter groups. Compared with s.c. insulin action, glucose excursions were smaller and shorter, and insulin action was at least twice as great after INH. Thus, at the glucose dose and insulin levels chosen, peripheral insulin delivery was associated with greater whole-body glucose disposal than endogenous (portal) insulin secretion. INH administration resulted in increased insulin sensitivity in nonhepatic but not in hepatic tissues compared with s.c. delivery.

Topics: Administration, Inhalation; Animals; Area Under Curve; Blood Glucose; C-Peptide; Data Interpretation, Statistical; Dogs; Hypoglycemic Agents; Injections, Subcutaneous; Insulin; Insulin Resistance; Male

Metabolic syndrome (MetS) defines cardiovascular disease (CVD) risks. Despite higher rates of obesity, type 2 diabetes, and hypertension, African Americans have lower rates of MetS when compared to Caucasians, which is paradoxical, since African Americans are more insulin resistant and have higher rates of cardiovascular morbidity and mortality when compared to White Americans. We hypothesized that genetic inheritance predisposes African Americans to the greater cardiovascular risk and the associated morbidity and mortality. Therefore, we investigated the prevalence of components of MetS in obese, glucose-tolerant, first degree relatives of African American patients with type 2 diabetes.. We examined the clinical and metabolic characteristics of 201 first-degree relatives (159 females and 42 males, mean age 41 +/- 8 years, and mean body mass index (BMI) of 32 +/- 8 (kg/m2). The subjects were categorized with MetS according to the Adult Treatment Panel (ATP) III criteria. Insulin sensitivity (Bergman minimal model method) and insulin resistance (homeostasis model assessment [HOMA]) were determined. We compared the clinical and metabolic characteristics in the relatives with and without MetS. Where appropriate, we compared the prevalence of the components of MetS in our African American sample with those of African American data in the National Health and Nutrition Evaluation Survey (NHANES) III.. Comparing the MetS group (n=65) vs control subjects (n=136), the mean age, BMI, and percent body fat were greater in the MetS group. Mean fasting serum glucose, insulin and C-peptide levels were also greater in the MetS group. Insulin resistance index (HOMA-IR) was higher in the MetS group (HOMA-IR: 3.7 +/- 2.7 vs 2.2 +/- 1.7, P=.0002). Mean insulin sensitivity tended to be lower in the MetS group (2.16 +/- 2.64 vs 2.82 +/- 2.31, P=.08). In addition, despite the moderately severe insulin resistance, the MetS group had very low serum triglyceride levels and was the parameter least likely to meet the ATP criteria. The metabolic cutoff points for ATP III criteria were much lower in African American first-degree relatives with MetS. Of the five components of the ATP III criteria, waist circumference was the single most common parameter to likely meet the MetS criteria. We found that the prevalence of MetS was 29% in women and 40% in men when compared with 20.9% in African American women and 13.9% for African American men in the NHANES III.. We found that: 1) the prevalence of MetS is higher in a subgroup of African Americans who were first-degree relatives of patients with type 2 diabetes than that of African Americans in the NHANES III; and 2) waist circumference rather than metabolic parameters was the single most important parameter and was more likely to meet the MetS criteria in African American relatives.

Topics: Adult; Biomarkers; Black or African American; Blood Glucose; Blood Pressure; Body Mass Index; C-Peptide; Case-Control Studies; Cholesterol, HDL; Cholesterol, LDL; Diabetes Mellitus, Type 2; Family; Female; Genetic Predisposition to Disease; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Male; Metabolic Syndrome; Middle Aged; Nutrition Surveys; Obesity; Ohio; Pedigree; Prevalence; Research Design; Severity of Illness Index; Sex Factors; Triglycerides; Waist-Hip Ratio

To observe related factors in the stress hyperglycemia (SHG) of critical illness and to investigate possible pathogenesis of insulin-resistance (IR).. Blood glucose (BG), insulin (INS), C-peptide (C-P), cortisol (Cor), somatostatin (SS), glucagon (Gluc), tumor necrosis factor-alpha (TNF-alpha),soluble tumor necrosis factor receptor I (sTNFRI) and sTNFRII were determined respectively by radioimmunoassay (RIA) or enzyme linked immunoadsorbent assay (ELISA) in 47 SHG patients with critical illness and 15 healthy volunteers serving as normal controls. Their insulin sensitivity index (ISI) was calculated.. (1)Eleven of 47 patients died, while 36 cases survived. Mean acute pathology and chronic health evaluation II (APACHEII) was (13.89+/-6.29) scores within 24 hours after admission to intensive care unit (ICU), mean days of stay in ICU was (5.5+/-6.3) days,and mean duration of mechanical ventilation (MV) was (51.49+/-66.01) hours. (2)The concentrations of INS, ISI, C-P, Cor, Gluc, TNF-alpha, sTNFRI and sTNFRII in 47 SHG patients with critical illness were significantly higher than those in normal controls, except for SS, the differences among groups were significant (P<0.05 or P<0.01). (3)The results of analysis of severity of SHG showed that the more severe SHG was, the higher C-P and INS were, and the less prominent ISI was. (4)Analysis of scores of APACHEII in 47 cases of SHG showed that BG was not increased, but duration of MV, Cor, Gluc, SS, TNF-alpha, sTNFRI and sTNFRII were significantly increased with higher scores of APACHEII. (5)The effect of SHG was significant on MV (F=10.438,P<0.01), but not significant for outcome and days of stay in ICU. (6)The main correlative factors of BG were respectively concentrations of INS (r=0.674, P<0.01), C-P(r=0.552,P<0.01), ISI (r=-0.787, P<0.01), APACHE II(r=0.267,P<0.05) and sTNFRI(r=0.465, P<0.01).. These results show that main reason of SHG in critical illness is IR. There is no strong significant correlation between acute stress hormones and the level of SHG. sTNFRI has an influence on SHG. However, the over release of TNF-alpha and sTNFRII could be the results of seriousness of the critical illness. There is closely correlation between BG and MV, but not with the age, outcome and days of stay in ICU. The strategy of control and therapy of SHG should be alleviation of stress and improve the utilization of BG in the tissue, and increase sensitivity of INS in the tissue.

Topics: Adult; Aged; C-Peptide; Critical Illness; Female; Glucagon; Humans; Hydrocortisone; Hyperglycemia; Insulin; Insulin Resistance; Intensive Care Units; Male; Middle Aged; Stress, Physiological; Tumor Necrosis Factor-alpha; Young Adult

Hormono-metabolic status was assayed before and after month 6, 12, 24, 36, 48, 54 and 60 of therapy in 72 patients with receptor-positive tumors of the breast who completed 5 years of adjuvant tamoxifen (20 mg/24 hrs) or letrozole (2.5 mg/24 hrs). Eleven patients were not followed up, 11 relapsed and had metastases while 50 completed therapy. Significant fall in body mass (Ketle's index), in C-peptide concentration after an insignificant rise and C-peptide/insulin ratio 129 min after glucose loading, low basal blood level of estradiol as well as stable estradiolemia throughout treatment were characteristic of cases of pre-treatment recurrence and metastastic spread. Insulin resistance status, basal serum-estradiol level and fasting its course of development during hormonotherapy should be the subject of further research in criteria for adjuvant hormonotherapy efficacy.

Topics: Aged; Antineoplastic Agents, Hormonal; Biomarkers, Tumor; Breast Neoplasms; C-Peptide; Chemotherapy, Adjuvant; Estradiol; Female; Humans; Insulin; Insulin Resistance; Letrozole; Middle Aged; Nitriles; Receptors, Estrogen; Receptors, Progesterone; Tamoxifen; Time Factors; Triazoles

Normal glucose tolerance is expressed over a wide range of glucose concentrations. Whether there is a continuum of risk for developing type 2 diabetes mellitus even when the 2-h plasma glucose is still within this normal range is uncertain. Oral glucose tolerance tests were performed in 407 obese normal glucose tolerance youth (4-20 yr) to examine the relationship between variations in 2-h plasma glucose levels and beta-cell responsiveness. Individuals were grouped by 2-h plasma glucose levels as follows: 1) less than 100 mg/dl, 2) 100-119 mg/dl, and 3) 120-139 mg/dl. Subsequent analysis stratified each 2-h plasma level by insulin sensitivity index. Increased 2-h glucose level was associated with a progressive increase in glucose between 0 and 30 min (P < 0.05). The Delta (0-30 min) insulin did not vary significantly across levels, thus resulting in a decreased insulinogenic index (P < 0.02). This pattern was observed at every level of insulin sensitivity (P < 0.02). These data translated to an unfavorable (leftward) shift in the insulin feedback system for increasing 2-h glucose level (P < 0.005). Increased 2-h plasma glucose within the range of normal glucose tolerance in obese youth is associated with a specific impairment of beta-cell responsiveness distinct from the deterioration of insulin sensitivity.

Topics: Adolescent; Adult; Blood Glucose; Body Mass Index; C-Peptide; Child; Child, Preschool; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Kinetics; Obesity

To investigate early secretory defects in prediabetes, we evaluated beta-Cell function and insulin sensitivity (M value, by euglycemic clamp) in 26 normotolerant first-degree relatives of type 2 diabetic patients (FDR) and 17 age- and weight-matched control subjects. beta-Cell function was assessed by modeling analysis of glucose and C-peptide concentrations measured during 24 h of standardized living conditions. Fasting and total insulin secretion (ISR) were increased in FDR, as was ISR at a reference 5 mM glucose level (ISR5, 107 +/- 6 vs. 87 +/- 6 pmol x min(-1) x m(-2), P < 0.05). ISR5 was inversely related to M in controls (ISR5 = k/M1.23, rho = -0.74, P < 0.005) but not in FDR; when M was accounted for (by calculating a compensation index ISR5 x M1.23), compensation for insulin resistance was impaired in FDR (10.8 +/- 1.0 vs. 13.4 +/- 0.6 units, P < 0.05). Potentiation of ISR, expressing relative transient increases in glucose-stimulated ISR during meals, was impaired in FDR (1.29 +/- 0.08 vs. 1.62 +/- 0.08 during 1st meal, P < 0.02). Moreover, the potentiation time course was related to glucose-dependent insulin-releasing polypeptide (GIP) concentrations in both groups, and the sensitivity of potentiation to GIP derived from this relationship tended to be impaired in FDR. Compensation index, potentiation, and sensitivity to GIP were interrelated parameters (P < 0.05 or less). beta-Cell function parameters were also related to mean 24-h glucose levels (r2 = 0.63, P < 0.0001, multivariate model). In conclusion, although in absolute terms ISR is increased in insulin-resistant FDR, beta-cell function shows a cluster of interrelated abnormalities involving compensation for insulin resistance, potentiation, and sensitivity to GIP, suggesting a beta-cell defect in the amplifying pathway of insulin secretion.

Topics: Adult; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Diet; Energy Intake; Family; Female; Gastric Inhibitory Polypeptide; Glucagon; Glucagon-Like Peptide 1; Glucose Clamp Technique; Glucose Intolerance; Humans; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Linear Models; Male; Models, Biological; Multivariate Analysis; Peptide Fragments; Protein Precursors

The aim of this study was to investigate the influence of changes in insulin resistance and early insulin secretion on the insulin secretagogic effects of nateglinide.. Oral glucose tolerance testing (OGTT, 75 g) was performed in obese patients before and after weight loss on 2 consecutive days (first day OGTT without nateglinide, second day OGTT with nateglinide), to compare any weight loss associated changes in the nateglinide-induced insulin response to glucose loading.. Reductions in visceral fat, liver fat, skeletal muscle fat and homeostasis model assessment (HOMA)-R due to weight loss were associated with increased Delta insulin 30 min/Delta glucose 30 min (DeltaI30/DeltaG30), and reduced area under the curve (AUC) for plasma glucose as seen in OGTT results. Results from OGTT showed that nateglinide administration was associated with reductions in plasma glucose AUC, both before and after weight loss. Before weight loss, although there was a significant elevation of DeltaI30/DeltaG30 associated with nateglinide treatment, no major change in the insulin-secreting dynamics after glucose loading was observed. After weight loss, nateglinide administration produced a significant increase in DeltaI30/DeltaG30, with insulin secretion peaking more quickly.. Insulin response to nateglinide after glucose loading varied greatly in conjunction with weight loss. This may be accounted for not only by the enhancement of early insulin response to nateglinide associated with the improvement of early insulin response with weight loss but also by the reduced visceral fat, which in turn led to reduced levels of free fatty acids in portal blood and hepatic triglycerides, as well as increased hepatic insulin clearance.

Topics: Adipose Tissue; Administration, Oral; Blood Glucose; C-Peptide; Cyclohexanes; Fatty Acids, Nonesterified; Female; Glucose Tolerance Test; Homeostasis; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Liver; Male; Middle Aged; Muscle, Skeletal; Nateglinide; Obesity; Phenylalanine; Weight Loss

One of the clinical features of myotonic dystrophy is insulin resistance with non-obese diabetes mellitus (DM). Recently, the mechanism of insulin resistance in patients with myotonic dystrophy was revealed. The optimal treatment of DM with myotonic dystrophy has not been established. We report the effect of metformin in a patient with myotonic dystrophy without obesity.. A 58-year-old woman (BMI = 22.1 kg/m2) with myotonic dystrophy and DM was followed at our clinic. She had been treated with glimepiride for DM for the last 6 months, without achieving good control (HbA(1c) 9.3%). She was admitted with congestive heart failure and cholecystitis. She was treated with diuretics, antibiotics and insulin. As her blood glucose fell, we discontinued insulin and started glimepiride, but her glycaemic control had worsened. We started metformin instead of glimepiride. After 4 weeks of metformin, HbA(1c) was decreased to 7.4%, while HOMA-IR during glimepiride treatment was 4.9, and 3.7 with metformin. Three months later, HbA(1c) was maintained (7.5%).. It is important to choose the optimal treatment for DM in myotonic dystrophy, because the patients have hyperinsulinemia caused by specific mechanism and could not reduce the insulin resistance. Metformin improved hyperglycemia through increased insulin-independent glucose uptake in peripheral muscle. We believe metformin is the optimal agent for these patients.

Topics: Blood Glucose; C-Peptide; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Metformin; Middle Aged; Myotonic Dystrophy; Sulfonylurea Compounds

Non-alcoholic fatty liver disease (NAFLD) has been associated with the metabolic syndrome. However, it is not clear whether insulin resistance is an independent feature of NAFLD, and it remains to be determined which of the in vivo actions of insulin are impaired in this condition.. We performed a two-step (1.5 and 6 pmol min(-1) kg(-1)) euglycaemic insulin clamp coupled with tracer infusion ([6,6-2H2]glucose and [2H5]glycerol) and indirect calorimetry in 12 non-obese, normolipidaemic, normotensive, non-diabetic patients with biopsy-proven NAFLD and six control subjects.. In NAFLD patients, endogenous glucose production (basal and during the clamp) was normal; however, peripheral glucose disposal was markedly decreased (by 30% and 45% at the low and high insulin doses, respectively, p<0.0001) at higher plasma insulin levels (p=0.05), due to impaired glucose oxidation (p=0.003) and glycogen synthesis (p<0.001). Compared with control subjects, glycerol appearance and lipid oxidation were significantly increased in NAFLD patients in the basal state, and were suppressed by insulin to a lesser extent (p<0.05-0.001). The lag phase of the in vitro copper-catalysed peroxidation of LDL particles was significantly shorter in the patients than in the control subjects (48+/-12 vs 63+/-13 min, p<0.04). Lipid oxidation was significantly related to endogenous glucose production, glucose disposal, the degree of hepatic steatosis, and LDL oxidisability.. Insulin resistance appears to be an intrinsic defect in NAFLD, with the metabolic pattern observed indicating that adipose tissue is an important site.

Topics: 3-Hydroxybutyric Acid; Adipose Tissue; Adult; Blood Glucose; Body Composition; C-Peptide; Calorimetry, Indirect; Enzymes; Fasting; Fatty Acids, Nonesterified; Fatty Liver; Glucose; Glucose Clamp Technique; Glycerol; Humans; Insulin; Insulin Resistance; Lipid Metabolism; Lipids; Lipoproteins, LDL; Liver; Male; Middle Aged; Oxidation-Reduction

We studied plasma adiponectin, insulin sensitivity, and insulin secretion before and after oral glucose challenge in normal glucose tolerant, impaired glucose tolerant, and type 2 diabetic first degree relatives of African-American patients with type 2 diabetes.. We studied 19 subjects with normal glucose tolerance (NGT), 8 with impaired glucose tolerance (IGT), and 14 with type 2 diabetes. Serum glucose, insulin, C-peptide, and plasma adiponectin levels were measured before and 2 hours after oral glucose tolerance test. Homeostasis model assessment-insulin resistance index (HOMA-IR) and HOMA-beta cell function were calculated in each subject using HOMA. We empirically defined insulin sensitivity as HOMA-IR<2.68 and insulin resistance as HOMA-IR>2.68.. Subjects with IGT and type 2 diabetes were more insulin resistant (as assessed by HOMA-IR) when compared with NGT subjects. Mean plasma fasting adiponectin levels were significantly lower in the type 2 diabetes group when compared with NGT and IGT groups. Plasma adiponectin levels were 2-fold greater (11.09+/-4.98 vs. 6.42+/-3.3811 microg/mL) in insulin-sensitive (HOMA-IR, 1.74+/-0.65) than in insulin-resistant (HOMA-IR, 5.12+/-2.14) NGT subjects. Mean plasma adiponectin levels were significantly lower in the glucose tolerant, insulin-resistant subjects than in the insulin sensitive NGT subjects and were comparable with those of the patients with newly diagnosed type 2 diabetes. We found significant inverse relationships of adiponectin with HOMA-IR (r=-0.502, p=0.046) and with HOMA-beta cell function (r=-0.498, p=0.042) but not with the percentage body fat (r=-0.368, p=0.063), serum glucose, BMI, age, and glycosylated hemoglobin A1C (%A1C).. In summary, we found that plasma adiponectin levels were significantly lower in insulin-resistant, non-diabetic first degree relatives of African-American patients with type 2 diabetes and in those with newly diagnosed type 2 diabetes. We conclude that a decreased plasma adiponectin and insulin resistance coexist in a genetically prone subset of first degree African-American relatives before development of IGT and type 2 diabetes.

Topics: Adiponectin; Black People; Blood Glucose; Blood Pressure; C-Peptide; Cohort Studies; Diabetes Mellitus, Type 2; Family Health; Female; Genetic Predisposition to Disease; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Intercellular Signaling Peptides and Proteins; Male; Middle Aged; Postprandial Period; Risk Factors; Statistics, Nonparametric

As acylation stimulating protein (ASP) acts on adipocytes mainly as a paracrine factor to increase triglyceride synthesis and storage; hypothetically, it may play a similar role in the pathogenesis of nonalcoholic fatty liver disease (NAFLD).. Forty-six male patients with NAFLD (group A), age-matched 30 male patients with chronic viral hepatitis (group B) and 30 age-matched and body mass index (BMI)-matched healthy male subjects were enrolled in the study.. Among the NAFLD patients, 10 patients (24.4%) had simple steatosis and 36 patients (69.6%) had nonalcoholic steatohepatitis (NASH). The mean levels of ASP, complement 3, insulin, C-peptide, HOMA-IR, triglyceride, and very low-density lipoprotein (VLDL) were significantly higher in group A patients than both controls and group B. ASP levels correlated significantly in a positive manner with BMI, insulin, and HOMA-IR.. Dysregulation of the ASP pathway may have important metabolic consequences in NASH and is associated with insulin resistance.

Topics: Adipocytes; Adult; Biopsy, Needle; C-Peptide; Complement C3; Complement C3a; Fatty Liver; Hepatitis B, Chronic; Hepatitis C, Chronic; Humans; Insulin Resistance; Lipoproteins, VLDL; Liver; Liver Cirrhosis; Liver Function Tests; Male; Middle Aged; Reference Values; Statistics as Topic; Triglycerides

Obesity is linked to the insulin resistance syndrome (IRS), type 2 diabetes (T2D) and cardiovascular disease. Markers of chronic subclinical inflammation such as high-sensitive C-reactive protein (hs-CRP) and interleukin 6 (IL-6) are closely related to insulin resistance and obesity. Recent evidence suggests that adiponectin, a protein whose circulating levels are decreased in obesity, has anti-inflammatory properties, and also appears to enhance potently insulin action and therefore appears to function as a signal produced by adipose tissue that influences whole-body glucose metabolism.. We investigated the cross-sectional and longitudinal association of adiponectin with CRP and IL-6 in 41 morbidly obese women with different stages of glucose tolerance before and 17 months after significant weight loss induced by gastric surgery. Adiponectin was measured by RIA. CRP and IL-6 were determined by commercially available ELISA systems.. Weight loss induced a significant shift from T2D (preoperatively 34% vs postoperatively 2%) to impaired glucose tolerance (IGT) (37% preoperatively vs 30% postoperatively) and normal glucose tolerance (NGT) (29% preoperatively vs 68% postoperatively). Preoperatively adiponectin levels were negatively correlated with CRP (r=-0.59, P<0.0006), IL-6 (r=-0.42, P<0.02) and leukocytes (r=-0.41, P<0.007). After gastroplasty, adiponectin concentrations increased significantly (15.4+/-8.2 vs 19.8+/-6.2 microg/ml, P<0.005) associated with changes of weight and body mass index (r=-0.45, P<0.007; r=-0.35, P<0.04). Furthermore, preoperative CRP was significantly associated with changes in adiponectin even after adjustment for sex, age, preoperative body mass index (BMI) impaired glucose metabolism and changes in BMI and changes in BMI (standardized beta 0.61, P=0.005).. Levels of adiponectin, which are associated with markers of chronic subclinical inflammation, could be significantly increased after weight loss in morbidly obese patients. This increase was more pronounced in patients with NGT compared to those with T2D and IGT. Preoperative levels of CRP are predictive for changes of adiponectin after weight loss.

Topics: Adiponectin; Adult; Biomarkers; Blood Glucose; C-Peptide; C-Reactive Protein; Chi-Square Distribution; Cross-Sectional Studies; Female; Gastroplasty; Glycated Hemoglobin; Humans; Inflammation; Insulin; Insulin Resistance; Intercellular Signaling Peptides and Proteins; Interleukin-6; Longitudinal Studies; Middle Aged; Obesity, Morbid; Weight Loss

The profile of insulin secretion and the role of proinsulin processing across the spectrum of glucose tolerance in obese youth have not been studied. The aims of this study were to define the role of insulin secretion and proinsulin processing in glucose regulation in obese youth. We performed hyperglycemic clamps to assess insulin secretion, applying a model of glucose-stimulated insulin secretion to the glucose and C-peptide concentration data. Thirty obese youth with normal glucose tolerance (NGT), 22 with impaired glucose tolerance (IGT), and 10 with type 2 diabetes were studied. The three groups had comparable anthropometric measures and insulin sensitivity. The glucose sensitivity of first-phase secretion showed a significant stepwise decline from NGT to IGT and from IGT to type 2 diabetes. The glucose sensitivity of second-phase secretion was similar in NGT and IGT subjects yet was significantly lower in subjects with type 2 diabetes. Proinsulin-to-insulin ratios were comparable during first- and second-phase secretion between subjects with NGT and IGT and were significantly increased in type 2 diabetes. Obese youth with IGT have a significant defect in first-phase insulin secretion, while a defect in second-phase secretion and proinsulin processing is specific for type 2 diabetes in this age-group.

Topics: Adolescent; Adult; Blood Glucose; C-Peptide; Child; Diabetes Mellitus, Type 2; Female; Humans; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Male; Obesity; Proinsulin

The levels of the liporegulatory hormone leptin are increased in obesity, which contributes to the metabolic syndrome; the latter is associated with elevated cardiovascular risk and morbidity. Leptin may play a role in the metabolic syndrome since correlations have been observed between serum leptin levels and several components of the metabolic syndrome. The association of leptinemia and hypertension or diabetes is inconsistent. Leptin levels are higher in females versus males and obese versus lean individuals. We investigated if correlations exist between leptin levels and several indices of the metabolic syndrome in obese and lean Moroccan subjects with (63 males, 129 females) and without (123 males, 234 females) diabetes and/or hypertension. Plasma glucose and insulin and systolic and diastolic blood pressures were higher in obese versus lean individuals. Obesity had no effect on lipid profile, plasma IGF-1, or C-peptide levels. Leptin levels were higher in females versus males and in obese versus lean individuals. The levels correlated significantly with body mass index. Serum leptin concentration did not correlate with either systolic or diastolic blood pressure, although there was a trend for higher blood pressure with increased leptin levels in females. There was no significant difference in leptin levels between NIDDM patients and healthy controls. However, in hypertensive patients, leptin levels were significantly higher in both lean males and females with diabetes as compared to those without diabetes. Similarly, the higher leptin levels paralleled elevated insulin levels in obese nondiabetic males and females, and in male and female diabetics with hypertension. Correlations were observed between leptin levels and C-peptide (an estimate of endogenous insulin secretion), but not with serum IGF-1. The calculated values of HOMA-IR, a marker of insulin resistance, were somewhat higher, parallel with elevated leptin levels, in obese male and female individuals compared to their lean counterparts. There was no relationship between leptin levels and serum lipids. There was a trend for increased serum uric acid levels with higher leptin concentrations. Thus, leptinemia is related to some components of metabolic syndrome, and in turn, it may contribute to the syndrome. This study is novel in that relationships were determined between leptin levels and various indices of metaboli syndrome in a large population of the same ethnic/regional background.

Topics: Aged; Blood Glucose; Blood Pressure; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Female; Humans; Hypertension; Insulin; Insulin Resistance; Insulin-Like Growth Factor I; Leptin; Lipids; Male; Metabolic Syndrome; Middle Aged; Morocco; Obesity; Sex Characteristics; Uric Acid

To determine serum leptin levels in hypertensive disorder of pregnancy.. In this prospective, cross-sectional, case control study, we measured serum leptin levels of 58 hypertensive pregnant women and 54 normal pregnant women. We also did blood and urine analysis for the evaluation of the severity of hypertensive disorder of pregnancy. The patients were followed until after delivery and information about labour was recorded. We analysed the difference and correlation between anthropometric measures, hormonal and biochemical parameters, and serum leptin levels in two groups.. In the study group, serum leptin levels were determined to be higher than the control group. Neonatal birth weight was significantly lower in the hypertensive group. While the serum uric acid, urea, aspartate aminotransferase, fibronectin, and fasting blood glucose levels were found to be higher, serum total protein and albumin levels were significantly lower among the hypertensive pregnant women. Hypertensive pregnant women were more insulin resistant. Serum leptin levels were highly and positively correlated with serum fibronectin, and C peptide levels. A negative significant correlation was observed between maternal serum leptin levels and neonatal birth weight among the pregnant women having the hypertensive disorders.. Serum leptin levels in hypertensive pregnant women appear to be higher. The determination of serum leptin levels may be as important as serum fibronectin and C peptide levels in the management of hypertensive disorder of pregnancy. C peptide and insulin may be due to hyperinsulinemia which leads to increased stimulation of leptin production by fatty tissue. Insulin resistance which appears in late pregnancy is more significant especially in pregnancies complicated by preeclampsia.

Topics: Birth Weight; Body Mass Index; C-Peptide; Cross-Sectional Studies; Female; Fibronectins; Humans; Hypertension, Pregnancy-Induced; Insulin Resistance; Leptin; Logistic Models; Pregnancy; Prospective Studies; Proteinuria; Skinfold Thickness

Ovarian enlargement is a constant feature of syndromes of extreme insulin resistance. The objective of this study is to show the role of insulin on ovarian growth in the presence of low gonadotropin levels.. Seven young patients with syndromes of extreme insulin resistance (five with lipodystrophy, one with Type B syndrome and one with Rabson-Mendenhall syndrome) were studied.. Baseline LH concentrations and luteinizing hormone releasing hormone (LHRH) tests were performed. Total testosterone, insulin and C-peptide values were measured. Pelvic ultrasounds were performed.. Four patients were prepubertal (age range 7-10 years old) and had prepubertal gonadotropin levels, and 2 of the 4 who were tested did not respond to LHRH (NIH 10 and RM-PAL). Three patients were Tanner stage 4 (age range 13-17 years old) and had low gonadotropins that did not respond to LHRH stimulation test. All seven patients had marked hyperinsulinaemia and 6 of 7 had at least one enlarged ovary. Testosterone values were increased in 4 of 7 patients.. This represents the first example of the pathologic role of insulin to stimulate ovarian growth with low circulating gonadotropins. Thus, while ovarian growth and steroidogenesis are normally stimulated by gonadotropins at puberty, hyperinsulinaemia stimulates pathologic growth of the ovary and an androgenic steroid profile that is active at all ages. We suggest that these patients constitute a model to separate the effect of insulin from gonadotropin in stimulating ovarian growth and/or steroidogenesis.

Topics: Adolescent; C-Peptide; Child; Female; Gonadotropin-Releasing Hormone; Gonadotropins; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Leptin; Lipodystrophy; Luteinizing Hormone; Ovary; Puberty; Testosterone; Ultrasonography

To compare the degree of insulin resistance in women with gestational diabetes mellitus (GDM) who do and do not develop preeclampsia.. We conducted a prospective cohort study of initially normotensive women with GDM who underwent oral glucose tolerance tests (OGTTs), intravenous glucose tolerance tests (IVGTTs), and glucose clamp studies in the early third trimester (n = 150) and 15 months postpartum (n = 89). After delivery, the women were categorized as nonpreeclamptic or preeclamptic (systolic blood pressure [SBP] > or = 140 mmHg, diastolic blood pressure [DBP] > or = 90 mmHg, and at least >1+ proteinuria or >300 mg/24 h). Metabolic parameters between the groups were compared by chi2 or Fisher's exact tests and ANOVA with P < 0.05 as significant.. A total of 29 women (19%) developed preeclampsia, which was mild in 21 and severe in 8 women. At entry, there were no differences in age, weight indexes, and glycemic measures between the nonpreeclamptic and preeclamptic groups. Those with preeclampsia were significantly taller (61.5 +/- 2.4 vs. 60.1 +/- 2.3 in, P = 0.003), were more often nulliparous (38 vs. 16%, P = 0.01), and had higher entry SBP (112 +/- 10 vs. 103 +/- 6.9 mmHg, P < 0.0001) and DBP (64 +/- 9 vs. 59 +/- 5 mmHg, P = 0.002). No significant differences between the groups were found in any measures of the OGTT glucose levels, insulin sensitivity index, glucose effectiveness, acute response to glucose, or disposition index, nor were there any differences found in the euglycemic clamp measures of basal or steady-state levels of glucose, insulin, free fatty acid, hepatic glucose output, peripheral glucose clearance, C-peptide, or glucagon. At 15 months postpartum, blood pressure levels remained significantly higher in the preeclamptic group (n = 19) compared with the nonpreeclamptic group (n = 70). No differences in any glycemic or insulin resistance measures were found.. Women with GDM were uniformly insulin resistant. Those who developed preeclampsia, when compared with those who remained nonpreeclamptic, were not more insulin resistant in either the third trimester or 15 months postpartum. However, women who developed preeclampsia had blood pressure levels that were significantly higher, although still in the normal range, than those of women who remained nonpreeclamptic.

Topics: Adult; Blood Glucose; C-Peptide; Cohort Studies; Diabetes, Gestational; Fatty Acids, Nonesterified; Female; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Longitudinal Studies; Parity; Postpartum Period; Pre-Eclampsia; Pregnancy

Insulin hypersecretion and insulin resistance are physiologically linked features of obesity. We tested whether extreme hypersecretion impairs beta-cell function under free-living conditions and whether major weight loss modifies insulin hypersecretion, insulin sensitivity, and beta-cell function. Plasma glucose, C-peptide, and free fatty acid concentrations were measured at hourly intervals during 24 h of normal life (including calorie-standardized meals) in 20 morbidly obese nondiabetic patients (BMI 48.4 +/- 1.7 kg/m2) and 7 nonobese age- and sex-matched control subjects; 8 of the obese patients were restudied 6 months and 2 years following biliopancreatic diversion. Insulin secretion was reconstructed from C-peptide levels by deconvolution and related to concurrent glucose levels through a mathematical model incorporating key features of beta-cell function: rate sensitivity, beta-cell glucose sensitivity, and potentiation. Insulin sensitivity (by the euglycemic insulin clamp technique) was reduced by 50% in obese subjects (23.1 +/- 2.5 of obese subjects vs. 52.9 +/- 4.9 micromol.min(-1) . kg(FFM)(-1) of control subjects, means +/- SE, P = 0.0004) as was mean 24-h insulin clearance (median 809 [interquartile range 451] vs. 1,553 [520] ml.min(-1) . m(-2), P < 0.001) due to a 50% reduction in hepatic insulin extraction (P < 0.01). Over 24 h, insulin secretion was doubled in obese subjects (468 nmol [202] in obese subjects vs. 235 [85] of control subjects, P=0.0002). Despite the hypersecretion, beta-cell glucose sensitivity, rate sensitivity, and potentiation were similar in obese and control subjects. Six months postoperatively (weight loss = 33 +/- 3 kg), both insulin hypersecretion (282 nmol [213]) and insulin sensitivity (51.6 +/- 3.7 micromol.min(-1).kg(FFM)(-1)) were normalized. At 2 years (weight loss = 50 +/- 8 kg), insulin sensitivity was supernormal (68.7 +/- 3.3 micromol.min(-1).kg(FFM)(-1)) and insulin secretion was lower than normal (167 nmol [37]) (both P < 0.05 vs. control subjects). In conclusion, severe uncomplicated obesity is characterized by gross insulin hypersecretion and insulin resistance, but the dynamic aspects of beta-cell function are intact. Malabsorptive bariatric surgery corrects both the insulin hypersecretion and the insulin resistance at a time when BMI is still high. With continued weight loss over a 2-year period, moderately obese subjects become supersensitive to insulin and, correspondingly, insulin hyposecretors.

Topics: Adult; Biliopancreatic Diversion; Blood Glucose; Body Mass Index; C-Peptide; Fatty Acids, Nonesterified; Female; Glucose Clamp Technique; Humans; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Male; Obesity, Morbid; Weight Loss

Compensatory hyperinsulinemia permitting insulin-resistant individuals to maintain normal glucose tolerance is associated with a left shift in the glucose-stimulated insulin secretion rate (GS-ISR) dose-response curve and decrease in the insulin metabolic clearance rate (I-MCR). To see whether these changes would reverse with improvement in insulin sensitivity, 14 nondiabetic insulin-resistant subjects received rosiglitazone for 12 weeks (4 mg daily for 4 weeks and then 8 mg daily for 8 weeks). Insulin-mediated glucose uptake was quantified by measuring the steady-state plasma glucose concentration during the insulin suppression test. GS-ISR and I-MCR were determined during a 240-min graded intravenous glucose infusion. I-MCR was also calculated during the insulin suppression test. After rosiglitazone treatment, insulin sensitivity improved with significant fall in steady-state plasma glucose (means +/- SE from 13.5 +/- 0.62 to 9.8 +/- 1.02 mmol/l, P < 0.001). In response, the integrated GS-ISR decreased by 21% (P < 0.001), with a right shift in the dose-response curve. Calculated I-MCR increased by 34% (P = 0.008) during the insulin suppression test and by 21% (P = 0.03) during the graded glucose infusion. In conclusion, enhanced insulin sensitivity in rosiglitazone-treated nondiabetic insulin-resistant individuals was associated with a shift to the right in the GS-ISR dose-response curve and an increase in I-MCR.

Topics: Adult; Blood Glucose; Body Mass Index; C-Peptide; Female; Glucose; Glucose Tolerance Test; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Male; Metabolic Clearance Rate; Middle Aged; Obesity; Rosiglitazone; Thiazolidinediones

The aim of this study was to assess the implications of insulin resistance on the clinical and biochemical profiles of Korean type 2 diabetic patients. 122 patients with type 2 diabetes underwent a short insulin tolerance test to assess insulin resistance. Subjects were classified in tertiles according to ISI (insulin sensitivity index), and the tertile I (the insulin- resistant group) and tertile III (the insulin-sensitive group) clinical and biochemical parameters were compared. Age, waist circumference (WC), systolic blood pressure (SBP), HbA1c, body fat content, and fasting plasma glucose were significantly higher in tertile I than tertile III (all p < 0.05). The frequency of hypertension and family history of cerebrovascular disease (CVD) were greater in tertile I than III (p < 0.05). To evaluate the factors affecting ISI, multiple regression was performed, and age, WC, SBP, HbA1c, and body fat content were found to be independently related to insulin resistance (p < 0.05). Old age, hypertension, central obesity, and poor glycemic control were identified as clinical parameters of insulin resistance in Korean type 2 diabetic patients.

Topics: Adult; Aged; Blood Glucose; C-Peptide; Cholesterol, HDL; Diabetes Mellitus, Type 2; Female; Glycated Hemoglobin; Humans; Insulin Resistance; Male; Middle Aged

We examined insulin sensitivity and secretion, together with the levels of selected glucoregulatory hormones, in 15 female patients with severe hypothyroidism (H) and during subsequent thyroid hormone replacement therapy (HRT) using the euglycaemic hyperinsulinaemic clamp technique. Insulin action, as evaluated by glucose disposal, the insulin sensitivity index, and fasting post-hepatic insulin delivery rate were established. The basal levels of insulin, C-peptide and counter-regulatory hormones were measured in basal condition. In H, glucose disposal (p<0.01), the insulin sensitivity index (p<0.01) and post-hepatic insulin delivery rate (p<0.05) were significantly lower than during HRT. No significant changes in the levels of fasting insulin and C-peptide were observed. The levels of counter-regulatory hormones in patients with H were significantly higher than during HRT (glucagon, p<0.05; epinephrine, p<0.01; cortisol, p<0.05; growth hormone, p<0.05). In H, an inverse correlation between insulin sensitivity and insulin secretion was observed (p<0.05). Cortisol was the most important factor affecting the variability of insulin sensitivity values, regardless of thyroid function (p=0.0012). In conclusion, H altered both insulin sensitivity and the levels of selected counter-regulatory hormones. The situation was restored by HRT, as manifested not only by normalisation of insulin sensitivity, secretion and levels of glucoregulatory hormones, but also by improvement of their relationships.

Topics: Adult; Blood Glucose; C-Peptide; Epinephrine; Female; Glucagon; Glucose Clamp Technique; Hormones; Human Growth Hormone; Humans; Hydrocortisone; Hypothyroidism; Insulin; Insulin Resistance; Insulin Secretion; Thyroid Hormones

Excessive secretion of the insulin precursor proinsulin, as manifested by an increased serum proinsulin-to-insulin ratio, has been associated with beta-cell dysfunction. In women with gestational diabetes mellitus (GDM), previous studies of the proinsulin-to-insulin ratio have yielded conflicting results, despite the presence of beta-cell dysfunction. The interpretation of the proinsulin-to-insulin ratio, however, may be confounded by the variable effects of hepatic insulin extraction. Thus, we sought to determine whether GDM is characterized by relative hyperproinsulinemia as measured by the proinsulin-to-C-peptide ratio, an alternate measure of proinsulin secretion that is not affected by hepatic insulin extraction.. Serum proinsulin, C-peptide, and insulin were measured in a cross-sectional study of 180 women undergoing oral glucose tolerance tests (OGTTs) in the late second or early third trimester. Based on the OGTT, participants were stratified into three groups: 1) normal glucose tolerance (NGT; n = 93), 2) impaired glucose tolerance (IGT; n = 39), and 3) GDM (n = 48). Insulin sensitivity (IS) was measured using the IS(OGTT) index of Matsuda and DeFronzo, which has been previously validated in pregnant women.. There were no significant differences in mean fasting proinsulin-to-C-peptide ratio between the three glucose tolerance groups (NGT, 0.024; IGT, 0.022; GDM, 0.019; P = 0.4). Furthermore, adjustment for age, weeks' gestation, prepregnancy BMI, ethnicity, previous GDM, and family history of diabetes did not reveal any association between the proinsulin-to-C-peptide ratio and glucose tolerance status. Using Spearman univariate correlation analysis, fasting proinsulin-to-C-peptide ratio was significantly correlated with IS(OGTT) (r = 0.29, P < 0.0001) and inversely related to the homeostasis model assessment of insulin resistance (r = -0.36, P < 0.0001) and prepregnancy BMI (r = -0.23, P < 0.005). On multiple linear regression analysis, IS(OGTT) emerged as the strongest independent correlate of the dependent variable proinsulin-to-C-peptide ratio. Furthermore, after adjustment for potential covariates, a stepwise decrease in proinsulin-to-C-peptide ratio was observed per decreasing tertile of IS(OGTT) (trend P = 0.0019), consistent with enhanced efficiency of proinsulin processing (i.e., reduced proinsulin-to-C-peptide ratio) as insulin resistance increases.. GDM is not independently associated with hyperproinsulinemia as measured by the proinsulin-to-C-peptide ratio. Instead, in pregnant women, increased insulin resistance is associated with decreased proinsulin-to-C-peptide ratio, independently of glucose tolerance status. These data suggest that relative proinsulin secretion in late pregnancy is primarily related to insulin resistance and does not necessarily reflect beta-cell function.

Topics: Adult; Area Under Curve; Blood Glucose; C-Peptide; Cross-Sectional Studies; Diabetes, Gestational; Fasting; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Pregnancy; Pregnancy Trimester, Second; Pregnancy Trimester, Third; Proinsulin

To characterize the features of type 2 diabetes mellitus among children and adolescents in Al-Ain, the records of every child with diabetes attending a teaching hospital in the city from January 1990 to December 2001 were retrospectively examined. Of 96 young people newly diagnosed with diabetes mellitus, 11 were identified as type 2. The clinical characteristics were: pubertal onset, female preponderance, obesity, strong family history of type 2 diabetes mellitus, high plasma glucose at presentation, adequate beta cell reserve and serum pancreatic islet cell antibody negativity. This case series adds to the evidence that type 2 diabetes mellitus is emerging among children in our region.

Topics: Adolescent; Age of Onset; Blood Glucose; C-Peptide; Child; Diabetes Mellitus, Type 2; Epidemiologic Studies; Fasting; Female; Hospitals, Teaching; Hospitals, Urban; Humans; Insulin; Insulin Resistance; Islets of Langerhans; Male; Obesity; Pedigree; Puberty; Retrospective Studies; Risk Factors; Sex Distribution; United Arab Emirates

Increased levels of C-peptide, a cleavage product of proinsulin, circulate in patients with insulin resistance and early type 2 diabetes, a high-risk population for the development of a diffuse and extensive pattern of arteriosclerosis. This study tested the hypothesis that C-peptide might participate in atherogenesis in these patients.. We demonstrate significantly higher intimal C-peptide deposition in thoracic aorta specimens from young diabetic subjects compared with matched nondiabetic controls as determined by immunohistochemical staining. C-peptide colocalized with monocytes/macrophages in the arterial intima of artery specimen from diabetic subjects. In vitro, C-peptide stimulated monocyte chemotaxis in a concentration-dependent manner with a maximal 2.3+/-0.4-fold increase at 1 nmol/L C-peptide. Pertussis toxin, wortmannin, and LY294002 inhibited C-peptide-induced monocyte chemotaxis, suggesting the involvement of pertussis toxin-sensitive G-proteins as well as a phosphoinositide 3-kinase (PI3K)-dependent mechanism. In addition, C-peptide treatment activated PI3K in human monocytes, as demonstrated by PI3K activity assays.. C-peptide accumulated in the vessel wall in early atherogenesis in diabetic subjects and may promote monocyte migration into developing lesions. These data support the hypothesis that C-peptide may play an active role in atherogenesis in diabetic patients and suggest a new mechanism for accelerated arterial disease in diabetes.

Topics: Adolescent; Adult; Androstadienes; Aorta, Thoracic; Aortic Diseases; Arteriosclerosis; C-Peptide; Cells, Cultured; Chemotaxis; Chromones; Diabetes Mellitus, Type 2; Disease Progression; Enzyme Inhibitors; Female; GTP-Binding Proteins; Humans; Hyperinsulinism; Insulin Resistance; Macrophages; Male; Metabolic Syndrome; Models, Biological; Monocytes; Morpholines; Pertussis Toxin; Phosphatidylinositol 3-Kinases; Wortmannin

We evaluated insulin release and insulin sensitivity in women with basal and/or postprandial hyperglycemia but normal oral glucose tolerance test (OGTT) in previous pregnancy (GHG). These women were individually matched with females without previous hyperglycemia (NGT). Both groups consisted of normal glucose-tolerant women at the time of this study. They underwent OGTT (75 g; n=32 pairs) and hyperglycemic clamp experiments (10 mmoll(-1); n=27 pairs) with plasma glucose, insulin, and C-peptide measurements and calculation of insulinogenic index, first- and second-phase insulin release, and insulin sensitivity index (ISI). The GHG group showed higher glycosylated hemoglobin levels (6.2+/-0.6% versus 5.8+/-0.8%; P<0.05); lower insulinogenic index at 30 min (134.03+/-62.69 pmol mmol(-1) versus 181.59+/-70.26 pmol mmoll(-1); P<0.05) and diminished C-peptide response in relation to glucose (4.05+/-0.36 nmol mmol(-1) versus 4.23+/-0.36 nmol mmol(-1); P<0.05) at OGTT. Both groups did not show difference in insulin secretion and ISI by hyperglycemic clamp technique. We concluded that in up to 12 years from index pregnancy, women with previous GHG, presenting normal glucose tolerance and well-matched with their controls, showed beta-cell dysfunction without change in ISI. As women with previous GHG are at risk of type 2 diabetes, beta-cell dysfunction may be its primary defect.

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Food; Glucose Clamp Technique; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Hyperglycemia; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Pregnancy; Risk Factors

To evaluate the effect of massive weight loss on insulin sensitivity, soluble adhesion molecules, and markers of the insulin resistance syndrome (IRS).. Eighteen morbidly obese patients underwent gastric banding and were evaluated before and 6 and 12 months after surgery. Total insulin secretion, hepatic insulin extraction, and insulin sensitivity were analyzed by oral glucose-tolerance test model analysis. In addition, soluble intercellular adhesion molecule-1, vascular cell adhesion molecule-1, E-selectin, leptin, high-sensitivity C-reactive protein, plasminogen activating factor-1 (PAI-1), and tissue plasminogen activator were measured.. BMI dropped from 45.22 +/- 5.62 to 36.99 +/- 4.34 kg/m(2) after 6 months and 33.72 +/- 5.55 kg/m(2) after 12 months (both p < 0.0001). This intervention resulted in a significant reduction of blood pressure (p < 0.00001), triglycerides (p < 0.01), fasting blood glucose (p = 0.03), basal insulin (p < 0.001), and basal C-peptide (p = 0.008) levels. Total insulin secretion decreased (p < 0.05), whereas hepatic insulin extraction (p < 0.05) and oral glucose insulin sensitivity index (p < 0.0001) increased compared with baseline. Leptin (p < 0.0001) and E-selectin levels decreased significantly after 6 and 12 months (p = 0.05), whereas significantly lower levels of intercellular adhesion molecule-1 and PAI-1 were only seen after 6 months. Subclinical inflammation, measured by high-sensitivity C-reactive protein, was lowered to normal ranges. No changes were observed in vascular cell adhesion molecule-1 and tissue plasminogen activator levels.. Although gastric banding ameliorates several features of the IRS, including 29.05% improvement in insulin sensitivity and blood pressure and reduction of soluble adhesion molecules and PAI-1, considerable weight loss did not normalize all components of the IRS in morbidly obese patients.

Topics: Adult; Arteriosclerosis; C-Peptide; Cell Adhesion Molecules; E-Selectin; Female; Glucose Tolerance Test; Humans; Hypertension; Insulin; Insulin Resistance; Intercellular Adhesion Molecule-1; Leptin; Male; Obesity, Morbid; Plasminogen Activators; Stomach; Vascular Cell Adhesion Molecule-1; Weight Loss

Many extremely preterm infants develop hyperglycemia in the first week of life during continuous glucose infusion. The objective of this study was to determine whether defective insulin secretion or resistance to insulin was the primary factor involved in transient hyperglycemia of extremely preterm infants.. A prospective comparative study was conducted in appropriate-for-gestational-age preterm infants <30 weeks of gestational age with the aim specifically to evaluate the serum levels of proinsulin, insulin, and C-peptide secreted during transient hyperglycemia by specific immunoassays. Three groups of infants were investigated hyperglycemic (n = 15) and normoglycemic preterm neonates (n = 12) and normal, term neonates (n = 21). In addition, the changes in beta-cell peptide levels were analyzed during and after intravenous insulin infusion in the hyperglycemic group. Data were analyzed using analysis of variance and analysis of variance for repeated measures.. At inclusion, insulin and C-peptide levels did not differ in hyperglycemic subjects and in preterm controls. Proinsulin concentration was significantly higher in the hyperglycemic group (36.5 +/- 3.9 vs 23.2 +/- 0.9 pmol/L). Compared with term neonates, proinsulin and C-peptide levels were higher in normoglycemic preterm infants (23.2 +/- 0.9 vs 18.9 +/- 2.71 pmol/L and 1.67 +/- 0.3 vs 0.62 +/- 0.12 nmol/L, respectively). During and after insulin infusion in hyperglycemic neonates, plasma glucose concentration fell and proinsulin and C-peptide levels were lowered (18.4 +/- 7.6 and 20.7 +/- 4.5 pmol/L, respectively).. These data suggest that 1) preterm neonates are sensitive to changes in plasma glucose concentration, but proinsulin processing to insulin is partially defective in hyperglycemic preterm neonates; 2) hyperglycemic neonates are relatively resistant to insulin because higher insulin levels are needed to achieve euglycemia in this group compared with normoglycemic neonates. These results also show that insulin infusion is beneficial in extremely preterm infants with transient hyperglycemia.

Topics: Blood Glucose; C-Peptide; Female; Humans; Hyperglycemia; Infant, Newborn; Infant, Premature; Infant, Premature, Diseases; Insulin; Insulin Resistance; Islets of Langerhans; Male; Proinsulin; Prospective Studies

Hyperinsulinemia and insulin resistance are commonly observed in essential hypertension, which is part of the metabolic syndrome. The aim of this study was to examine whether insulin secretion abnormalities or alterations in insulin sensitivity and glucose tolerance are also present in healthy men, offspring of patients with essential hypertension. Twelve young (27 +/- 3.6 years), lean normotensive offspring were compared with 14 age-, sex-, and body mass index (BMI)-matched controls without a family history of hypertension, diabetes mellitus, and coronary heart disease. We studied glucose tolerance, insulin secretion, and sensitivity using 10-hour hyperglycemic and 10-hour hyperinsulinemic-euglycemic clamps (HIC). Glucose tolerance was comparable in the offspring and controls. However, the offspring had higher insulin and C-peptide levels during the hyperglycemic clamp (HGC) compared with controls (P <.05). There was no difference in the early phase of insulin secretion between the groups. The insulin sensitivity index (glucose infusion rate/serum insulin) was significantly lower in the offspring during both clamps. Moreover, the offspring had higher systolic (P <.001) and diastolic (P <.001) blood pressure and had higher serum cholesterol (P <.01) and triglyceride (P <.05) levels. Apparently healthy, young, lean individuals with a genetic predisposition to essential hypertension and with normal glucose tolerance had higher insulin secretion and lower insulin sensitivity than controls. These abnormalities, together with higher blood pressure and altered lipid metabolism, may play a role in the development of hypertension and an increased risk of cardiovascular morbidity and mortality in these individuals.

Topics: Adult; C-Peptide; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Hypertension; Insulin; Insulin Resistance; Insulin Secretion; Male; Parents; Statistics as Topic

The incidence of type 2 diabetes mellitus (DM2) in children has increased worldwide and is commonly associated with overweight. Forty-four children with DM2 were studied by clinical histories, anthropometric measurements, and biochemical analysis. Homeostasis model assessment (HOMA-IR) and quantitative insulin sensitivity check index (QUICKI) were determined to evaluate insulin resistance. Only five patients presented normal body mass index (BMI); the remainder were overweight, and 76% had acanthosis nigricans. Laboratory results yielded hyperglycemia, elevated glycosylated hemoglobin, insulin and C-peptide. Elevated HOMA-IR and decreased QUICKI values suggest insulin resistance. No significant difference was found between sexes, although overweight in girls had more influence over blood pressure and lipid levels (p <0.05). Time from diagnosis and HOMA-IR yielded relevant values (p = 0.010). Laboratory results, QUICKI, and HOMA-IR values suggested that these patients present DM2 and decreased insulin sensitivity. We recommend prevention of overweight and sedentary life-style.

Topics: Acanthosis Nigricans; Adolescent; Blood Glucose; Blood Pressure; Body Mass Index; Body Weight; C-Peptide; Child; Diabetes Mellitus, Type 2; Female; Homeostasis; Humans; Insulin; Insulin Resistance; Lipids; Male; Mexico; Sex Factors

Colorectal cancer and type 2 diabetes share many risk factors, and hyperinsulinemia appears to be associated with an increased risk of colorectal cancer. We used the concentration of plasma C-peptide (an indicator of insulin production) to determine whether insulin and insulin resistance are associated with the risk of developing colorectal cancer.. We conducted a nested case-control study in the Physicians' Health Study. Plasma samples were collected from 14 916 cancer-free men from August 1982 through December 1984. Plasma C-peptide concentration, measured with an enzyme-linked immunosorbent assay, was available for 176 case patients who developed incident colorectal cancer through December 31, 1995, and 294 age- and smoking status-matched control subjects. Information on four other insulin resistance-related factors at baseline was obtained. We used conditional logistic regression models to investigate associations. All statistical tests were two-sided.. Plasma C-peptide concentration was positively associated with age, body mass index (BMI), and number of insulin resistance-related factors, and it was inversely associated with fasting time before the blood draw, alcohol consumption, and vigorous exercise. An increased concentration of plasma C-peptide was statistically significantly associated with an increased risk of colorectal cancer (relative risk [RR] for the highest versus lowest quintile of plasma C-peptide = 2.7, 95% confidence interval [CI] = 1.2 to 6.2; P(trend) =.047), after adjusting for age, smoking status, fasting, BMI, alcohol consumption, vigorous exercise, and aspirin assignment in the Physicians' Health Study. The association became even stronger when the analysis was further adjusted for factors related to insulin resistance other than insulin levels (RR for the highest versus lowest quintile = 3.4, 95% CI = 1.4 to 8.3; P(trend) =.02) or when data from case patients who were diagnosed during the first 5 years of follow-up were excluded (RR for the highest versus the lowest quintile = 3.4, 95% CI = 1.3 to 8.8; P(trend) =.03). Adjusting for plasma levels of insulin-like growth factor I (IGF-I) and its binding protein 3 (IGFBP-3) did not materially change the results. There was no apparent modification of risk by BMI, insulin resistance-related factors, or vigorous exercise.. Elevated insulin production, as reflected by elevated concentrations of plasma C-peptide, may predict the risk of developing colorectal cancer, independently of BMI, factors related to insulin resistance, or levels of IGF-I and IGFBP-3.

Topics: Adult; Aged; Aged, 80 and over; Biomarkers, Tumor; Body Mass Index; Boston; C-Peptide; Case-Control Studies; Cluster Analysis; Colorectal Neoplasms; Enzyme-Linked Immunosorbent Assay; Humans; Insulin; Insulin Resistance; Insulin-Like Growth Factor Binding Protein 3; Insulin-Like Growth Factor I; Logistic Models; Male; Middle Aged; Physicians; Predictive Value of Tests; Prospective Studies; Randomized Controlled Trials as Topic; Risk Assessment; Risk Factors; United States

Offspring of diabetic or hypertensive patients are insulin resistant at a prediabetic/prehypertensive stage. We tested the hypothesis that insulin action may be impaired in the offspring of obese nondiabetic parents.. Twenty-one lean offspring of nonobese subjects [(OL) 22 +/- 3 years of age] were matched to 23 lean offspring of obese subjects (OOb) by gender distribution, age, BMI, and waist circumference. Anthropometry, oral glucose tolerance, in vivo insulin sensitivity [by a euglycemic insulin clamp (6 pmol/min per kilogram(FFM); where FFM represents fat-free mass)], and thermogenesis (by indirect calorimetry) were measured in each subject. The study subjects were from a population of 267 nuclear families (one offspring and both his/her parents) in which there was statistically significant (chi2 = 30.2, p = 0.001) concordance of BMI between parents and offspring.. In comparing OOb with OL, no statistically significant difference or trend toward a difference was detected in fasting plasma glucose and insulin concentrations, glucose and insulin responses to oral glucose, insulin sensitivity [metabolism value = 45 +/- 12 (OOb) vs. 47 +/- 17 micro mol/min per kilogram(FFM) (OL)], insulin-induced inhibition of protein and lipid oxidation, stimulation of glucose oxidation and nonoxidative glucose disposal, respiratory quotient, resting energy expenditure, and glucose-induced thermogenesis.. The metabolic similarity between lean offspring of obese parents and those of nonobese parents suggests that insulin resistance and its correlates are not co-inherited with the predisposition to develop obesity.

Topics: Adult; Blood Glucose; Body Composition; Body Constitution; Body Mass Index; C-Peptide; Female; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Male; Obesity; Parents

Subjects with impaired glucose tolerance (IGT) are usually overweight and exhibit insulin resistance with a defective compensation of insulin secretion. In this study, we sought to establish the interrelation between insulin secretion and insulin sensitivity after oral glucose in non-obese subjects with IGT and we also examined this interrelation in relation to the 2 main incretins, glucagon-like peptide (GLP-1) and gastric inhibitory polypeptide (GIP). To that end, 13 women with IGT and 17 women with normal glucose tolerance (NGT) underwent an oral glucose tolerance test (OGTT) with measurements of glucose, insulin, C-peptide, GLP-1, and GIP. Insulin secretion (TIS) and insulin sensitivity (OGIS) were assessed using models describing the relationship between glucose, insulin and C-peptide data. These models allowed estimation also of the hepatic extraction of insulin. The age (54.2 +/- 9.7 [mean +/- SD] years) and body mass index (BMI; 26.0 +/- 4.0 kg/m(2)) did not differ between the groups. Subjects with IGT displayed lower TIS during the initial 30 minutes after oral glucose (0.97 +/- 0.17 [mean +/- SEM] v 1.75 +/- 0.23 nmol/L in NGT; P =.018) and lower OGIS (397 +/- 21 v 463 +/- 12 mL/min/m(2); P =.005). The incremental 30-minute TIS times OGIS (reflecting insulin secretion in relation to insulin sensitivity) was significantly reduced in IGT (359 +/- 51 v 774 +/- 91 nmol/min/m(2), P =.001). This measure correlated inversely to the 2-hour glucose level (r = -0.71; P <.001). In contrast, TIS over the whole 180-minute period was higher in IGT (26.2 +/- 2.4 v 20.0 +/- 2.0 nmol/L; P =.035). Hepatic insulin extraction correlated linearly with OGIS (r = 0.71; P <.001), but was not significantly different between the groups although there was a trend with lower extraction in IGT (P =.055). Plasma levels of GLP-1 and GIP increased after oral glucose. Total secretion of these incretin hormones during the 3-hour test did not differ between the 2 groups. However, the 30-minute increase in GLP-1 concentrations was lower in IGT than in NGT (P =.036). We conclude that also in non-obese subjects with IGT, when adiposity is controlled for in relation to NGT, defective early insulin secretion after oral glucose is a key factor. This defective beta-cell function is associated with, and may be caused by, a reduced early GLP-1 response.

Topics: Administration, Oral; Area Under Curve; Blood Glucose; Body Weight; C-Peptide; Case-Control Studies; Female; Gastric Inhibitory Polypeptide; Glucagon; Glucagon-Like Peptide 1; Glucose; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Liver; Middle Aged; Peptide Fragments; Protein Precursors; Regression Analysis; Time Factors

The hormones adiponectin and resistin have been associated with insulin resistance. This paper analyzed the potential relationship between adiponectin and resistin and insulin resistance-related phenotypes in baboons.. One hundred eight adult baboons (84 female and 24 male) were studied. Weight was measured, and a blood sample was collected under fasting conditions for plasma and monocyte isolation. Fasting glucose, insulin, C-peptide, and adiponectin levels in plasma were measured by standard methods. Insulin resistance was calculated by the homeostasis model assessment index. Resistin mRNA abundance in monocytes was determined by real-time quantitative reverse transcription-polymerase chain reaction. Data were clustered by weight tertiles for statistical analysis.. As observed in humans, the insulin resistance-related phenotypes were related to weight, plasma levels of adiponectin, and C-peptide. No significant relationship between resistin circulating levels or expression in monocytes and insulin resistance-related phenotypes was found in baboons.. These findings suggest that resistin is not associated with insulin resistance. However, previous observations of relationships among weight, adiponectin, and insulin resistance are confirmed.

Topics: Adiponectin; Animals; Blood Glucose; C-Peptide; Fasting; Female; Gene Expression; Homeostasis; Hormones, Ectopic; Insulin; Insulin Resistance; Intercellular Signaling Peptides and Proteins; Male; Monocytes; Papio; Phenotype; Proteins; Resistin; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger

Diabetes mellitus (DM) is frequently observed in patients with chronic hepatitis caused by hepatitis C virus infection (CHC). The present study was designed to determine the pathogenic factors responsible for glucose intolerance in CHC patients.. A total of 131 patients with CHC were enrolled in this study. Insulin resistance and beta-cell function were determined after 75 g oral glucose tolerance tests.. Glucose intolerance was detected in 27.5% (36/131) of CHC patients; 10 had DM and 26 impaired glucose tolerance. HOMA-R [insulin 0xglucose 0/22.5] was greater in patients with both impaired glucose tolerance and DM than in those with normal glucose tolerance (P<0.01). Matsuda index [10(4)/ (square root) (mean insulinxmean glucosexglucose 0xinsulin 0)] was lower in diabetic patients than in those with normal glucose tolerance (P<0.05). The insulinogenic index [Deltainsulin 30-0/Deltaglucose 30-0] and DeltaC-peptide 30 [DeltaC-peptide 30-0/Deltaglucose 30-0] were significantly lower even in patients with impaired glucose tolerance than in patients with normal glucose tolerance (P<0.01).. Both insulin resistance and beta-cell dysfunction contribute to glucose intolerance in CHC patients.

Topics: Adult; C-Peptide; Female; Glucose Intolerance; Glucose Tolerance Test; Hepatitis C, Chronic; Humans; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Liver Cirrhosis; Male; Middle Aged; Prevalence

It has been shown that short-term exercise training improves insulin resistance parameters in patients with ischaemic heart disease. The effects of such a rehabilitation programme in patients with hypertension have not been well established.. To assess whether short-term endurance training after coronary artery bypass grafting (CABG) may improve metabolic parameters and reduce blood pressure in patients with hypertension.. The study group consisted of 30 male patients (15 with hypertension and 15 normotensive) aged 55+/-2.1 years who underwent CABG 1 to 6 months before the initiation of a 3-week endurance training. Glucose, insulin and C-peptide blood levels as well as binding and degradation of 125I-insulin by erythrocyte receptors were assessed before and after the training programme. The effects of training on blood pressure values were also evaluated.. A significant improvement (p<0.01) in the insulin resistance parameters, i.e. binding and degradation of labelled insulin was noted only in patients with hypertension. This was accompanied by a significant (p<0.05) increase in the HDL-cholesterol level. In the subgroup with hypertension, both the exercise systolic and diastolic pressures decreased significantly (p<0.05 and p<0.01, respectively), and similar changes were noted in the resting systolic and diastolic blood pressures values (p<0.05).. Rehabilitation after CABG based on the endurance training was especially effective in patients with hypertension in whom beneficial changes in some metabolic risk factors of ischaemic heart disease as well as the reduction in the blood pressure values were observed.

Topics: Adult; Aged; Blood Glucose; C-Peptide; Case-Control Studies; Coronary Artery Bypass; Erythrocytes; Humans; Hypertension; Insulin; Insulin Resistance; Iodine Radioisotopes; Male; Middle Aged; Physical Endurance; Time Factors; Treatment Outcome

An oral glucose tolerance test (O-GTT) was conducted in 96 non-obese healthy children (7 to approximately 11 years old) and adolescents (12 to approximately 16 years old) to obtain the index of insulin resistance from the insulin (IRI) and C-peptide (CPR) values of fasting. 2-hour postload conditions and the sigma values, and the homeostasis model assessment ratio (HOMA-R) by assuming the value of the mean + 2SD to be the upper limit of the normal value for each clinical variable. The results show that the adolescents, whose insulin resistance is thought to increase, showed higher IRI and CPR values of the 2-hour postload condition and sigma values compared to those of the children, but there were no differences between the 2 age groups in the values of the fasting condition, as well as in the HOMA-R values which were calculated from the fasting values. These findings indicate that there is a limitation in using fasting values to judge insulin resistance. Instead, using the 2-hour postload values and/or the sigma values is more appropriate.

Topics: Adolescent; C-Peptide; Child; Female; Glucose Tolerance Test; Homeostasis; Humans; Insulin Resistance; Male

The strong relation between type 2 diabetes mellitus and obesity with acanthosis nigricans is widely concerned. This study investigated the pancreatic beta-cell function in obese children with acanthosis nigricans, so as to find out the role of insulin secretion and insulin resistance in obese children with acanthosis nigricans.. Thirty-five obese children with acanthosis nigricans (19 males and 16 females with mean age 12.8 +/- 1.5 years) were enrolled in this study. Thirty-eight obese children (21 boys and 17 girls with mean age 11.9 +/- 2.6 years) and 39 normal children (20 boys and 19 girls with mean age 11.2 +/- 2.2 years) were recruited as obese and normal control groups. The levels of serum fasting insulin, C-peptide, proinsulin and true insulin were measured in all the subjects. The ratios of proinsulin/insulin and proinsulin/C-peptide were calculated. Homeostasis model assessment was applied to assess the status of insulin resistance and basic function of pancreatic beta-cell.. The levels of fasting insulin, C-peptide proinsulin, true insulin, the ratios of proinsulin/insulin and proinsulin/C-peptide, insulin resistance index and insulin secretion index of obese children with acanthosis nigricans, obese control children and normal control children were: 18.5 (5.0-60.5) pmol/L, 12.4 (6.1-35.8) pmol/L and 5.1 (2.0-32.8) pmol/L; 3.9 (1.3-14.0) microg/L, 2.4 (1.1-4.0) microg/L and 1.1 (1.0-4.2) microg/L; 28.8 (9.9-64.2) pmol/L, 9.5 (2.2-34.5) pmol/L and 4.2 (2.0-16.0) pmol/L; 33.0 (6.2-66.0) pmol/L, 10.6 (4.8-29.4) pmol/L and 4.5 (1.3-30.1) pmol/L; 1.2 (0.4-8.9), 0.9 (0.2-1.9) and 0.8 (0.4-2.0); 6.9 (2.5-36.6), 4.7 (1.2-12.3) and 3.6 (1.2-9.6); 5.0 (0.8-14.1), 2.6 (1.3-8.1) and 1.2(0.4-6.9); 303.3 (52.2-1,163.8), 213.6 (84.6-572.0) and 51.1 (19.1-561.4). The levels of fasting insulin, C-peptide, proinsulin, true insulin, the ratios of proinsulin/insulin and proinsulin/C-peptide, insulin resistance index and insulin secretion index in obese children with acanthosis nigricans were significantly higher than those in obese children (P < 0.001) and normal children (P < 0.001).. Obese children with acanthosis nigricans had higher insulin resistance and pancreatic beta-cell dysfunction; acanthosis nigricans may be a skin sign of high risk of type 2 diabetes mellitus.

Topics: Acanthosis Nigricans; Adolescent; C-Peptide; Child; Diabetes Mellitus, Type 2; Female; Humans; Insulin; Insulin Resistance; Islets of Langerhans; Male; Obesity; Proinsulin

To describe the clinical, biochemical and immunological characteristics of young-onset diabetes in Asia.. Clinical, biochemical and immunological variables were assessed in 919 newly diagnosed (duration less than 12 months) young onset Asian diabetic patients aged between 12 and 40 years. The subjects constituted 57% Chinese, 29% Indians and 14% Malays, recruited from diabetes centres in China, Hong Kong, India, Malaysia and Singapore.. The mean age (+/- sd) was 31.6 +/- 7.2 years, with the majority (66%) in the 31-40 years age group. Mean body mass index (BMI) (+/- sd) was 25.3 +/- 5.0 kg/m2 with 47% exceeding the suggested Asian cut-off point for obesity (BMI > or = 25). Ethnic difference in clinical characteristics included BMI, blood pressure, mode of treatment and degree of insulin resistance. Most patients had a clinical presentation of Type 2 diabetes. About 10% had a classical combination of ketotic presentation, presence of autoimmune-markers and documented insulin deficiency indicative of Type 1 diabetes. Forty-eight percent were receiving oral hypoglycaemic agents (OHAs) while 31% were on diet only, 18% were receiving insulin and 2% were on a combination of insulin and OHA.. Young onset diabetes patients in Asia represent a heterogeneous group in terms of their clinical and biochemical characteristics and classical Type 1 diabetes is relatively uncommon. The 5-year follow up study will determine the progress of these patients and help to clarify the natural history.

Topics: Administration, Oral; Adolescent; Adult; Blood Glucose; Blood Pressure; Body Mass Index; C-Peptide; Child; China; Diabetes Mellitus; Diabetes Mellitus, Type 2; Family Health; Female; Glycated Hemoglobin; Hong Kong; Humans; Hypoglycemic Agents; India; Insulin Resistance; Malaysia; Male; Singapore

To compare brain perfusion in hypertensive patients with diabetes mellitus type 2 (DM2) or metabolic (MS) syndrome and hypertensive patients without clinicobiochemical signs of DM2 or MS; to study enoxaparin effects on brain perfusion in DM2 and arterial hypertension (AH).. Seventy patients included in the study were divided into three groups: 30 patients with DM2 and AH (group 1), 30 patients with MS and AH (group 2) and 10 AH patients without manifestations of MS or DM2 (group 3). All the patients have undergone single-photon emission computed tomography (SPECT) of the brain, carbohydrate and lipid metabolism were examined.. Deterioration of brain perfusion was more prominent in DM2 and MS patients with AH than in hypertensive patients with normal metabolism. Stress test with acetasolamide revealed defective autoregulation of cerebral blood flow in hypertensive patients with DM2. A 6-week therapy with enoxaparin significantly improved brain perfusion in hypertensive patients with DM2.. Enoxaparin treatment of hypertensive DM2 and MS patients with abnormal perfusion of the brain can be used for prevention of cerebrovascular complications.

Topics: Adult; Anticoagulants; Blood Glucose; Blood Pressure; Body Mass Index; Brain; C-Peptide; Cardiovascular Diseases; Cerebrovascular Circulation; Diabetes Mellitus, Type 2; Enoxaparin; Female; Glucose Tolerance Test; Humans; Hypertension; Insulin Resistance; Lipids; Male; Metabolic Syndrome; Postprandial Period; Radionuclide Imaging; Risk

Inadequate compensatory beta cell hyperplasia in insulin-resistant states triggers the development of overt diabetes. The mechanisms that underlie this crucial adaptive response are not fully defined. Here we show that the compensatory islet-growth response to insulin resistance in 2 models--insulin receptor (IR)/IR substrate-1 (IRS-1) double heterozygous mice and liver-specific IR KO (LIRKO) mice--is severely restricted by PDX-1 heterozygosity. Six-month-old IR/IRS-1 and LIRKO mice both showed up to a 10-fold increase in beta cell mass, which involved epithelial-to-mesenchymal transition. In both models, superimposition of PDX-1 haploinsufficiency upon the background of insulin resistance completely abrogated the adaptive islet hyperplastic response, and instead the beta cells showed apoptosis resulting in premature death of the mice. This study shows that, in postdevelopmental states of beta cell growth, PDX-1 is a critical regulator of beta cell replication and is required for the compensatory response to insulin resistance.

Topics: Aging; Animals; Blood Glucose; C-Peptide; Cell Division; Homeodomain Proteins; Hyperplasia; Insulin Receptor Substrate Proteins; Insulin Resistance; Islets of Langerhans; Mice; Mice, Knockout; Phosphoproteins; Trans-Activators

Several of the possible molecular mechanisms that contribute to the insulin resistance associated with burn injury were examined in a rat model of thermal injury. Rats were subjected to full thickness scald injury (25% total body surface area, 10 sec burn) and resuscitated with saline. After 1, 2 and 3 weeks, urinary C-peptide excretion was measured in burned and sham-treated control animals. At 3 weeks after injury, glucose production by the liver and utilization by skeletal muscle was measured under insulin clamp conditions, insulin receptor binding was measured in skeletal muscle, liver and adipose tissue membranes and IRS-1 expression was measured by Western blot methods. Urinary C-peptide excretion was significantly elevated at 1, 2 and 3 weeks after injury. At 3 weeks after injury, several key metabolic processes were blunted, including the ability of insulin infusion to stimulate glucose uptake by skeletal muscle, the potency of insulin infusion for inhibiting hepatic glucose production, and the ability of a bolus injection of insulin to simulate phosphorylation of IRS-1 in liver, skeletal muscle or adipose tissue. In contrast, there were no apparent alterations in the binding of insulin to membranes from liver, skeletal muscle or adipose tissue. These findings support the concept that the burn injury stimulates insulin production 3 weeks after burn injury, and produces insulin resistance in skeletal muscle, adipose tissue and liver by processes that are associated with post-receptor alterations in the absence of changes in insulin receptor binding.

Topics: Adipose Tissue; Animals; Burns; C-Peptide; Glucose; Insulin; Insulin Receptor Substrate Proteins; Insulin Resistance; Liver; Male; Membranes; Muscle, Skeletal; Phosphoproteins; Phosphotyrosine; Rats; Rats, Sprague-Dawley; Receptor, Insulin; Temperature

Circulating C-peptide concentrations are associated with insulin resistance and the development of type 2 diabetes. However, associations between fructose and the quantity and quality of total carbohydrate intake in relation to C-peptide concentrations have not been adequately examined.. We assessed the association of dietary fructose, glycemic load, and carbohydrate intake with fasting C-peptide concentrations.. Plasma C-peptide concentrations were measured in a cross-sectional setting in 1999 healthy women from the Nurses' Health Study I and II. Dietary fructose, glycemic load, and carbohydrate intake were assessed with the use of semiquantitative food-frequency questionnaires.. After multivariate adjustment, subjects in the highest quintile of energy-adjusted fructose intake had 13.9% higher C-peptide concentrations (P for trend = 0.01) than did subjects in the lowest quintile. Similarly, in the multivariate model, subjects in the highest quintile of glycemic load had 14.1% (P for trend = 0.09) and 16.1% (P for trend = 0.04) higher C-peptide concentrations than did subjects in the lowest quintile after further adjustment for total fat or carbohydrate intake, respectively. In contrast, subjects with high intakes of cereal fiber had 15.6% lower (P for trend = 0.03) C-peptide concentrations after control for other covariates.. Our results suggest that high intakes of fructose and high glycemic foods are associated with higher C-peptide concentrations, whereas consumption of carbohydrates high in fiber, such as whole-grain foods, is associated with lower C-peptide concentrations. Furthermore, our study suggests that these nutrients play divergent roles in the development of insulin resistance and type 2 diabetes.

Topics: Adult; Aged; C-Peptide; Cohort Studies; Diabetes Mellitus, Type 2; Dietary Carbohydrates; Dietary Fiber; Dose-Response Relationship, Drug; Fasting; Feeding Behavior; Female; Fructose; Glycemic Index; Humans; Insulin Resistance; Middle Aged; Multivariate Analysis; Nurses; Surveys and Questionnaires

To evaluate the role of insulin resistance in development of postprandial dyslipidemia in type 2 diabetic patients in an experimental setting in which these patients were compared with nondiabetic subjects at similar glucose and insulin blood levels.. Eight type 2 diabetic patients in optimal blood glucose control and 7 control subjects (aged 50.0+/-2.6 and 48.1+/-1.3 years; body mass index 28.3+/-1.2 and 25.6+/-1.1 kg/m2; fasting plasma triglycerides 1.12+/-0.13 and 0.87+/-0.08 mmol/L, respectively; mean+/-SEM; NS) consumed a mixed meal during an 8-hour hyperinsulinemic glycemic clamp. Mean blood glucose during clamp was approximately 7.8 mmol/L, and plasma insulin during the preprandial steady state was approximately 480 pmol/L in both groups, that differed for insulin sensitivity (M/I value lower in diabetic subjects [1.65+/-0.30 and 3.42+/-0.60; P<0.05]). Subjects with diabetes had higher postprandial levels of lipids and apolipoprotein B (apoB) in large very low-density lipoprotein (incremental area for triglycerides 1814+/-421 versus 549+/-153 micromol/Lx6 hours; P<0.05; cholesterol 694+/-167 versus 226+/-41 micromol/Lx6 hours; P<0.05; apoB-48 6.3+/-1.0 versus 2.6+/-0.7 mg/Lx6 hours; P<0.05; apoB-100 56.5+/-14.9 versus 26.2+/-11.0 mg/Lx6 hours; NS). Basal lipoprotein lipase (LPL) activity before and after meal was higher in diabetic subjects, whereas postheparin LPL activity 6 hours after the meal was similar.. Insulin resistance is also associated with postprandial lipoprotein abnormalities in type 2 diabetes after acute correction for hyperglycemia and hyperinsulinemia.

Topics: Apolipoproteins B; Blood Glucose; C-Peptide; Chylomicrons; Diabetes Mellitus, Type 2; Fatty Acids, Nonesterified; Female; Glucose; Humans; Infusions, Intravenous; Insulin; Insulin Resistance; Lipase; Lipids; Lipoprotein Lipase; Lipoproteins; Lipoproteins, HDL; Lipoproteins, IDL; Lipoproteins, LDL; Lipoproteins, VLDL; Male; Middle Aged; Postprandial Period; Triglycerides

The fasting serum lipid profile [triglycerides (TGs), total cholesterol (TC), and LDL- and HDL-cholesterol (LDL-C and HDL-C)] is used to calculate lipid ratios (TC/HDL-C, LDL-C/HDL-C, TG/HDL-C) that allow identification of individuals at increased risk for cardiovascular disease. Because these individuals are also frequently insulin resistant, this study analyzed the relationships between lipid ratios and insulin sensitivity.. In 132 obese [mean (SE) body mass index, 37.5 (0.6) kg/m(2)] outpatients without known diabetes mellitus, fasting serum lipid profiles and 75-g oral glucose tolerance tests were performed. Insulin sensitivity was assessed from surrogate estimates for fasting (QUICKI) and dynamic (OGIS) conditions.. After exclusion of other endocrine diseases (n = 35), the remaining patients were classified as glucose tolerant (n = 56), glucose intolerant (n = 22), or as having type 2 diabetes (n = 19). QUICKI and OGIS indicated severe insulin resistance in all individuals with type 2 diabetes and impaired glucose tolerance compared with glucose-tolerant individuals: QUICKI, glucose tolerant, 0.302 (0.002); glucose intolerant, 0.290 (0.002); type 2 diabetes, 0.281 (0.005); P <0.001; OGIS (mL . m(-2) . min(-1)), glucose tolerant, 343 (7), glucose intolerant, 293 (9); type 2 diabetes, 256 (12); P <0.001. Serum TG (P <0.005) and TG/HDL-C ratios (P <0.05) were increased in individuals with impaired glucose tolerance. TG/HDL-C ratios negatively correlated with QUICKI (r = -0.370; P < 0.001) and OGIS (r = -0.333; P < 0.005) in nondiabetic individuals (glucose tolerant plus glucose intolerant), but not in patients with type 2 diabetes (not significant).. This study demonstrates that the TG/HDL-C ratio positively correlates with insulin resistance in severely obese nondiabetic individuals.

Topics: Adult; C-Peptide; Cholesterol; Cholesterol, HDL; Cholesterol, LDL; Female; Glucose Tolerance Test; Humans; Insulin Resistance; Lipoproteins; Male; Middle Aged; Obesity; Triglycerides

The onset of diabetes and impaired glucose metabolism among schizophrenic patients has been the topic of numerous recently published articles, with research implicating weight gain, the use of antipsychotic medication, history of diabetes mellitus in family members, and the diagnosis of schizophrenia itself as risk factors. Therefore, it was the aim of this study to determine the glucose metabolism parameters in noncompliant unmedicated schizophrenic patients (antipsychotic-free) and first-episode antipsychotic-naive schizophrenic patients to investigate whether there is a preexisting impairment of glucose metabolism in never-medicated schizophrenic patients.. Plasma glucose, insulin, C-peptide, and leptin concentrations were determined in 50 antipsychotic-free and 50 antipsychotic-naive DSM-IV schizophrenia patients and 50 healthy control subjects. Insulin resistance was calculated through the homeostatic model assessment (HOMA). The General Linear Model (univariate) procedure was used to perform analysis of covariance. Patients were recruited from July 2001 to December 2002.. Antipsychotic-free patients showed significantly increased insulin (p = .001) and C-peptide (p = .02) concentrations and a significantly higher degree of insulin resistance (p = .003), as measured with the HOMA index, in comparison with the antipsychotic-naive patients and the control group. Significantly increased leptin concentrations (p = .000) were also noted in the antipsychotic-free patients and were attributed to the effects of body mass index (p = .000) and sex (p = .000).. The results reported in this study suggest the effect of previous antipsychotic treatment on glucose metabolism parameters and weight-related hormones such as leptin, while ruling out a preexisting impairment of glucose metabolism in never-medicated first-episode schizophrenic patients.

Topics: Adolescent; Adult; Aged; Antipsychotic Agents; Blood Glucose; Body Mass Index; C-Peptide; Female; Glucose; Humans; Insulin; Insulin Resistance; Leptin; Male; Middle Aged; Psychiatric Status Rating Scales; Schizophrenia; Treatment Refusal

Previous research has suggested a genetic contribution to the development of insulin resistance and obesity. We hypothesized that the same genes influencing insulin resistance might also contribute to the variation in adiposity.. A total of 601 (200 male, 401 female) adult baboons (Papio hamadryas) from nine families with pedigrees ranging in size from 43 to 121 were used in this study. Plasma insulin, glucose, C-peptide, and adiponectin were analyzed, and homeostasis model assessment of insulin resistance (HOMA IR) was calculated. Fat biopsies were collected from omental fat tissue, and triglyceride concentration per gram of fat tissue was determined. Body weight and length were measured, and BMI was derived. Univariate and bivariate quantitative genetic analyses were performed using SOLAR.. Insulin, glucose, C-peptide, and adiponectin levels, HOMA IR, triglyceride concentration of fat tissue, body weight, and BMI were all found to be significantly heritable, with heritabilities ranging from 0.15 to 0.80. Positive genetic correlations (r(G)s) were observed for HOMA IR with C-peptide (r(G) = 0.88 +/- 0.10, p = 0.01), triglyceride concentration in fat tissue (r(G) = 0.86 +/- 0.33, p = 0.02), weight (r(G) = 0.50 +/- 0.20, p = 0.03), and BMI (r(G) = 0.64 +/- 0.22, p = 0.02).. These results suggest that a set of genes contributing to insulin resistance also influence general and central adiposity phenotypes. Further genetic research in a larger sample size is needed to identify the common genes that constitute the genetic basis for the development of insulin resistance and obesity.

Topics: Adiponectin; Adipose Tissue; Animals; Blood Glucose; Body Composition; C-Peptide; Female; Homeostasis; Insulin; Insulin Resistance; Intercellular Signaling Peptides and Proteins; Male; Omentum; Papio; Triglycerides

To investigate serum concentration of tumor necrosis factor (TNF)-alpha and its correlation with insulin resistance in pregnant women with gestational diabetes mellitus (GDM).. Enzyme-linked immunosorbent assay was used to measure the fasting serum TNF-alpha levels of 42 women with GDM (28 approximately 39 gestational weeks), and 40 cases of normal pregnant women in the third trimester. Fasting plasma glucose, insulin, C-peptide and glycosylated hemoglobin (HbA1c) were also measured at the same time. Insulin sensitive index (ISI) was calculated.. (1) Significantly elevated serum TNF-alpha was found in the women with GDM (5.2 +/- 1.6) ng/L as compared with the healthy pregnant women in third trimester (4.5 +/- 0.5) ng/L (P < 0.01); ISI between the two groups was significantly different, (-4.3 +/- 0.5) and (...3.8 +/- 0.3) (P < 0.01). (2) fasting plasma glucose, insulin, C-peptide, HbA1c in GDM group were (5.5 +/- 0.7) mmol/L, (13.4 +/- 3.8) mU/L, (1.6 +/- 0.4) nmol/L, (5.6 +/- 0.5)%, being significantly higher than those in the normal pregnant women (P < 0.01 or P < 0.05). (3) Significant negative linear correlation was revealed between TNF-alpha and ISI (r = -0.703, P < 0.01), and positive linear correlations between TNF-alpha and plasma glucose, C-peptide, and HbA1c were found (r = 0.512, 0.629, 0.386); but no correlation between TNF-alpha and insulin was found in GDM group. In normal group the correlation between ISI and TNF-alpha was also found (r = -0.390, P < 0.05), but less significant than that in the GDM group.. Fasting plasma TNF-alpha levels in pregnant women with GDM is significantly higher than in normal pregnant women. A negative relationship between TNF-alpha and insulin sensitivity index is found in GDM, suggesting increased TNF-alpha may contribute to insulin resistance in pregnant women with gestational diabetes.

Topics: Adult; Blood Glucose; C-Peptide; Diabetes, Gestational; Fasting; Female; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Pregnancy; Tumor Necrosis Factor-alpha

Obesity and insulin resistance are common features of Type 2 Diabetes. A new protein called resistin has been shown to be secreted by adipocytes in mice and to influence insulin sensitivity. The goal of the present study was to investigate the associations between one polymorphism (g-420C>G) of the human resistin gene and phenotypes related to adiposity and glucose metabolism. We genotyped 725 (including 42 diabetics) adult subjects participating in the Quebec Family Study (QFS) by a minisequencing method. Forty-two were diabetic subjects. Phenotypes measured were: body mass index (BMI) and waist circumference (WC), % body fat (PFAT) and fat mass (FM) assessed by under water weighing, abdominal total, subcutaneous and visceral fat assessed by computed tomography and fasting plasma glucose, insulin and C-peptide and their responses to an oral glucose tolerance test (OGTT). Comparisons between genotypes were performed in non-diabetic men (no.=280) and women (no.=403) separately by analyses of covariance (ANCOVA). Among men, g-420 G homozygotes had less visceral fat (p < 0.05), lower levels of acute insulin responses to an OGTT and lower levels of C-peptide in a fasting state and in responses to an OGTT than carriers of the C allele (p < 0.01). These associations were independent of age and adiposity but were not observed in women. These results suggest that in men, the human resistin gene is associated with reduced amount of visceral obesity and lower insulin secretory responses to a glucose load.

Topics: Abdomen; Adipose Tissue; Adolescent; Adult; Aged; Aged, 80 and over; Blood Glucose; Body Composition; C-Peptide; Cohort Studies; Diabetes Mellitus, Type 2; Female; Genotype; Glucose Tolerance Test; Hormones, Ectopic; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Male; Middle Aged; Obesity; Pedigree; Phenotype; Polymorphism, Genetic; Quebec; Resistin

To investigate the possibility of using C-peptide to replace insulin in homeostasis model assessment (Homa) to evaluate insulin resistance and islet beta cell function.. Oral glucose tolerance test (OGTT) was performed in 21 normal subjects, whose venous blood was drawn before taking glucose and 30, 60, 120 minutes after taking glucose. Insulin and C-peptide were determined with radioimmune assay. Homa indices of insulin resistance and islet beta cell function were calculated. Multiple stepwise linear regression model of insulin resistance was measured using C-peptide x blood glucose as independent variables and Homa-IR was used as the dependent variable, while the model of islet beta cell function was determined using C-peptide/(fasting blood glucose - 3.5) as the independent variable and Homaislet as the dependent variable.. The modified Homa formula were: Homa-IR (CP) = 1.5 + fasting blood glucose x fasting C-peptide/2800 (F = 5. 511, P = 0.029), Homa-islet (CP-Normal) = 0.27 x fasting C-peptide /(fasting blood glucose - 3.5) + 50, and Homa-islet (CP-DM) = 0.27 x fasting C-Peptide/(fasting blood glucose - 3.5) (F = 212.961, P = 0.000), respectively. The modified Homa-IR (CP) and Homa-IR, Homa-islet (CP) and Homa-islet were highly correlated (r =0.689 and r = 0.788; all P = 0.000). Using Homa and modified Homa formula to evaluate the insulin resistance and islet beta cell function both in the normal and diabetic subjects was similar.. Fasting C-peptide can substitute insulin in Homa model to assess insulin resistance and islet beta cell function. The modified homeostasis model assessment may be applied in the diabetics using exogenous insulin.

Topics: Adult; Aged; Blood Glucose; C-Peptide; Diabetes Mellitus; Female; Glucose Tolerance Test; Homeostasis; Humans; Insulin; Insulin Resistance; Islets of Langerhans; Male; Mathematics; Middle Aged

To understand the day-to-day pathophysiology of impaired muscle glycogen storage in type 2 diabetes, glycogen concentrations were measured before and after the consumption of sequential mixed meals (breakfast: 190.5 g carbohydrate, 41.0 g fat, 28.8 g protein, 1253 kcal; lunch: 203.3 g carbohydrate, 48.1 g fat, 44.0 g protein, 1497.5 kcal) by use of natural abundance (13)C magnetic resonance spectroscopy. Subjects with diet-controlled type 2 diabetes (n = 9) and age- and body mass index-matched nondiabetic controls (n = 9) were studied. Mean fasting gastrocnemius glycogen concentration was significantly lower in the diabetic group (57.1 +/- 3.6 vs. 68.9 +/- 4.1 mmol/l; P < 0.05). After the first meal, mean glycogen concentration in the control group rose significantly from basal (97.1 +/- 7.0 mmol/l at 240 min; P = 0.005). After the second meal, the high level of muscle glycogen concentration in the control group was maintained, with a further rise to 108.0 +/- 11.6 mmol/l by 480 min. In the diabetic group, the postprandial rise was markedly lower than that of the control group (65.9 +/- 5.2 mmol/l at 240 min, P < 0.005, and 70.8 +/- 6.7 mmol/l at 480 min, P = 0.01) despite considerably greater serum insulin levels (752.0 +/- 109.0 vs. 372.3 +/- 78.2 pmol/l at 300 min, P = 0.013). This was associated with a significantly greater postprandial hyperglycemia (10.8 +/- 1.3 vs. 5.3 +/- 0.2 mmol/l at 240 min, P < 0.005). Basal muscle glycogen concentration correlated inversely with fasting blood glucose (r = -0.55, P < 0.02) and fasting serum insulin (r = -0.57, P < 0.02). The increment in muscle glycogen correlated with initial increment in serum insulin only in the control group (r = 0.87, P < 0.002). This study quantitates for the first time the subnormal basal muscle glycogen concentration and the inadequate glycogen storage after meals in type 2 diabetes.

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Fatty Acids, Nonesterified; Female; Glycogen; Humans; Insulin; Insulin Resistance; Lactic Acid; Magnetic Resonance Spectroscopy; Male; Middle Aged; Muscle, Skeletal; Postprandial Period; Triglycerides

To investigate the sites of the free fatty acid (FFA) effects to increase basal hepatic glucose production and to impair hepatic insulin action, we performed 2-h and 7-h Intralipid + heparin (IH) and saline infusions in the basal fasting state and during hyperinsulinemic clamps in overnight-fasted rats. We measured endogenous glucose production (EGP), total glucose output (TGO, the flux through glucose-6-phosphatase), glucose cycling (GC, index of flux through glucokinase = TGO - EGP), hepatic glucose 6-phosphate (G-6-P) content, and hepatic glucose-6-phosphatase and glucokinase activities. Plasma FFA levels were elevated about threefold by IH. In the basal state, IH increased TGO, in vivo glucose-6-phosphatase activity (TGO/G-6-P), and EGP (P < 0.001). During the clamp compared with the basal experiments, 2-h insulin infusion increased GC and in vivo glucokinase activity (GC/TGO; P < 0.05) and suppressed EGP (P < 0.05) but failed to significantly affect TGO and in vivo glucose-6-phosphatase activity. IH decreased the ability of insulin to increase GC and in vivo glucokinase activity (P < 0.01), and at 7 h, it also decreased the ability of insulin to suppress EGP (P < 0.001). G-6-P content was comparable in all groups. In vivo glucose-6-phosphatase and glucokinase activities did not correspond to their in vitro activities as determined in liver tissue, suggesting that stable changes in enzyme activity were not responsible for the FFA effects. The data suggest that, in overnight-fasted rats, FFA increased basal EGP and induced hepatic insulin resistance at different sites. 1) FFA increased basal EGP through an increase in TGO and in vivo glucose-6-phosphatase activity, presumably due to a stimulatory allosteric effect of fatty acyl-CoA on glucose-6-phosphatase. 2) FFA induced hepatic insulin resistance (decreased the ability of insulin to suppress EGP) through an impairment of insulin's ability to increase GC and in vivo glucokinase activity, presumably due to an inhibitory allosteric effect of fatty acyl-CoA on glucokinase and/or an impairment in glucokinase translocation.

Topics: Allosteric Regulation; Animals; Blood Glucose; C-Peptide; Enzyme Activation; Fatty Acids, Nonesterified; Female; Glucokinase; Glucose Clamp Technique; Glucose-6-Phosphatase; Glycerol; Insulin; Insulin Resistance; Liver; Rats; Rats, Wistar; Triglycerides

This study examined the relationship of fasting serum glucose, insulin, C-peptide, glycosylated hemoglobin A (HbA1c), and Homeostasis Model Assessment (HOMA)-insulin resistance to risk of chronic kidney disease (CKD) among 6453 persons without diabetes (fasting glucose <126 mg/dl and not taking diabetes medication) who participated in the Third National Health and Nutrition Examination Survey and were aged 20 yr or older. CKD was defined as an estimated GFR <60 ml/min per 1.73 m(2). The prevalence of CKD was significantly and progressively higher with increasing levels of serum insulin, C-peptide, HbA1c, and HOMA-insulin resistance. After adjustment for potential confounding variables, the odds ratio of CKD for the highest compared with the lowest quartile was 4.03 (95% confidence interval [CI], 1.81 to 8.95; P = 0.001), 11.4 (95% CI, 4.07 to 32.1; P < 0.001), 2.67 (95% CI, 1.31 to 5.46; P = 0.002), and 2.65 (95% CI, 1.25 to 5.62; P = 0.008) for serum insulin, C-peptide, HbA1c levels, and HOMA-insulin resistance, respectively. For a one SD higher level of serum insulin (7.14 micro U/ml), C-peptide (0.45 Deltamol/ml), HbA1c (0.52%), and HOMA-insulin resistance (1.93), the odds ratio (95% CI) of CKD was 1.35 (1.16 to 1.57), 2.78 (2.25 to 3.42), 1.69 (1.28 to 2.23), and 1.30 (1.13 to 1.50), respectively. These findings combined with knowledge from previous studies suggest that the insulin resistance and concomitant hyperinsulinemia are presented in CKD patients without clinical diabetes. Further studies into the causality between insulin resistance and CKD are warranted.

Topics: Blood Glucose; C-Peptide; Chronic Disease; Female; Glycated Hemoglobin; Homeostasis; Humans; Insulin; Insulin Resistance; Kidney Diseases; Male; Middle Aged; Nutrition Surveys; Risk Factors; United States

Recent studies have demonstrated that C-peptide exerts beneficial effects on endothelial function. To investigate the relationship between residual pancreatic C-peptide secretion and endothelial function in patients with well controlled or poorly controlled Type II diabetes, we studied 100 patients with Type II diabetes that were free from diabetic neuropathy. In all patients, insulin resistance, residual pancreatic C-peptide secretion, endothelial function and oxidative stress were investigated using the homoeostasis model assessment (HOMA) index, glucagon bolus test, brachial reactivity, Trolox equivalent antioxidant capacity (TEAC) and thiobarbituric acid-reacting substances (TBARS). The patients were categorized into quartiles on the basis of plasma HbA(1c) (glycated haemoglobin) concentration. Analysis of the data showed significant increases in plasma glucose concentration, HOMA index, microalbuminuria and TBARS, and significant decreases in plasma C-peptide, AUC (area under the curve) plasma C-peptide and TEAC, through the different quartiles (from the lowest to the highest HbA(1c) concentration). With regard to parameters of endothelial function, changes in diameter showed a significant declining trend through the different quartiles. Endothelial-dependent changes in diameter were independently and significantly associated with AUC C-peptide levels, TEAC and TBARS. In conclusion, our study demonstrated that patients with Type II diabetes with good residual C-peptide secretion are better protected from endothelial dysfunction that those with poor C-peptide secretion.

Topics: Aged; Analysis of Variance; Area Under Curve; Brachial Artery; C-Peptide; Diabetes Mellitus, Type 2; Endothelium, Vascular; Female; Glucagon; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Nitroglycerin; Oxidative Stress; Regional Blood Flow; Thiobarbituric Acid Reactive Substances; Ultrasonography; Vasodilator Agents

The mechanisms responsible for the deterioration in glucose tolerance associated with protease inhibitor-containing regimens in HIV infection are unclear. Insulin resistance has been implicated as a major factor, but the affected tissues have not been identified. Furthermore, beta-cell function has not been evaluated in detail. The present study was therefore undertaken to assess the effects of protease inhibitor-containing regimens on hepatic, muscle, and adipose tissue insulin sensitivity as well as pancreatic beta-cell function. We evaluated beta-cell function in addition to glucose production, glucose disposal, and free fatty acid (FFA) turnover using the hyperglycemic clamp technique in combination with isotopic measurements in 13 HIV-infected patients before and after 12 weeks of treatment and in 14 normal healthy volunteers. beta-Cell function and insulin sensitivity were also assessed by homeostasis model assessment (HOMA). Treatment increased fasting plasma glucose concentrations in all subjects (P < 0.001). Insulin sensitivity as assessed by HOMA and clamp experiments decreased by approximately 50% (P < 0.003). Postabsorptive glucose production was appropriately suppressed for the prevailing hyperinsulinemia, whereas glucose clearance was reduced (P < 0.001). beta-Cell function decreased by approximately 50% (P = 0.002), as assessed by HOMA, and first-phase insulin release decreased by approximately 25%, as assessed by clamp data (P = 0.002). Plasma FFA turnover and clearance both increased significantly (P < 0.001). No differences at baseline or in responses after treatment were observed between drug naïve patients who were started on a nucleoside reverse transcriptase inhibitor (NRTI) plus a protease inhibitor and patients who had been on long-term NRTI treatment and had a protease inhibitor added. The present study indicates that protease inhibitor-containing regimens impair glucose tolerance in HIV-infected patients by two mechanisms: 1) inducement of peripheral insulin resistance in skeletal muscle and adipose tissue and 2) impairment of the ability of the beta-cell to compensate.

Topics: Adipose Tissue; Adult; Blood Glucose; Body Composition; Body Constitution; C-Peptide; CD4 Lymphocyte Count; Fatty Acids, Nonesterified; Female; Glucagon; Glucose Clamp Technique; Glucose Intolerance; Glycated Hemoglobin; Glycerol; HIV Infections; HIV Protease Inhibitors; Homeostasis; Humans; Insulin; Insulin Resistance; Islets of Langerhans; Lipids; Liver; Male; Middle Aged; Muscle, Skeletal; Proinsulin; Viral Load

Highly active antiretroviral therapy (HAART) has dramatically reduced HIV-related mortality, but is associated with severe metabolic adverse events, such as lipodystrophy and insulin resistance, the mechanisms of which are unknown. Adiponectin is a adipocytokine that is decreased in insulin resistant conditions. In mice, adiponectin decreases liver and muscle fat content and enhances insulin sensitivity. We determined serum adiponenctin and adiponectin mRNA concentrations in subcutaneous adipose tissue in HIV-positive HAART-treated patients with (HAART+LD+, n = 30) and without lipodystrophy (HAART+LD-, n = 13). The HAART+ LD+ group had significantly less subcutaneous and more intra-abdominal fat than the HAART+LD- group. Liver fat content (spectroscopy), serum insulin, C-peptide and triglyceride concentrations were significantly higher, and HDL cholesterol concentration lower in the HAART+LD+ than the HAART+LD- group. Serum adiponectin (3.4 +/- 0.4 vs 8.5 +/- 1.0 micro g/mL, p < 0.001) and adiponectin mRNA concentration in subcutaneous adipose tissue (7 +/- 1 x 10(-4) vs 24 +/- 6 x 10(-4), p < 0.001) were significantly lower in the HAART+LD+ than the HAART+LD- group. Both serum adiponectin and mRNA concentrations correlated closely with features of insulin resistance, including liver fat content. These data suggest that the decreased production of adiponectin in lipoatrophic adipose tissue may contribute to hepatic insulin resistance in these patients.

Topics: Abdomen; Actins; Adiponectin; Adipose Tissue; Adult; Antiretroviral Therapy, Highly Active; Body Composition; C-Peptide; Cholesterol, HDL; Female; Gene Expression; HIV-Associated Lipodystrophy Syndrome; Humans; Insulin; Insulin Resistance; Intercellular Signaling Peptides and Proteins; Liver; Magnetic Resonance Imaging; Male; Middle Aged; Proteins; RNA, Messenger; Triglycerides

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by loss of immunologic self-tolerance and the subsequent development of autoantibodies. These antibodies are thought to be important in relation to the clinical manifestations of the disease. One example is the development of multiple cytopenias secondary to cytolytic or cytotoxic antibodies directed toward red blood cells, platelets, and white blood cells. Other antibodies may mediate abnormal cellular mechanisms such as those seen with neuropsychiatric manifestations of SLE. We report the occurrence of autoantibodies directed toward insulin receptors and the subsequent development of type B insulin resistance syndrome in a woman with SLE. This syndrome was treated successfully with cyclophosphamide and mycophenolate mofetil.

Topics: Adult; C-Peptide; Cyclophosphamide; Female; Glycated Hemoglobin; Humans; Hyperinsulinism; Immunosuppressive Agents; Insulin; Insulin Resistance; Lupus Erythematosus, Systemic; Mycophenolic Acid; Treatment Outcome

Interactions between leptin and insulin have been shown previously, in vitro and in vivo. In this study, we evaluate the associations of leptin levels with insulin secretion and insulin sensitivity in type 2 diabetes. Fasting leptin levels, HbA 1c, glucose, insulin, C-peptide, intact and des-31,32-proinsulin were measured in 100 non-insulin-treated type 2 diabetic patients. Glucose, insulin and C-peptide were measured 2 hours after an oral glucose load. Insulin resistance and beta-cell function were calculated using HOMA. Leptin levels were found to be associated with all measures of beta-cell secretion: with fasting and 2 hours insulin and C-peptide, with intact and des-31,32-proinsulin concentrations, and with beta-cell secretion estimated with HOMA. This association was independent of age and body fat in women, but in men, associations with insulin and C-peptide weakened after controlling for fat mass, whereas those with intact and des-31,32-proinsulin disappeared. Fasting insulin and C-peptide levels were also significant in multiple regression analyses, besides gender and fat mass. Insulin resistance, as assessed by HOMA, was strongly correlated with leptin, also after correction for age and fat mass in both genders. We conclude that, besides fat mass and gender - the main determinants for leptin levels in type 2 diabetic subjects as in healthy subjects - insulin secretion and the degree of insulin resistance also seem to contribute significantly to leptin levels.

Topics: Adipose Tissue; Blood Glucose; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Diet, Diabetic; Female; Glucose Tolerance Test; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Leptin; Male; Middle Aged; Sex Characteristics

Mutations in the peroxisome proliferator-activated receptor-gamma 2 (PPAR-gamma 2) gene may cause obesity and insulin resistance. Therefore we investigated whether known variants in the PPAR-gamma 2 gene are associated with obesity and extreme insulin resistance in obese patients with impaired glucose tolerance (IGT). The Pro115 Gln, Pro12Ala, Pro467Leu, Val290Met and a silent polymorphism C478 T were examined in 48 subjects with IGT and insulin resistance (IR), characterized by euglycemic hyperinsulinemic clamps, and in 52 healthy insulin sensitive (IS) controls. We found one proband in the IR group with the Pro115 Gln variant. This subject showed a lower whole body glucose uptake (18 micromol/kg per min) compared to the entire IR group (29 micromol/kg per min). The body weight of the proband (BMI 28.5 kg/m2) was within the average of the IR group (30.3 +/- 0.8 kg/m2). The Pro12Ala variant was not associated with differences in BMI, in the degree of insulin resistance between the IR and IS group. The Pro467Leu, Val290Met mutations and the silent polymorphism CAC478CAT were not detected in any group. In conclusion, the Pro115 Gln variant, but not the Pro12Ala mutation in the PPAR-gamma 2 gene, could be a rare cause of severe insulin resistance.

Topics: Adult; Aged; Amino Acid Substitution; Blood Glucose; C-Peptide; DNA; Female; Genetic Variation; Glucose Intolerance; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Mutation, Missense; Obesity; Receptors, Cytoplasmic and Nuclear; Transcription Factors

We studied the contribution of the tumor necrosis factor system and leptin to insulin resistance during the course of normal pregnancy.. Forty-five healthy pregnant women (15 in the 1st, 15 in the 2nd2 and 15 in the 3rd3 trimester) and 25 age-matched healthy nonpregnant women as controls. Twenty-three newborns delivered by women followed in the 2nd and 3rd trimesters were also investigated. Fasting serum immunoreactive tumor necrosis factor-alpha, soluble tumor necrosis factor receptor-1, soluble tumor necrosis factor receptor-2, leptin (by enzyme-linked immunoassay) and C-peptide (by radioimmunoassay) concentrations in the patients and controls were measured. Body weight, length and head circumference of the newborns were analyzed in connection with the measured maternal parameters.. Significantly elevated tumor necrosis factor-alpha, tumor necrosis factor receptor-1 and -2, leptin, and C-peptide levels were found in the 3rd3 trimester as compared with the 1st1 and 2nd2 trimesters and with the nonpregnant controls. Tumor necrosis factor-alpha, tumor necrosis factor receptor-2, C-peptide, leptin concentrations and body mass index were found to be in a significant positive linear correlation with each other. Significant negative linear correlations were calculated among maternal serum C-peptide, tumor necrosis factor-alpha and leptin concentrations and the head circumference of the newborns.. In conclusion, increased tumor necrosis factor-alpha and leptin levels may contribute to insulin resistance in late pregnancy. Tumor necrosis factor-alpha and leptin may be regulators of intrauterine bone development of newborns.

Topics: Adult; Anthropometry; Antigens, CD; Birth Weight; Body Height; Body Mass Index; C-Peptide; Case-Control Studies; Enzyme-Linked Immunosorbent Assay; Female; Humans; Infant, Newborn; Insulin Resistance; Leptin; Pregnancy; Pregnancy Trimesters; Radioimmunoassay; Receptors, Leptin; Receptors, Tumor Necrosis Factor; Receptors, Tumor Necrosis Factor, Type II; Tumor Necrosis Factor-alpha

We report two black adolescent subjects who presented with diabetic ketoacidosis, but who lacked autoimmune markers and demonstrated clinical and biochemical characteristics more typical of Type 2 diabetes, including obesity, acanthosis nigricans, positive family history for Type 2 diabetes, and Type 2 diabetic dyslipidaemia. Subsequent to acute presentation, insulin was discontinued in both subjects and excellent glycaemic control was achieved with metformin therapy alone. Four months following acute presentation, both had adequate C-peptide responses to intravenous glucagon. Type 2 diabetes can present as diabetic ketoacidosis in obese adolescent subjects.

Topics: Acanthosis Nigricans; Adolescent; Blood Glucose; Body Weight; C-Peptide; Diabetes Mellitus, Type 2; Diabetic Ketoacidosis; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Male; Metformin; Obesity

Androgens are suggested to interact with leptin production and with insulin sensitivity in both polycystic ovary syndrome (PCOS) and obesity. The aim of the study was to follow these interactions along with two forms of antiandrogen treatment. Twenty women with PCOS were treated with ethinylestradiol and high dose of cyproteroneacetate (EE-CA) and 8 with the gonadotrophin-releasing hormone (GnRH) analogue goserelin for 6 months. The patients were divided into a low and a high body weight group and compared with a group of overweight women without PCOS. Both treatments resulted in a significant reduction of free testosterone but the concentration of leptin remained unchanged. EECA treatment resulted in deterioration and GnRH in improvement of insulin sensitivity. Serum leptin correlated only with body weight and body fat. It is concluded that leptin levels do not adequately reflect changes in insulin sensitivity or androgen levels after short-term antiandrogen or antigonadotropin treatment.

Topics: Adipose Tissue; Adult; Androgen Antagonists; Apolipoproteins A; Apolipoproteins B; Blood Glucose; Body Composition; Body Constitution; Body Mass Index; Body Weight; C-Peptide; Cyproterone Acetate; Dehydroepiandrosterone Sulfate; Ethinyl Estradiol; Female; Gonadotropin-Releasing Hormone; Goserelin; Humans; Insulin; Insulin Resistance; Leptin; Lipoprotein(a); Obesity; Polycystic Ovary Syndrome; Sex Hormone-Binding Globulin; Testosterone; Triglycerides

Impaired glucose tolerance (IGT) is an insulin-resistant state and a risk factor for Type 2 diabetes. The relative roles of insulin resistance and insulin deficiency in IGT have been disputed.. In 40 IGT subjects and 63 sex-, age-, and weight-matched controls with normal glucose tolerance (NGT), we measured (i) indices of insulin sensitivity of fasting glucose production (by tracer glucose) and glucose disposal (M value on a 240 pmol x min(-1) x m(-2) insulin clamp) and (ii) indices of beta-cell function (glucose sensitivity, rate sensitivity, and potentiation) derived from model analysis (Am J Physiol 283:E1159-E1166, 2002) of the insulin secretory response (by C-peptide deconvolution) to oral glucose.. In comparison with NGT, IGT were modestly insulin resistant (M=29+/-2 vs 35+/-2 micromol x min(-1) x kg(FFM)(-1), p=0.01); insulin sensitivity of glucose production also was reduced, in approximate proportion to M. Despite higher baseline insulin secretion rates, IGT was characterized by a 50% reduction in glucose sensitivity [53 (36) vs 102 (123) pmol x min(-1) x m(-2) x mM(-1), median (interquartile range), p=0.001] and impaired potentiation [1.6 (0.8) vs 2.0 (1.5) units, p<0.04] of insulin release, whereas rate sensitivity [1.15 (1.15) vs 1.38 (1.28) nmol x m(-2) x mM(-1)] was not significantly reduced. Glucose sensitivity made the single largest contribution (approximately 50%) to the observed variability of glucose tolerance.. In IGT the defect in glucose sensitivity of insulin release quantitatively predominates over insulin resistance in the genesis of the reduced tolerance to oral glucose.

Topics: Adult; Blood Glucose; C-Peptide; Fasting; Female; Glucose; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Kinetics; Male; Reference Values

Insulin resistance is nearly universal in patients with nonalcoholic steatohepatitis (NASH) when tested by glucose tolerance tests or clamp methods. However, the pattern of insulin resistance in these patients after a physiological challenge is unknown. We conducted a study to characterize the metabolic response to a mixed meal in nondiabetic patients with NASH (NDN) and to identify anthropometric determinants of insulin resistance in these patients.. Serum insulin, C-peptide, glucose, and free fatty acid (FFA) levels were measured at 0, 30, 60, 90, and 120 min after a 500-kcal standard meal in 18 NDN and 18 age-, gender-, and body mass index (BMI)-matched controls. Correlations were made between insulin resistance and various anthropometric, calorimetric, and serological variables.. Compared with controls, NDN had significantly higher levels of insulin and C-peptide at baseline and after the mixed meal. However, glucose levels were not different either at baseline or after the meal. NDN had higher fasting levels of FFA than the controls (459 +/- 190 vs 339 +/- 144 micro mol/L, respectively, p = 0.03); however, meal-induced suppression in lipolysis was similar between the two groups (39 +/- 113% vs 46 +/- 60%, p = 0.8). Insulin resistance was significantly correlated with BMI (r = 0.39, p = 0.02) and visceral fat (r = 0.50, p = 0.004). Whereas BMI, percent total body fat, and subcutaneous abdominal fat were similar between the groups, the NASH group had significantly higher percent visceral fat compared with controls (28 +/- 10% vs 22 +/- 14%, p = 0.02).. NDN are significantly hyperinsulinemic, both at fasting and after the mixed meal; however, their glucose homeostasis and suppression in lipolysis after a meal challenge are maintained. Insulin resistance in these patients is likely related to their higher visceral fat mass.

Topics: Adult; Anthropometry; C-Peptide; Chronic Disease; Diabetes Mellitus; Dietary Fats; Fatty Liver; Female; Glucose; Humans; Hyperinsulinism; Insulin Resistance; Lipid Metabolism; Lipolysis; Male; Middle Aged

This study aimed at elucidating the effects of interferon (IFN)-alpha on glucose metabolism in patients with chronic hepatitis B and C infections. Twenty-eight biopsy-proven patients with chronic hepatitis B (ten cases) and hepatitis C (18 cases) were given IFN-alpha for a total of 24 weeks. The patients received a 75 g oral glucose tolerance test (OGTT), glucagon stimulation test, tests for type 1 diabetes-related autoantibodies and an insulin suppression test before and after IFN-alpha therapy. Ten of the 28 patients responded to IFN-alpha therapy. Steady-state plasma glucose of the insulin suppression test decreased significantly in responders (13.32+/-1.48 (S.E.M.) vs 11.33+/-1.19 mmol/l, P=0.0501) but not in non-responders (12.29+/-1.24 vs 11.11+/-0.99 mmol/l, P=0.2110) immediately after completion of IFN-alpha treatment. In the oral glucose tolerance test, no significant difference was observed in plasma glucose in either responders (10.17+/-0.23 vs 10.03+/-0.22 mmol/l) or non-responders (10.11+/-0.22 vs 9.97+/-0.21 mmol/l) 3 Months after completion of IFN-alpha treatment. However, significant differences were noted in C-peptide in both responders (2.90+/-0.13 vs 2.20+/-0.09 nmol/l, P=0.0040) and non-responders (2.45+/-0.11 vs 2.22+/-0.08 nmol/l, P=0.0287) before vs after treatment. The changes of C-peptide in an OGTT between responders and non-responders were also significantly different (P=0.0028), with responders reporting a greater reduction in C-peptide. No case developed autoantibodies during the treatment. In patients who were successfully treated with IFN-alpha, insulin sensitivity improved and their plasma glucose stayed at the same level without secreting as much insulin from islet beta-cells.

Topics: Adult; Alanine Transaminase; Analysis of Variance; Autoantibodies; Blood Glucose; C-Peptide; Chi-Square Distribution; Diabetes Mellitus, Type 1; DNA, Viral; Female; Glucagon; Glucose Tolerance Test; Hepatitis B e Antigens; Hepatitis B, Chronic; Hepatitis C, Chronic; Homeostasis; Humans; Insulin; Insulin Resistance; Insulin Secretion; Interferon-alpha; Islets of Langerhans; Male; Middle Aged

The effects of tibolone on body weight, body composition, and fasting carbohydrate measures in surgically postmenopausal cynomolgus monkeys were compared to those of conjugated equine estrogens (CEE) with and without medroxyprogesterone acetate (MPA). Monkeys were fed a moderately atherogenic diet with either no hormones (control n = 29), CEE (0.042 mg/kg, n = 27), CEE + MPA (0.167 mg/kg, n = 29), low-dose tibolone (LoTib, 0.05 mg/kg, n = 30), or high-dose tibolone (HiTib, 0.20 mg/kg, n = 31) daily for 2 years. Body weight (BW) was measured throughout the study, and dual-energy x-ray absorptiometry (DEXA) scans of the abdominal region (lumbar vertebrae 1 through 5) were performed at the end of the trial to assess abdominal body composition. Fasting carbohydrate measures (glucose, insulin, C-peptide, and fructosamine) were determined at baseline and after 2 years of treatment. Compared to controls, BW significantly increased and abdominal soft tissue mass was greater (analysis of variance [ANOVA], P <.001, P = 0.003, respectively) in all but the CEE-treated group (P =.78, P =.94, respectively). HiTib-treated monkeys had greater abdominal lean mass compared to controls (P =.008), while there was no significant treatment effect on abdominal fat mass (analysis of covariance [ANCOVA], P =.29). Fasting insulin concentrations and fasting insulin/glucose ratios were greater in CEE + MPA- (P =.002, P =.03, respectively) and HiTib-treated monkeys (P =.03, P =.02, respectively) compared to controls. There was a strong trend for a treatment effect on fasting blood glucose concentration (ANCOVA, P =.06) with CEE + MPA-treated animals having the greatest values, despite no difference in fructosamine concentration (ANCOVA, P =.57). Using these fasting measures, the homeostasis model assessment (HOMA-IR) revealed significant insulin resistance with CEE + MPA treatment compared to controls (P =.008), while the quantitative insulin sensitivity check index (QUICKI) showed significantly impaired insulin sensitivity in all hormone replacement therapy (HRT) groups (all P values <.03), except CEE (P =.12). In conclusion, HRT with CEE + MPA or tibolone results in greater BW, abdominal soft tissue, and insulin resistance (CEE + MPA and HiTib) compared to control-treated monkeys.

Topics: Animals; Arteriosclerosis; Blood Glucose; Body Composition; Body Weight; C-Peptide; Carbohydrates; Dietary Fats; Energy Intake; Estrogen Replacement Therapy; Estrogens, Conjugated (USP); Fasting; Female; Fructosamine; Insulin; Insulin Resistance; Macaca fascicularis; Medroxyprogesterone Acetate; Norpregnenes; Ovariectomy; Postmenopause

The aim of this study was to establish the effect of polycystic ovary syndrome (PCOS) adjusted for adiposity on proinsulin concentrations.. Ninety-one women with PCOS and 72 normal cycling (NC) women were recruited. A 2 h, 75 g oral glucose tolerance test was performed. Glucose and insulin were measured in each sample. Proinsulin and C-peptide were determined at 0 and 30 min and the fasting proinsulin/insulin ratio (PI/I) was calculated. Insulin sensitivity was estimated by insulin sensitivity index (ISI) composite, and beta-cell function was estimated by insulinogenic index.. Insulin, proinsulin and C-peptide concentrations were higher in women with PCOS than in NC women (P < 0.05). PI/I and insulinogenic index were similar in both groups. Proinsulin concentrations increased with body mass index (P < 0.05) only in women with PCOS; therefore, proinsulin concentrations were higher in obese PCOS patients compared with obese control women (P < 0.05). Moreover, a positive association between proinsulin concentrations and waist diameter adjusted for C-peptide (P < 0.05) and a negative association between proinsulin concentrations and ISI composite values were observed in PCOS patients (P < 0.05).. Data suggest that in PCOS patients an elevated proinsulin concentration could reflect insulin resistance more than beta-cell dysfunction. However, the elevated concentration of proinsulin in these patients could also result from impaired beta-cell function resulting from intra-abdominal obesity independently of insulin resistance.

Topics: Adolescent; Adult; Blood Glucose; Body Constitution; Body Mass Index; C-Peptide; Fasting; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Islets of Langerhans; Obesity; Polycystic Ovary Syndrome; Proinsulin

Glutathione peroxidase (GPx) is one of the most important antioxidant enzymes in humans. We studied the relationship between erythrocyte GPx activity and fasting serum insulin, plasma glucose, and C-peptide, estimates of insulin resistance from the homeostasis model of assessment as well as dietary fat intake in 408 normotensive nondiabetic pregnant women from Camden, NJ. GPx activity and the metabolic parameters were determined at entry to care (16 wk of pregnancy) and during the third trimester. GPx activity and the levels of insulin resistance increased significantly between entry and the third trimester. Statistically significant associations, all positive, were observed between GPx activity and fasting insulin (beta = 0.009, P < 0.001), glucose (beta = 0.975, P < 0.05), C-peptide (beta = 1.537, P < 0.01), and insulin resistance from the homeostasis model of assessment (beta = 0.209, P < 0.01). Dietary intakes of fat and polyunsaturated fatty acids were positively correlated with GPx activity as well. African Americans had significantly higher GPx activity, dietary fat, and polyunsaturated fatty acid intake than Hispanics and Caucasians. In conclusion, we demonstrated that normal pregnancy is associated with increased GPx activity and insulin resistance. There are ethnic differences in antioxidant response and dietary fat intake. Our findings suggest a potential link among antioxidant defenses, insulin resistance, and dietary fat intake.

Topics: Adult; Black or African American; Blood Glucose; C-Peptide; Cohort Studies; Dietary Fats; Dietary Fats, Unsaturated; Erythrocytes; Fasting; Female; Glutathione Peroxidase; Hispanic or Latino; Homeostasis; Humans; Insulin; Insulin Resistance; Pregnancy; Prospective Studies; Reference Values; White People

To investigate the effect of elevated plasma free fatty acid (FFA) concentrations on splanchnic glucose uptake (SGU), we measured SGU in nine healthy subjects (age, 44 +/- 4 yr; body mass index, 27.4 +/- 1.2 kg/m(2); fasting plasma glucose, 5.2 +/- 0.1 mmol/l) during an Intralipid-heparin (LIP) infusion and during a saline (Sal) infusion. SGU was estimated by the oral glucose load (OGL)-insulin clamp method: subjects received a 7-h euglycemic insulin (100 mU x m(-2) x min(-1)) clamp, and a 75-g OGL was ingested 3 h after the insulin clamp was started. After glucose ingestion, the steady-state glucose infusion rate (GIR) during the insulin clamp was decreased to maintain euglycemia. SGU was calculated by subtracting the integrated decrease in GIR during the period after glucose ingestion from the ingested glucose load. [3-(3)H]glucose was infused during the initial 3 h of the insulin clamp to determine rates of endogenous glucose production (EGP) and glucose disappearance (R(d)). During the 3-h euglycemic insulin clamp before glucose ingestion, R(d) was decreased (8.8 +/- 0.5 vs. 7.6 +/- 0.5 mg x kg(-1) x min(-1), P < 0.01), and suppression of EGP was impaired (0.2 +/- 0.04 vs. 0.07 +/- 0.03 mg x kg(-1) x min(-1), P < 0.01). During the 4-h period after glucose ingestion, SGU was significantly increased during the LIP vs. Sal infusion study (30 +/- 2 vs. 20 +/- 2%, P < 0.005). In conclusion, an elevation in plasma FFA concentration impairs whole body glucose R(d) and insulin-mediated suppression of EGP in healthy subjects but augments SGU.

Topics: Adult; Blood Glucose; C-Peptide; Fat Emulsions, Intravenous; Fatty Acids, Nonesterified; Female; Glucose; Humans; Injections, Intravenous; Insulin; Insulin Resistance; Male; Middle Aged; Reference Values; Time Factors; Viscera

Nonalcoholic steatohepatitis (NASH) is a disorder characterized by hepatic steatosis, inflammation, and fibrosis. Leptin is an adipocyte-derived antiobesity hormone that in rodents prevents "lipotoxicity" by limiting triglyceride accumulation and also regulates matrix deposition (fibrosis) during wound healing. We therefore determined serum leptin levels in patients with NASH to determine whether relationships existed between leptin levels and severity of hepatic steatosis or fibrosis. We used a radioimmunoassay to determine serum [total] leptin concentrations in 27 men and 20 women with NASH and 47 controls matched for gender and body mass index (BMI; and partly for age). Serum leptin values were correlated with hepatic steatosis, fibrosis, and inflammation (each categorized semiquantitatively on liver histology), and with anthropometric indices, serum lipids, glucose, insulin, c-peptide, and alanine aminotransferase (ALT) levels. Compared with the controls, mean serum leptin levels were raised in both men and women with NASH (men 14 +/- 11 ng/mL vs. 7.2 +/- 4.1 ng/mL, P =.003; women 35 +/- 16 ng/mL vs. 15 +/- 8.2 ng/mL, P <.001). Leptin values correlated with serum c-peptide levels but not with BMI. In a multivariate analysis, serum leptin (P =.027), serum c-peptide (P =.001), and age (P =.027) were selected as independent predictors of the severity of hepatic steatosis. However, serum leptin was not an independent predictor of hepatic inflammation or fibrotic severity. In conclusion, hyperleptinemia occurs in NASH and is not explained simply by gender, obesity, or the presence of type 2 diabetes. Furthermore, leptin levels correlate directly with the severity of hepatic steatosis but not with inflammation or fibrosis. We propose that the relationship between leptin and steatosis reflects a pathogenic role of leptin in hepatic insulin resistance and/or a failure of the antisteatotic actions of leptin ("peripheral leptin resistance").

Topics: Adult; Aged; C-Peptide; Fatty Liver; Female; Hepatitis; Humans; Insulin; Insulin Resistance; Leptin; Liver Cirrhosis; Male; Middle Aged; Multivariate Analysis; Severity of Illness Index; Sex Factors; Triglycerides

Human fetuin/alpha(2)-HS-glycoprotein (AHSG) is a 49 kDa serum and tissue protein which is a natural inhibitor of insulin receptor signaling. We investigated serum AHSG levels during pregnancy and whether the protein is involved in insulin resistance observed in healthy pregnant women and patients with gestational diabetes.. One hundred and four healthy pregnant women and 23 of their neonates, 30 patients with gestational diabetes and their neonates and 30 healthy age-matched non-pregnant females as a control group were investigated in a case-control cross-sectional study.. Serum AHSG was determined by radial immunodiffusion.. We observed an increase of serum AHSG concentration in the second and third trimesters. Gestational diabetes patients had significantly higher AHSG levels than healthy pregnant women and non-pregnant controls. There was a highly significant positive correlation between serum AHSG concentration and indirect parameters of insulin resistance, i.e. tumor necrosis factor-alpha (TNF-alpha), leptin, C-peptide and C-peptide/blood glucose ratio. There was also a negative correlation between maternal AHSG, TNF-alpha, leptin levels and head circumference, body length and body weight of newborns.. AHSG, TNF-alpha and leptin may contribute to insulin resistance during normal pregnancy and gestational diabetes. AHSG along with these cytokines may also negatively regulate neonatal skeletal development.

Topics: alpha-2-HS-Glycoprotein; Blood Glucose; Blood Proteins; Body Height; Body Weight; C-Peptide; Cephalometry; Diabetes, Gestational; Female; Gestational Age; Humans; Infant, Newborn; Insulin Resistance; Leptin; Pregnancy; Tumor Necrosis Factor-alpha

To investigate in depth the metabolic effects of oestradiol-17 beta both alone and in combination with the progestagen dydrogesterone.. Fifteen hysterectomised postmenopausal women were studied before treatment and after 24 weeks taking oestradiol-17 beta alone (2 mg per day), then following a further 6 (oestrogen-alone phase) and 12 (oestrogen plus progestagen phase) weeks with inclusion of dydrogesterone (10 mg per day for days 17-28 of each 28 day cycle). Measurements at each visit included fasting serum lipid and lipoprotein concentrations, insulin sensitivity, secretion and elimination by modelling analysis of intravenous glucose tolerance test glucose, insulin and C-peptide concentrations, body fat distribution by dual-energy X-ray absorptiometry (DXA) and arterial function by carotid artery ultrasound.. Significant reductions were seen throughout in total and LDL cholesterol. The net reductions in total and LDL cholesterol by the end of the study were 5.8% (P<0.05) and 18.4% (P<0.001), respectively. HDL and HDL subfraction cholesterol concentrations rose during treatment with oestradiol alone, the rise being primarily in the HDL(2) subfraction (+21.6%, P<0.001). Fasting serum triglycerides rose 30% on oestradiol treatment. These increases were unaffected by the addition of dydrogesterone. Insulin sensitivity, secretion and elimination, body fat distribution and arterial function were not significantly affected at any stage of the therapy.. The small study sample and high variability in measures of glucose and insulin metabolism may have contributed to the absence of the expected significant improvement in these parameters. Orally administered oestradiol had beneficial effects on total, LDL and HDL cholesterol which were unaffected by the addition of dydrogesterone.

Topics: Absorptiometry, Photon; Adult; Aged; Analysis of Variance; Blood Glucose; C-Peptide; Carotid Arteries; Drug Administration Schedule; Drug Therapy, Combination; Dydrogesterone; Estradiol; Female; Humans; Hysterectomy; Insulin; Insulin Resistance; Lipid Metabolism; Lipids; Lipoproteins; Middle Aged; Models, Theoretical; Postmenopause; Progesterone Congeners; Pulsatile Flow; Triglycerides

To compare androgens and sex hormone-binding globulin (SHBG) levels, and indices of insulin sensitivity (the response of plasma insulin and C-peptide in OGTT, insulin resistance and beta-cell activity estimated with the homeostasis assessment model (HOMA model) in healthy obese premenopausal women with different body fat distributions.. Free testosterone, androstenedione, SHBG levels and responses of plasma glucose, insulin and C-peptide in OGTT were examined in 74 healthy premenopausal women (19 with lower-body obesity (WHR < 0.80), 20 with pure abdominal obesity (WHR > 0.85), 19 with predominant abdominal obesity (WHR 0.81-0.85) and 18 normal-weight women). Insulin resistance and beta-cell function were estimated with the HOMA model.. Both fasting and glucose-induced insulin levels were higher in women with pure abdominal obesity than in the controls (p < 0.001) and in those with lower-body obesity (P < 0.01). Insulin resistance was also higher in women with pure abdominal obesity than in the controls (p < 0.01) and those with lower-body obesity (p < 0.05). Free testosterone (p < 0.01) was higher and SHBG (p < 0.001) was lower in women with abdominal obesity than in the control group and those with lower-body obesity. Insulin significantly correlated with SHBG, and this correlation was independent of androgens, obesity and obesity type. Beta-cell function positively correlated with free testosterone, whereas insulin resistance negatively correlated with SHBG, and was independent of obesity and obesity type.. In healthy premenopausal women, increased BMI and more pronounced abdominal fat accumulation was associated with increased androgenic activity (higher free testosterone and lower SHBG levels) and with insulin resistance estimated using the HOMA model, as well as with increasing basal and glucose-induced insulin levels. SHBG levels correlated with insulin and insulin resistance independently of the degree of obesity, obesity type and androgens, whereas beta-cell function correlated only with free testosterone.

Topics: Adult; Androgens; Body Composition; Body Constitution; Body Mass Index; C-Peptide; Female; Glucose Tolerance Test; Humans; Insulin Resistance; Islets of Langerhans; Premenopause; Reference Values; Sex Hormone-Binding Globulin

The mechanisms of the impairment in hepatic glucose metabolism induced by free fatty acids (FFAs) and the importance of FFA oxidation in these mechanisms remain unclear. FFA-induced peripheral insulin resistance has been linked to membrane translocation of novel protein kinase C (PKC) isoforms, but the role of PKC in hepatic insulin resistance has not been assessed. To investigate the biochemical pathways that are induced by FFA in the liver and their relation to glucose metabolism in vivo, we determined endogenous glucose production (EGP), the hepatic content of citrate (product of acetyl-CoA derived from FFA oxidation and oxaloacetate), and hepatic PKC isoform translocation after 2 and 7 h Intralipid + heparin (IH) or SAL in rats. Experiments were performed in the basal state and during hyperinsulinemic clamps (insulin infusion rate, 5 mU. kg(-1). min(-1)). IH increased EGP in the basal state (P < 0.001) and during hyperinsulinemia (P < 0.001) at 2 and 7 h. Also, 7-h infusion of IH induced resistance to the suppressive effect of insulin on EGP (P < 0.05). Glycerol infusion (resulting in plasma glycerol levels similar to IH infusion) did not have any effect on EGP. IH increased hepatic citrate content by twofold, independent of the insulin levels and the duration of IH infusion. IH induced hepatic PKC-delta translocation from the cytosolic to membrane fraction in all groups. PKC-delta translocation was greater at 7 compared with 2 h (P < 0.05). In conclusion, 1) increased FFA oxidation may contribute to the FFA-induced increase in EGP in the basal state and during hyperinsulinemia but is not associated with FFA-induced hepatic insulin resistance, and 2) the progressive insulin resistance induced by FFA in the liver is associated with a progressive increase in hepatic PKC-delta translocation.

Topics: Animals; Blood Glucose; C-Peptide; Fatty Acids, Nonesterified; Female; Glucose Clamp Technique; Glycerol; Insulin Resistance; Isoenzymes; Liver; Oxidation-Reduction; Protein Kinase C; Protein Kinase C-delta; Rats; Rats, Wistar; Triglycerides

Role of tumour necrosis factor-alpha (TNF-alpha) was studied in insulin resistance during pregnancy.. Serum TNF-alpha (ELISA) and fasting C-peptide (Cp) (RIA) concentrations were measured in 40 healthy pregnant women (15, 12 and 13 of them in the 1st, 2nd and 3rd trimesters, respectively) and in 25 healthy non-pregnant women in a case-control study.. TNF-alpha (X+/-S.D.: 5.33+/-0.46 pg/ml) and Cp levels (3.37+/-1.30 ng/ml) were significantly higher in the 3rd trimester as compared with matched healthy controls (TNF: 4.07+/-0.26, Cp: 1.05+/-0.36) and to the pregnant women in 1st (TNF: 4.04+/-0.26, Cp: 1.34+/-0.59) and 2nd (TNF: 4.35+/-0.32, Cp: 1.11+/-0.35) trimesters. Significant positive linear correlation was calculated among TNF-alpha, Cp, Cp/blood glucose ratio (indirect parameters of insulin resistance) and body mass indexes (BMIs) of pregnant women (P<0.01).. TNF-alpha may contribute to the insulin resistance during the course of normal pregnancy.

Topics: Adult; Blood Pressure; Body Constitution; Body Mass Index; C-Peptide; Case-Control Studies; Female; Humans; Insulin Resistance; Pregnancy; Pregnancy Complications; Pregnancy Trimester, Third; Tumor Necrosis Factor-alpha

We aimed to characterize a cohort of 'atypical' diabetic patients of sub-Saharan African origin and to analyse possible determinants of long-term remission.. Over 6 years, we studied the clinical and therapeutic profile of 42 consecutive patients undiagnosed or untreated prior to inclusion presenting with cardinal features of diabetes mellitus. We measured insulin secretion and sensitivity at inclusion. Immunogenetic (anti-GAD, anti-ICA and HLA class II) markers of Type 1 diabetes were compared with a 90-non-diabetic unrelated adult African population.. Twenty-one ketonuric patients (age 42 +/- 9 (sd) years; body mass index (BMI) 26 +/- 3 kg/m2) were initially insulin-treated (IT), and 21 non-ketonuric patients (age 38 +/- 8 years; BMI 26 +/- 5 kg/m2) had oral and/or diet therapy (NIT). Insulin could be discontinued in 47.6% (10/21) IT with adequate glycaemic control (HbA1c 6.7 +/- 1.3%), while insulin was secondarily started in 38.1% (8/21) NIT in expectation of better control. The initial basal (odds ratio (OR) 9.1, 95% confidence interval (CI) 1.3-64.4) and stimulated C-peptide (OR 8.17, 95% CI 1.5-44.1) were independently associated with remission. Insulin resistance was present in all the groups, more marked in the insulin-treated NIT. Anti-GAD antibodies and ICA were rare, but 38.1% IT vs. 1.1% controls had Type 1 diabetes HLA susceptibility haplotypes (P < 0.001) without significant difference between the subgroups.. Prolonged discontinuation of insulin is frequent in African diabetic patients initially presenting with signs of insulinopenia. In our patients, long-term insulin therapy was not associated with immunogenetic markers of Type 1 diabetes. The initial measure of insulin secretion seemed a good predictor of long-term remission.

Topics: Acute Disease; Adult; Africa South of the Sahara; Autoantibodies; C-Peptide; Diabetes Mellitus; Drug Administration Schedule; Follow-Up Studies; Genetic Predisposition to Disease; HLA-DR3 Antigen; HLA-DR4 Antigen; Humans; Insulin; Insulin Resistance; Islets of Langerhans; Logistic Models; Middle Aged; Remission Induction; Time Factors

In a family with agenesis of the dorsal pancreas only the mother presents with insulin-dependent diabetes mellitus, whereas her sons are glucose tolerant. We examined whether metabolic defects can be detected early in this disease. Plasma glucose profiles were obtained from patients with dorsal pancreas agenesis and from matched healthy subjects. Hepatic glycogen synthesis and breakdown were determined from the time course of glycogen concentrations using noninvasive (13)C nuclear magnetic resonance spectroscopy. Gluconeogenesis was calculated from the difference between glucose production (measured with D-[6,6-(2)H(2)]glucose) and glycogen breakdown. Frequently sampled iv glucose tolerance tests were performed to assess insulin secretion and sensitivity. The mean plasma glucose level was higher (12.9 +/- 0.4 vs. 5.9 +/- 0.1 mmol/liter), whereas the peak plasma insulin level was lower (236 vs. 397 +/- 23 pmol/liter) in the diabetic mother than in her nondiabetic sons and healthy subjects. In all patients, however, glycogen synthesis and breakdown were reduced by approximately 55% (P < 0.05) and 40% (P < 0.02), respectively. Gluconeogenesis (6.8 +/- 0.8 vs. 4.2 +/- 0.3 micro mol/kg.min; P < 0.05) and hepatic insulin clearance (6.8 +/- 1.3 vs. 2.8 +/- 1.0 ml/kg.min) were increased in all patients. In conclusion, patients with complete agenesis of the dorsal pancreas exhibit marked defects in hepatic glycogen metabolism, which are present even in the nondiabetic offspring.

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus, Type 1; Fatty Acids, Nonesterified; Female; Glucagon; Gluconeogenesis; Glucose Tolerance Test; Glycogen; Human Growth Hormone; Humans; Hydrocortisone; Insulin; Insulin Resistance; Insulin Secretion; Kinetics; Leptin; Liver; Magnetic Resonance Spectroscopy; Male; Middle Aged; Norepinephrine; Pancreas

To validate fasting indices of insulin sensitivity and secretion in a diverse pediatric population against gold standard estimates from euglycemic and hyperglycemic clamps.. A total of 31 children (mean BMI 25.1 +/- 4.9 kg/m(2), mean age 8.7 +/- 1.4 years, 15 girls and 16 boys, 12 black and 19 white) underwent euglycemic and hyperglycemic clamps 2-6 weeks apart to derive insulin sensitivity indices (SI (Eug clamp) and SI (Hyper clamp)). Fasting samples were used to derive the homeostasis model assessment of insulin resistance index (HOMA-IR), HOMA of percent beta-cell function (HOMA-B%), quantitative insulin sensitivity check index (QUICKI), insulinogenic index, antilipolytic insulin sensitivity index (ISI-FFA), and C-peptide-to-insulin ratio.. The QUICKI correlated best with SI (Eug clamp) (r = 0.69, P < 0.05) and had greater correlations to SI (Eug clamp) than did either SI (Hyper clamp) (r = 0.45, P < 0.05) or the HOMA-IR (r = -0.51, P < 0.05). Both fasting insulin and the insulinogenic index correlated well with first- and steady-phase insulin secretion (r's from 0.79 to 0.86, P < 0.05). HOMA-B% was not as highly correlated (r = 0.69-0.72, P < 0.05). Fasting C-peptide-to-insulin ratio was not significantly correlated with clamp-derived metabolic clearance rate of insulin. ISI-FFA was not correlated with the degree of free fatty acid suppression obtained from the clamps.. The QUICKI, fasting insulin, and the insulinogenic index all closely correlate with corresponding clamp-derived indices of insulin sensitivity and secretion in this diverse pediatric cohort. These results, if replicated in similarly diverse populations, suggest that estimates based on fasting samples can be used to rank order insulin secretion and sensitivity in pediatric cohorts.

Topics: Black or African American; Blood Glucose; Body Mass Index; C-Peptide; Child; Copper; District of Columbia; Fasting; Female; Glucose Clamp Technique; Humans; Insulin; Insulin Resistance; Insulin Secretion; Male; Maryland; Obesity; Puberty; Reference Values; Regression Analysis; Reproducibility of Results; Software; White People

Human liver cirrhosis is commonly associated with increased fasting and glucose induced insulin concentrations. However, whether the hyperinsulinaemia is a consequence of increased pancreatic insulin secretion, decreased hepatic insulin removal, or impaired feedback regulation of insulin secretion is still doubtful. To investigate these issues, insulin secretion-during 24 hours of standardised living conditions-insulin sensitivity, and hepatic insulin extraction were assessed in cirrhotic patients compared with matched healthy subjects.. Nine Child's disease grade B cirrhotic patients and seven healthy volunteers, participated in the study. The subjects were studied on two separate days, one for the assessment of insulin secretion during a standardised 24 hour life period (calorimetric chamber), and one for the determination of insulin sensitivity.. Insulin secretion rates were reconstructed from plasma C peptide concentrations by deconvolution, and indices of beta cell function were derived using a mathematical model describing the functional dependence of insulin secretion on plasma glucose concentrations. Insulin sensitivity was determined using the euglycaemic hyperinsulinaemic clamp technique.. Cirrhotic patients showed a marked hypersecretory response, both in absolute terms (mean (SEM) 295 (53) versus 138 (11) nmol/m(2), p<0.02), and in relation to glucose (175 (26) versus 57 (5) pmol/min/m(2), p<0.02). In particular, the beta cell dose-response function was shifted upward compared with controls. The sensitivity of insulin secretion to the rate of glucose change was also increased. Insulin sensitivity, markedly reduced in cirrhosis (157 (10) versus 296 (30) ml/min/m(2), p<0.002), was strongly inversely correlated (r=0.89, p<0.002) in these patients with insulin secretion at 5 mM glucose. Insulin clearance and hepatic insulin extraction were not reduced. A frank hypermetabolism with increased lipid oxidation was found in this series.. This study suggests that hyperinsulinaemia, at least in Child's disease grade B cirrhotic patients, is the consequence of increased beta cell sensitivity to glucose, while hepatic insulin extraction does not seem to play a significant part.

Topics: Biomarkers; Blood Glucose; C-Peptide; Case-Control Studies; Female; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Liver; Liver Cirrhosis; Male; Middle Aged; Models, Biological; Monitoring, Physiologic; Regression Analysis; Statistics, Nonparametric

Postmenopausal hormone replacement therapy (HRT) protects women from the risk of cardiovascular system disease, osteoporosis, and dementia. There are conflicting reports about the effects of HRT on insulin resistance. The purpose of this study was to investigate the effects of HRT on insulin resistance with the hyperinsulinemic euglycemic clamp technique, the most sensitive technique measuring insulin resistance. Conjugated estrogen (0.625 mg/d) and medroxyprogesterone acetate (5 mg/d) were given to 15 postmenopausal women with insulin resistance. After 3 mo of HRT, the M value (total glucose consumption) increased 28% (p < 0.001), low-density lipoprotein (LDL) cholesterol decreased 12.9% (p < 0.044), high-density lipoprotein (HDL) cholesterol increased 17% (p < 0.009), total cholesterol decreased 9.1% (p < 0.016), and serum insulin decreased 33% (p < 0.022) compared to baseline values before HRT was started. No significant changes in glucose, C-peptide, and triglyceride levels were observed. Whereas there were no differences regarding glucose, total cholesterol, LDL cholesterol, HDL cholesterol, and triglyceride levels between the insulin-resistant (n = 15) and non-insulin-resistantwomen (n = 24) (p > 0.05), there were significant differences in M value, insulin, and C-peptide levels between these groups (p < 0.05). We believe that HRT with this combination may protect postmenopausal women from coronary artery disease (CAD) through its beneficial effects on insulin resistance, hyperinsulinemia, and lipid levels, which are considered to be important factors in CAD pathogenesis.

Topics: C-Peptide; Cholesterol, HDL; Cholesterol, LDL; Estrogen Replacement Therapy; Estrogens, Conjugated (USP); Female; Glucose Clamp Technique; Humans; Insulin; Insulin Resistance; Medroxyprogesterone Acetate; Middle Aged; Reference Values; Triglycerides

The objective of this study was to compare insulin resistance relative to body fat and the associated compensatory responses in 57 healthy children living in Los Angeles, California (14 Caucasians, 15 African-Americans, and 28 Hispanics).. Insulin sensitivity and acute insulin response were determined by intravenous glucose tolerance test. Insulin secretion, hepatic insulin extraction, and insulin clearance were estimated by C-peptide and insulin modeling.. Insulin sensitivity was significantly lower in Hispanics and African-Americans compared with Caucasian children, and acute insulin response was significantly higher in African-American children. No ethnic differences were noted in the first-phase secretion, but second-phase insulin secretion was significantly higher in Hispanic children than in African-American children (200 +/- 53 vs. 289 +/- 41 nmol/min; P = 0.03). The greater acute insulin response in African-Americans, despite lower secretion, was explained by a lower hepatic insulin extraction in African-Americans compared with Hispanics (36.6 +/- 2.9 vs. 47.3 +/- 2.2%; P = 0.0006).. In conclusion, Hispanic and African-American children are more insulin resistant than Caucasian children, but the associated compensatory responses are different across ethnic groups.

Topics: Absorptiometry, Photon; Adipose Tissue; Black or African American; Blood Glucose; C-Peptide; Child; Fatty Acids, Nonesterified; Glucose Tolerance Test; Hispanic or Latino; Humans; Insulin; Insulin Resistance; Least-Squares Analysis; White People

Patients with cirrhosis of the liver suffer from hyperinsulinaemia and a certain degree of insulin resistance. More frequently than in the rest of the population they have diabetes. Transjugular intrahepatic portosystemic shunts (TIPS) as a therapeutic method in complications of portal hypertension lead to rapid haemodynamic changes in the liver. The objective of the submitted work was to assess whether TIPS has an impact on insulinaemia and whether it influences insulin resistance in patients with cirrhosis of the liver.. The authors evaluated a group of 22 patients with cirrhosis of the liver (10 diabetics and 12 subjects without diabetes) indicated for TIPS. They investigated the insulin and C-peptide concentration in blood obtained by catheterization from the hepatic and portal vein before and after TIPS and in the peripheral blood before TIPS, 1 hour, 1 day, 1 week and 1 month after TIPS. The insulin resistance was examined by the method of the hyperinsulin euglycaemic clamp (HEC) before TIPS, 1 day, 1 week, and 1 month after TIPS. The levels of C-peptide and insulin were assessed by the IRMA method. The blood sugar level in HEC was measured by means of a Hemocue apparatus. The results were evaluated by the non-parametric Wilcoxon test for two dependent samples.. Both groups (diabetics and non-diabetics) were comparable as to age, sex, etiology of liver cirrhosis and indication for TIPS. After introduction of TIPS a change of insulin clearance occurred (p = 0.01) and a change of the insulin level in the hepatic vein immediately after TIPS (p = 0.02). Insulin clearance before TIPS was 37-90% (median 54%) and after TIPS it declined to 0-79% (median 38%) (p = 0.01). Already 1 hour after the operation the authors observed a rise of the insulin level in peripheral blood as compared with baseline values (p = 0.002). Statistically significant hyperinsulinaemia persisted one month after TIPS (p = 0.005). Values of C-peptide did not change significantly in time, neither in the hepatic vein nor in the peripheral blood. On examination of IR no statistically significant changes occurred after TIPS. On evaluation of different groups of diabetics and non-diabetics the IR was more marked in patients with DM (mean M = 1.7 mg/kg/min.) than in patients without DM (3.7 mg/kg/min.) (p = 0.03). The authors did not record significant changes of IR in time in different groups. Compensation of DM was not influenced by TIPS. The fasting blood sugar levels before TIPS and 1 month after TIPS were comparable.. After TIPS a rise of the insulin level in peripheral blood occurred due to the reduced insulin clearance in the liver. Despite hyperinsulinaemia which persisted for one month after the operation, the insulin resistance did not deteriorate. Compensation of diabetes was not affected by TIPS.

Topics: Adult; Aged; C-Peptide; Diabetes Complications; Diabetes Mellitus; Female; Humans; Hypertension, Portal; Insulin; Insulin Resistance; Liver Cirrhosis; Male; Middle Aged; Portasystemic Shunt, Transjugular Intrahepatic

The contribution of the tumor necrosis factor (TNF) system and leptin was studied in insulin resistance and neonatal development during the course of normal pregnancy and gestational diabetes mellitus (GDM). Thirty patients with GDM and their neonates (n = 30), 35 healthy pregnant women (15 in the first, nine in the second and 11 in the third trimester) and their neonates (n = 20), and 25 healthy matched non-pregnant women participated in the study. Significantly elevated levels of maternal TNF-alpha, sTNF receptor (R)-1 and R-2, leptin (detected by enzyme-linked immunosorbent assay) and fasting C-peptide (measured by radioimmunossay and raised body mass index (BMI) were found in GDM patients and in the third trimester of normal pregnancies. TNF-alpha, sTNFR-2, C-peptide, leptin concentrations and BMI positively correlated with each other in GDM. An inverse relationship between the body length, head circumference and body weight of the newborns, and maternal TNF-alpha, leptin and C-peptide concentrations was shown in GDM. In healthy pregnancies the maternal serum leptin level was in a negative linear correlation with the head circumference of the newborns. In conclusion, increased TNF-alpha and leptin levels may contribute to insulin resistance in GDM and in the third trimester of normal pregnancy and may negatively influence the anthropometric parameters of the newborns.

Topics: Adult; Anthropometry; Antigens, CD; Birth Weight; Body Height; C-Peptide; Cephalometry; Diabetes, Gestational; Female; Humans; Infant, Newborn; Insulin Resistance; Leptin; Pregnancy; Receptors, Leptin; Receptors, Tumor Necrosis Factor; Receptors, Tumor Necrosis Factor, Type II; Tumor Necrosis Factor-alpha

When compared with values recorded in 14 control subjects, the 15 overweight patients with type 2 diabetes displayed significantly increased activities of serum alanineaminotransferase (172% of mean values in controls), gamma-glutamyltransferase (253%) and cholinesterase (139%). A much wider dispersion of individual values for the two firstly mentioned enzymes was however noted so that their correlation with serum triglycerides levels were weaker (r = 0.373; p < 0.05 and r = 0.451; p < 0.05 respectively) than the same correlation obtained for serum cholinesterase (r = 0.760; p < 0.001). In two other studies including 28 controls and 30 diabetic patients serum cholinesterase was found to be significantly correlated with serum levels of insulin (r = 0.622; p < 0.001), C-peptide (r = 0.652; p < 0.001) and free fatty acid (r = 0.821; p < 0.001). Circumstantial evidence is provided that insulin resistance and an increased flux of free fatty acids from adipose tissue to the liver would stimulate the hepatic synthesis of serum cholinesterase.

Topics: Adult; C-Peptide; Cholinesterases; Diabetes Mellitus, Type 2; Fatty Acids, Nonesterified; Female; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Obesity

To investigate the relationships between serum concentrations of soluble adhesion molecules and hyperglycemia, insulin resistance, or other conventional risk factors in type 2 diabetes, we measured soluble intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), E-selectin (sE-selectin), insulin sensitivity, and conventional risk factors in 150 Japanese type 2 diabetic patients without apparent diabetic macroangiopathy. High serum concentrations of sVCAM-1 and sE-selectin were observed in patients with type 2 diabetes. Serum concentrations of soluble adhesion molecules were not significantly influenced by sex, hypertension, dyslipidemia, or microangiopathy. Spearman correlation showed that sVCAM-1 concentrations correlated significantly with fasting plasma glucose (FPG), fasting C-peptide, and insulin sensitivity [K index of the insulin tolerance test (K(ITT))] (rho=0.19,0.23, and -0.23, respectively). Soluble E-selectin concentrations correlated significantly with body mass index (BMI), FPG, fasting C-peptide, insulin sensitivity, and triglyceride (rho=0.33,0.42,0.26,-0.48, and 0.29, respectively). Multiple regression analysis showed that FPG, fasting C-peptide, and total cholesterol were independent factors that correlated with sVCAM-1 levels. BMI, FPG, and insulin sensitivity were independent factors that correlated with sE-selectin levels. Serum concentrations of sE-selectin significantly increased associated with clustering of conventional risk factors those obesity, hypertension, dyslipidemia, and current smoking (P<0.01). Thus, sVCAM-1 and sE-selectin levels are related to both hyperglycemia and insulin resistance. Soluble E-selectin levels may be related to obesity, hyperglycemia, and insulin resistance and may reflect the presence of a multiple risk factor clustering syndrome.

Topics: Blood Glucose; Body Mass Index; C-Peptide; Cell Adhesion Molecules; Cholesterol; Diabetes Mellitus, Type 2; E-Selectin; Fasting; Female; Humans; Hyperglycemia; Insulin Resistance; Intercellular Adhesion Molecule-1; Male; Middle Aged; Risk Factors; Solubility; Triglycerides; Vascular Cell Adhesion Molecule-1

The availability of quantitative indexes describing beta-cell function in normal life conditions is important for the characterization of impaired mechanisms of insulin secretion in pathophysiological states. Recently, an oral C-peptide minimal model has been proposed and applied to subjects with normal glucose tolerance (NGT) during graded up-and-down glucose infusion protocols (40-min periods at 4, 8, 16, 8, 4, and 0 mg.kg(-1).min(-1)) and oral glucose tolerance tests. These tests are characterized by slow glucose and C-peptide dynamics, which reproduce prandial conditions. In view of the importance of beta-cell dysfunction in the pathogenesis of type 2 diabetes, our aim was to test and use the oral minimal model in subjects with impaired glucose tolerance (IGT) to identify deranged mechanisms of beta-cell function. Plasma C-peptide and glucose data from graded up-and-down glucose infusions were analyzed in nine NGT and four IGT subjects using the classic deconvolution approach and the oral minimal model, and indexes of beta-cell function were derived. An index of insulin sensitivity was also obtained for each subject from minimal model analysis of glucose and insulin levels achieved during the test. Both deconvolution and minimal model analyses revealed that individuals with IGT have a relative defect in the ability to secrete enough insulin to adequately compensate for insulin resistance. Additionally, minimal model analysis suggests that insulin secretory defect in IGT arises from delays in the timing of the beta-cell response to glucose.

Topics: Adult; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Male; Models, Biological; Predictive Value of Tests; Reaction Time

Insulin resistance with increased insulin and C-peptide levels is the basis of the metabolic X-syndrome, so it is reasonable to expect them to be a good predictor of associated cardiovascular risk factors.. A total of 29 patients (21 postmenopausal women and 8 men) with type 2 diabetes mellitus (mean duration 14.6 years, 95% CI 11.9 to 17.3 years), all older than 50, were studied for possible links between fasting serum C-peptide levels and other vascular risk factors. The mean value of the C-peptide in the group was 0.627 nmol/l (95% CI: 0.464 to 0.789 nmol/l).. We found statistically significant correlations between C-peptide and triacylglycerols (TG; r=0.474; p=0.009), HDL-cholesterol (inverse; r = -0.567; p = 0.001) and various lipoprotein ratios: atherogenic index (= total/HDL cholesterol: r = 0.599; p = 0.0006) or TG/HDL (r = 0.587; p = 0.0008). C-peptide also correlated with the body mass index (BMI: r = 0.519; p= 0.004) and leptin (r = 0.492; p = 0.007). After the coefficient CpG (C-peptide x fasting glycemia) was introduced, the correlations with lipoproteins became even stronger.. We suggest that elevated (fasting) serum C-peptide levels constitute a clinically important marker of the cardiovascular risks associated with the metabolic X-syndrome. It can be used as an effective tool for the early detection of diabetic patients at particular risk for atherosclerotic cardiovascular diseases and needing early preventive measures or aggressive treatment.

Topics: Aged; C-Peptide; Cardiovascular Diseases; Diabetes Mellitus, Type 2; Female; Humans; Hyperlipoproteinemias; Insulin; Insulin Resistance; Lipoproteins; Male; Metabolic Syndrome; Middle Aged; Peptides; Postmenopause; Risk Factors

To study whether antibodies to glutamic acid decarboxylase (GADab) are associated with subclinical beta-cell damage and impaired insulin secretion, we screened 441 nondiabetic patients with autoimmune thyroiditis (AT) for GADab, and 15 (3.4%) were found positive. Antibodies to IA-2 were found in two GADab+ and one GADab- patients. We matched 11 GADab+ and 13 GADab- AT patients who were euthyroid on thyroxin supplementation, and 13 control subjects for sex, age, and body mass index and measured insulin, C-peptide, and glucagon response to glucose and arginine at three blood glucose concentrations (fasting, 14 mmol/liter, >25 mmol/liter). In the fasting state, all groups had similar blood glucose concentration and HbA1c level, but the serum insulin concentration was higher in the AT patients compared with the control subjects (P < 0.04). The acute insulin response to arginine was lower in GADab+ than in GADab- thyroiditis subjects at glucose concentration of 14 and >25 mmol/liter (AIR(14): 76.8 +/- 52.0 vs. 158.2 +/- 118.2 mU/liter, P = 0.040; AIR(>25): 84.3 +/- 64.4 vs. 167.9 +/- 101.5 mU/liter, P = 0.035). In conclusion, GADab were associated with a decreased insulin secretion capacity in nondiabetic subjects with thyroiditis, which suggests that GADab positivity could be a marker of subclinical insulitis.

Topics: Adult; Aged; Antibodies; Arginine; C-Peptide; Chronic Disease; Female; Follow-Up Studies; Glucagon; Glucose; Glutamate Decarboxylase; Humans; Injections, Intravenous; Insulin; Insulin Resistance; Islets of Langerhans; Male; Middle Aged; Thyroiditis, Autoimmune

Diabetes mellitus (DM) is a complication of tacrolimus therapy. This prospective study evaluated the prevalence of DM in South African black and white patients receiving tacrolimus after kidney transplantation and factors that could identify patients before transplantation who may be at risk of developing DM.. Fasting blood samples from 17 patients (11 black, 6 white) were analyzed immediately pretransplantation and at 1 and 3 months posttransplantation for glucose, HbAIC, insulin, C-peptide, free fatty acids, lipids, urea, and creatinine. Insulin resistance (IR) was calculated using the homeostasis model assessment (HOMA) and quantitative insulin sensitivity check index (QUICKI) formulas.. Eight patients (47%) became diabetic (six black, two white), and nine patients (five black, four white) remained nondiabetic. Mean glucose concentrations in the diabetic group were significantly higher at 1 month (P=0.03) and 3 months (P=0.01). Mean insulin level was also significantly raised at 3 months (P=0.01) as was HbAIC (P=0.001). C-peptide concentrations did not change significantly in either group. Significant correlations emerged between fasting glucose concentrations at 3 months posttransplantation and initial HOMA (r=0.486; P=0.048) and initial QUICKI (r=-0.582; P=0.014).. Occurrence of DM was high and somewhat greater in black patients. IR was the main mechanism involved, together with inadequate beta-cell compensation. IR pretransplantation predicts the subsequent development of DM.

Topics: Adult; Black People; Blood Glucose; C-Peptide; Diabetes Mellitus; Female; Glycated Hemoglobin; Homeostasis; Humans; Immunosuppressive Agents; Insulin; Insulin Resistance; Kidney Transplantation; Male; Middle Aged; Models, Biological; Regression Analysis; South Africa; Tacrolimus; Time Factors; White People

The aim of the study was to investigate the pathophysiological role of the tumor necrosis factor (TNF) system in insulin resistance in patients with gestational diabetes (GDM) and during the course of normal pregnancy.. Thirty women with GDM (16-39 gestational weeks), 35 healthy pregnant women (15 first, nine second and 11 third trimester) and 25 healthy age-matched non-pregnant women were studied. Serum TNF-alpha, and its soluble receptors 1 and 2 (sTNFR-1 and -2) were measured.. In non-diabetic pregnant women in the third trimester all measures were significantly higher (P<0.05 or less) than in the first trimester and in non-pregnant women (BMI 27.6 +/- 4.1 (+/- S.D.), 24.1 +/- 2.6, 22.4 +/- 2.4 kg/m(2)), serum TNF-alpha (4.6 +/- 0.6, 4.1 +/- 0.4, 4.1 +/- 0.4 ng/l), sTNFR-1 (2.7 +/- 0.9, 2.0 +/- 0.5, 2.0 +/- 0.1 microg/l), sTNFR-2 (5.6 +/- 2.6, 4.6 +/- 2.1, 3.3 +/- 0.2 microg/l), C-peptide (3.1 +/- 1.7, 1.1 +/- 0.7, 1.1 +/- 0.8 microg/l), and C-peptide:blood glucose ratio (0.6 +/- 0.2, 0.2 +/- 0.1, 0.2 +/- 0.1 microg/mmol). In GDM these measures were even higher than in any subgroup of healthy pregnant women (BMI) (33.4 +/- 6.4 kg/m(2), TNF-alpha) (6.3 +/- 0.6 microg/l), sTNFR-1 (3.0 +/- 0.5 microg/l), sTNFR-2 (10.0 +/- 6.9 microg/l, C-peptide 6.0 +/- 2.7 microg/l, C-peptide:blood glucose ratio: 1.2 +/- 0.5 microg/mmol, P<0.01). Significant (P<0.01) positive linear correlations were found in gestational diabetic and non-diabetic women between serum TNF-alpha, C-peptide levels, and BMI. In gestational diabetic women, in multivariate analysis studying the dependency of C-peptide only BMI remained significant (r(2)=0.67, P=0.01).. Our observation emphasizes the obesity-related component of insulin resistance driven by adipocytokines, such as TNF-alpha and its receptors during the course of normal pregnancy and GDM.

Topics: Antigens, CD; Blood Glucose; Body Mass Index; C-Peptide; Diabetes, Gestational; Female; Fructosamine; Glycated Hemoglobin; Health Status; Humans; Insulin Resistance; Pregnancy; Receptors, Tumor Necrosis Factor; Receptors, Tumor Necrosis Factor, Type I; Receptors, Tumor Necrosis Factor, Type II; Reference Values; Regression Analysis; Tumor Necrosis Factor-alpha

The aim of this present investigation was to study the relationship between the reduction in insulin sensitivity accompanying 5 days of treatment with growth hormone (GH; 0.05 mg.24 h(-1).kg(-1)) and intracellular substrate oxidation rates in six healthy subjects, while maintaining glucose flux by a constant glucose infusion and adjusting insulin infusion rates to achieve normoglycaemia (feedback clamp). Protein synthesis rates in skeletal muscle (flooding dose of L-[(2)H(5)]phenylalanine) were determined under these conditions. We also compared changes in insulin sensitivity after GH treatment with simultaneous changes in energy requirements, protein synthesis rates, nitrogen balance, 3-methylhistidine excretion in urine, body composition and the hormonal milieu. After GH treatment, 70% more insulin was required to maintain normoglycaemia (P<0.01). The ratio between glucose infusion rate and serum insulin levels decreased by 34% at the two levels of glucose infusion tested (P<0.05). Basal levels of C-peptide, insulin-like growth factor (IGF)-I and IGF-binding protein-3 increased almost 2-fold, while levels of glucose, insulin, glucagon, GH and IGF-binding protein-1 remained unchanged. Non-esterified fatty acid levels decreased (P<0.05). In addition, 24 h urinary nitrogen excretion decreased by 26% (P<0.01) after GH treatment, while skeletal muscle protein synthesis and 3-methylhistidine excretion in urine remained unchanged. Energy expenditure increased by 5% (P<0.05) after treatment, whereas fat and carbohydrate oxidation were unaltered. In conclusion, when glucose flux was normalized by compensatory hyperinsulinaemia under conditions of GH-induced insulin resistance, intracellular rates of oxidation of glucose and fat remained unchanged. The nitrogen retention accompanying GH treatment seems to be due largely to improved nitrogen balance in non-muscle tissue.

Topics: Adult; Blood Glucose; Body Composition; C-Peptide; Calorimetry, Indirect; Drug Administration Schedule; Energy Metabolism; Fatty Acids, Nonesterified; Glucose; Glucose Clamp Technique; Human Growth Hormone; Humans; Insulin; Insulin Resistance; Insulin-Like Growth Factor Binding Protein 3; Insulin-Like Growth Factor I; Male; Muscle Proteins; Muscle, Skeletal; Nitrogen; Oxidation-Reduction; Plethysmography, Whole Body

Iron is an important factor in the process of oxidation stress and atherogenesis which is as a rule potentiated in subjects with the insulin resistance syndrome. Hypertension is one of the main components of this syndrome. Ferritin due to its relationship with impaired insulin sensitivity becomes a candidate for a new indicator of insulin resistance. The subject of the present study was to assess whether we shall find in young healthy offspring of hypertensive parents changes in the ferritin level, oxidizability of LDL and whether these are related to parameters of glucose tolerance, insulin secretion and sensitivity. Twelve young (27 +/- 3.6 years) non-obese, normotesive offspring of hypertensive parents were compared with a group of 14 controls. Glucose tolerance, insulin secretion and sensitivity were examined by means of a hyperglycaemic clamp and oGTT. As to the ferritin level, the offspring of hypertensive parents did not differ significantly from controls, differences were not fond in the oxidizability of LDL-C. The glucose tolerance was comparable in the two groups. Offspring of hypertensive parents had however a significantly higher insulin and C peptide level when using the clamp and during the glucose tolerance test (p < 0.05), and a reduced insulin sensitivity (p < 0.05). The negative correlation between the index of insulin sensitivity and ferritin suggests that ferritin could be associated with the syndrome of insulin resistance.

Topics: Adult; Arteriosclerosis; C-Peptide; Ferritins; Glucose Tolerance Test; Humans; Hypertension; Insulin; Insulin Resistance; Lipoproteins, LDL; Male; Oxidative Stress; Risk Factors

One important mechanism whereby obesity-associated insulin resistance leads to VLDL overproduction is thought to be by the increased flux of free fatty acids (FFAs) from extrahepatic tissues to liver, which arises as a direct consequence of impaired insulin action in adipose tissue and skeletal muscle. The aim of the present study was to address whether direct measures of peripheral tissue insulin sensitivity with regard to FFAs and glucose in the fasting state are good predictors of postabsorptive VLDL triglyceride secretion rate (VLDL-TG ASR) in humans, independent of obesity. Eighteen healthy control subjects, after an overnight fast, underwent three studies 3 weeks apart, in random order. Study 1: VLDL-TG levels, fractional clearance rate (per h), and VLDL-TG ASR were determined after an intravenous bolus of [1,1,2,3,3-(2)H(5)] glycerol. Study 2: Insulin sensitivity (S(I)), acute insulin response (AIR), and acute C-peptide response to glucose were assessed by frequently sampled intravenous glucose tolerance test using the minimal model approach. Study 3: Insulin-mediated suppression of plasma FFAs (k) and insulin clearance were assessed in response to a low-dose stepwise intravenous insulin infusion. BMI (R(2) = 0.54), AIR, and fasting insulin levels were positively and S(I) negatively correlated with VLDL-TG ASR, but there was no significant association with plasma FFAs or k. Only BMI remained significantly associated with VLDL-TG ASR in multivariate analysis. The best multivariate model for VLDL-TG ASR (R(2) = 0.61, P = 0.0008) included BMI (P = 0.0008) and S(I) (P = 0.12, inversely correlated). VLDL-TG secretion is predicted by BMI, independently of direct measures of insulin sensitivity. The sensitivity to insulin's acute suppressive effect on plasma FFA levels during fasting is not an important determinant of postabsorptive VLDL-TG secretion in humans.

Topics: Adolescent; Adult; Apolipoproteins B; Body Mass Index; C-Peptide; Deuterium; Fasting; Fatty Acids, Nonesterified; Female; Glucose Tolerance Test; Glycerol; Humans; Insulin; Insulin Resistance; Lipoproteins, VLDL; Male; Metabolic Clearance Rate; Triglycerides

To clarify informative value of secretory ability of pancreatic beta-cells and correspondence of insulin values to glycemia in the course of standard glucose tolerance test (GTT) in detection of insulin-resistance in patients with arterial hypertension (AH) to verify metabolic syndrome (MS).. Correlation and factor analyses were performed of correlations between glycemia, immunoreactive insulin (IRI), C-peptide, glucose/IRI in the course of GTT in 111 AH patients divided into groups by the sum of metabolic disturbances.. The greatest number of correlations were seen for glucose/IRI fasting index. According to the factor analysis, changed sensitivity to insulin and hyperinsulinemia are the first stage of metabolic disturbances in AH irrespective of body mass. In obesity the number of the above correlations is maximal. Multivariance analysis has shown significant differences between AH patients and healthy subjects irrespective of body mass and glucose tolerance.. Basal index glucose/IRI < 6 relative units is informative in all the studied variants of metabolic syndrome as regards insulin resistance.

Topics: Adult; Blood Glucose; C-Peptide; Factor Analysis, Statistical; Female; Glucose Tolerance Test; Humans; Hypertension; Insulin; Insulin Resistance; Male; Metabolic Syndrome; Middle Aged; Predictive Value of Tests; Sensitivity and Specificity

First-degree relatives of Type II (non-insulin-dependent) diabetic patients in cross-sectional studies have increased insulin resistance, associated cardiovascular risk factors and abnormalities of fibrinolysis and coagulation. To minimise between-family genetic and environmental confounders, we investigated within-family relationships between early hyperglycaemia and risk factors.. Thirteen age and gender matched sibling pairs of Type II (non-insulin-dependent) diabetic patients, one hyperglycaemic, one normoglycaemic (fasting plasma glucose at screening 6.0-7.7 mmol.l(-1) and < 6.0 mmol.l(-1), respectively) were assessed for plasminogen activator inhibitor antigen (PAI-1), tissue plasminogen activator antigen (t-PA), fibrinogen, Factor VII and Factor VIII/von Willebrand factor antigen. Fasting lipid profiles, blood pressure and HOMA insulin sensitivity (%S) were also measured in siblings and in matched subjects without family history of diabetes.. Hyperglycaemic and normoglycaemic siblings (7 female, 6 male) were aged, mean (SD) 56.8 (8.7) and 55.8 (8.4) years. Hyperglycaemic siblings had increased PAI-1 antigen, geometric mean (i.q.r.): 26.3 (15.1-45.6) vs 11.1 (2.1-23.3) ng/ml, p=0.0002, similar t-PA antigen, mean (SD) 9.5 (4.3) vs 7.4 (2.5) ng/ml, p=0.2 and fibrinogen 2.2 (0.3) vs 2.3 (0.6) g/l, p=0.5, and reduced %S 66.3 (30.5) vs 82.9 (25), p=0.04. PAI-1 correlated negatively with %S ( r=-0.55, p=0.005). No significant differences were found in blood pressure or fasting lipids.. A minor increase in plasma glucose in non-diabetic sibling pairs of Type II (non-insulin-dependent) diabetic patients was associated with reduced insulin sensitivity, increased central adiposity and a doubling of PAI-1 antigen concentration, suggesting impaired fibrinolysis. It is possible that this could contribute to increased cardiovascular risk in these subjects.

Topics: Blood Glucose; C-Peptide; Cross-Sectional Studies; Diabetes Mellitus; Diabetes Mellitus, Type 2; Female; Humans; Hyperglycemia; Insulin; Insulin Resistance; Islets of Langerhans; Male; Middle Aged; Obesity; Plasminogen Activator Inhibitor 1; Proinsulin; Reference Values; Siblings; Smoking

To assess insulin sensitivity and beta cell secretion in indigenous Ghanaian subjects with a spectrum of glucose intolerance.. We evaluated beta cell secretion, insulin sensitivity (Si) and glucose effectiveness (Sg) in three groups: group 1, 15 healthy control subjects without family history of type 2 diabetes; group 2, 11 healthy non-diabetic first-degree relatives of Ghanaian patients with type 2 diabetes; and group 3, 10 patients with type 2 diabetes living in Accra, Ghana, West Africa. A standard oral glucose tolerance test (OGTT) and frequently sampled intravenous glucose tolerance (FSIGT) test were performed for each subject. Si and Sg were measured using Bergman's minimal model method.. The mean body mass index (BMI) and lean body mass were not different among the three groups. However, the waist-to-hip circumference ratio, total body fat as well as triceps and biceps skinfolds were significantly greater in group 3 (diabetic patients) than in group 2 (relatives) and group 1 (healthy controls). Mean fasting and postprandial serum glucose levels were not significantly different between the relatives and healthy controls during oral glucose challenge. The mean fasting and postprandial serum glucose levels were significantly higher in the group 3 diabetic patients than in the non-diabetic groups. Mean fasting serum insulin and C-peptide levels tended to be higher in group 3 than in groups 1 and 2. However, mean serum insulin and C-peptide responses after oral glucose load were significantly greater in group 2 than in the group 1 healthy controls. The insulin responses in the two non-diabetic groups after oral glucose challenge were significantly greater than in the diabetic patients. During the FSIGT, the mean serum glucose responses were similar in the two non-diabetic groups (groups 1 and 2). The serum glucose responses were significantly greater in group 3 than in the non-diabetic groups. Mean total and acute first and second phases of insulin and C-peptide responses were greater in group 2 than group 1. However, acute phases of insulin secretion were severely blunted in group 3 when compared with groups 1 and 2 during FSIGT in our Ghanaians. We found that the mean Si was slightly lower in group 2 (1.72 +/- 0.32) than in the healthy controls in group 1 (1.9 +/- 0.55, P = NS). Mean Si was remarkably lower in the diabetic patients in group 3 (1.30 +/- 0.35 x 10(-4)/min (microU/ml)) when compared with the relatives and healthy controls, but the differences were not statistically significant. Mean glucose effectiveness at basal insulin level (Sg) was not significantly different among the relatives in group 2 (2.38 +/- 0.50), the healthy controls in group 1 (2.66 +/- 0.38) and the diabetic patients in group 3 (2.27 +/- 0.49 x 10(-2)/min).. We conclude that (i) the pathogenetic mechanisms of type 2 diabetes in indigenous Ghanaians are characterised by severe beta cell dysfunction and moderate reduction in Si. Although the healthy relatives manifest insulin resistance with compensatory hyperinsulinaemia, our study suggests that the conversion of such subjects to type 2 diabetes is determined by deterioration in beta cell function and perhaps Si but not tissue Sg in Ghanaians. Prospective studies are needed to examine the sequential changes that lead to the development of type 2 diabetes in indigenous Ghanaians.

Topics: Adult; Anthropometry; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Genetic Predisposition to Disease; Ghana; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Islets of Langerhans; Male

The simultaneous assessment of quantitative indexes of insulin secretion and action in a single individual is important when quantifying their relative role in the evolution of glucose tolerance in different physiopathological states. Available methods quantify these indexes in relatively nonphysiological conditions, e.g., during glucose clamps or intravenous glucose tolerance tests. Here, we present a method based on a physiological test applicable to large-scale genetic and epidemiologic studies-the oral glucose tolerance test (OGTT). Plasma C-peptide, insulin, and glucose data from a frequently sampled OGTT with 22 samples throughout 300 min (FSOGTT300-22) were analyzed in 11 subjects with various degrees of glucose tolerance. In each individual, two indexes of pancreatic sensitivity to glucose (phis [10(9) min(-1)] and phid [10(9)]) and the insulin sensitivity index (SI) (10(5) dl/kg per min per pmol/l) were estimated by using the minimal model of C-peptide secretion and kinetics originally proposed for intravenous graded glucose infusion and the minimal model approach recently proposed for meal/OGTTs. The indexes obtained from FSOGTT300-22 were used as a reference for internal validation of OGTT protocols with reduced sampling schedules. Our results show that 11 samples in a 300-min period (OGTT300-11) is the test of choice because the indexes it provides (phis = 36 +/- 3 [means +/- SE]; phid = 710 +/- 111; SI = 10.2 +/- 2.4) show excellent correlation and are not statistically different from those of FSOGTT300-22 (phis = 33 +/- 3; phid = 715 +/- 120; SI = 10.1 +/- 2.3). In conclusion, OGTT300-11, interpreted with C-peptide and glucose minimal models, provides a quantitative description of beta-cell function and insulin sensitivity in a single individual while preserving the important clinical classification of glucose tolerance provided by the standard 120-min OGTT.

Topics: Adult; Blood Glucose; C-Peptide; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Islets of Langerhans; Male; Models, Biological; Specimen Handling

Insulin resistance is associated with atherosclerosis, and hyperinsulinemia is predictive of coronary heart disease. However, a quantitative estimation of in vivo insulin sensitivity in juvenile myocardial infarction is still lacking and the mechanism of hyperinsulinemia is unknown. We estimated insulin sensitivity, beta-cell secretion, and hepatic insulin extraction using the minimal model analysis of a frequently sampled intravenous glucose tolerance test (FSIGT) in 25 normal-weight subjects without glucose intolerance and hypertension who had an acute myocardial infarction before the age of 40 years, and 10 control subjects comparable for age, sex, body mass index, and blood pressure. All patients underwent a coronary angiography. Insulin sensitivity was significantly lower in patients than in control subjects (mean +/- SEM, 4.6 +/- 0.6 v8.5 +/- 1.2 10(-4). min(-1)(microU/mL), P = .002). The basal C-peptide secretion rate (P = .02), total C-peptide secretion (P = .005), area under the curve (AUC) of insulin (P = .04) and C-peptide (P = .01), and hepatic insulin extraction (P = .04) were higher in patients versus control subjects. In conclusion, insulin resistance is evident in subjects with early myocardial infarction accurately selected to avoid the influence of other factors known to reduce insulin sensitivity, and hyperinsulinemia is due to an increase in beta-cell secretion rather than a decrease in hepatic insulin extraction.

Topics: Adult; Age Factors; Blood Glucose; C-Peptide; Coronary Vessels; Female; Humans; Insulin; Insulin Resistance; Islets of Langerhans; Male; Myocardial Infarction; Time Factors

To examine whether factors controlling glucose tolerance, i.e., insulin sensitivity (SI) and first-(phi1) and second-phase insulin secretion (phi2), are impaired in after orthotopic liver transplantation (OLT), they were assesssed in patients that had undergone OLT for cirrhosis (n = 10) with cyclosporin A and low-dose steroid therapy (5 mg prednisone per day) and were compared with those of healthy matched control subjects (n = 10). These factors were determined by means of computer-based analysis of frequently sampled intravenous glucose tolerance tests (FSIGTT). Glucose and insulin profiles (posthepatic insulin) did not differ between both groups, whereas C-peptide levels (prehepatic insulin) were elevated in the transplant group after the FSIGTT, indicating an increased hepatic insulin degradation. SI and (phi1 did not differ between both groups. phi2, however, was significantly enhanced (23.94 +/- 2.63 vs 13.88 +/- 1.25 min(-1), P < 0.05). These results indicate that cyclosporine and low-dose steroid therapy do not impair SI and phi1. However, enhanced phi2 compensates the increased hepatic insulin clearance.

Topics: Adult; Blood Glucose; C-Peptide; Case-Control Studies; Cyclosporine; Female; Glucocorticoids; Glucose Tolerance Test; Humans; Immunosuppressive Agents; Insulin; Insulin Resistance; Islets of Langerhans; Liver; Liver Transplantation; Male; Middle Aged; Prednisone

Insulin resistance is known as an important risk factor for coronary artery disease (CAD). However, CAD-related mortality in Japanese type 2 diabetics is lower than in Caucasians. To investigate whether insulin resistance is related to CAD in Japanese type 2 diabetics, we measured insulin sensitivity and several coronary risk factors in Japanese patients with type 2 diabetes with and without CAD. Thirty-three patients with definite CAD and 33 age- and sex-matched patients without CAD (control) were studied. Insulin sensitivity was assessed by the K index of insulin tolerance test (KITT). Clinical characteristics, classical risk factors, lipoprotein (a), and insulin sensitivity were compared between the two groups. Patients with CAD had a significantly longer duration of diabetes (9.0 +/- 1.4 vs. 5.5 +/- 0.9 years, P < 0.05, respectively), were mostly hypertensive (69.7 vs. 39.4%, P < 0.05), and more likely to be treated with insulin (45.5 vs. 18.2%, P < 0.05) compared with the control. Concerning the metabolic parameters, patients with CAD had a significantly higher insulin resistance than control (2.40 +/- 0.15 vs. 3.23 +/- 0.17%/min, P < 0.01, respectively), higher triglyceride (1.39 +/- 0.10 vs. 1.05 +/- 0.05 mmol/l, P < 0.05), lower HDL cholesterol (1.05 +/- 0.05 vs. 1.28 +/- 0.06 mmol/l, P < 0.05), and higher lipoprotein (a) (27.5 +/- 4.3 vs. 17.4 +/- 2.0 mg/dl, P < 0.05). Multiple logistic regression analysis indicated that hypertension, insulin resistance, high lipoprotein (a) and triglyceride, and low HDL cholesterol were independently related to CAD. Our results suggest that insulin resistance per se is a significant risk factor for CAD in Japanese patients with type 2 diabetes.

Topics: Aged; Asian People; Blood Glucose; Blood Pressure; C-Peptide; Cholesterol; Cholesterol, HDL; Coronary Disease; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Female; Glycated Hemoglobin; Humans; Insulin Resistance; Japan; Lipoprotein(a); Male; Middle Aged; Myocardial Infarction; Risk Factors; Smoking; Triglycerides; White People

Insulin resistance as well as marked changes in body weight and energy metabolism are associated with pregnancy. Its impact on plasma leptin is not known and was determined in this longitudinal study in both diabetic and normal pregnancy.. At 28 gestational weeks plasma concentrations of leptin and B-cell hormones were measured at fasting and after an oral glucose load (OGTT:75 g) in women with gestational diabetes and pregnant women with normal glucose tolerance and compared with women who were not pregnant (C).. Plasma leptin (ng/ml) was higher (p < 0.001) in women with gestational diabetes (24.9 +/- 1.6) than in women with normal glucose tolerance (18.2 +/- 1.5) and increased in both groups when compared with the non-pregnant women (8.2 +/- 1.3; p < 0.0005). No change in plasma leptin concentrations was induced by OGTT in any group. Basal insulin release was higher (p < 0.05) in women with gestational diabetes compared with the pregnant women with normal glucose tolerance. Marked insulin resistance was confirmed by a 20 % lower (p < 0.05) insulin sensitivity in subgroup analysis and a decrease of almost 40% in fasting glucose/insulin ratio (p < 0.005) in women with gestational diabetes. Leptin correlated in women with gestational diabetes with basal plasma concentrations of glucose (p < 0.02), insulin (p < 0.004) and proinsulin (p < 0.01) as well as with BMI (p < 0.001) and overall pregnancy induced maternal weight gain (p < 0.009). With normalisation of blood glucose 8 weeks after delivery in women with gestational diabetes their plasma leptin decreased (p < 0.0005) to 17.3 +/- 1.9 ng/ml but did not completely normalize (p < 0.05 vs non-pregnant women).. Our data show that women with gestational diabetes without any change in plasma leptin upon oral glucose loading have increased plasma leptin concentrations during and after pregnancy, a clear association of plasma leptin with the respective concentration of glucose and insulin resistance as well as with changes in body weight, and a failure to normalize spontaneously BMI to the same extent as pregnant women with normal glucose tolerance when compared with matched control subjects.

Topics: Adult; Birth Weight; Blood Glucose; Body Mass Index; C-Peptide; Diabetes, Gestational; Fasting; Female; Gestational Age; Glucose Tolerance Test; Humans; Infant, Newborn; Insulin; Insulin Resistance; Insulin Secretion; Leptin; Postpartum Period; Pregnancy; Proinsulin; Regression Analysis; Weight Gain

Phosphatase and tensin homologue deleted from chromosome ten (PTEN) has recently been characterized as a novel member in the expanding network of proteins regulating the intracellular effects of insulin. By dephosphorylation of phosphatidyl-inositol-(3, 4, 5)-trisphosphate (PIP3) the PTEN protein regulates the insulin-dependent phosphoinositide 3-kinase (PI3K) signalling cassette and accordingly might function as a regulator of insulin sensitivity in skeletal muscle and adipose tissue. In this study we tested PTEN as a candidate gene for insulin resistance and late-onset Type II (non-insulin-dependent) diabetes mellitus in a Danish Caucasian population.. The nine exons of the PTEN, including intronic flanking regions were analysed by PCR-SSCP and heteroduplex analysis in 62 patients with insulin-resistant Type II diabetes.. No mutations predicted to influence the expression or biological function of the PTEN protein but four intronic polymorphisms were identified: IVS1-96 A-->G (allelic frequency 0.22, 95 % CI: 0.12-0.32), IVS3 + 99 C-->T (0.01, CI: 0-0.03), IVS7-3 TT-->T (0.10, CI: 0.03-0.18) and IVS8 + 32 G-->T (0.35, CI: 0.23-0.47). The IVS8 + 32 G-->T polymorphism was used as a bi-allelic marker for the PTEN locus and examined in 379 patients with Type II diabetes and in 224 control subjects with normal glucose tolerance. The IVS8 + 32 G-->T polymorphism in the PTEN was not associated with Type II diabetes and it did not have any effect on body-mass index, blood pressure, HOMA insulin resistance index, or concentrations of plasma glucose, serum insulin or serum C peptide obtained during an oral glucose tolerance test (OGTT).. Variability in the PTEN is not a common cause of Type II diabetes in the Danish Caucasian population.

Topics: Adipose Tissue; Adult; Aged; Blood Glucose; Blood Pressure; C-Peptide; Denmark; Diabetes Mellitus, Type 2; Exons; Fasting; Gene Frequency; Humans; Insulin; Insulin Resistance; Middle Aged; Muscle, Skeletal; Phosphatidylinositol 3-Kinases; Phosphatidylinositol Phosphates; Phosphoric Monoester Hydrolases; Polymerase Chain Reaction; Polymorphism, Genetic; Polymorphism, Restriction Fragment Length; Polymorphism, Single-Stranded Conformational; PTEN Phosphohydrolase; Tumor Suppressor Proteins; White People

Abnormalities in mitochondrial DNA(mtDNA) have been implicated in the pathogenesis of diabetes mellitus. We recently reported that decreased mtDNA content precedes the development of diabetes mellitus and is associated with parameters of insulin resistance. In this study, we examined whether there is any relation between mtDNA content and insulin secretion. We compared the mtDNA content of peripheral blood leukocytes with the parameters of insulin secretion measured by hyperglycemic clamp in a group of healthy young men. There were statistically significant correlations between mtDNA content in peripheral blood and fasting plasma insulin (r=-0.43, P<0.05) and C-peptide levels (r=-0.44, P<0.05). MtDNA content also correlated negatively with acute insulin response(r=-0.48, P<0.05), late insulin response (r=-0.50, P<0.05) during hyperglycemic clamp and insulin secretion after glucagon stimulation (r=-0.60, P<0.01). mtDNA content in peripheral blood correlated negatively with homeostasis model (HOMA) insulin resistance (r=-0.45, P<0.05) although it did not correlate with the insulin insensitivity index (M/I) during hyperglycemic clamp. In summary, the mtDNA content of peripheral blood correlated negatively with indices of insulin resistance and insulin secretion in healthy young men. The compensatory response of pancreas beta cells to insulin resistance might contribute in part to increased insulin secretion in these subjects.

Topics: Adult; Anthropometry; C-Peptide; DNA, Mitochondrial; Glucagon; Glucose Clamp Technique; Homeostasis; Humans; Hyperglycemia; Insulin; Insulin Resistance; Insulin Secretion; Leukocytes; Male; Reference Values

Insulin resistance in chronic liver disease (CLD) is well documented. This study investigated whether similar changes occur in acute liver failure (ALF). Patients with ALF (n = 10) were recruited within 72 hours of their peak prothrombin time (range 42-120 seconds). All patients were ventilated for encephalopathy (grade III-IV). Peripheral and endogenous insulin sensitivity were assessed by a hyperinsulinemic euglycemic clamp (Human Actrapid 1.5 mU/min/kg) with an infusion of D-[6,6-(2)H(2)] glucose. The clamp was performed on day 0 and then on day 7 and day 14. During the insulin infusion, the mean total peripheral glucose uptake (area under the curve [AUC]) was 1,422 (SD, 1,253), 2,244 (SD, 1,392), and 4,500 (SD, 1,120) micromol/kg on days 0, 7, and 14, respectively. Significant changes occurred from day 0 to 14 (day 14-day 0: 3,078 [95% CI, 1,798 to 4,359]; P =.001) and day 7 to 14 (day 14-day 7: 2,256 [95% CI, 923 to 3,589]; P =.001). No significant difference in endogenous glucose production was demonstrated over time. Mean peripheral insulin sensitivity altered over time, increasing from 0.09 (SD, 0.09) micromol/kg/min/mU/L on day 0 to 0.24 (SD, 0.16) on day 7 and 0.5 (SD, 0.1) on day 14. Significant changes occurred between days 0, 7, and 14 (day 7-day 0: 0.15 [95% CI, 0.04 to 0.26], P =.006; day 14-day 0: 0.4 [95% CI, 0.28 to 0.5], P =.001; day 14-day 7: 0.2 [95% CI, 0.12 to 0.38], P =.001). This study demonstrates that in ALF, impaired peripheral uptake of glucose occurs, peripheral insulin sensitivity being restored at 2 weeks in subjects who survived.

Topics: Acetaminophen; Adult; Blood Glucose; C-Peptide; Fatal Outcome; Fatty Acids, Nonesterified; Female; Glucagon; Glucose Clamp Technique; Humans; Insulin; Insulin Resistance; Insulin-Like Growth Factor I; Kinetics; Liver Failure, Acute; Male; Metabolic Clearance Rate; Middle Aged; Multiple Organ Failure

Insulin inhibition of insulin secretion has been described in normal lean subjects. In this study, we examined whether this phenomenon also occurs in the morbidly obese who often have severe peripheral insulin resistance.. Twelve obese patients, normotolerant to glucose (8 F/4 M, body mass index (BMI)=54.8+/-2.5 kg/m(2), 39 y) and 16 lean control subjects (10 F/6 M, BMI=22.0+/-0.5 kg/m(2), 31 y).. An experimental study using various parameters, including an euglycemic hyperinsulinemic clamp (280 pmol/min/m(2) of body surface), an oral glucose tolerance test (OGTT), electrical bioimpedance and indirect calorimetry.. The obese subjects were insulin resistant (M=19.8+/-1.6 vs 48.7+/-2.6 micromol/min kg FFM, P<0.0001) and hyperinsulinemic in the fasted state and after glucose ingestion. Fasting plasma C-peptide levels (obese 1425+/-131 pmol/l vs lean 550+/-63 pmol/l; P<0.0001) decreased less during the clamp in the obese groups (-16.9+/-6.9% vs -43.0+/-5.6% relative to fasting values; P=0.007). In the lean group, the C-peptide decrease during the clamp (percentage variation) was related to insulin sensitivity, M/FFM (r=0.56, P=0.03), even after adjustment for the clamp glucose variation.. We conclude that, in lean subjects, insulin inhibits its own secretion, and this may be related to insulin sensibility. This response is blunted in morbidly obese patients and may have a role in the pathogenesis of fasting hyperinsulinemia in these patients.

Topics: Adult; Body Composition; Body Mass Index; C-Peptide; Calorimetry, Indirect; Case-Control Studies; Electric Impedance; Female; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Male; Obesity, Morbid

Plasma free fatty acids and intramyocellular triglycerides (IMCL) content modulate whole body insulin sensitivity in humans. To test whether the interactions between fatty acid metabolism and insulin action in nonobese humans are related to gender factors, we studied 15 young, normal weight, healthy men and 15 women matched for life habits and whole body insulin sensitivity, determined with the euglycemic-hyperinsulinemic clamp, by means of indirect calorimetry to assess substrate oxidation, localized (1)H nuclear magnetic resonance spectroscopy of calf muscles to assess IMCL content, and dual energy x-ray absorption to assess body composition. In addition, to test whether perturbation of the feminine hormonal milieu modifies these interactions, we studied 15 matched females using oral steroidal contraception (OSC). Insulin sensitivity in women, notwithstanding increased body fatness, plasma free fatty acids, IMCL content, and circulating beta-hydroxybutyrate levels and reduced lipid oxidation, was similar to that in men. Women using OSC showed a 40% reduction of insulin sensitivity associated with increased plasma free fatty acids, beta-hydroxybutyrate, cholesterol, and triglycerides levels and a slight increment in IMCL content compared with women with intact hormonal cycles. In all groups the IMCL content was inversely related to insulin sensitivity. In conclusion, nonobese, healthy, young women are as insulin sensitive as men, notwithstanding the higher levels of postabsorptive circulating and tissue-stored fatty acids; OSC-induced insulin resistance is associated with abnormal fatty acid metabolism and loss of this gender-related feature.

Topics: 3-Hydroxybutyric Acid; Absorptiometry, Photon; Adult; Blood Glucose; Body Composition; C-Peptide; Calorimetry, Indirect; Cholesterol; Contraceptives, Oral; Fatty Acids, Nonesterified; Female; Glucose Clamp Technique; Humans; Insulin; Insulin Resistance; Leptin; Magnetic Resonance Spectroscopy; Male; Muscle, Skeletal; Receptors, Tumor Necrosis Factor; Regression Analysis; Sex Characteristics; Triglycerides

Ninety-seven women with polycystic ovary syndrome (PCOS) were tested for insulin resistance and glucose tolerance by means of the continuous infusion of glucose with model assessment (CIGMA) test. The mean concentrations of glucose and insulin at 50, 55 and 60 min of glucose infusion were interpreted using a mathematical model of glucose and insulin homeostasis, and an insulin resistance index (IR1) was obtained. Using insulin and glucose values at 60 min only, a new insulin resistance index (IR2) was obtained using the same mathematical method. In addition, fasting insulin, fasting C-peptide, fasting glucose, fasting insulin:glucose ratio and fasting C-peptide:glucose ratio were also used to assess insulin resistance. There were significant correlations between IR1 and IR2, fasting glucose, fasting insulin, fasting insulin:glucose ratio, fasting C-peptide:glucose ratio. IR2 had the highest correlation with IR1 (r = 0.97, p < 0.001) and provided the best combination of sensitivity (82.9%), specificity (93.9%), positive predictive value (91.9%) and negative predictive value (86.8%). In conclusion, the simplified CIGMA test, using insulin and glucose concentration at 60 min of glucose infusion only, is a highly sensitive and specific measure of insulin sensitivity in women with PCOS.

Topics: Adult; Blood Glucose; C-Peptide; Fasting; Female; Glucose Tolerance Test; Homeostasis; Humans; Insulin; Insulin Resistance; Kinetics; Mathematics; Models, Biological; Polycystic Ovary Syndrome; ROC Curve; Sensitivity and Specificity

After short-term exposure to high altitude (HA), men appear to be less sensitive to insulin than at sea level (SL). We hypothesized that the same would be true in women, that reduced insulin sensitivity would be directly related to the rise in plasma epinephrine concentrations at altitude, and that the addition of alpha-adrenergic blockade would potentiate the reduction. To test the hypotheses, 12 women consumed a high-carbohydrate meal at SL and after 16 h at simulated 4,300-m elevation (HA). Subjects were studied twice at each elevation: once with prazosin (Prz), an alpha(1)-adrenergic antagonist, and once with placebo (Pla). Mathematical models were used to assess insulin resistance based on fasting [homeostasis model assessment of insulin resistance (HOMA-IR)] and postprandial [composite model insulin sensitivity index (C-ISI)] glucose and insulin concentrations. Relative to SL-Pla (HOMA-IR: 1.86 +/- 0.35), insulin resistance was greater in HA-Pla (3.00 +/- 0.45; P < 0.05), SL-Prz (3.46 +/- 0.51; P < 0.01), and HA-Prz (2.82 +/- 0.43; P < 0.05). Insulin sensitivity was reduced in HA-Pla (C-ISI: 4.41 +/- 1.03; P < 0.01), SL-Prz (5.73 +/- 1.01; P < 0.05), and HA-Prz (4.18 +/- 0.99; P < 0.01) relative to SL-Pla (8.02 +/- 0.92). Plasma epinephrine was significantly elevated in HA-Pla (0.57 +/- 0.08 ng/ml; P < 0.01), SL-Prz (0.42 +/- 0.07; P < 0.05), and HA-Prz (0.82 +/- 0.07; P < 0.01) relative to SL-Pla (0.28 +/- 0.04), but correlations with HOMA-IR, HOMA-beta-cell function, and C-ISI were weak. In women, short-term exposure to simulated HA reduced insulin sensitivity compared with SL. The change does not appear to be directly mediated by a concurrent rise in plasma epinephrine concentrations.

Topics: Adrenergic alpha-1 Receptor Antagonists; Adult; Altitude; Altitude Sickness; Blood Glucose; C-Peptide; Dietary Carbohydrates; Epinephrine; Fasting; Female; Homeostasis; Humans; Insulin; Insulin Resistance; Insulin Secretion; Male; Models, Biological; Placebos; Prazosin; Receptors, Adrenergic, alpha-1; Reference Values; Sex Characteristics; Time Factors

The human beta(3)-adrenergic receptor (beta(3)AR) is expressed specifically in adipose tissues, and its activation is activated in brown adipose tissues during thermogenesis and in white adipose tissues during lipolysis. We investigated the relationship between a polymorphism of the beta(3)AR gene and the clinical features of type 2 diabetes mellitus. Studies were conducted in 30 type 2 diabetic patients (15 males and 15 females). Analysis of polymorphisms of the beta(3)AR gene was performed by a pin-point sequencing method using the hair of the subjects. Preperitoneal (P-fat) and subcutaneous fat (S-fat) levels were determined by ultrasonography. We found a Trp(64)Arg allele of the beta(3)AR gene in the hair of 27% of all patients. The patients with this mutation showed a significantly younger onset-age of diabetes than those of the wild type. The body mass index, serum GPT levels, fasting immunoreactive insulin (IRI) and daily urinary C-peptide reaction (CPR) in the mutation group were markedly higher than in the wild type group. The P-fat, serum cholesterol and leptin concentrations tended to be higher in the mutation group. Patients in the mutation group had a significantly higher prevalence of hypertension (80%) compared with those in the wild type group (20%).. The present results suggest that the clinical features of diabetic patients with a missense mutation in the beta(3)AR gene are substantially distinct from those of the wild type patients. These specific features include obesity, hyperinsulinemia, hypertension, and an increase in preperitoneal fat.

Topics: Adipose Tissue; Age of Onset; Blood Glucose; C-Peptide; Cholesterol; Diabetes Mellitus, Type 2; DNA; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Leptin; Male; Middle Aged; Polymorphism, Genetic; Receptors, Adrenergic, beta-3; Triglycerides

Small dense low density lipoprotein (LDL) and remnant lipoproteins are potent atherogenic lipoproteins, often elevated in the plasma of patients with type 2 diabetes. The alpha1-blocker doxazosin has been reported to favorably affect the plasma lipid profile. We examined whether doxazosin could reduce these atherogenic lipoproteins in hypertensive subjects with and those without type 2 diabetes. Seventeen nondiabetic hypertensive patients and 33 hypertensive patients with type 2 diabetes were studied. Doxazosin (2 to 4 mg) was administered alone or with other previously received antihypertensive drugs for 6 months. Mean LDL size was measured by 2% approximately 16% gradient gel electrophoresis. Remnant-like particle (RLP)-cholesterol was measured with the use of an affinity column containing anti-apoA1 and B100 monoclonal antibodies. Doxazosin effectively decreased blood pressure (BP) without significantly affecting glucose, glycosylated hemoglobin (HbA1c), or C-peptide levels in both nondiabetic and diabetic patients. Doxazosin significantly reduced triglyceride, apo CIII, and apo B, but did not alter total-, LDL- or HDL-cholesterol. Mean LDL particle diameter was significantly increased from 25.6+/-0.6 nm to 25.9+/-0.4 nm (P < .001) by doxazosin treatment, regardless of the presence of diabetes. Consequently, the prevalence of small dense LDL (<25.5 nm) was halved in both groups. The increase in LDL size significantly correlated with decrease in triglyceride level (r=-0.798, P < .0001). Doxazosin significantly reduced RLP-cholesterol in both groups. These results suggest that doxazosin may help to prevent coronary artery disease by reducing atherogenic lipoproteins, including small dense LDL and remnant lipoproteins, in hypertensive patients, regardless of the presence of diabetes.

Topics: Aged; Antihypertensive Agents; Apolipoproteins; Blood Glucose; Blood Pressure; C-Peptide; Cholesterol; Diabetes Mellitus, Type 2; Doxazosin; Female; Glycated Hemoglobin; Humans; Hypertension; Insulin Resistance; Lipids; Lipoproteins; Lipoproteins, LDL; Male; Middle Aged; Prevalence; Triglycerides

Relationships have been demonstrated between insulin sensitivity and the fatty acid (FA) composition of serum and tissue lipids in adult humans. The present study aimed to investigate the above relationships in different groups of type 2 diabetic patients (DM2). The FA composition of serum phospholipids (S-PL) measured by gas liquid chromatography and insulin action during a 2-step hyperinsulinemic isoglycemic clamp (1 and 10 mU/kg. min) were determined in 21 newly diagnosed DM2 subjects (DMN), in groups of long-term DM2 patients treated with hypoglycemic agents (DMH; n = 21) or diet alone (DMD; n = 11), and in 24 healthy subjects (HS). In diabetics, the metabolic clearance rates of glucose at both insulin levels (MCR(glu)submax and MCR(glu)max) were significantly reduced compared with HS (MCR(glu)submax DMN, 5.35 +/- 2.7 mL x kg(-1) x min(-1), DMH, 5.38 +/- 2.17 mL x kg(-1) x min(-1); DMD, 5.48 +/- 2.35 mL x kg(-1) x min(-1) v HS, 10.9 +/- 3.3 mL x kg(-1) x min(-1); P <.01; MCR(glu)max DMN, 13.3 +/- 3.3 mL x kg(-1) x min(-1); DMH, 12.5 +/- 3.0 mL x kg(-1) x min(-1); DMD, 13.3 +/- 3.0 mL x kg(-1) x min(-1) v HS, 17.4 +/- 3.8 mL x kg(-1) x min(-1); P <.05). Increased contents of highly unsaturated n-6 family FA (P <.01), arachidonic acid in particular (DMN, 10.98% +/- 1.79%; DMD, 10.78% +/- 1.64%; DMH, 10.97% +/- 1.7% v HS, 8.51% +/- 1.53%; P <.001), were found in all groups of diabetics compared with HS, while lower levels of linoleic acid were seen in DMN (P <.001) and DMH (P <.05). The contents of saturated FA and monounsaturated FA were comparable in HS, DMN, and DMD. While in HS there were significant negative correlations between MCR(glu) and the contents of saturated FA and a positive association between insulin action and proportions of linoleic and arachidonic acids, no significant relationships were found in diabetic subjects. Different groups of DM2 patients show an altered FA pattern of S-PL, which is not related to insulin action. The above data support the hypothesis that changes in FA composition may play a role in modulating insulin action in peripheral tissues, but cannot explain the insulin resistance (IR) in DM2 patients.

Topics: Adult; Arachidonic Acid; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Fatty Acids; Fatty Acids, Omega-3; Fatty Acids, Omega-6; Fatty Acids, Unsaturated; Glucose Clamp Technique; Glycated Hemoglobin; Humans; Insulin; Insulin Resistance; Kinetics; Linoleic Acid; Male; Metabolic Clearance Rate; Middle Aged; Phospholipids

In this study, the authors assessed the endocrine system and glucose tolerance in obese and non-obese women chronically treated with typical antipsychotic drugs (AP). In particular, we tested the hypotheses that these subjects display hypogonadism and increased insulin resistance compared to healthy weight-matched controls, as these abnormalities create a tendency towards excessive body weight gain. Twenty-six AP-treated women were matched with 26 healthy women by age, body mass index and day of the menstrual cycle. The following serum variables were evaluated in each subject: glucose tolerance after an oral glucose overload, insulin, leptin, beta-endorphin, reproductive hormones, adrenal steroids and lipids. Compared to controls, AP-treated women displayed significantly higher levels of basal glucose, insulin after 60 min of the glucose overload, prolactin, thyroid stimulating hormone and beta-endorphin, with lower levels of C-Peptide, progesterone, 17-OH progesterone, androstenedione and high-density lipoprotein cholesterol. The levels of estradiol, estrone and leptin did not differ between the groups. Thus, women treated with typical AP appeared to display more insulin resistance than healthy controls, predisposing them to excessive weight gain. Insulin sensitivity might be further impaired when the subject switches to atypical AP administration. Metformin and related agents may reduce body weight in these subjects. The high levels of the opiate beta-endorphin suggest that opiate antagonists such as naloxone and naltrexone might be useful as well. Even though the luteal phase of the menstrual cycle appears to be severely disturbed, the normal serum levels of estradiol and estrone do not support the proposal derived from animal experimental studies about the use of estrogens or tamoxifen to counteract AP-induced obesity.

Topics: Adrenal Glands; Adult; Antipsychotic Agents; beta-Endorphin; Blood Glucose; C-Peptide; Endocrine System; Female; Gonadal Steroid Hormones; Humans; Hypogonadism; Insulin; Insulin Resistance; Leptin; Lipids; Multivariate Analysis; Obesity; Prolactin; Sex Hormone-Binding Globulin; Thyroid Hormones

To clarify the insulin action and insulin secretion in newly diagnosed type 2 diabetic subjects, we investigated insulin and C-peptide response to an oral glucose tolerance test (OGTT) in 15 newly diagnosed type 2 diabetic patients and 17 healthy subjects. For insulin action, we found fasting hyperinsulinemia (8.4 +/- 0.8 vs. 6.0 +/- 0.5 microIU/ml, p = 0.014), higher insulin resistance by homeostasis model assessment (HOMA) (4.33 +/- 0.2 vs. 1.34 +/- 0.1 microIU/ml.mmol/l, p < 0.001), and lower insulin sensitivity index (ISI) (51.0 +/- 0.7 vs. 104.0 +/- 0.8, p < 0.001) in newly diagnosed diabetic patients compared to normal subjects. For insulin secretion, the increments of AUCI (area under curve of insulin) and AUCC-P (area under curve of C-peptide) (increment of AUCI: 26.1 +/- 1.4 vs. 82.8 +/- 4.5 microIU/ml.hour, p < 0.001; increment of AUCC-P: 3.9 +/- 0.2 vs. 11.4 +/- 0.6 ng/ml.hour, p < 0.001), insulin secretion by HOMA model (20.7 +/- 1.2 vs. 79.1 +/- 3.8 IU/mol, p < 0.001), and ratio of 30 min increment of fasting insulin to glucose during OGTT (1.14 +/- 0.1 vs. 13.1 +/- 0.5 IU/mol, p < 0.001) were significantly lower in the newly diagnosed diabetic patients than normal subjects. In addition, body mass index (BMI) in our type 2 diabetes is relatively lower (24 +/- 0.65 kg/m2) than those in western countries. These findings revealed poor insulin action and decreased insulin secretion in relatively less obese Taiwanese with newly diagnosed type 2 diabetes.

Topics: Adult; Aged; Blood Glucose; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Male; Middle Aged

Our study was aimed at determining whether beneficial modification of carbohydrate metabolism can be obtained after a short-term training program and whether it is associated with an increase in binding and degradation of (125)I-insulin by erythrocyte receptors that suggests a decrease in insulin resistance.. The study was conducted in a group of 20 patients aged 56 +/- 1.9 years (mean +/- SEM), within 1 to 6 months after coronary bypass surgery. All patients completed 15 training sessions based on 30 min of cycling with a constant load. Before and after a 3-week training program, glucose, insulin, and C-peptide blood levels, as well as binding and degradation of (125)I-insulin by erythrocyte receptors, were determined.. A statistically significant decrease was found in the blood glucose level, from 111.2 +/- 4.2 to 97.8 +/- 3.5 mg/dL (p < 0.01); this decrease was not accompanied by significant insulin concentration changes. There was also a significant increase in insulin binding, from 0.535 +/- 0.059 to 0.668 +/- 0.042 pg (125)I/10(11) RBCs (p < 0.01), and degradation from 7.64 +/- 0.54 to 9.49 +/- 0.58 pg (125)I/10(11) RBCs (p < 0.05).. The results indicated that even short-term endurance training in patients rehabilitated after coronary bypass surgery induced favorable modification of glucose metabolism, presumably caused by a decrease in insulin resistance.

Topics: Adult; Aged; Blood Glucose; Body Mass Index; C-Peptide; Coronary Artery Bypass; Coronary Disease; Exercise; Exercise Therapy; Humans; Insulin; Insulin Resistance; Lipids; Male; Middle Aged; Treatment Outcome

Diabetes mellitus frequently complicates cirrhosis but the pathogenic mechanisms are unknown. To assess the contribution of reduced insulin action and secretion, 24 cirrhotic-diabetic patients waiting for liver transplant because of an unresectable hepatocarcinoma underwent an oral glucose tolerance test (OGTT) to assess the beta-cell function and an insulin clamp combined with [3-(3)H]glucose infusion to measure whole body glucose metabolism before and 2 years after the transplant. Seven cirrhotic nondiabetic patients, 11 patients with chronic uveitis on similar immunosuppressive therapy, and 7 healthy subjects served as control groups. Cirrhotic patients showed a profound insulin resistance, and diabetics in addition also showed increased endogenous glucose production (P <.05) and insulin deficiency during the OGTT (P <.05). Liver transplantation normalized endogenous glucose production and insulin sensitivity but failed to cure diabetes in 8 of the 24 patients because a markedly low insulin response during the OGTT. Age, body mass index, family history of diabetes, immunosuppressive drugs, and pathogenesis of cirrhosis did not predict in whom liver transplant was going to cure diabetes. On the contrary, a reduced secretory response characterized the patients in whom the transplant would not be curative. In summary, insulin resistance was a primary event complicating cirrhosis but additional beta-cell secretory defects were crucial for development of diabetes. Liver transplantation, lessening insulin resistance, cured hepatogenous diabetes in 67% of cirrhotic-diabetic patients; nevertheless 33% were still diabetics because the persistence of a reduced beta-cell function, which makes these patients eventually eligible for combined islet transplantation.

Topics: Blood Glucose; Body Mass Index; C-Peptide; Carcinoma, Hepatocellular; Diabetes Complications; Diabetes Mellitus; Follow-Up Studies; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Liver Cirrhosis; Liver Neoplasms; Liver Transplantation; Middle Aged

Plasma glucose, insulin, and C-peptide concentrations were determined in response to graded infusions of glucose, and insulin secretion rates were calculated over each sampling period. Measurements were also made of insulin clearance, resistance to insulin-mediated glucose, uptake, and the plasma glucose, insulin, and C-peptide concentrations at hourly intervals from 8:00 AM to 4:00 PM in response to breakfast and lunch. Plasma glucose, insulin, and C-peptide concentrations were significantly (P < 0.01) higher in obese women in response to the graded intravenous glucose infusion, associated with a 40% (P < 0.005) greater insulin secretory response. Degree of insulin resistance correlated positively (P < 0.05) with the increase in insulin secretion rate in both nonobese (r = 0.52) and obese (r = 0.58) groups and inversely (P < 0.05) with the decrease in insulin clearance in obese (r = -0.46) and nonobese (r = -0.39) individuals. Weight loss was associated with significantly lower plasma glucose, insulin, and C-peptide concentrations in response to graded glucose infusions and in day-long insulin concentrations. Neither insulin resistance nor the insulin secretory response changed after weight loss, whereas there was a significant increase in the rate of insulin clearance during the glucose infusion. It is concluded that 1) obesity is associated with a shift to the left in the glucose-stimulated insulin secretory dose-response curve as well as a decrease in insulin clearance and 2) changes in insulin secretion and insulin clearance in obese women are more a function of insulin resistance than obesity.

Topics: C-Peptide; Female; Glucose; Humans; Infusions, Intravenous; Insulin; Insulin Resistance; Insulin Secretion; Middle Aged; Obesity; Osmolar Concentration; Weight Loss

We examined the determinants of glycaemic control in a consecutive cohort of 562 newly-referred Chinese type 2 diabetic patients (57% women) during a 12-month period. All patients underwent a structured assessment with documentation of clinical and biochemical characteristics. Pancreatic beta-cell function was assessed by fasting plasma C-peptide concentration. Insulin deficiency was defined as fasting plasma C-peptide <0.2 pmol/ml. Insulin resistance (IR) was calculated using the homeostasis model assessment (HOMA) based on a product of fasting plasma glucose and insulin concentrations. Treatment was considered appropriate when insulin-deficient patients were treated with insulin and non-insulin-deficient patients were treated with oral agents or diet. Mean (+/-SD) age was 54.3+/-13.8 years (range 17-87 years) and disease duration was 5.0+/-5.9 years. At the time of referral, 70.5% (n=396) were on drug therapy (9% on insulin and 62.8% on oral agents), 20.6% (n=116) were on diet and 9% (n=50) had not received any form of treatment. The mean HbA(lc) was 8.4+/-2.3%. The geometric mean (x// antilog SD) of IR was 4.62x//2.51 (range 0. 63-162.7) and correlated only with waist : hip ratio (WHR, p=0.008). The geometric mean of plasma C peptide was 0.47x//2.89 nmol/l and correlated with BMI (p<0.001). Glycated haemoglobin was correlated positively with age (p=0.013), disease duration (p<0.001), IR (p<0. 001) and negatively with BMI (p<0.001). Glycated haemoglobin was lower in patients who had seen a dietitian (7.9% vs. 8.7%, p<0.001) or diabetes nurse (7.8% vs. 8.7%, p<0.001) or who performed self blood glucose monitoring (7.9% vs. 8.6%, p=0.001) and higher among smokers (8.9% vs. 8.2%, p=0.003). Compared to insulin-deficient patients (n=118), non-insulin-deficient patients (n=413) had features resembling that of the Metabolic Syndrome with increased WHR (p=0.005), blood pressure (p<0.001), BMI (p=0.001) and were older (p=0.04). Amongst the insulin-deficient patients, 27% were treated with oral agents or diet. Patients receiving appropriate therapy (n=362) had a lower HbA(lc) than those treated inappropriately (n=173) (8.2% vs. 8.7%, p=0.02). On multivariate analysis, short disease duration (p<0.001), low IR (p<0.001), high BMI (p=0.001), diabetes education (p<0.001), lack of smoking (p=0. 014) and choice of appropriate treatment (p=0.009) were the independent determinants of good glycaemic control.

Topics: Adolescent; Adult; Age Factors; Aged; Aged, 80 and over; Blood Glucose; Blood Glucose Self-Monitoring; Blood Pressure; Body Weight; C-Peptide; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Islets of Langerhans; Male; Middle Aged; Multivariate Analysis; Patient Education as Topic

The type B insulin-resistance syndrome is characterized by the presence of anti-insulin receptor antibodies that cause severe insulin resistance. Treatments including steroids, cyclophosphamide, plasmapheresis, or insulin-like growth factor-1 (IGF-1) are chosen according to severity of insulin resistance. We describe a patient with type B insulin resistance syndrome who was treated successfully with human recombinant (hr) IGF-1, although this treatment provoked a severe allergic reaction. An elderly man with impaired glucose tolerance and unpredictable hypoglycemic episodes which were gradually worsening increased in hemoglobin (Hb)A1c concentration from 6.5 to 13.4%. His fasting and postprandial hyperglycemia were associated with severe hyperinsulinemia. The patient was diagnosed with type B insulin-resistance syndrome by the presence of anti-insulin receptor antibodies. Double-filtration plasmapheresis, plasma exchange, and immunosuppressive therapy with cyclophosphamide and cyclosporin all failed to suppress anti-insulin receptor antibodies more than transiently. When we attempted the treatment by daily administration of hrIGF-1, fasting and postprandial plasma glucose concentrations became normal and HbA1c levels decreased to 7.1% over 2 months, until on one occasion administration resulted in anaphylaxis. After the patient became stable, desensitization therapy was performed successfully, and hrIGF-1 could be administered again with the plasma glucose returning. We concluded that IGF-1 therapy was an effective treatment choice for type B insulin-resistance syndrome in cases whose plasma exchange and immunosuppressive therapy have failed.

Topics: Aged; Autoantibodies; Blood Glucose; C-Peptide; Cyclophosphamide; Cyclosporine; Desensitization, Immunologic; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Hyperglycemia; Immunosuppressive Agents; Insulin Resistance; Insulin-Like Growth Factor I; Male; Plasma Exchange; Plasmapheresis; Receptor, Insulin; Syncope

Microvascular angina has been found to be associated with insulin resistance. However, many factors known to affect insulin sensitivity were not excluded in patient selection. We aimed to evaluate whether microvascular angina is per se associated with insulin resistance.. We performed a Frequently Sampled Intravenous Glucose Tolerance Test (0.33 g kg(-1) b.w.) in 10 normal weight and normotensive patients with microvascular angina, with normal glucose tolerance and normal plasma lipids. Ten healthy subjects, comparable for age, sex, body mass index, blood pressure and plasma lipids, were used as control group.. Fasting serum glucose (4.49+/-0.2 SEM vs. 4.52+/-0.13 mmol L(-1), P = 0.9), insulin (39.46 +/-3.68 SEM vs. 47.12+/-4.6 pmol L(-1), P = 0.21) and C-peptide (0.56 +/-0.05 SEM vs. 0.53+/-0.05 nmol L(-1), P = 0. 68) values, as well as estimated parameters of insulin secretion and hepatic insulin extraction were similar in the two groups. Insulin sensitivity values (median, range) were also similar in the patients and control subjects (5.76 (3.39-12.30) vs. 7.54 (3.68-13.89. 10(-4) x min(-1)/(microU/mL), P = 0.97).. Microvascular angina per se is not associated with hyperinsulinaemia or insulin resistance when other confounding factors are excluded in patient selection.

Topics: Adult; Blood Glucose; C-Peptide; Cholesterol; Female; Glucose Tolerance Test; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Liver; Male; Microvascular Angina; Middle Aged; Triglycerides

Standard glucose-tolerance test (SGTT) was carried out in 73 patients with endometrial tumors. Elevated concentrations of plasma insulin and C-peptide were established in endometrial carcinoma patients (irrespective of age and reproductive status) after night fast and 120 min after SGTT start, as compared to healthy subjects and breast cancer patients. Obese (BMI index 28 kg/m2) reproductive endometrial carcinoma patients showed pronounced hyperinsulinemia and resistance to insulin. Menopausal patients with endometrial tumors (BMI index < = 28) were characterized by a much faster metabolic clearance of insulin, as compared with all other patients. Therefore, degree of insulin resistance in endometrial carcinoma is determined by both enhanced secretion of insulin and lowered metabolic clearance of this hormone which in turn is associated with obesity.

Topics: Adipose Tissue; Adult; Aged; Blood Glucose; Body Constitution; Body Mass Index; Breast Neoplasms; C-Peptide; Endometrial Neoplasms; Female; Humans; Insulin; Insulin Resistance; Menopause; Middle Aged; Obesity

To examine whether an elevated blood pressure (BP) level and an impaired reduction in nocturnal BP are already present in nondiabetic first-degree relatives of type 2 diabetic patients.. We examined 253 offspring of type 2 diabetic patients using ambulatory BP monitoring and compared the BP level and profile with 275 offspring of nondiabetic subjects. Anthropometric measures and cholesterol, fasting blood glucose, and insulin levels were also compared between groups.. No significant differences in BP level (P > 0.05) or diurnal BP profile were evident between the nondiabetic glucose-tolerant offspring of type 2 diabetic subjects and the offspring of nondiabetic subjects. BMI (P < 0.05 and P < 0.01, male vs. female), waist-to-hip ratio (P < 0.05), fasting blood glucose (P < 0.01), C-peptide (P < 0.05 and P < 0.01, male vs. female), insulin resistance index (P < 0.05 and P < 0.01, male vs. female), triglycerides (P < 0.05), apolipoprotein B (apoB) (P < 0.01 and P < 0.05, male vs. female), and apoA1/apoB (P < 0.01) were significantly higher in the nondiabetic offspring of type 2 diabetic subjects than in the offspring of nondiabetic subjects.. This study shows a preserved diurnal BP profile and a normal BP level in the nondiabetic glucose-tolerant offspring of type 2 diabetic subjects compared with the offspring of nondiabetic subjects, although the offspring of diabetic patients are characterized by features of the metabolic syndrome.

Topics: Aged; Blood Glucose; Blood Pressure; C-Peptide; Cholesterol; Circadian Rhythm; Denmark; Diabetes Mellitus, Type 2; Electrocardiography, Ambulatory; Female; Glucose Intolerance; Humans; Insulin Resistance; Male; Middle Aged; Nuclear Family; Prevalence; Reference Values; Risk Factors

With the aim of investigating glucose-mediated glucose disposal (glucose effectiveness [GE]) in 15 (3 female and 12 male subjects) insulin-resistant normoglycemic relatives of patients with type 2 diabetes (DM2), and 15 age-, sex-, and BMI-matched control subjects without a family history of DM2, we performed 2 studies: 1) a 5-h euglycemic near-normoinsulinemic pancreatic clamp with somatostatin (360 microg/h), insulin (0.25 mU x kg(-1) x min(-1)), glucagon (0.5 ng x kg(-1) x min(-1)), growth hormone (6 ng x kg(-1) x min(-1)), and tritiated glucose infusion and indirect calorimetry; and 2) on a separate day, an identical 5-h clamp but at hyperglycemia (approximately 12 mmol/l) over the last 2 h. Fasting plasma insulin (PI) concentrations were elevated in the relatives compared with control subjects (49 +/- 6 vs. 32 +/- 5 pmol/l, P < 0.04), whereas plasma glucose (PG) was not (5.6 +/- 0.1 vs. 5.5 +/-0.1 mmol/l). At the end (i.e., 4.5-5.0 h) of the euglycemic clamp (PG, 6.1 +/- 0.4 vs. 5.6 +/- 0.1 mmol/l; PI, 78 +/- 5 vs. 73 +/-6 pmol/l), peripheral glucose uptake (Rd(euglycemia)) was decreased in the relatives (2.93 +/- 0.08 vs. 3.70 +/-0.23 mg x min(-1) x kg(-1) fat free mass [FFM], P < 0.005), due to a decreased nonoxidative glucose disposal (0.83 +/-0.21 vs. 1.62 +/- 0.19 mg x min(-1) x kg(-1) FFM, P < 0.01), but hepatic glucose production (HGP) was increased (1.97 +/-0.19 vs. 1.50 +/- 0.13 mg x min(-1) x kg(-1) FFM, P < 0.05). At the matched end of the hyperglycemic clamp (PG, 12.7 +/-0.2 vs. 12.6 +/- 0.2 mmol/l; PI, 87 +/- 5 vs. 78 +/- 7 pmol/l), peripheral glucose disposal (Rd(hyperglycemia)) (5.52 +/- 0.22 vs. 5.92 +/- 0.29 mg x min(-1) x kg(-1) FFM, NS), nonoxidative glucose disposal (2.93 +/- 0.18 vs. 2.78 +/- 0.25 mg x min(-1) x kg(-1) FFM, NS), and HGP(hyperglycemia) (1.20 +/- 0.09 vs. 1.37 +/-0.23 mg x min(-1) x kg(-1) FFM, NS) were all identical. When the effectiveness of glucose itself on glucose uptake and production [(Rd(hyperglycemia) - Rd(euglycemia))/deltaPG and (HGP(euglycemia)- HGP(hyperglycemia))/deltaPG] was calculated, the relatives had a 22% increase in peripheral uptake (0.022 +/- 0.002 vs. 0.018 +/- 0.002 mg x min(-1) x kg(-1) FFM per mg/dl), due to a significantly increased nonoxidative glucose metabolism and enhanced suppression of HGP (0.0076 +/- 0.0021 vs. 0.0011 +/- 0.0022 mg x min(-1) x kg(-1) FFM per mg/dl, P < 0.05). In conclusion, in insulin-resistant relatives of DM2 patients, whole-body glucose-mediated glucose disposa

Topics: Adult; Blood Glucose; C-Peptide; Cholesterol; Cholesterol, HDL; Cholesterol, LDL; Diabetes Mellitus, Type 2; Fasting; Female; Glucose; Glucose Clamp Technique; Glucose Tolerance Test; Human Growth Hormone; Humans; Infusions, Intravenous; Insulin; Insulin Resistance; Male; Nuclear Family; Radioisotope Dilution Technique; Reference Values; Somatostatin; Triglycerides; Tritium

Sex hormone-binding globulin (SHBG) is a plasma glycoprotein with high binding affinity for testosterone and dihydrotestosterone and lower affinity for estradiol. SHBG is synthesized in the liver, and its plasma level is important in the regulation of plasma free and albumin-bound androgens and estrogens. Obesity and particularly excess visceral fat, known risk factors for cardiovascular and metabolic diseases, are associated with decreased testosterone levels in males and SHBG levels in both sexes. SHBG is usually positively correlated with high-density lipoprotein cholesterol and negatively correlated with triglyceride and insulin concentrations. A positive association between SHBG and various measures of insulin sensitivity has been demonstrated in both sexes, suggesting that decreased SHBG levels may be one of the components of the metabolic syndrome. We have examined pituitary-adrenocortical function, glucose tolerance, and lipoprotein and hormone levels in a large cohort of Finnish males. Abdominal obesity appears to be associated with slight hypocortisolemia and increased sensitivity to exogenous adrenocorticotropin stimulation, which may contribute to the hyperinsulinemia and related metabolic changes including decreased SHBG levels in males.

Topics: Adrenal Glands; Adult; Blood Glucose; Blood Pressure; Body Constitution; Body Mass Index; C-Peptide; Cholesterol, HDL; Finland; Homeostasis; Humans; Insulin; Insulin Resistance; Liver; Male; Middle Aged; Obesity; Pituitary Gland; Regression Analysis; Sex Hormone-Binding Globulin; Testosterone; Triglycerides

Polycystic ovary syndrome (PCOS) is connected with insulin resistance (IR), and often with the hypersecretion of adrenal androgens. Mutual relationships between IR and adrenal and ovarian steroidogenesis were investigated in the group of 19 oligo/amenorhoeic women with PCOS. The age and body mass index (BMI) of the patients were 21+/-4.7 years and 26.4+/-5 kg/m2 (average+/-SD), respectively. All underwent a 60-minute adrenocorticotrophic hormone (ACTH) stimulation test, a gonadoliberin analogue (GnRHa) test with buserelin and an oral glucose tolerance test (oGTT) in the early follicular phase of the menstrual cycle. When absolute stimulated steroid levels after GnRHa were studied, a significant positive correlation between DHEA and area under curve during oGTT for C peptide (AUC-CP) (r=0.477, p= 0.039) and a borderline negative correlation (r=-0.404, p= 0.087) between AUC-CP and 17-OH progesterone, were found. Considering steroid values after ACTH, a significant positive correlation of IR index was found only with 17-OH-progesterone (r=0.499, p= 0.03). When stimulated enzymatic activities (expressed as product/ precursor ratios) were analyzed using factor analysis, a positive relationship between IR and ovarian C17,20-lyase in both delta4 and delta5 pathway was revealed. On the other hand, no relationship was confirmed between IR and enzymatic activities in the adrenals. The authors conclude that insulin resistance and/or hyperinsulinemia is probably not the primary factor responsible for the exaggerated adrenal androgen secretion found in a great number of patients with PCOS.

Topics: 17-alpha-Hydroxyprogesterone; 3-Hydroxysteroid Dehydrogenases; Adrenal Glands; Adrenocorticotropic Hormone; Adult; Androgens; Blood Glucose; C-Peptide; Dehydroepiandrosterone; Factor Analysis, Statistical; Female; Glucose Tolerance Test; Humans; Hydrocortisone; Insulin Resistance; Ovary; Polycystic Ovary Syndrome; Reference Values; Steroid 17-alpha-Hydroxylase

The rate of glucose disposal was determined in 10 black and 10 white obese nondiabetic urban women from South Africa to assess insulin resistance.. Euglycemic hyperinsulinemic clamp and body composition analysis.. Age, body mass index (BMI), anthropometric measurements and body composition were similar in both groups of women. A five-level computed tomography (CT) scan showed a similar mean subcutaneous fat mass in both groups of women (black obese women 555 +/- 9.0 vs white obese women 532 +/- 6.0 cm2), but less visceral fat in black obese women (90 +/- 3.0 vs 121 +/- 3.1 cm2; P< 0.05). Black obese women had higher fasting free fatty acid (997 +/- 69 vs 678 +/- 93 micromol/l; P < 0.05) and lactate concentrations (1,462 +/- 94 vs 1,038 +/- 39 micromol/l; P < 0.05), but lower fasting insulin levels (87 +/- 12 vs 155 +/- 9 pmol/l; P < 0.001). Black obese women also had a more favorable HDL: total cholesterol ratio (30.5% vs 23.0%; P< 0.04). The mean glucose disposal rate (M) and disposal expressed as glucose sensitivity index (M/I) were reduced in the black obese women vs white obese women (M: 7.1 +/- 0.8 vs 13.7 +/- 1.0 mmol/kg min(-1) x 100; P< 0.01, and M/I: 0.12 +/- 0.01 vs 0.24 +/- 0.02 mmol/kg x min(-1)/pmol/1 x 1,000; P < 0.01). Only black obese women showed a significant decrease in C-peptide levels during the clamp (2.9 +/- 0.22 vs 1.2 +/- 0.12 nmol/l; P<0.001). During the euglycemic period, the black obese women had higher lactate levels at all time points, but only the white obese women had increased lactate levels (918 +/- 66 to 1,300 +/- 53 micromol/l; P< 0.05).. Black obese women demonstrate a higher degree of insulin resistance, despite less visceral fat and a higher HDL: total-cholesterol ratio. In addition, endogenous beta-cell secretory function in black obese women appears to be more sensitive to the suppressive effect of exogenous insulin administration. The significant increase in lactate levels in white obese women confirms that they are more insulin sensitive.

Topics: Adult; Black or African American; Black People; Blood Glucose; Body Composition; Body Mass Index; C-Peptide; Female; Glucose Clamp Technique; Humans; Insulin; Insulin Resistance; Lactates; Lipids; Obesity; Prevalence; South Africa; White People

Type 2 diabetes mellitus has never previously been described in UK children, although an increasing incidence in childhood is recognized in international studies. The prevalence of obesity in UK children is increasing and is a recognized risk factor for the development of diabetes. The aim of this study was to identify and characterize children with Type 2 diabetes in the West Midlands and Leicester.. Children were identified by contacting paediatricians responsible for diabetes in five hospitals. Details were collected on demographics, mode of presentation, investigations and treatment on a standard proforma.. Eight girls were identified with Type 2 diabetes, aged 9-16 years and who were of Pakistani, Indian or Arabic origin. They were all overweight (percentage weight for height 141-209%) and had a family history of diabetes in at least two generations. They presented insidiously with hyperglycaemia and glycosuria without ketosis and five were asymptomatic. Islet cell antibodies measured in seven patients were negative. Four had acanthosis nigricans which is a cutaneous marker of insulin resistance and the other four had high plasma levels of insulin and/or C peptide. These patients are distinct from those with maturity-onset diabetes of the young (MODY). All were initially managed with dietary measures, seven have been treated with oral anti-diabetic agents of whom two have subsequently required insulin.. These are the first UK case reports of Type 2 diabetes in children. Paediatricians need to be aware of the risk of Type 2 diabetes developing in childhood in high-risk ethnic groups, particularly in association with obesity and a positive family history.

Topics: Acanthosis Nigricans; Adolescent; Body Mass Index; C-Peptide; Child; Diabetes Mellitus; Diabetes Mellitus, Type 2; Diet, Reducing; Female; Glycosuria; Humans; Hyperglycemia; Hypoglycemic Agents; India; Insulin; Insulin Resistance; Obesity; Pakistan; Saudi Arabia; United Kingdom

Colonic fermentation of organic matter to short-chain fatty acids has been implicated in the improvement in insulin sensitivity achieved by feeding diets rich in complex carbohydrates. The present study assessed the potential role of the colon in determining postprandial glucose kinetics. Metabolic responses to a complex-carbohydrate test meal were determined in conjunction with a primed continuous infusion of D-[6,6-2H]glucose in a group of ileostomists and sex-matched controls. Glucose disposal (GD) was computed using Steele's (1959) non-steady-state kinetics on a single compartment model. Insulin sensitivity was derived using cumulative GD as the dependent variable, and time and the integrated insulin concentration as independent variables. The ileostomist group had a significantly higher postprandial plasma insulin concentration ( P = 0.034) compared with the control group, but no difference in the plasma glucose concentration. Total GD was similar in each group, although the insulin-dependent GD was substantially lower in the ileostomists (0.46 v. 0.13 mg glucose/min per pmol, P = 0.015). The ileostomist group also showed a 50% lower rate of glucose oxidation in the postprandial period (p = 0.005), although the rate of non-oxidative GD was not significantly affected. The present study indicates that loss of the colon is associated with several characteristics of the insulin resistance syndrome, and favours a view that the colon has a role in the control of postprandial glucose.

Topics: Adult; Aging; Blood Glucose; C-Peptide; Colectomy; Colon; Humans; Ileostomy; Insulin; Insulin Resistance; Male; Middle Aged; Oxidation-Reduction; Postoperative Period; Postprandial Period

We evaluated the effect of troglitazone (given orally 400 mg/day) on glucose intolerance and on the plasma levels of tumour necrosis factor-alpha (TNF-alpha) in 12 obese patients with type 2 diabetes for 12 weeks. Troglitazone significantly decreased fasting plasma glucose, serum C-peptide, serum insulin and HbA1c levels. Plasma levels of TNF-alpha were significantly reduced by troglitazone administered for 8 and 12 weeks. Troglitazone administration significantly improved insulin resistance, but did not affect pancreatic beta-cell function as evaluated by the homeostasis model assessment (HOMA). In the present study, we reported for the first time that troglitazone administration significantly reduces plasma levels of TNF-alpha in obese patients with type 2 diabetes.

Topics: Blood Glucose; C-Peptide; Chromans; Diabetes Mellitus; Diabetes Mellitus, Type 2; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Obesity; Thiazoles; Thiazolidinediones; Troglitazone; Tumor Necrosis Factor-alpha

We surveyed 1447 men and 1800 women aged 30 years (mean 46.7 years) with normal glucose tolerance in Kin-Chen, Kinmen. Correlations of fasting serum insulin and C-peptide with various clinical and biochemical parameters were analyzed by multiple linear regression analysis. Women had significantly higher levels of insulin than men (98+/-43 vs. 91+/-43 pM, p<0.0001), yet they also had a more favorable cardiovascular risk profile. Insulin was positively associated with the female sex, height, body mass index, waist-to-hip ratio, serum triglyceride, total cholesterol, uric acid, and fasting plasma glucose, and was negatively associated with age, smoking, and high-density lipoprotein cholesterol. Independent correlates for C-peptide were similar to those of insulin, except for the addition of mean blood pressure and the exclusion of age and total cholesterol. Significant interaction of sex-body mass index (coefficient = -0.0051, p = 0.0232) was detected for C-peptide only. In conclusion, both fasting serum insulin and C-peptide are quantitatively associated with cardiovascular risk factors in this homogeneous Chinese population with normal glucose tolerance. The female sex is independently associated with higher insulin and C-peptide levels, and the strength of the positive association between the female sex and C-peptide reduces when the body mass index increases.

Topics: Adult; Aged; Aged, 80 and over; Asian People; Biomarkers; Blood Glucose; Body Mass Index; C-Peptide; China; Fasting; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Male; Microvascular Angina; Middle Aged; Retrospective Studies; Sex Characteristics; Surveys and Questionnaires

The aim of the study was to analyse the role of tumour necrosis factor-alpha (TNF-alpha) in insulin resistance and endothelial dysfunction in patients with different types of obesity.. Fasting serum TNF-alpha immunoreactive concentration (enzyme-linked immunosorbent assay, ELISA) and bioactivity (L929 cell cytotoxicity assay), endothelin-1 and C-peptide levels (radioimmunoassay, RIA) were measured in 15 patients with android- and 13 patients with gynoid-type obesity and 15 lean healthy controls with normal glucose tolerance and blood pressure.. Significantly (P<0.01) higher TNF-alpha concentration (8.92 +/- 0.44 pg/ml) and bioactivity (3.12 +/- 0.48 U/ml) were found in patients with android obesity as compared to patients with gynoid obesity (7.01 +/- 0.30 pg/ml, 0.97 +/- 0.11 U/ml) and to the lean controls (6.88 +/- 0.26 pg/ml, 0.88 +/- 0.08 U/ml). Serum endothelin-1 (5.38 +/- 0.30 pg/ml) and C-peptide levels (4.82 +/- 0.71 ng/ml) were also significantly higher (P < 0.01) in patients with android-type obesity than in controls (3.89 +/- 0.43 pg/ml, 1.46 +/- 0.25 ng/ml, respectively). In patients with gynoid-type obesity, only the C-peptide levels proved to be significantly higher (2.84 +/- 0.29 ng/ ml). Endothelin-1 levels, although were found to be slightly higher, did not differ statistically from in controls (4.56 +/- 0.31 pg/ml). There were significant positive linear correlations only in patients with android-type obesity between TNF-alpha, body mass index (BMI), serum endothelin-1 and C-peptide levels.. TNF-alpha may be one of the factors contributing to insulin resistance and vascular dysfunction in patients with android obesity.

Topics: Adult; Body Mass Index; C-Peptide; Case-Control Studies; Endothelin-1; Endothelium, Vascular; Enzyme-Linked Immunosorbent Assay; Humans; Insulin Resistance; Linear Models; Obesity; Tumor Necrosis Factor-alpha

Topics: Adaptation, Physiological; C-Peptide; Cytokines; Diabetes Mellitus, Type 2; Female; Humans; Immune System; Insulin Resistance; Interleukin-12; Male; Pregnancy; Tumor Necrosis Factor-alpha

Sympathetic activation has been considered as a link between insulin resistance, hyperinsulinemia, and hypertension. However, little is known about the association between insulin sensitivity and autonomic regulation or about the effect of acute hyperinsulinemia on cardiac sympathovagal balance. The aim of this study was to investigate heart rate variability (HRV) during the euglycemic-hyperinsulinemic clamp in nondiabetic offspring of patients with type 2 diabetes. We studied 35 nondiabetic offspring of patients with type 2 diabetes and 19 control subjects. Probands were chosen from a 10-year follow-up study of patients with well-characterized type 2 diabetes according to their fasting C-peptide level (selected from both ends of the distribution) and from control subjects to form three groups: 1) a group including subjects who were offspring of type 2 diabetic patients with low C-peptide levels (deficient insulin secretion group [IS group], n = 17), 2) a group including subjects who were offspring of type 2 diabetic patients with high C-peptide levels (insulin-resistant group [IR group], n = 18), and 3) a control group without a history of type 2 diabetes in first-degree relatives (n = 19). HRV was assessed at baseline and at the steady state during the euglycemic-hyperinsulinemic clamp. Rates of whole-body glucose uptake (M value) were lower in the IR group than in the IS group and the control group (41+/-3 vs. 54+/-2 vs. 60+/-4 micromol x kg(-1) x min(-1), P < 0.01 and P < 0.01, respectively). In all groups, heart rate increased significantly during hyperinsulinemia. In the IR group, insulin infusion increased total power of HRV [from 7.70+/-0.15 to 8.05+/-0.15 ln(ms2), P < 0.01] and the low frequency-to-high frequency ratio (from 0.62+/-0.14 to 1.14+/-0.18, P < 0.01) and decreased power of the high frequency spectral component (from 5.73+/-0.17 to 5.43+/-0.16 ln(ms2), P < 0.05), whereas in other groups, changes in HRV were not significant. We conclude that the HRV response to acute hyperinsulinemia in the offspring of type 2 diabetic probands was likely to be modulated by the type 2 diabetic phenotype of the parent. In insulin-resistant subjects, autonomic dysfunction may be an earlier defect than hitherto acknowledged.

Topics: Adult; Autonomic Nervous System; C-Peptide; Diabetes Mellitus, Type 2; Female; Glucose Tolerance Test; Heart Rate; Humans; Hyperinsulinism; Insulin Resistance; Male; Middle Aged; Phenotype; Smoking

The study was devised to measure the effect of intrauterinely delivered levonorgestrel and transdermal estradiol on insulin sensitivity in postmenopausal women and compare this effect with that induced by transdermal estradiol alone.. An open, prospective, comparative study of healthy postmenopausal women without earlier use of hormone replacement therapy. The estrogen therapy group consisted of eight hysterectomized women, who used a transdermal patch delivering a daily dose of 50 microg of estradiol continuously for 6 months. The estrogen-progestin therapy group consisted of 13 women with an intact uterus, who received a simultaneous combination of a transdermal patch and a levonorgestrel (20 microg/day) intrauterine system for the same length of time. Fasting plasma concentrations of glucose, insulin and C-peptide and an insulin tolerance test were used to measure glucose metabolism and insulin sensitivity.. Neither therapy changed the fasting plasma levels of glucose, insulin or C-peptide. Transdermal estrogen improved insulin sensitivity by 22%, as measured by an insulin tolerance test, while a small increase of 3.6% was observed using the combination therapy.. Transdermal estradiol improves insulin sensitivity in healthy postmenopausal women. Combining intrauterine levonorgestrel to transdermal estradiol reverses this effect. This combination does not, however, seem to induce insulin resistance.

Topics: Administration, Cutaneous; Blood Glucose; C-Peptide; Estradiol; Female; Hormone Replacement Therapy; Humans; Hysterectomy; Insulin; Insulin Resistance; Levonorgestrel; Middle Aged; Postmenopause; Progesterone Congeners

Similarities in certain biochemical variables between preeclampsia and the insulin resistance syndrome imply a possible link between insulin resistance and preeclampsia. We measured insulin sensitivity by the minimal model technique between 29 and 39 weeks of gestation in 22 preeclamptic and 16 control women, whose glucose tolerance was first confirmed as normal by an oral glucose tolerance test. In addition, we measured the fasting levels of serum C-peptide, uric acid, lipids, and lipoproteins. Preeclamptic women showed a higher insulin response (P = .001) during the oral glucose tolerance test than the controls. Insulin sensitivity in preeclamptic women (1.11+/-0.15 x 10(-4) x min(-1) x microU/mL) was 37% lower (P = .009) than in control women (1.77+/-0.19 x 10(-4) x min(-1) x microU/mL). The free fatty acid (FFA) concentration in preeclamptic women (0.17+/-0.01 g/L, P = .0004) was 70% higher than in control women (0.10+/-0.01 g/L). Also, baseline serum levels of C-peptide, uric acid, and triglyceride were higher in preeclamptic women. Insulin sensitivity increased fourfold to fivefold within the first 3 postpartum months, but insulin sensitivity in preeclamptic women was still 26% lower (P = .04) than in control women. Preeclampsia is a state of increased insulin resistance, and it persists for at least 3 months after pregnancy. This may be a pathogenetic factor in preeclampsia and may contribute to the excess cardiovascular morbidity among women with prior preeclampsia.

Topics: Adult; C-Peptide; Fatty Acids, Nonesterified; Female; Glucose Tolerance Test; Humans; Insulin Resistance; Lipids; Lipoproteins; Pre-Eclampsia; Pregnancy; Reference Values; Triglycerides; Uric Acid

Fasting hyperglycemia has been associated with HIV protease inhibitor (PI) therapy.. To determine whether absolute insulin deficiency or insulin resistance with relative insulin deficiency and an elevated body mass index (BMI) contribute to HIV PI-associated diabetes.. Cross-sectional evaluation.. 8 healthy seronegative men, 10 nondiabetic HIV-positive patients naive to PI, 15 nondiabetic HIV-positive patients receiving PI (BMI = 26 kg/m2), 6 nondiabetic HIV-positive patients receiving PI (BMI = 31 kg/m2), and 8 HIV-positive patients with diabetes receiving PI (BMI = 34 kg/m2). All patients on PI received indinavir.. Fasting concentrations of glucoregulatory hormones. Direct effects of indinavir (20 microM) on rat pancreatic beta-cell function in vitro.. In hyperglycemic HIV-positive subjects, circulating concentrations of insulin, C-peptide, proinsulin, glucagon, and the proinsulin/insulin ratio were increased when compared with those of the other 4 groups (p < .05). Morning fasting serum cortisol concentrations were not different among the 5 groups. Glutamic acid decarboxylase (GAD) antibody titers were uncommon in all groups. High BMI was not always associated with diabetes. In vitro, indinavir did not inhibit proinsulin to insulin conversion or impair glucose-induced secretion of insulin and C-peptide from rat beta-cells.. The pathogenesis of HIV PI-associated diabetes involves peripheral insulin resistance with insulin deficiency relative to hyperglucagonemia and a high BMI. Pancreatic beta-cell function was not impaired by indinavir. HIV PI-associated diabetes mirrors that of non-insulin-dependent diabetes mellitus and impaired insulin action in the periphery.

Topics: Adult; Animals; Anti-HIV Agents; C-Peptide; Cells, Cultured; Cross-Sectional Studies; Diabetes Mellitus, Type 1; Glucagon; HIV Infections; HIV Protease Inhibitors; Humans; Indinavir; Insulin; Insulin Resistance; Islets of Langerhans; Male; Phospholipases A; Proinsulin; Rats; Rats, Sprague-Dawley

To assess whether reported gestational differences in glucose tolerance in Caucasian and Black women could be due to alterations in insulin secretion, clearance or sensitivity.. Cross sectional survey.. Antenatal Clinic, Harare; Department of Medical Laboratory Sciences, University of Zimbabwe.. 90 healthy women in all the trimesters of pregnancy and 30 healthy non-pregnant women of reproductive age.. Fasting (basal) plasma insulin, C-peptide and glucose concentration. Fasting plasma C-peptide, C-peptide to insulin ratio and glucose to insulin ratio were used as indices of insulin secretion, hepatic insulin clearance and insulin sensitivity respectively.. Not all means of the fasting plasma glucose levels amongst the four groups of women were equal (p < 0.001), with all possible comparisons being significant except for the first and second trimester groups. Among the comparisons of the means of the glucose:insulin ratio in the four groups of women, only the means of the first and second trimester women differed (mean difference = 0.23, honestly significance difference = 0.20). All groups were comparable in the means of plasma insulin, C-peptide levels and the C-peptide:insulin ratio.. Since fasting plasma insulin, C-peptide and C-peptide:insulin ratio were not significantly altered in all trimesters of pregnancy, these data suggest normal basal insulin secretion and clearance during gestation in these sub-Saharan African women.

Topics: Analysis of Variance; Black People; Blood Glucose; C-Peptide; Cross-Sectional Studies; Female; Humans; Insulin; Insulin Resistance; Insulin Secretion; Metabolic Clearance Rate; Pregnancy; Zimbabwe

Although glycemic control has an important impact on the clinical outcomes of patients with diabetes undergoing dialysis, there is a paucity of data on the relationship between glucose metabolism and clinical parameters in these patients. In this study, we compared a cohort of 48 patients with type II diabetes undergoing continuous ambulatory peritoneal dialysis (CAPD) with 84 age- and sex-matched patients with type II diabetes with similar disease duration but normal renal function. Compared with those with normal renal function, patients with type 2 diabetes undergoing CAPD had greater serum angiotensin-converting enzyme activity (median, 57.4 U/L; range, 33.5 to 100.0 U/L v 46.9 U/L; range, 11.6 to 111.2 U/L; P < 0.005), fasting C-peptide (median, 9.1 ng/mL; range, 0.9 to 30.0 ng/mL v 2.2 ng/mL; range, 0.2 to 20.3 ng/mL; P < 0.0001) and triglyceride levels, and lower serum albumin concentrations. Among the patients undergoing CAPD, there was a preponderance of men in the insulin-treated group. Insulin-treated patients also had greater plasma albumin levels and body weights and lower fasting serum C-peptide levels (2.81 +/- 1.77 v 3.12 +/- 2.04 ng/mL; analysis of variance, P = 0.007 adjusted for fasting glucose concentration). Multivariate analysis showed duration of diabetes, hemoglobin A(1c) (HbA(1c)) level, and body weight were independent determinants of insulin requirement in patients undergoing CAPD. The daily insulin dosage required was related to the duration of diabetes (r = 0.5; P = 0.007). In summary, among patients with end-stage renal failure, insulin-treated patients had greater body weights and plasma albumin levels but lower cholesterol levels. Plasma C-peptide concentration and duration of diabetes were the main determinants of insulin requirement, reflecting a decrease in beta-cell reserve, whereas the daily insulin dose correlated mainly with body weight, HbA(1c) level, and duration of diabetes. Kt/V had no effect on insulin resistance or insulin requirement of the patients.

Topics: Adult; Aged; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Diabetic Nephropathies; Dose-Response Relationship, Drug; Female; Glycated Hemoglobin; Homeostasis; Humans; Insulin; Insulin Resistance; Kidney Failure, Chronic; Kidney Function Tests; Male; Middle Aged; Peptidyl-Dipeptidase A; Peritoneal Dialysis, Continuous Ambulatory; Serum Albumin; Treatment Outcome

To investigate the relationship between leptin concentrations, various metabolic indices and body composition in six different groups.. Anthropometric measurements, fasting plasma glucose, serum insulin, C-peptide, FFA and leptin levels were performed. In the obese and diabetic subjects, body composition was analysed with bio-impedance equipment and as a 5 level CT scan.. Five lipoatrophic diabetes mellitus (LDM) patients, five normal subjects (N), nine white and nine black obese women (WW, BW), and nine white and nine black diabetic women (DWW, DBW) were investigated after an overnight fast.. In both ethnic groups there was a positive correlation between leptin and BMI (black group: r=0.8; P<0.0001, white group: r=0.7, P<0.002) and leptin and SC fat mass (black group: r=0.6; P<0.005, white group: r=0.6; P<0.004).. Across the groups, there were positive linear correlations between leptin concentrations, BMI, SC fat mass and FFA levels. Leptin and FFA concentrations are higher and insulin levels lower in both groups of black women compared to the two groups of white women, despite a similar BMI and body fat mass. In the DBW the large increase in visceral fat mass may be indicative of a more complex relationship between compensatory insulin resistance, elevated FFA levels and leptin secretion.

Topics: Adult; Anthropometry; Black People; Blood Glucose; Body Composition; C-Peptide; Diabetes Mellitus, Type 2; Fatty Acids, Nonesterified; Female; Humans; Insulin; Insulin Resistance; Leptin; Obesity; South Africa; White People

To determine whether 3-month GnRH analogue (GnRH-a) administration to hyperandrogenic anovulatory patients and healthy women affects glucose utilization or endogenous glucose production (EGP) in the postabsorptive state and during variable hyperglycemic-hyperinsulinemic infusions.. Prospective, nonrandomized study.. Academic research environment.. Twelve hyperandrogenic anovulatory patients and 11 healthy women matched by body mass index and waist to hip circumference ratio.. Variable hyperglycemic-hyperinsulinemic infusions replicated physiological increases in circulating glucose and insulin levels before and after 3-month GnRH-a administration.. Glucose utilization and EGP.. In the postabsorptive state, plasma glucose and insulin levels, glucose utilization, and EGP were similar in hyperandrogenic patients and healthy women. During variable hyperglycemic-hyperinsulinemic infusions, glucose use increased and EGP decreased to similar degrees in both groups of women. Three-month GnRH-a administration to hyperandrogenic patients and healthy women did not affect plasma glucose and insulin levels, glucose utilization and EGP in the postabsorptive state, or glucose utilization and EGP during variable hyperglycemic-hyperinsulinemic infusions.. Glucose use and EGP in the postabsorptive state and during variable hyperglycemic-hyperinsulinemic infusions are similar in hyperandrogenic anovulatory patients and healthy women of similar body fat distribution and are unaffected by 3-month GnRH-a administration.

Topics: Adolescent; Adrenal Glands; Adult; Anovulation; Blood Glucose; Body Composition; C-Peptide; Female; Glucagon; Human Growth Hormone; Humans; Hyperandrogenism; Insulin; Insulin Resistance; Leuprolide; Middle Aged; Ovary; Prospective Studies; Steroids

Topics: Adult; C-Peptide; Fatty Liver; Female; Hepatitis; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Lipids; Liver; Male; Obesity; Reference Values

To study metabolic effects of berlipril-5 (enalapril) in patients with non-insulin-dependent diabetes mellitus (NIDDM) and arterial hypertension (AH).. 24 patients with NIDDM and AH were divided into three groups by the level of basal C-peptide: > 2 ng/ml (group 1), 2-4 ng/ml (group 2) and < 4 ng/ml (group 3).. A correlation was found between the level of basal C-peptide and duration of AH (r = 0.7) and NIDDM (r = -0.47), between the level of triglycerides (TG) and glycolized hemoglobin Hb A1c (r = 0.48). Berlipril treatment reduced basal C-peptide level in groups 2 and 3 by 20.65 +/- 1.95% and elevated it in group 1 by 16.4 +/- 1.5%. Fasting glucose levels lowered by 9.2 +/- 1.95% indicating better sensitivity of the liver to insulin. Blood glucose levels 2 hours after meal fell by 8.3 +/- 0.95% (p < 0.05) and Hb A1c by 8.14 +/- 1.25% showing indirectly diminishing insulin-resistance at the level of peripheral tissues. TG and VLDLP significantly declined.. Inhibitors of angiotensin converting enzyme (enalapril, in particular) produce a positive effect on carbohydrate and lipid metabolism in patients with NIDDM and AH.

Topics: Angiotensin-Converting Enzyme Inhibitors; Biomarkers; Blood Glucose; Blood Pressure; C-Peptide; Diabetes Mellitus, Type 2; Enalapril; Female; Glycated Hemoglobin; Humans; Hypertension; Insulin Resistance; Lipoproteins, VLDL; Male; Middle Aged; Treatment Outcome; Triglycerides

To investigate the late sequellae of necrotizing pancreatitis on the endocrine function of the pancreas.. Twenty patients, 15 men (mean +/- SEM age 52.2+/-2.6 years and BMI 26.8+/-0.8 kg/m2) and 5 women (age 51.0+/-7.6 years and BMI 26.7+/-0.8 kg/m2) were submitted to a glucagon stimulation test 63 (range 8-136) months after an attack of pancreatitis. All nondiabetic patients (n = 15) were also submitted to an oral glucose tolerance test. For comparison, 16 healthy volunteers, 8 men (age 56.0+/-0.9 years and BMI 26.3+/-0.4 kg/m2) and 8 women (age 50.5+/-1.0 years and BMI 28.2+/-0.6 kg/m2), were also studied.. Five patients (25%) had diabetes mellitus and needed insulin treatment, 6 patients (30%) had an impaired glucose tolerance (IGT). Nondiabetic patients (IGT included) had a significantly higher basal insulin level (15.8+/-1.9 vs. 10.9 +/-2.2 mU/l, p < 0.05) and a lower glucose/insulin ratio (p < 0.05) compared with controls. The serum concentrations of insulin and C peptide, after stimulation with glucagon, calculated as peak value, maximal increment and as area under the curve were not significantly different in the nondiabetic patients compared to controls. The subgroup of IGT patients had a significantly higher basal C peptide (p < 0.05) and a reduced maximal increment (p < 0.05).. After nonresectional therapy for necrotizing pancreatitis, there is a high prevalence of disturbances in glucose metabolism. Patients with IGT have signs of both loss of beta-cell function and insulin resistance.

Topics: C-Peptide; Diabetes Mellitus; Female; Follow-Up Studies; Glucagon; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Islets of Langerhans; Male; Middle Aged; Pancreatitis, Acute Necrotizing; Postoperative Complications

The correlation between hypertension and related risk factors has been studied in 733 type 2 diabetic patients. Hypertension was more frequent in women (65.35%) than in men (50.35%) (p < 0.0001).. Hypertensive patients showed older age (p < 0.0001) and greater Body Mass Index (BMI) (p < 0.03) than normotensive. In the diabetic group on diet only basal insulinaemia was higher (p < 0.05) in hypertensive than in normotensive diabetic men, but not in women. Such a difference, was not seen in patients of both sexes treated with oral hypoglycaemic agents; besides there was no difference in fasting C-peptide levels between hypertensive and normotensive insulin treated patients. In both sexes hypertension was independently correlated with age, BMI, increased urinary albumin excretion, triglycerides. The strongest correlation was with the family history of hypertension. On the contrary there was no correlation between hypertension and waisthip ratio.. In conclusion, the association between hypertension and type 2 diabetes depends on various risk factors, but a relationship with insulin levels is not surely demonstrable.

Topics: Administration, Oral; Adult; Age Factors; Aged; Albuminuria; Blood Glucose; Body Constitution; Body Mass Index; C-Peptide; Comorbidity; Diabetes Mellitus; Diabetes Mellitus, Type 2; Female; Genetic Predisposition to Disease; Humans; Hypercholesterolemia; Hyperinsulinism; Hypertension; Hypertriglyceridemia; Hypoglycemic Agents; Insulin; Insulin Resistance; Italy; Male; Middle Aged; Obesity; Prevalence; Risk Factors

Hyperinsulinemia secondary to a poorly characterized disorder of insulin action is a feature of polycystic ovarian disease (PCOD). On the other hand, being generally admitted that opioids may play a role in glycoregulation and that opioid tone is altered in PCOD, an involvement of the opioids in determining the hyperinsulinemia of PCOD patients could be suggested. The aim of this study was to evaluate the effect of a chronic opioid blockade on insulin metabolism and peripheral insulin sensitivity in PCOD hyperinsulinemic patients. Twenty-three women with PCOD were studied. An oral glucose tolerance test (OGTT) and a clamp study were performed at baseline (during the follicular phase) and after 6 weeks of naltrexone administration (50 mg/d orally). Based on the insulinemic response to the OGTT, 16 women were classified as hyperinsulinemic and seven as normoinsulinemic. Naltrexone treatment significantly reduced fasting (P < .05) and area under the curve (AUC) (P < .02) plasma insulin levels only in the hyperinsulinemic group. Moreover, hyperinsulinemic patients showed similar C-peptide incremental areas after naltrexone treatment, whereas in the same patients the fractional hepatic insulin extraction calculated from the incremental areas of insulin and C-peptide was found to be increased after chronic opioid blockade by naltrexone. For peripheral insulin sensitivity, the hyperinsulinemic group showed significantly lower (P < .01) total-body glucose utilization (M) compared with the normoinsulinemic group. No change in the M value was found after treatment in both groups. These data suggest that the insulin sensitivity and hyperinsulinemia after an OGTT are two distinct deranged features of the insulin disorder of PCOD patients.

Topics: Adolescent; Adult; C-Peptide; Female; Glucose; Humans; Hyperinsulinism; Insulin Resistance; Naltrexone; Opioid Peptides; Polycystic Ovary Syndrome

To evaluate basal pancreatic beta-cell secretion and suppression during infused insulin and the metabolic clearance rate of insulin in women with normal and abnormal glucose tolerance prior to conception and during pregnancy.. Seven women with normal glucose tolerance and nine women with abnormal glucose tolerance during gestation were evaluated prior to conception, in early (12-14 weeks) and late (34-36 weeks) gestation. Basal insulin and C-peptide were measured after an 11-h fast and during the last 40 min of a 2-h hyperinsulinemic-euglycemic clamp at 40 mU.m-2.m-1. Suppression of basal C-peptide was calculated as the steady-state C-peptide/basal C-peptide. The metabolic clearance rate of insulin was calculated by dividing the insulin infusion rate by the steady-state insulin concentration, which was corrected for residual beta-cell secretion.. No significant differences were noted in the following parameters between women with normal and abnormal glucose tolerance with advancing gestation: increase in basal insulin (P = 0.20) and C-peptide (P = 0.12), ability of infused insulin to decrease basal C-peptide concentration (P = 0.22), and metabolic clearance rate of insulin (P = 0.76). There was a significant 65% increase in both basal insulin (P = 0.0005) and C-peptide (P = 0.0002) concentrations in all subjects with advancing gestation. There was a significant (P = 0.0001) decrease in the ability of the infused insulin to decrease basal C-peptide concentration. C-peptide as a percentage of the basal was 64% before conception, 74% in early pregnancy, and 108% in late pregnancy. The metabolic clearance rate of insulin significantly (P = 0.0005) increased with advancing gestation: pregravid 442 ml.m-2.min-1, early pregnancy 514 ml.m-2. min-1, and 526 ml.m-2.min-1 in late pregnancy.. Pregnancy is accompanied by progressive alterations in insulin kinetics, which are partly responsible for the hyperinsulinemia of this condition. These alterations are more likely a homeostatic response to the increased physiological insulin resistance of pregnancy.

Topics: Adult; Blood Glucose; C-Peptide; Creatinine; Female; Fertilization; Glucose Clamp Technique; Glucose Intolerance; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Longitudinal Studies; Pregnancy; Pregnancy Complications; Pregnancy Trimester, First; Pregnancy Trimester, Third; Prospective Studies; Time Factors

Immunoreactive serum leptin was analysed in 49 women with polycystic ovary syndrome (PCOS) distributed on a wide range of body mass index (BMI; kg/m2) and in 32 normally menstruating women with comparable age, BMI, physical activity and dietary habits. All women with PCOS had increased androgen concentrations and obese women with PCOS (BMI > or = 25, n=24) also showed decreased insulin sensitivity and a preferential accumulation of truncal-abdominal body fat. Anthropometric and hormonal variables, insulin sensitivity, and pancreatic beta-cell activity were investigated in all women. Percentage body fat was calculated using gender-specific regression equations based on skinfold measurements. Serum leptin concentrations were higher in obese than in non-obese women (P < 0.001), but did not differ between the women with PCOS and controls, nor did they differ between glucose intolerant and glucose tolerant, or hirsute and non-hirsute women with PCOS. Both groups showed strong correlations between serum leptin concentrations and percentage body fat, BMI, body fat distribution, fasting plasma insulin and C-peptide, early insulin secretion, the free androgen index (FAI), and the degree of insulin resistance. After correcting for percentage body fat, only the FAI in the women with PCOS remained significant (P < 0.05). However, in a multiple regression analysis with both percentage body fat and the FAI as independent variables, the FAI increased only minimally (2%) the explained variation in leptin concentrations. Thus, serum leptin concentrations are almost exclusively determined by the total amount of body fat, independent of its location, and do not confirm the hypothesis that leptin is involved in the development of the hormonal and metabolic abnormalities in the PCOS.

Topics: Adolescent; Adult; Androgens; Body Composition; Body Constitution; Body Mass Index; C-Peptide; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Leptin; Obesity; Polycystic Ovary Syndrome; Proteins; Skinfold Thickness

We have previously reported that GH-deficient (GHD) adults are severely insulin resistant. In the present study, we determined the effects of 6 months (n = 7) and 24 months (long-term; n = 11) of recombinant human GH (rhGH) therapy (approximately 0.22 IU/kg.week) on body composition and fasting biochemical (including lipid) parameters, and baseline and insulin-stimulated: 1) rates of hepatic glucose production, total glucose disposal (Rd), total glycolysis (GF) and glucose storage (GS); and 2) skeletal muscle glucose processing [using the euglycemic-hyperinsulinemic (approximately 60 mU/L) clamp technique with tritiated glucose infusion coupled with skeletal muscle biopsies]. To allow baseline comparison, these measurements were also obtained from 10 control subjects matched to the pretreated GHD adults for age, sex, and body mass index. Long-term rhGH therapy in GHD adults induced significant improvements in fat mass, abdominal fat mass and fat free mass, and reductions in fasting cholesterol and low-density lipoprotein-cholesterol levels (P < 0.05-0.01 vs. pretreatment values). However, there was a significant increase in fasting insulin (13.1 +/- 0.9 vs. 8.6 +/- 1.1 mU/L; P < 0.01) and connecting peptide (0.56 +/- 0.05 vs. 0.41 +/- 0.06 nmol/L; P < 0.05). Although rates of baseline hepatic glucose production, GF, and GS were unchanged, the insulin-stimulated increment (delta) in Rd, GF, and GS remained markedly attenuated in the long-term rhGH-treated GHD adults [pretreatment: delta Rd 16.6 +/- 3.4, delta GF 3.0 +/- 1.2, delta GS 13.6 +/- 3.0 vs. 24 months of rhGH: delta Rd 17.2 +/- 3.3, delta GF 3.1 +/- 0.9, delta GS 14.1 +/- 2.5 vs. controls: delta Rd 42.6 +/- 4.3, delta GF 9.2 +/- 1.9, delta GS 35.9 +/- 4.5 mumol/kg fat free mass.min; P < 0.05-0.01 vs. controls]. Additionally, there was a sustained reduction in the insulin-stimulated skeletal muscle glycogen synthase fractional velocity (pretreatment: 0.29 +/- 0.03 vs. 24 months of rhGH: 0.24 +/- 0.03 vs. controls: 0.48 +/- 0.04; both P < 0.05 vs. controls), which was accompanied by a sustained 44% decrease in baseline glycogen content and a 70% increase in baseline im glucose concentrations in the presence of low-to-normal glucose 6-phosphate levels and persisting euglycemia. Stepwise regression analysis revealed that body weight and fasting free fatty acid and high-density lipoprotein (HDL)-cholesterol accounted for 82% of the variance in the insulin sensitivity index in long-term rhGH-treated adu

Topics: Adult; Body Composition; Body Constitution; C-Peptide; Female; Glucose; Glucose Clamp Technique; Glycolysis; Human Growth Hormone; Humans; Insulin; Insulin Resistance; Insulin-Like Growth Factor I; Liver; Male; Middle Aged; Muscle, Skeletal; Time Factors

Numerous factors impinge on beta-cell function, and include the genetic background and insulin sensitivity of the individual. The aim of the present study was to evaluate the impact of a family history of non-insulin-dependent diabetes mellitus (NIDDM) on beta-cell function and to determine whether the relationships between beta-cell function and insulin sensitivity and age are influenced by a family history of diabetes. Thirty-three healthy control subjects (CON), 20 normal glucose-tolerant first-degree relatives of known NIDDM patients (REL), and 12 nondiabetic identical twins with an identical twin with known NIDDM were studied. Insulin and C-peptide responses to an acute intravenous glucose (AIRg) and glucagon bolus (at euglycemia [AIR[G.GON]]) were measured, as well as each individual's insulin sensitivity. Fasting insulin and C-peptide levels were similar in all groups. AIRg was significantly reduced by 65% in the nondiabetic twins compared with the CON and REL groups, with the latter group being similar to CON, whereas for the AIR[G.GON], the insulin responses in the twin subjects were reduced only by 35% compared with CON. Following stepwise (default) multiple regression analysis, three independent variables (insulin sensitivity, 23%; family history of NIDDM, 20%; and fasting glucose, 7%) were identified, and these combined to fit a model for prediction of acute beta-cell responses to glucose that yielded an R2 (adjusted) value of 50%. Following analysis of covariance (ANCOVA), a positive family history of NIDDM and insulin sensitivity but not the age of the subject were confirmed as separate factors affecting AIRg. In conclusion, in subjects with normal or mild glucose intolerance, the individual's genetic background and insulin sensitivity are important determinants of insulin secretion.

Topics: Adolescent; Adult; Age Factors; Aged; Biomarkers; Blood Glucose; Body Constitution; Body Mass Index; C-Peptide; Data Interpretation, Statistical; Diabetes Mellitus, Type 2; Family Health; Fasting; Female; Glucagon; Glucose; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Linear Models; Male; Middle Aged

Abdominal obesity is associated with insulin resistance and cardiovascular risk factors, but there has been little information published to advance the use of abdominal anthropometry in the care of diabetic patients.. A cross-sectional survey of municipal hospital outpatients recently diagnosed with type 2 diabetes (73 men and 142 women of whom 89% were African Americans). Age-adjusted linear regression was used to compare the supine sagittal abdominal diameter (SAD), supine waist circumference, four anthropometric ratios, and the body mass index (kg/m2) for their ability to predict serum fasting C-peptide and lipid levels.. The best predictor of log-transformed C-peptide was SAD/height (p<0.0001 for men; p=0.0003 for women). SAD/thigh circumference was the best predictor of log-transformed triglycerides for men (p=0.002) and of total cholesterol/HDL cholesterol for women (p=0.043). The body mass index was less able to predict C-peptide, HDL cholesterol and total cholesterol/HDL cholesterol than was SAD/height or SAD/thigh circumference or waist circumference/height.. Anthropometric indices of abdominal obesity appear to be correlated with insulin production and lipid risk factors among municipal-hospital, type 2 diabetic patients much as they are in other studied populations. Since anthropometric data are inexpensively obtained and immediately available to the practitioner, their utility for preliminary clinical assessment deserves to be tested in prospective outcome studies.

Topics: Abdomen; Adult; Anthropometry; Black People; Body Constitution; Body Mass Index; C-Peptide; Cholesterol, HDL; Diabetes Mellitus, Type 2; Female; Humans; Insulin Resistance; Linear Models; Lipids; Male; Middle Aged; Obesity; Supine Position; Triglycerides; United States

To study the metabolic effects of insulin derived from islet grafts, oral glucose tolerance (OGT) and glucose turnover were examined in streptozotocin-induced diabetic Lewis rats rendered normoglycemic by syngeneic islet grafts in the renal subcapsular space (REN), in REN with renal vein-to-mesenteric vein anastomosis (REN-RMA), in the liver (intrahepatic [IH]), or in a parahepatic omental pouch (POP) and compared with normal rats. Normal OGT was found at 1 month posttransplant in all animals receiving approximately 3,000 islets, with hyperinsulinemic responses in the REN group compared with the other groups, and with higher C-peptide responses in the IH group than in the other groups (P < 0.05 by one-way analysis of variance). Glucose turnover studies in the insulin-stimulated steady state (INS-SS; infusion of insulin at 10 pmol x kg(-1) x min(-1)) at 2 months posttransplant showed that whole body glucose disappearance rates (Rd) were similar in all groups, but the REN group had higher steady-state insulin levels than the other groups. Glucose infusion rates (GIRs) were lower in the REN and IH groups than in the other groups. Apparent endogenous glucose production (EGP) was not completely inhibited in the REN and IH groups, while complete inhibition was observed in the other groups. When INS-SS insulin levels were matched to the level in REN rats by increasing the insulin infusion rate to 20 pmol x kg(-1) x min(-1) in REN-RMA, IH, and normal rats, GIR and Rd were elevated, exceeding those values in REN rats, but GIR in IH rats was still lower than in REN-RMA and normal rats. Thus, 1) in the REN group, impairment of inhibition of EGP and of stimulation of Rd by exogenous insulin contribute to insulin resistance; 2) in the IH group, incomplete inhibition of EGP is the major determinant of insulin resistance; and 3) with portal delivery of insulin in the REN-RMA and POP groups, normal insulin sensitivity is preserved. The present study confirms that hepatic portal delivery of islet secretions is necessary for physiological regulation of glucose metabolism. The study also suggests the IH grafts do not provide physiological regulation of glucose metabolism, raising the question of whether the liver is an appropriate site for insulin-secreting tissue replacement therapy in diabetes.

Topics: Anastomosis, Surgical; Animals; Blood Glucose; C-Peptide; Diabetes Mellitus, Experimental; Food; Glucagon; Glucose; Glucose Tolerance Test; Insulin; Insulin Resistance; Islets of Langerhans Transplantation; Kidney; Liver; Male; Mesenteric Veins; Rats; Rats, Inbred Lew; Renal Veins

The insulin resistance syndrome has been characterized by hypertension, upper body obesity, insulin resistance, hyperinsulinemia, glucose intolerance, and hypertriglyceridemia. Previous studies are inconsistent regarding the relationship between blood pressure and insulin resistance. We therefore compared the metabolic profile in 60 hypertensive subjects (mean+/-SD arterial pressure, 116+/-7 mm Hg) and 60 normotensive subjects (mean arterial pressure, 88+/-5 mm Hg) matched for age, gender, and body mass index. Hypertensives had significantly higher waist-to-hip ratio than normotensives (P=0.002). The groups did not differ in fasting plasma glucose (0.2 mmol/L, P=0.09), insulin (6 pmol/L, P=0.14), insulin sensitivity index (-0.01 micromol x kg(-1) x min(-1) x pmol/L(-1), P=0.7), and suppression of nonesterified fatty acids during a hyperglycemic clamp (1%, P=0.40). There were significant differences in fasting levels of C-peptide (50 pmol/L, P=0.004) and proinsulin (2 pmol/L, P=0.01), 2-hour postload levels of glucose (0.8 mmol/L, P=0.01) and insulin (84 pmol/L, P=0.01) after oral glucose challenge, and hepatic glucose production during the clamp (2.87 micromol x kg(-1) x min(-1), P=0.02). These differences were not significant when controlling for waist-to-hip ratio. Body mass index and waist-to-hip ratio were similarly associated with the insulin sensitivity index in the hypertensive (r=-0.59, P=0.0001 and r=-0.32, P=0.05) and normotensive (r=-0.58, P=0.0001 and r=-0.39, P=0.05) groups. Hypertension per se is not associated with insulin resistance. However, even small increments in both body mass index and waist-to-hip ratio, as often seen in hypertension, may lead to impairment in insulin sensitivity, probably mediated through altered lipid metabolism.

Topics: Adipose Tissue; Adult; Alcohol Drinking; Blood Glucose; Blood Pressure; Body Mass Index; C-Peptide; Data Interpretation, Statistical; Fasting; Fatty Acids, Nonesterified; Female; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Hypertension; Insulin; Insulin Resistance; Life Style; Lipids; Male; Middle Aged; Physical Exertion; Proinsulin; Radioimmunoassay; Sex Factors; Smoking

Topics: Age Factors; C-Peptide; Diabetes Mellitus; Diabetes Mellitus, Type 2; Female; Glucagon; Humans; Insulin Resistance; Male; Middle Aged; Obesity; Reference Values; Sex Characteristics; Tumor Necrosis Factor-alpha

To evaluate the influence of family history of hypertension on insulin sensitivity in obese normotensive adults, comparing them with lean subjects.. 136 normotensives (N)(mean 24 h blood pressure < 130/80 mmHg; age range 35-45 y): 32 lean (body mass index, BMI < or = 25 kg/m2) N with normotensive parents (F-), 37 lean N with one or two parents hypertensive (F+), 32 obese (BMI > or = 30 kg/m2) NF- and, 35 obese NF+.. 24 h ambulatory blood pressure monitoring; glucose, insulin and C-peptide before and 30, 60, 90 and 120 min after an oral glucose load; index of insulin peripheral activity (Ia: 10(4)/insulin x glucose values at glucose peak); fasting insulin/C-peptide ratio (I/Cp).. The four groups were comparable for age, gender and blood pressure values throughout the 24 h. Glucose, fasting and during test, and I/Cp were similar among the four groups; insulin and C-peptide, fasting and stimulated, were significantly higher and Ia lower in obese N than in lean N; at similar BMI, insulin and C-peptide were significantly higher and Ia lower, in F+ than in F-. The correlation between insulin and BMI was significantly closer in F- than in F+.. Family history of hypertension appears to be significantly associated with insulin sensitivity in both lean and obese normotensive adults; moreover, overweight and a genetic predisposition to hypertension may have additive adverse effects on insulin sensitivity in normotensive adult subjects.

Topics: Adult; Blood Glucose; Blood Pressure Monitoring, Ambulatory; Body Constitution; Body Mass Index; C-Peptide; Female; Glucose Tolerance Test; Humans; Hypertension; Insulin; Insulin Resistance; Male; Middle Aged; Obesity

Topics: Blood Glucose; Blood Pressure; C-Peptide; Humans; Hypertension; Insulin; Insulin Resistance

Obesity is characterized by variable degrees of hyperinsulinaemia, which has been attributed to either beta-cell hypersecretion or reduced hepatic insulin extraction, or both. To investigate this controversial issue, a 4-h frequently sampled i.v. glucose tolerance test (glucose dose 12.8 g m(-2)) was performed in 13 normotolerant, grossly obese adolescents (10 F/3 M; 13+/-1 y; body mass index 32+/-0.9; pubertal stage 4-5; obesity duration 7.8+/-3 y) and in a comparable group of 8 healthy, normal-weight subjects. Glucose, insulin and C-peptide time-course were analysed by the minimal model technique, which estimates beta-cell secretion, insulin sensitivity (Si), glucose effectiveness (SG) and hepatic insulin extraction (HE). Despite similar fasting and after load glucose patterns (SG similar in the two groups), obese adolescents showed sustained peripheral hyperinsulinaemia (total insulin area under the concentration curve 67.2+/-10.8 vs 19.1+/-1.2 pmol l(-1) in 240 min; p <0.002) and a 71% reduction in Si (2.02+/-0.33 vs 6.95+/-1.03 x 10(4) min(-1) (microU ml(-1)); p < 0.001). Compared with control subjects, the total amounts of prehepatic insulin secretion and posthepatic insulin delivery were also increased significantly in obese adolescents by 30% and 46%, respectively; HE was reduced by 15% during the first 30 min of the test, but recovered within the normal range during the rest of the test. In conclusion, severely obese adolescents are insulin resistant and their hyperinsulinaemia is primarily caused by beta-cell hypersecretion, whereas the reduction in insulin hepatic extraction is a transient metabolic phenomenon.

Topics: Adolescent; Blood Glucose; C-Peptide; Female; Glucose Tolerance Test; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Insulin Secretion; Liver; Male; Obesity

The authors have previously demonstrated abnormalities in glucose and insulin metabolism in nondiabetic black American (BA) adults versus white American (WA) adults. Whether similar glucoregulatory alterations extend to BA adolescents remain unknown. In addition, obesity, a known risk factor for insulin resistance and hyperinsulinemia, occurs in a greater proportion of BA adults and children when compared to WA. The objective of the present study was to examine the differential effects of obesity on glucose homeostasis in BA and WA adolescents.. We examined glucose homeostasis in BA and WA adolescents using oral glucose tolerance test (OGTT), intravenous glucose tolerance test (IVGTT), and [6,6-2H2]-glucose infusion. The study consisted of four age-, sex-, and pubertal stage-matched groups: 15 lean BA, 29 lean WA, 7 obese BA, and 9 obese WA.. Both obese groups had significantly increased insulin and C-peptide area under the curve (AUC) during OGTT and IVGTT when compared to their same-race lean counterparts. During OGTT, obese BA demonstrated greater insulin and C-peptide when compared to obese WA. During IVGTT, first- and second-phase insulin were significantly greater in obese BA versus obese WA.. In summary, BA adolescents demonstrated insulin resistance which is markedly exaggerated in the face of obesity when compared to WA adolescents, implying a differential impact for obesity on glucose homeostasis that is unique to the obese BA adolescent group. In conclusion, there is a need for early aggressive weight management in obese BA adolescents.

Topics: Adolescent; Black People; Blood Glucose; C-Peptide; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Liver; Male; Obesity; White People

Topics: Adolescent; Adult; beta-Thalassemia; Blood Glucose; C-Peptide; Child; Child, Preschool; Fasting; Glucose Intolerance; Humans; Infant; Insulin; Insulin Resistance; Insulin Secretion; Kinetics; Proinsulin

To study the insulin resistance in the pathogenesis of pregnancy induced hypertension (PIH), and its relationship to perinatal outcome.. In 111 PIH and 155 control group, the concentration of C peptide and insulin of maternal blood samples before and after 32 gestational weeks, and fetal blood samples just after delivery was determined. Fetal outcomes were assessed by the neonatal weight at delivery, Apgar scores and the quality and quantity of amniotic fluid.. The maternal concentration of C peptide and insulin in PIH was higher than that of control group (P < 0.05, or P < 0.01). In PIH group, the maternal concentration of C peptide and insulin in the subgroup of adverse perinatal outcomes tended to be higher than that in the subgroup of good perinatal outcomes; but in control group, there was no significantly difference between these two subgroups.. Insulin resistance may be one of the factors which couse PIH, and it has significant relationship with advese perinatal outcomes.

Topics: Adult; C-Peptide; Female; Fetal Growth Retardation; Humans; Insulin; Insulin Resistance; Pre-Eclampsia; Pregnancy; Pregnancy Outcome

We determined the metabolic effects of insulin derived from renal subcapsular islet grafts, either with systemic delivery of insulin through renal venous drainage (REN) or with portal delivery of insulin after renal vein-to-superior mesenteric vein anastomosis (RMA), in streptozotocin-induced diabetic Lewis rats, in comparison with normal rats. After gavage glucose, the plasma glucose responses were similar to normal in REN and RMA rats; however, hyperinsulinemia occurred in REN rats (area under the concentration curves [AUCs] of insulin, 27 +/- 3 nmol x 1(-l) min) in comparison with RMA (14 +/- 2) and normal rats (19 +/- 2), P < 0.003, with no difference in C-peptide responses. The ratio of AUC C-peptide to AUC insulin was lower in REN (2.0 +/- 0.2) than in RMA (3.4 +/- 0.3) and normal animals (3.2 +/- 0.3), P < 0.0005. In euglycemic-hyperinsulinemic clamp studies using the same insulin infusion rate (10 pmol x kg(-1) x min(-1), insulin resistance was found in REN animals (mean glucose infusion rate [GIR], REN: 7.5 +/- 1.2; RMA: 12.0 +/- 1.2; normal: 12.7 +/- 1.0 mg x kg(-1) x min(-1); P < 0.008), with higher steady-state insulin levels in REN (554 +/- 63 pmol/l) than in RMA (291 +/- 26) and normal rats (269 +/- 60), P < 0.0001. With matching steady-state insulin levels in RMA and REN rats during infusion of insulin at 20 pmol x kg(-1) x min(-1) in RMA rats (steady-state insulin 623 +/- 64 pmol/l), GIR was 15.7 +/- 0.7 mg x kg(-1) x min(-1). Thus, systemic delivery of insulin from islet grafts is associated with hyperinsulinemia, insulin resistance, and decreased metabolic clearance of insulin. These abnormalities are prevented by portal delivery of insulin from islet grafts in the same site. The findings are consistent with the hypothesis that portal delivery of insulin is important in maintenance of normal whole-body insulin sensitivity.

Topics: Anastomosis, Surgical; Animals; Blood Glucose; C-Peptide; Diabetes Mellitus, Experimental; Glucagon; Glucose Clamp Technique; Hyperinsulinism; Infusions, Intravenous; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans Transplantation; Liver; Male; Mesenteric Veins; Organ Size; Rats; Rats, Inbred Lew; Renal Veins

The effects of cigarette smoking on insulin resistance, postprandial lipemia following a mixed meal, lipoproteins and other aspects of the insulin resistance syndrome (IRS) were investigated in healthy middle-aged men.. 36 smoking and 25 age- and body mass index (BMI)-matched non-smoking men participated. They were non-obese (BMI < 27), healthy and without any medication. The smokers had been smoking more than 10 cigarettes per day for more than 20 years; the non-smokers had never been habitual smokers. Body composition and several metabolic and cardiovascular risk factors were studied, including the prevalence of small dense LDL-particles, lipoprotein and hepatic lipase activity and triglyceride levels after a mixed test meal. For determination of degree of insulin sensitivity the euglycemic hyperinsulinemic clamp technique was used.. The smokers had lower HDL-cholesterol and lipoprotein A-I levels but higher fasting triglycerides, as well as an increased proportion of small dense LDL-particles and higher postheparin hepatic lipase activity. They also had higher levels of fibrinogen, plasminogen activator inhibitor 1 (PAI-1) activity and fasting and steady-state C-peptide levels during the clamp. The smokers were insulin resistant and lipid intolerant with an impaired triglyceride clearance after a mixed test meal. This lipid intolerance was not mirrored by fasting hypertriglyceridemia.. This study, using the euglycemic hyperinsulinemic clamp technique, shows that smokers are both insulin resistant and lipid intolerant. The postprandial lipid intolerance is also seen in individuals with normal fasting triglyceride levels and is related to an increased prevalence of atherogenic small dense LDL. IRS is likely to be an important reason for the increased cardiovascular morbidity in smokers.

Topics: Adult; Apolipoprotein A-II; Apolipoproteins B; Blood Glucose; Body Mass Index; C-Peptide; Fibrinogen; Glucose Clamp Technique; Humans; Insulin Resistance; Lipids; Lipoprotein Lipase; Male; Middle Aged; Plasminogen Activator Inhibitor 1; Postprandial Period; Radioimmunoassay; Risk Factors; Smoking; Syndrome; Uric Acid

The objective of the study was to determine if male subjects with coronary atherosclerotic heart disease (CHD) without major CHD risk factors have hyperinsulinemia and related metabolic changes. Previous studies suggested that hyperinsulinemia is a CHD risk factor, but they did not entirely exclude concurrent metabolic abnormalities. A prospective, comparative, cross-sectional study in a tertiary care teaching hospital in Mexico City was conducted in 15 men who had suffered myocardial infarction 6 to 24 months before and had significant coronary occlusion on angiography. Control group was formed by 15 age-matched healthy men. None had hypertension, obesity, diabetes, gout, glucose intolerance or hyperlipidemia. Body mass index (BMI), waist/hip ratio (WHR), blood pressure (BP); oral glucose tolerance test (OGTT) with measurement of serum glucose, insulin and C-peptide every 30 min for 2 h, fasting serum cholesterol, triglycerides and uric acid, areas under curve (AUC) of glucose and insulin, insulin/glucose ratio and insulin sensitivity index were calculated. BMI, WHR and BP were similar in both groups. Fasting and post-load serum glucose and insulin concentrations were significantly higher in CHD than in control group (p < 0.01); fasting glucose 5.9 +/- 0.6 vs. 4.8 +/- 0.7 nmol/1, 2-h glucose 8.3 +/- 0.6 vs. 7.3 +/- 0.9 mmol/l, fasting insulin 17.5 +/- 1.2 vs. 15.3 +/- 1.7 pmol/l, 2 h insulin 448 +/- 108 vs. 282 +/- 87 pmol/l in CHD and control group, respectively. AUC of glucose, AUC of insulin, insulin/glucose ratio, post load C-peptide, serum cholesterol, triglycerides and uric acid levels were also significantly higher in CHD than in healthy controls. Insulin sensitivity index was significantly lower in patients with CHD (27.7 +/- 8.3) than in healthy control subjects (73.9 +/- 18) (p < 0.001). Patients with CHD have hyperinsulinemia and subtle metabolic abnormalities related with insulin resistance even in absence of overt risk factors.

Topics: Adult; Aged; Anthropometry; Blood Glucose; Blood Pressure; C-Peptide; Comorbidity; Convalescence; Coronary Artery Disease; Cross-Sectional Studies; Glucose Tolerance Test; Humans; Hyperinsulinism; Insulin Resistance; Lipids; Male; Mexico; Middle Aged; Myocardial Infarction; Prospective Studies; Risk Factors; Uric Acid

In idiopathic recurrent calcium urolithiasis (RCU) the state of insulin and carbohydrate metabolism, and relationships to minerals such as phosphate, are insufficiently understood. Therefore, in two groups of males with RCU (n = 30) and healthy controls (n = 8) the response to an oral carbohydrate- and calcium-rich test meal was studied with respect to glucose, insulin, and C-peptide in peripheral venous blood (taken before and up to 180 min post-load), and phosphate and glucose in fasting and post-load urine. In one RCU group (n = 16) the meal was supplemented with ascorbic acid (ASC; 5 mg/kg body weight). The mean age (RCU 29, RCU + ASC 30, controls 27 years) and mean body mass index [RCU 24.4, RCU + ASC 25.0, controls 24.0 kg/m2] were similar. Insulin resistance (synonymous sensitivity of peripheral organs to insulin) was calculated from insulin serum concentration, as was also integrated insulin, C-peptide, and glucose. Untreated stone patients (RCU) developed hyperinsulinaemia between 60 and 120 min post-load, increased integrated insulin, and insulin resistance (P < or = 0.05 vs controls), whereas the rise of C-peptide and glycaemia (absolute and integrated values) was only of borderline significance. Fasting phosphaturia was low in both RCU subgroups vs controls; however, phosphaturia in untreated RCU rose in response to the meal, contrasting sharply with a decrease in controls. ASC supplementation of the meal (in the RCU + ASC subgroup) normalized insulin, failed to normalize post-load phosphaturia, but reduced post-load glucosuria and urinary pH significantly (mean pH values 5.55 vs 5.93 in untreated RCU, controls 5.50). Postprandial urinary oxalate, calcium, protein, and supersaturation products were not changed. The postprandial changes in phosphaturia and insulin sensitivity were inversely correlated (n = 38, r = -0.44, P = 0.007). It was concluded that in younger RCU males: (1) postprandial hyperinsulinaemia, the failure to reduce phosphaturia and - within limits - glucosuria, appropriately, as well as poor urine acidification are important features of the metabolism; (2) these phenomena are probably caused by insulin resistance of organs, the kidney included; and (3) the addition of a supraphysiological dose of ASC to a meal, the subsequent abolition of hyperinsulinaemia, and the restoration of normal urine acidification suggest that this antioxidant is capable of counteracting some pre-existing basic abnormality of cell metabolism in RCU.

Topics: Adult; Ascorbic Acid; Blood Glucose; C-Peptide; Fasting; Glucose; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Male; Phosphates; Postprandial Period; Time Factors; Urinary Calculi; Urine

The aetiology of the metabolic syndrome remains unknown. This study investigated whether two components of this syndrome, higher blood pressure and higher plasma insulin concentrations, are related at birth. Neonates in the study were from 23 European, 25 Maori, 22 South Asian, and 25 Pacific Islands women having normal singleton pregnancies as well as 6 Maori, 5 Indian, and 19 Pacific Islands women with gestational diabetes (diagnosed by a 3 h 100 g oral glucose tolerance test at 28-32 weeks). Additional fasting glucose and fructosamine concentrations were measured at 36-38 weeks. Umbilical cord blood was taken for insulin, C-peptide, fructosamine and insulin-like growth factor I. Neonatal anthropometry and blood pressure were measured 24 h after delivery. Compared with those with a lower systolic blood pressure (SBP), neonates with a higher SBP had higher umbilical cord insulin (45.6 (39.6-52.8) vs 63.0 (54.6-72.6) pM, p < 0.01), C-peptide (0.22 (0.20-0.25) vs 0.28 (0.26-0.30) nmol l-1, p < 0.001) and fructosamine concentrations, higher maternal fructosamine concentrations and heavier placentas. These data suggest that neonatal hyperinsulinaemia, possibly driven by minor elevations in maternal glycaemia, may be linked to a higher neonatal SBP.

Topics: Asia; Birth Weight; Blood Glucose; Blood Pressure; Body Constitution; C-Peptide; Diabetes, Gestational; Diastole; Female; Fetal Blood; Fructosamine; Glucose Tolerance Test; Humans; India; Infant, Newborn; Insulin; Insulin Resistance; Insulin-Like Growth Factor I; Labor, Obstetric; Maternal Age; New Zealand; Pacific Islands; Parity; Prediabetic State; Pregnancy; Reference Values; Regression Analysis; Systole; White People

Topics: Adolescent; C-Peptide; Diabetes Mellitus; Female; Humans; Immunosuppressive Agents; Insulin Resistance; Kidney Transplantation; Tacrolimus

The significance of gestational diabetes mellitus (GDM) results from its short-term detrimental effects on the fetus and its long-term prediction of NIDDM in the mother. We compared several variables associated with insulin resistance between GDM and non-GDM pregnant women to show the similarities between GDM and NIDDM (and thus insulin resistance).. On the basis of a 3-h oral glucose tolerance test (OGTT), 52 GDM patients and 127 non-GDM patients were recruited from pregnant, non-diabetic women who had a nonfasting 1-h-50-g glucose screening test > or = 7.2 mmol/l (130 mg/dl) performed between 16 and 33 weeks of gestation (a total of 518 of 3,041 women drawn from six community health care prenatal clinics were screened positive). During the OGTT, several potential markers of insulin resistance were measured at fasting and 2-h time points, in addition to the standard glucose measurements. The relationship of these variables with the diagnosis of GDM was studied.. GDM patients, compared with non-GDM patients, had 1) higher prepregnancy weight (P = 0.011), prepregnancy BMI (P = 0.006), C-peptide at fasting (P = 0.002) and at 2 h (P < 0.001), insulin at fasting (P = 0.001) and at 2 h (P < 0.001), triglycerides at fasting (P = 0.005) and at 2 h (P = 0.003), free fatty acids at fasting (P = 0.017), beta-hydroxybutyrate at fasting (P = 0.007); and 2) lower HDL cholesterol at fasting (P = 0.029). These variables were all predictive of GDM (P < 0.036) individually. Using stepwise logistic regression with all of these variables available, fasting (P = 0.019) and 2-h (P < 0.001) insulin levels, fasting free fatty acids (P = 0.031), and fasting beta-hydroxybutyrate (P = 0.036) were statistically significant as jointly predictive of GDM. Comparisons between GDM patients and non-GDM patients matched by BMI confirmed that the metabolic abnormalities persisted when difference in BMI was taken into account. Concomitant blood pressure measurements in women with GDM did not differ significantly from those without GDM.. Our results show that many of the known metabolic components of the syndrome of insulin resistance (syndrome X) are predictive of GDM. These results are in keeping with the argument that GDM is one phase of the syndrome of insulin resistance. We suggest that GDM be looked upon as a component of the syndrome of insulin resistance that provides an excellent model for the study and prevention of NIDDM in a relatively young age-group.

Topics: Adolescent; Adult; Analysis of Variance; Blood Glucose; Blood Pressure; Body Mass Index; Body Weight; C-Peptide; Diabetes, Gestational; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Lipids; Lipoproteins; Odds Ratio; Pregnancy; Pregnancy Trimester, Second; Pregnancy Trimester, Third; Reference Values

Insulin mediators (inositol phosphoglycans) have been shown to mimic insulin action in vitro and in intact mammals, but it is not known which mediator is involved in insulin action under physiological conditions, nor is it known whether insulin resistance alters the mediator profile under such conditions. We therefore investigated the effects of glucose ingestion on changes in the bioactivity of serum inositol phosphoglycan-like substances (IPG) in healthy men and insulin resistant (obese, non-insulin-dependent diabetic) men. Two classes of mediators were partially purified from serum before and after glucose ingestion. The first was eluted from an anion exchange resin with HCl pH 2.0, and bioactivity was determined by activation of pyruvate dehydrogenase in vitro. The second was eluted with HCl pH 1.3, and bioactivity was determined by inhibition of cyclic AMP-dependent protein kinase. In healthy men, the bioactivity of the pH 1.3 IPG was not altered by glucose ingestion, whereas bioactivity of the pH 2.0 IPG increased to approximately 120% of the pre-glucose ingestion value at 60-240 min post-glucose ingestion (p < 0.05 vs pre-glucose). There was no change in either IPG after glucose ingestion in the insulin-resistant group. These data suggest that the pH 2.0 IPG plays an important role in mediating insulin's effect on peripheral glucose utilization in man under physiological conditions. The data further show, for the first time, a defective change in the bioactivity of an insulin mediator isolated from insulin-resistant humans after hyperinsulinaemia, suggesting that inadequate generation/release of IPGs is associated with insulin resistance.

Topics: Animals; Blood Glucose; C-Peptide; Diabetes Mellitus; Diabetes Mellitus, Type 2; Dietary Carbohydrates; Glucose; Humans; Inositol Phosphates; Insulin; Insulin Antagonists; Insulin Resistance; Kinetics; Male; Middle Aged; Myocardium; Obesity; Polysaccharides; Pyruvate Dehydrogenase Complex; Reference Values; Swine; Time Factors

Topics: Acanthosis Nigricans; C-Peptide; Female; Humans; Hyperinsulinism; Insulin Resistance; Lupus Erythematosus, Systemic; Middle Aged; Syndrome

Topics: Adolescent; Adult; C-Peptide; Child; Diabetes Mellitus, Type 2; Glycated Hemoglobin; Histocompatibility Testing; Humans; Insulin Resistance; Islets of Langerhans Transplantation; Liver Cirrhosis; Liver Transplantation; Middle Aged; Pilot Projects

Topics: Blood Glucose; C-Peptide; Denmark; Diabetes Mellitus, Type 2; Genetic Variation; Genotype; Heterozygote; Homozygote; Humans; Insulin; Insulin Resistance; Methionine; Point Mutation; Polymerase Chain Reaction; Polymorphism, Genetic; Receptor, Insulin; Reference Values; Valine; White People

Increasing attention is being paid to disturbances in glucose metabolism as key explanatory factors for the development of coronary artery disease. We studied the prevalence of impaired glucose tolerance and non-insulin-dependent diabetes and the levels of plasma insulin after an oral glucose tolerance test in 99 men with heart disease but without a history of diabetes referred to coronary arteriography; we also compared the outcome with a matched control group (n = 116). The severity of atherosclerosis in coronary angiograms was evaluated according to glucose tolerance status. Among the 99 patients with coronary artery disease, 37.4% had an abnormal oral glucose tolerance test result, whereas only 18.1% of the control group had an abnormal result (p < 0.01). Moreover, patients with heart disease and normal glucose tolerance were hyperinsulinemic compared with the control group (p < 0.01). By analysis of variance no statistically significant difference in severity of coronary atherosclerosis on coronary angiograms was found. In conclusion, we demonstrated frequent disturbances in glucose metabolism indicating insulin resistance in patients with ischemic heart disease without a history of diabetes, but we could not demonstrate a relation between these disturbances and degree of coronary atherosclerosis.

Topics: Adult; Aged; Albuminuria; Analysis of Variance; Blood Glucose; C-Peptide; Case-Control Studies; Coronary Angiography; Coronary Artery Disease; Coronary Disease; Diabetes Mellitus, Type 1; Glucose; Glucose Tolerance Test; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Male; Middle Aged; Myocardial Ischemia; Prevalence; Proinsulin

A case with diabetes mellitus associated with growth hormone (GH)-producing pituitary adenoma is described. A 56-year-old woman who had been treated for diabetes mellitus for 3 years, was admitted for the treatment of hyperglycemia. She showed a few acromegalic features and her plasma GH level was 146 +/- 16 ng/ml. After improvement of plasma glucose level by insulin injection, octreotide therapy (100 micrograms/8 hours) was started. Seven days after the initiation of octreotide therapy, the fasting plasma glucose level was almost normalized without insulin injection. After the octreotide treatment, urinary C-peptide excretion was significantly decreased and the plasma GH level became within normal range. In this case, octreotide appears to have improved the insulin sensitivity by reducing the plasma GH level.

Topics: Acromegaly; Adenoma; Antineoplastic Agents, Hormonal; Blood Glucose; C-Peptide; Diabetes Mellitus; Female; Glucose Intolerance; Human Growth Hormone; Humans; Hyperglycemia; Insulin Resistance; Middle Aged; Octreotide; Pituitary Neoplasms

The aim of the present study was to evaluate the relationship of C-peptide and the C-peptide/bloodsugar ratio with clinical/biochemical variables presenting a well-known association with insulin resistance in NIDDM patients in acceptable control, obtained without the use of exogenous insulin. A total of 118 non insulin dependent diabetes mellitus (NIDDM) patients treated with diet/oral drugs and having a HbA(1c) level < 7.5% have been studied. Non-stimulated C-peptide levels (RIA) and the C-peptide/bloodsugar ratio have been determined and their relationships with the blood pressure status, blood pressure figures, estimates of adiposity, age, known duration of diabetes, current therapies, plasma lipids, glycaemic control, urinary albumin excretion rate, uric acid and creatinine have been ascertained. C-peptide levels were significantly (P < 0.05) correlated with systolic (r = 0.21) and diastolic blood pressure (r = 0.19), BMI (r = 0.21), high density lipoprotein (HDL) (r = -0.22), non-HDL-cholesterol (r = 0.23), apolipoprotein B (r = 0.29), log of triglycerides (r = 0.39) and uric acid (r = 0.35). The C-peptide/bloodsugar ratio had statistically significant correlations with known duration of diabetes (r = -0.23), diastolic blood pressure (r = 0.21), body mass index (BMI) (r = 0.22), log of triglycerides (r = 0.23) and uric acid (r = 0.36). Hypertensives had higher C-peptide levels than normotensives (1.04 +/- 0.04 versus 0.88 +/- 0.04 nmol/ml, respectively (mean +/- S.E.), P < 0.05) and this statistically significant difference remained after adjustment for age and known duration of diabetes. In well-controlled NIDDM patients not receiving exogenous insulin, both C-peptide levels and the C-peptide/bloodsugar ratio have statistically significant relationships with clinical/biochemical variables presenting a well-known association with insulin resistance.

Topics: Administration, Oral; Aged; Apolipoproteins; Biguanides; Blood Glucose; Blood Pressure; Body Constitution; Body Mass Index; C-Peptide; Cholesterol; Cholesterol, HDL; Diabetes Mellitus, Type 2; Diastole; Diet; Drug Therapy, Combination; Evaluation Studies as Topic; Female; Glycated Hemoglobin; Humans; Hypertension; Hypoglycemic Agents; Insulin Resistance; Male; Middle Aged; Multivariate Analysis; Regression Analysis; Sulfonylurea Compounds; Systole; Triglycerides; Uric Acid

Impaired glucose tolerance and secondary diabetes are frequent in older patients with cystic fibrosis (CF), associated with increased frequency of infections and reduced life expectancy. Studies on the pathophysiology of islet cell secretion in CF are a prerequisite for a scientifically based therapeutic approach.. Oral glucose tolerance tests were performed in 71 patients (14.2 +/- 0.5 years; mean +/- SE) and 56 control subjects (16.5 +/- 0.9 years). Glucose, insulin, C-peptide, and proinsulin were measured every 30 min.. Glucose tolerance in CF patients was classified as normal (NGT, n = 48), impaired (IGT, n = 14), or diabetic (DM, n = 9). Even in CF patients with NGT, blood glucose was significantly elevated at 30, 60, and 90 min of the test. Surprisingly, the secretory responses of insulin and C-peptide were not reduced in CF patients with IGT or DM compared with both healthy controls or CF patients with normal glucose tolerance. However, peak insulin concentration was reached at 90 min in CF-IGT or CF-DM patients compared with 30 min in controls. The ratio of glucose to insulin, an indicator of insulin resistance, increased in CF patients with progression of carbohydrate intolerance. Proinsulin was significantly reduced in all CF patients compared with controls (p < 0.001; Wilcoxon's rank sum test).. In CF patients with impaired glucose tolerance or diabetes, integrated insulin release is not diminished, indicating that insulin resistance is likely to contribute to hyperglycemia in CF patients with IGT or DM. Reduced proinsulin levels in CF patients are compatible either with enhanced conversion of proinsulin to insulin in compensation for reduced beta-cell mass, or enhanced clearance of proinsulin.

Topics: Adolescent; Blood Glucose; C-Peptide; Cohort Studies; Cystic Fibrosis; Diabetes Mellitus, Type 1; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Male; Proinsulin; Reference Values; Time Factors

To investigate whether fasting hyperinsulinemia is associated with a clustering of cardiovascular disease (CVD) risk factors, manifesting as the insulin resistance syndrome (IRS), in a population of native Hawaiians.. A total of 574 native Hawaiians > or = 30 years of age were examined for blood pressure, waist-to-hip ratio (WHR), BMI, oral glucose tolerance, and fasting lipid, insulin, and C-peptide concentrations. All statistical analyses (n = 384) excluded 190 individuals who had NIDDM or who were taking hypertension medication. Using logistic regression analysis, fasting insulin and C-peptide levels were compared with CVD risk factors (glucose intolerance, hypertension, central adiposity, elevated triglyceride levels, and low HDL cholesterol levels) after adjusting for age and obesity.. Sixty-six percent of native Hawaiians were overweight or obese, and 70% were found to have central adiposity. Fasting insulin concentrations were correlated with BMI, WHR, blood pressure, and triglyceride, HDL cholesterol, and glucose concentrations. Fasting insulin was also significantly associated with an increasing number of CVD risk factors in each participant (P < 0.001). Fasting insulin and C-peptide concentrations were independently associated with glucose intolerance, high triglyceride levels, and low HDL cholesterol levels. However, only fasting C-peptide concentrations were independently associated with hypertension and central adiposity. Apparent differences in the correlates of fasting insulin and C-peptide may be related to multiple factors and warrant further evaluation.. This study provides cross-sectional data confirming the existence of the IRS in native Hawaiians. However, further longitudinal studies are needed to examine the relationship of insulin resistance and/or surrogate markers to increased rates of NIDDM and CVD mortality in native Hawaiians.

Topics: Adult; Asian; Body Constitution; C-Peptide; Cardiovascular Diseases; Cross-Sectional Studies; Fasting; Female; Hawaii; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Logistic Models; Male; Middle Aged; Obesity; Odds Ratio; Prevalence; Risk Factors; Sex Characteristics; Syndrome

We have examined the effect of a four-week intravenous treatment with 1 alpha-hydroxyvitamin D3 on insulin sensitivity in 14 patients on chronic hemodialysis compared with 10 healthy control subjects by the insulin tolerance test. Compared to controls, the uremic patients have featured increased levels of parathyroid hormone (1085.0 +/- 822.1 vs 74.2 +/- 8.7 pg/ml, p < 0.001), insulin resistance (the rate constant for plasma glucose disappearance, K(in): 3.1 +/- 0.5 vs 4.5 +/- 0.4%/dk, p < 0.002), increased levels of insulin (30.5 +/- 7.3 vs 20.4 +/- 2.8 microIU/ml, p < 0.04) and increased levels of C-peptide (6.0 +/- 2.1 vs 3.9 +/- 12, ng/ml, p < 0.001). Following treatment with 1 alpha-hydroxyvitamin D3, levels of parathyroid hormone decreased from 1085.0 +/- 822.1 to 772.1 +/- 620.1 pg/ml (p < 0.004), the K(in) values increased significantly (from 3.1 +/- 0.5 to 4.1 +/- 0.4%/dk, p < 0.004) and reached the level near to that of controls, the insulin concentrations decreased from 30.5 +/- 7.3 to 28.7 +/- 9.2 microIU/ml (p > 0.05) and C-peptide concentrations increased from 6.0 +/- 2.1 to 7.5 +/- 2.5 ng/ml (p < 0.02). In summary, uremic patients with secondary hyperparathyroidism developed insulin resistance and hyperinsulinemia. Intravenous 1 alpha-hydroxyvitamin D3 treatment has improved insulin sensitivity directly or by reducing secondary hyperparathyroidism in uremic patients on chronic hemodialysis.

Topics: Adult; Blood Glucose; C-Peptide; Calcium; Female; Glucose Tolerance Test; Humans; Hydroxycholecalciferols; Hyperparathyroidism, Secondary; Infusions, Intravenous; Insulin Resistance; Kidney Failure, Chronic; Male; Parathyroid Hormone; Radioimmunoassay; Renal Dialysis; Treatment Outcome

Epidemiological studies have suggested an association among chronic hyperinsulinemia, insulin resistance, and hypertension. However, the causality of this relationship remains uncertain. In this study, chronically catheterized conscious rats were made hyperinsulinemic for 7 days (approximately 90 mU/l, i.e., threefold over basal), while strict euglycemia was maintained (approximately 130 mg/dl, coefficient of variation < 10%) by using a modification of the insulin/glucose clamp technique. Control rats received vehicle infusion. Baseline mean arterial pressure and heart rate were 125 +/- 5 mmHg and 427 +/- 12 beats/min and remained unchanged during the 7-day infusion of insulin (127 +/- 7 mmHg; 401 +/- 12 beats/min) or vehicle (133 +/- 4 mmHg; 411 +/- 10 beats/min). Baseline plasma epinephrine (88 +/- 15 pg/ml), norepinephrine (205 +/- 31 pg/ml), and sodium balance (0.34 +/- 0.09 mmol) remained constant during the 7-day insulin or vehicle infusion. After 7 days of insulin or vehicle infusion, in vivo insulin action was determined in all rats using a 2-h hyperinsulinemic (1 mU/min) euglycemic clamp with [3-3H]glucose infusion to quantitate whole-body glucose uptake, glycolysis, glucose storage (total glucose uptake minus glycolysis), and hepatic glucose production. Compared with vehicle-treated rats, 7 days of sustained hyperinsulinemia resulted in a reduction (P < 0.01) in insulin-mediated glucose uptake, glucose storage, and glycolysis by 39, 62, and 26%, respectively. Hepatic glucose production was normally suppressed after 7 days of hyperinsulinemia. Neither insulin-stimulated glucose uptake nor glucose storage correlated with blood pressure or heart rate. In conclusion, 7 days of euglycemic hyperinsulinemia induces severe insulin resistance with respect to whole-body glucose metabolism but does not increase blood pressure, catecholamine levels, or sodium retention. This indicates that hyperinsulinemia-induced insulin resistance is not associated with the development of hypertension in rats who do not have a genetic predisposition for hypertension. Because hyperinsulinemia was initiated in normal rats under euglycemic conditions, additional (inherited or acquired) factors may be necessary to observe an effect of hyperinsulinemia and/or insulin resistance to increase blood pressure.

Topics: Animals; Blood Glucose; Blood Pressure; C-Peptide; Catecholamines; Glucagon; Glucose; Glucose Clamp Technique; Glycolysis; Heart Rate; Hyperinsulinism; Hypertension; Insulin Resistance; Liver; Male; Rats; Rats, Sprague-Dawley; Sodium

Topics: Acute-Phase Reaction; Adaptation, Physiological; C-Peptide; Dinoprostone; Energy Metabolism; Humans; Hydrocortisone; Insulin; Insulin Resistance; Insulin Secretion; Muscle Proteins; Muscle, Skeletal; Receptor, Insulin; Space Flight; Stress, Physiological

Several investigations have presented evidence that amylin inhibits insulin secretion and induces insulin resistance both in vitro and in vivo. However, basal and postmeal amylin concentrations proved similar in non-insulin-dependent diabetes mellitus (NIDDM) patients and controls. Since hyperglycemia may alter both amylin and insulin secretion, we examined basal and glucose-stimulated amylin secretion in eight glucose-tolerant, insulin-resistant Mexican-American subjects with both parents affected with NIDDM (offspring) and correlated the findings with the insulin sensitivity data acquired by an insulin clamp. Eight offspring and eight Mexican-Americans without any family history of diabetes (controls) underwent measurement of fat free mass (3H2O dilution method), 180-minutes, 75-g oral glucose tolerance test (OGTT), and 40-mU/m2, 180-minute euglycemic insulin clamp associated with 3H-glucose infusion and indirect calorimetry. Fasting amylin was significantly increased in offspring versus controls (11.5 +/- 1.4 v 7.0 +/- 0.8 pmol/L, P < .05). After glucose ingestion, both total (3,073 +/- 257 v 1,870 +/- 202 pmol.L-1.min-1, P < .01) and incremental (1,075 +/- 170 v 518 +/- 124 pmol.L-1.min-1, P < .05) areas under the curve (AUCs) of amylin concentration were significantly greater in offspring. The amylin to insulin molar ratio was similar in offspring and controls at all time points. Basal and postglucose insulin and C-peptide concentrations were significantly increased in the offspring. No correlation was found between fasting amylin, postglucose amylin AUC or IAUC, and any measured parameter of glucose metabolism during a euglycemic-hyperinsulinemic clamp (total glucose disposal, 7.21 +/- 0.73 v 11.03 +/- 0.54, P < .001; nonoxidative glucose disposal, 3.17 +/- 0.59 v 6.33 +/- 0.56, P < .002; glucose oxidation, 4.05 +/- 0.46 v 4.71 +/- 0.21, P = NS; hepatic glucose production, 0.29 +/- 0.16 v 0.01 +/- 0.11, P = NS; all mg.min-1.kg-1 fat-free mass, offspring v controls). In conclusion, these data do not support a causal role for amylin in the genesis of insulin resistance in NIDDM.

Topics: Adult; Amyloid; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Fasting; Female; Glucose; Glucose Tolerance Test; Humans; Hyperinsulinism; Infusions, Intravenous; Insulin; Insulin Resistance; Islet Amyloid Polypeptide; Male; Mexican Americans; Nuclear Family; United States

To assess the effects of GH treatment on carbohydrate and protein metabolism, we studied eight patients with short stature before and after the commencement of GH treatment. The hyperglycemic clamp procedure was employed to produce a hyperglycemic stimulus of 50 mg/dL above fasting levels for 120 min. These patients were then treated with 0.3 mg/kg. week GH for 6 months, after which they were restudied. Patients were compared to eight healthy control children matched for age, sex, and Tanner stage. Fasting plasma glucose did not change significantly, but fasting plasma insulin levels were higher after GH therapy (P < 0.005). Despite identical glucose increments during the glucose clamp procedure, both first, and second phase insulin responses were markedly greater after instituting GH treatment. Even in the face of higher mean plasma insulin levels after GH treatment, the rate of insulin-stimulated glucose metabolism did not differ during the last 60 min of both studies. Hence, the rate of insulin-stimulated glucose metabolism/mean plasma insulin ratio (an index of insulin sensitivity) was sharply reduced after GH treatment (P < 0.01). During the clamp, the fall in circulating branched chain amino acid levels was significantly greater after GH therapy (P < 0.02). We conclude that glucose-stimulated insulin responses are increased in short children treated with GH and that such hyperinsulinemic responses compensate for reductions in insulin sensitivity. The compensatory hyperinsulinemic responses induced by GH therapy may serve a beneficial role by augmenting insulin's anabolic effects on protein metabolism.

Topics: Adaptation, Physiological; Adolescent; Amino Acids, Branched-Chain; Body Height; C-Peptide; Child; Female; Glucose Clamp Technique; Growth Disorders; Human Growth Hormone; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Male

Non-diabetic first degree relatives of non-insulin-dependent diabetic (NIDDM) families are at increased risk of developing diabetes mellitus, and have been studied to identify early metabolic abnormalities. Hormone concentrations measured by specific enzyme immunoassays were assessed in non-diabetic relatives of North European extraction, and control subjects with no family history of diabetes were matched for age, sex and ethnicity. A 75-g oral glucose tolerance test was conducted and those with newly diagnosed NIDDM were excluded. Basal insulin resistance was determined by homeostasis model assessment (HOMA), and hepatic insulin clearance by C-peptide:insulin molar ratio. Relatives (n = 150) were heavier (BMI: p < 0.0001) than the control subjects (n = 152), and had an increased prevalence of impaired glucose tolerance (15 vs 3%, p < 0.01). The relatives had increased fasting proinsulin levels and decreased C-peptide levels following the glucose load, while insulin levels were increased at all time points. To examine whether the differences in hormone levels were secondary to the differences in glucose tolerance and adiposity, we studied 100 normal glucose tolerant relatives and control subjects pair-matched for age, sex, waist-hip ratio and BMI. The differences in proinsulin levels were no longer apparent. However, the relatives remained more insulin resistant, and had decreased C-peptide levels and C-peptide:insulin ratios at all time points. In conclusion, we have identified several metabolic abnormalities in the normal glucose tolerant relatives, and propose that the decreased hepatic insulin clearance helps to maintain normoglycaemia in the face of combined insulin resistance and decreased insulin secretion.

Topics: Adult; Blood Glucose; C-Peptide; Cohort Studies; Diabetes Mellitus, Type 2; Fatty Acids, Nonesterified; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Proinsulin; Reference Values

Recently, a gene encoding a novel human uncoupling protein, designated UCP2, was discovered. The murine UCP2 was mapped to a region on mouse chromosome 7 which in several models has been shown to be linked to obesity and hyperinsulinaemia. Single strand conformation polymorphism (SSCP) analysis and direct sequencing of the coding region of the UCP2 gene in 35 obese Caucasian NIDDM patients of Danish ancestry revealed one nucleotide substitution, replacing an alanine with a valine at codon 55. The amino acid polymorphism was present in 24 of the 35 (69%) examined subjects. The allelic frequency of the A/V55 variant was 48.3% (95% CI: 42.5-54.1%) among 144 subjects with juvenile onset obesity, 45.6% (40.5-50.7%) among 182 subjects randomly selected at the draft board examination, and 45.5% (37.1-53.9%) among lean control subjects selected from the same study cohort. Within these cohorts there were no differences in BMI values at different ages among wild-type carriers and A/V55 carriers. In a population-based sample of 369 young healthy Caucasians the variant showed no association with alterations in BMI, waist-to-hip ratio, fat mass or weight gain during childhood or adolescence. The A/V55 polymorphism was not related to alterations in fasting values of serum insulin and C-peptide or to an impaired insulin sensitivity index. We conclude that genetic variability in the human UCP2 gene is not a common factor contributing to NIDDM in obese Danish Caucasian subjects and the common A/V55 amino acid polymorphism of the gene is not implicated in the pathogenesis of juvenile or maturity onset obesity or insulin resistance in Caucasians.

Topics: Adult; Age of Onset; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Female; Genotype; Humans; Insulin; Insulin Resistance; Ion Channels; Male; Membrane Transport Proteins; Middle Aged; Mitochondrial Proteins; Mutation; Obesity; Polymorphism, Genetic; Polymorphism, Single-Stranded Conformational; Proteins; Uncoupling Protein 2; White People

We evaluated the influence of family history of hypertension on insulin sensitivity in lean and obese hypertensive subjects (H): 40 lean [body mass index (BMI) < or = 25 kg m-2] H with normotensive parents (F-), 50 lean H with one or two parents hypertensive (F+), 30 obese HF- (BMI > or = 30 kg m-2) and 35 obese HF+. The four groups were comparable in terms of age, sex and ambulatory blood pressure values. We evaluated glucose, insulin and C-peptide before and 30, 60, 90 and 120 min after an oral glucose load, insulin sensitivity index (ISI, fasting glucose/insulin ratio), fasting insulin/C-peptide ratio (I/Cp). Glucose, fasting and during test, and I/Cp were similar among the four groups; insulin and C-peptide, fasting and stimulated, were significantly higher and ISI lower in obese H than in lean H; at similar BMI, insulin and C-peptide were significantly higher in F+ than in F-. Insulin directly correlated with night-time blood pressure only in lean HF-. The correlation between insulin and BMI was significantly closer in F-than in F+. In conclusion, family history of hypertension appears to play a relevant role in insulin sensitivity in hypertensive subjects also in the presence of obesity.

Topics: Adult; Aging; Blood Glucose; Blood Pressure; Body Mass Index; Body Weight; C-Peptide; Female; Humans; Hypertension; Insulin; Insulin Resistance; Male; Middle Aged; Obesity; Regression Analysis; Sex Characteristics

To evaluate beta-cell secretion and glucose metabolism in lean subjects with gestational diabetes mellitus (GDM) compared with that in subjects with normal pregnancy and obesity.. Insulin secretion, insulin sensitivity (S1), and hepatic insulin extraction were assessed in pregnant women with GDM before and after delivery and in those with normal glucose tolerance (NGT) in comparison to healthy nonpregnant lean and obese women. Kinetic analysis of glucose, insulin, and C-peptide plasma concentrations during oral and intravenous glucose tolerance tests was performed by mathematical modeling.. S1 was blunted in pregnant women with GDM by 84% and in those with NGT by 66% compared with lean nonpregnant women (P < 0.005 vs. healthy nonpregnant lean control subjects; P < 0.05, GDM vs. pregnant women with NGT), whereas glucose effectiveness was decreased by 33% in both pregnant groups (P < 0.05 vs. healthy nonpregnant lean control subjects). Insulin secretion was 30% higher (P < 0.05) in subjects with GDM than in pregnant women with NGT or in nonpregnant lean women, but decreased (P < 0.005) when compared with obese women with a comparable degree of insulin resistance. Fractional hepatic insulin extraction was similar in both pregnant groups, being lower (P < 0.0001) by 30% versus nonpregnant females. beta-cell sensitivity to glucose for insulin release was decreased in subjects with GDM versus pregnant women with NGT as well as nonpregnant women by 40-50% (P < 0.01). Twelve weeks after delivery, GDM returned to normal glucose tolerance, but S1 remained 50% lower than that in lean nonpregnant women, while beta-cell sensitivity to glucose did not change (P < 0.01 vs. healthy nonpregnant lean control subjects).. Pregnancy is characterized by insulin resistance, diminished hepatic insulin extraction, and glucose effectiveness. Lean subjects with GDM are additionally characterized by having more pronounced insulin resistance and inadequate insulin secretion, which persist after delivery. Compared with other insulin-resistant prediabetic states like impaired glucose tolerance (IGT), defective insulin secretion seems to be a predominant defect in lean GDM subjects, indicating that it might represent a specific prediabetic condition.

Topics: Adult; Blood Glucose; C-Peptide; Cohort Studies; Diabetes, Gestational; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Pregnancy; Pregnancy Complications; Pregnancy Trimester, Second; Pregnancy Trimester, Third; Reference Values

To evaluate the effects of chronic cigarette smoking on insulin sensitivity in patients with noninsulin-dependent diabetes mellitus (NIDDM), we examined 28 smokers and 12 nonsmokers with NIDDM, of similar sex, age, body mass index, waist/hip ratio, alcohol consumption, physical activity level, glycometabolic control, diabetes duration, and treatment. Insulin and C-peptide responses to oral glucose load were significantly higher in smokers than nonsmokers, whereas glucose levels were not substantially different. During insulin clamp (20 mU/min.m2), carried out in combination with tritiated glucose infusion and indirect calorimetry, total glucose disposal was markedly reduced in smokers vs. nonsmokers [19 +/- 1.2 vs. 33 +/- 5 mumol/min.kg fat-free mass (FFM); P < 0.001], in a dose-dependent fashion (F = 6.8, P < 0.001 by ANOVA when subjects were categorized for number of cigarettes smoked per day). Oxidative (9 +/- 1 vs. 14 +/- 2 mumol/min.kg FFM; P < 0.01) and nonoxidative (10 +/- 1 vs. 19 +/- 4 mumol/min.kg FFM; P < 0.01) pathways of insulin-mediated intracellular glucose metabolism were similarly reduced in smokers vs. nonsmokers. Plasma free fatty acid levels (240 +/- 33 vs. 130 +/- 23 microEq/L; P < 0.05) and lipid oxidation rate (1.39 +/- 0.1 vs. 0.95 +/- 0.2 mumol/ min.kg FFM; P < 0.05) were less suppressed by hyperinsulinemia in smokers than nonsmokers. In conclusion, chronic cigarette smoking seems to markedly aggravate insulin resistance in patients with NIDDM.

Topics: Adult; Aged; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 2; Fatty Acids, Nonesterified; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Lipid Peroxidation; Male; Middle Aged; Smoking

The aim of this study was to evaluate the impact of reduced peripheral insulin sensitivity, beta cell hypersecretion and reduced hepatic insulin clearance in the hyper-insulinaemia of lean and obese PCOS patients. A total of 35 women with polycystic ovary syndrome (PCOS) and 10 lean normo-ovulatory controls underwent an oral glucose tolerance test and an euglycaemic-hyper-insulinaemic clamp study. PCOS patients were classified into four groups according to their BMI and insulin secretion (normo-lean; normo-obese; hyper-lean; hyper-obese), and results were compared between groups and with the controls. All the PCOS groups showed significantly higher insulin secretion than controls; there were no differences in insulin response to glucose load between lean and obese normo- and hyper-insulinaemic patients. Secretion of c-peptide was greater in PCOS groups than controls. All the hyper-insulinaemic PCOS patients had lower values of hepatic insulin clearance, independent of BMI, when compared either with controls (P < 0.001) or with PCOS normo-insulinaemic women (P < 0.01). Normo- and hyper-insulinaemic obese patients had similar total body glucose utilization (M value), which was lower than in lean PCOS subjects and controls. Our results suggest that evaluation of insulin resistance alone does not fully characterize the PCOS population; differences in liver metabolism of insulin are present in obese insulin resistant subjects and in lean patients with normal insulin sensitivity when divided into normo- and hyper-insulinaemic subgroups. Insulin resistance and hyper-insulinaemia may represent two distinct features of the insulin disorder in PCOS: the former appear to reflect the presence of obesity, while the latter may be a primary feature of PCOS.

Topics: Adolescent; Adult; Body Mass Index; C-Peptide; Female; Glucose Tolerance Test; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Liver; Obesity; Polycystic Ovary Syndrome

Topics: C-Peptide; Humans; Hypertension; Insulin; Insulin Resistance; Reference Values

The study was performed to elucidate, by means of a euglycemic-hyperinsulinemic clamp, whether insulin sensitivity, lipid levels, posthepatic insulin delivery, and insulin clearance are impaired in girls with Turner's syndrome in the absence of previous treatment (T0) and after 6 (T6) and 12 (T12) months of growth hormone (GH) therapy (GHT). The study was performed in six girls with Turner's syndrome and eight healthy girls. We found that previously untreated girls with Turner's syndrome had a normal insulin activity on glucose metabolism. GHT progressively and significantly decreased hepatic insulin sensitivity. In fact, residual hepatic glucose release (HGR), which was 19.6 +/- 4.7 mg/m2. min at T0, doubled at T6 (39.3 +/- 5.1 mg/m2.min) and showed a threefold increase at T12 (68.7 +/- 10.8 mg/m2.min, P < .05 v T0). On the contrary, GHT did not show an appreciable influence on peripheral insulin sensitivity. Insulin clearance was higher in girls with Turner's syndrome than in control girls at T0 (30.0 +/- 2.8 v 20.2 +/- 1.1 mL.kg-1.min-1). It decreased to normal values at T6 (18.2 +/- 2.0 mL.kg-1.min-1, P < .05 v T0) and remained at normal levels at T12 (23.8 +/- 2.9 mL.kg-1. min-1). The posthepatic insulin delivery rate significantly increased at T6 and T12, suggesting increased insulin secretion. In conclusion, we found that insulin-stimulated glucose turnover was normal in girls with Turner's syndrome before therapy. One year of GHT was successful in stimulating the growth rate, but significantly decreased the insulin suppressibility on HGR with only slight changes in peripheral insulin sensitivity. In addition, an increase in the insulin posthepatic delivery rate and a normalization of insulin clearance were present, probably to counteract hepatic insulin resistance.

Topics: Adolescent; C-Peptide; Child; Fasting; Female; Glucose; Growth; Growth Hormone; Humans; Insulin; Insulin Resistance; Insulin-Like Growth Factor I; Lipids; Liver; Recombinant Proteins; Turner Syndrome

We tested the hypothesis that glucose intolerance develops in genetically prone subjects when exogenous insulin resistance is induced by dexamethasone (dex) and investigated whether the steroid-induced glucose intolerance is due to impairment of beta-cell function alone and/or insulin resistance. Oral glucose tolerance (OGTT) and intravenous glucose tolerance tests with minimal model analysis were performed before and following 5 days of dex treatment (4 mg/day) in 20 relatives of non-insulin-dependent diabetic (NIDDM) patients and in 20 matched control subjects (age: 29.6 +/- 1.7 vs 29.6 +/- 1.6 years, BMI: 25.1 +/- 1.0 vs 25.1 +/- 0.9 kg/m2). Before dex, glucose tolerance was similar in both groups (2-h plasma glucose concentration (PG): 5.5 +/- 0.2 [range: 3.2-7.0] vs 5.5 +/- 0.2 [3.7-7.4] mmol/l). Although insulin sensitivity (Si) was significantly lower in the relatives before dex, insulin sensitivity was reduced to a similar level during dex in both the relatives and control subjects (0.30 +/- 0.04 vs 0.34 +/- 0.04 10(-4) min(-1) per pmol/l, NS). During dex, the variation in the OGTT 2-h PG was greater in the relatives (8.5 +/- 0.7 [3.9-17.0] vs 7.5 +/- 0.3 [5.7-9.8] mmol/l, F-test p < 0.05) which, by inspection of the data, was caused by seven relatives with a higher PG than the maximal value seen in the control subjects (9.8 mmol/l). These "hyperglycaemic" relatives had diminished first phase insulin secretion (O1) both before and during dex compared with the "normal" relatives and the control subjects (pre-dex O1: 12.6 +/- 3.6 vs 26.4 +/- 4.2 and 24.6 +/- 3.6 (p < 0.05), post-dex O1: 22.2 +/- 6.6 vs 48.0 +/- 7.2 and 46.2 +/- 6.6 respectively (p < 0.05) pmol x l(-1) x min(-1) per mg/dl). However, Si was similar in "hyperglycaemic" and "normal" relatives before dex (0.65 +/- 0.10 vs 0.54 +/- 0.10 10(-4) x min(-1) per pmol/l) and suppressed similarly during dex (0.30 +/- 0.07 vs 0.30 +/- 0.06 10(-4) x min(-1) per pmol/l). Multiple regression analysis confirmed the unique importance of low pre-dex beta-cell function to subsequent development of high 2-h post-dex OGTT plasma glucose levels (R2 = 0.56). In conclusion, exogenous induced insulin resistance by dex will induce impaired or diabetic glucose tolerance in those genetic relatives of NIDDM patients who have impaired beta-cell function (retrospectively) prior to dex exposure. These subjects are therefore unable to enhance their beta-cell response in order to match the dex-induced insulin resistan

Topics: Adult; Blood Glucose; C-Peptide; Cholesterol, HDL; Dexamethasone; Diabetes Mellitus, Type 2; Female; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Male; Risk Factors

Hyperinsulinemia and peripheral insulin resistance caused by systemic insulin delivery and prednisone therapy are recognized consequences of pancreas transplantation. However, there is little information about insulin action on the liver. To investigate hepatic insulin sensitivity in recipients of pancreas transplants, we devised a staged euglycemic hyperinsulinemic clamp to measure hepatic glucose production (HGP) in 10 type I diabetic pancreas transplant recipients, 10 pair-matched healthy control subjects, and 6 nondiabetic kidney transplant recipients. Clamps were performed in two sequential stages. In stage 1, a 2-h low-dose insulin infusion (0.4 mU.kg-1.min-1) was used to partially suppress HGP. In stage 2, insulin-mediated suppression of HGP was challenged by a 1.5-h glucagon infusion (0.8 ng.kg-1.min-1), while continuing the hyperinsulinemic euglycemic-clamp conditions. During both stages, somatostatin (250 micrograms/h) was infused to suppress endogenous insulin secretion. All subjects underwent stage 1, and all except one pancreas recipient and a respective matched healthy control subject completed stage 2. Fasting HGP was greater in pancreas recipients than in healthy control subjects (15.1 +/- 0.7 vs. 12.0 +/- 0.4 mumol.l-1.kg-1.min-1, P < 0.005) but similar in healthy control subjects and in kidney recipients. During stage 2, both total (706 +/- 28 vs. 469 +/- 31 mumol.l-1.kg-1, P < 0.005) and incremental (62 +/- 20 vs. -21 +/- 16 mumol.l-1.kg-1, P < 0.005) HGP responses to glucagon infusion were significantly greater in pancreas recipients than in healthy control subjects. Changes in HGP in kidney recipients during stage 2 were not significantly different from those in healthy control subjects. In conclusion, fasting HGP is increased in pancreas transplant recipients. Furthermore, recipients have hepatic insulin resistance as demonstrated by an enhanced stimulatory effect of glucagon on HGP during insulin-mediated HGP suppression. Because the magnitude of hepatic insulin resistance was a significant (P < 0.01) predictor of HbA1c level, we suggest that variable hepatic insulin resistance may be responsible for some of the variance observed in glycemic levels after successful pancreas transplantation.

Topics: Adult; Blood Glucose; C-Peptide; Diabetes Mellitus, Type 1; Female; Humans; Insulin Resistance; Liver; Male; Pancreas Transplantation

Earlier we found black-white contrast in insulin levels in adolescents. The purpose of this study is to assess whether this difference is attributable to alterations in insulin secretion and/or clearance.. Fasting circulating insulin and C-peptide concentrations were examined in 1157 adolescents aged 11 to 18 years from a biracial community. Fasting plasma C-peptide, C-peptide to insulin ratio, and glucose to insulin ratio were used as indices of insulin secretion, hepatic insulin clearance, and insulin sensitivity, respectively.. After adjusting several covariates (age, sexual maturation, and obesity), black adolescents had higher insulin levels (14.99 vs 12.66 microU/mL in girls). However, they had lower C-peptide levels than their white counterparts, indicating lower insulin secretion by pancreatic beta cells in black adolescents. Moreover, black adolescents had lower levels of C-peptide to insulin ratio than white adolescents (0.14 vs 0.17), suggesting reduced hepatic insulin clearance in black adolescents. In addition, significantly lower levels of glucose to insulin ratio in black girls suggest a reduced insulin sensitivity in this group. Further, differences in insulin levels between white and black girls disappeared after adjusting for differences in C-peptide to insulin ratio.. These data suggest that elevated insulin levels observed in black adolescents, especially in black girls, may be attributed to their decreased hepatic insulin clearance, not hypersecretion of insulin.

Topics: Adolescent; Age Factors; Black People; Blood Glucose; C-Peptide; Child; Cross-Sectional Studies; Fasting; Female; Humans; Insulin; Insulin Resistance; Insulin Secretion; Louisiana; Male; Metabolic Clearance Rate; Sex Factors; White People

The authors evaluated the significance of beta cell function, non-insulin-dependent glucose disposal (glucose effectiveness [Sg]), and insulin-dependent glucose disposal (insulin sensitivity) in African immigrants with varying degrees of glucose tolerance. Thirty-two African immigrants residing in Franklin County, Ohio, were studied. There were 16 subjects with normal glucose tolerance (NGT), 11 with intermediate glucose tolerance (IGT), and 5 with type II diabetes mellitus (DM). Insulin sensitivity index and Sg were measured by an insulin-modified, frequently sampled intravenous glucose tolerance test. The mean fasting and post-glucose serum glucose levels were lowest in the NGT, intermediate in the IGT group, and highest in the DM group. Mean serum insulin and c-peptide responses rose briskly by threefold to a peak in the NGT and the IGT groups. In the DM group, mean serum insulin and c-peptide responses were severely blunted to glucose stimulation. The sensitivity index was highest in the NGT (3.09 +/- 0.27), intermediate in the IGT (1.81 +/- 0.47), and lowest in the DM (0.48 +/- 0.28 x 10(-2).mins-1 (microU/ml)-1). The Sg was identical in the NGT (2.78 +/- 0.22) and IGT (2.78 +/- 0.27) groups but was slightly but not significantly lower in the DM (2.20 +/- 0.35 x 10(-2).mins-1). In addition, the glucose decay constant was not statistically different in the NGT (3.00 +/- 0.38) and IGT (2.25 +/- 0.19) group, but the mean values were significantly greater than in the patients with diabetes (0.78 +/- 0.15 percent/mins). The mean disposition index (sensitivity index X beta cell function as assessed by both insulin and c-peptide) was significantly greater in NGT than in the IGT (P<0.05) and in the diabetic group (P<0.001). In summary, the authors demonstrate that, in native African immigrants, type II diabetes is associated with significant reduction in beta cell function, insulin sensitivity, and glucose decay constant, but not in Sg. In patients with intermediate or impaired glucose tolerance, there is moderate insulin resistance and evidence of inadequate compensation by beta cell, but the Sg, the Sg at theoretical insulin concentration, and glucose decay constant remain normal. They conclude that, unlike other ethnic and racial groups, in glucose intolerant native African patients, alterations in Sg or non-insulin dependent glucose disposal (ie, tissue glucose sensitivity) do not appear to play a significant role in the impairment of glucose tolerance a

Topics: Adult; Black People; Blood Glucose; Body Mass Index; C-Peptide; Cohort Studies; Diabetes Mellitus, Type 2; Emigration and Immigration; Fasting; Ghana; Glucose Intolerance; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Ohio; Reference Values

To evaluate the relationships of total and differential white blood cell (WBC) count to the components of the so-called insulin resistance syndrome.. The study population consisted of a random sample of 90 38-year-old healthy men with normal glucose tolerance.. A 75 g oral glucose tolerance test was performed in all participants.. Total and differential WBC count, lipids, blood pressure, plasma glucose, C-peptide and insulin (at fasting and 2 h after glucose load).. Total WBC count correlated consistently with plasma 2-h glucose (r = 0.38; P < 0.001), fasting and 2-h postload insulin (r = 0.26 and r = 0.33; P < 0.01-0.001, respectively) and C-peptide (r = 0.28 and r = 0.32; P < 0.01-0.001) concentrations. Smokers had significantly higher total leukocytes (P < 0.01), neutrophils and lymphocytes than nonsmokers. Furthermore, total WBC count correlated positively with body mass index, blood pressure, plasma triglycerides, fibrinogen, and negatively with HDL cholesterol concentration. As differential WBC count, most variables correlated essentially to neutrophils and/or lymphocytes, whereas plasma insulin and C-peptide concentrations correlated essentially to lymphocytes and monocytes, but not to neutrophils. In a multiple linear regression analysis, only 2-h plasma glucose (P < 0.01) and fibrinogen (P < 0.05) were positive predictors of total WBC count after adjusting for all potentially confounding variables.. The results indicate that increased, albeit normal, WBC count associates with the cluster of metabolic and haemodynamic disorders typical of the insulin resistance syndrome, and suggest that increased WBC count may be yet another component of this syndrome.

Topics: Adult; C-Peptide; Cardiovascular Diseases; Glucose Tolerance Test; Hemodynamics; Humans; Insulin; Insulin Resistance; Leukocyte Count; Male; Predictive Value of Tests; Regression Analysis; Risk Factors; Smoking

Recently, a missense mutation replacing tryptophan with arginine at codon 64 of the beta 3-adrenergic receptor gene was shown to be associated with insulin resistance in nondiabetic subjects and to an earlier onset of NIDDM in Pima Indians. We studied whether the codon 64 amino acid polymorphism of the beta 3-adrenergic receptor gene in a cohort of young healthy Danes was associated with high birth weight, accelerated weight gain during childhood and adolescence, present obesity, or impaired insulin sensitivity. The protocol included 380 unrelated white subjects in whom insulin sensitivity and secretion were measured during a combined intravenous glucose and tolbutamide tolerance test. A number of biochemical and anthropometric characteristics were determined for each subject. The subjects were genotyped for the codon 64 polymorphism by applying polymerase chain reaction restriction fragment-length polymorphism screening with the use of endonuclease BstN1. The allelic frequency of the mutated allele was 7% (95% CI: 5-10%), and it was similar in obese and nonobese subjects. The beta 3-adrenergic receptor gene variant was not related to birth weight or weight gain during childhood or adolescence. In its heterozygous form, the gene variant was not associated with an altered insulin sensitivity index (SI) or other features of the insulin resistance syndrome (BMI, blood pressure, fasting serum lipid levels, or fasting serum fibrinolytic variables). Three homozygous carriers of the polymorphism were identified, and each had a significantly higher BMI (27.4 +/- 1.3 vs. 23.5 +/- 3.7 kg/m2 [mean +/- SD]; P = 0.032), lower SI [4.9 +/- 2.9 vs. 15.4 +/- 9.0 10(-5) x (min x pmol/l)-1; P = 0.013], and higher fasting serum C-peptide (730 +/- 155 vs. 471 +/- 158 pmol/l; P = 0.016) than the wild-type carriers. The homozygous carriers also had significantly higher levels of fasting serum triglyceride (P = 0.042) and serum LDL cholesterol (P = 0.013). When adjustments were made for age, sex, BMI, and VO2max in a multiple regression analysis, a significantly negative association was found between homozygosity for the codon 64 variant and the SI (P = 0.009). We conclude that in young healthy Danes, the homozygous form but not the heterozygous form of the codon 64 amino acid polymorphism of the beta 3-adrenergic receptor may be associated with obesity and, independent of BMI, with a low SI. Since only three homozygous carriers were identified among 380 subjects, the results mu

Topics: Adult; Birth Weight; Body Weight; C-Peptide; Denmark; Female; Gene Frequency; Glucose; Heterozygote; Homozygote; Humans; Insulin; Insulin Resistance; Male; Obesity; Point Mutation; Polymorphism, Genetic; Receptors, Adrenergic, beta

In order to evaluate the steady state plasma glucose (SSPG) method by using a new somatostatin derivative, octreotide acetate (Sandostatin) instead of somatostatin that we had used for the insulin sensitivity test, we examined whether octreotide was able to suppress C-peptide (CPR), glucagon (IRG), and GH to a similar degree to that achieved with somatostatin. A total of 52 studies were performed in 45 essential hypertensive subjects and 7 healthy subjects. Octreotide was given subcutaneously in a does of 50 micrograms or 100 micrograms 10 min before the test (sc 50, sc 100 groups) or intravenously infused over 2 h (10 micrograms in bolus followed by a constant infusion, 50, 100, or 150 micrograms/2 h: i.v. 50, i.v. 100, i.v. 150 groups). In all of the groups the plasma immunoreactive insulin (IRI) concentration increased gradually after insulin injection and reached the steady state plasma insulin (SSPI) level between 40 and 60 microU/ml at 60 min through 120 min. Plasma CPR at 120 min was the most suppressed (by 67% of the basal level in i.v. 150 group during the study period), but on the other hand in both the sc 100 and i.v. 100 groups the plasma CPR concentration at 120 min was suppressed by nearly 40%, but not significantly suppressed in either the sc 50 or the i.v. 50 group. Plasma IRG and GH were strongly suppressed after 60 min in all groups during the study period. Plasma glucose had increased significantly at 30 min and reached the steady state at 90 min through 120 min in hypertensive and healthy subjects. The results indicated that the modified SSPG method with continuous intravenous infusion of Octreotide at 150 micrograms/2 h was adequate for the measurement of insulin sensitivity.

Topics: Blood Glucose; C-Peptide; Female; Hormones; Humans; Hypertension; Insulin; Insulin Resistance; Kinetics; Male; Middle Aged; Octreotide

The effects of recombinant human erythropoietin (rHuEPO) on the glucose metabolism were evaluated by intravenous glucose tolerance test in 20 maintenance hemodialysis patients. In 8 cases the glucose tolerance tests were performed before and after a single intravenous injection of 50 IU/kg of rHuEPO and in 12 cases before and after 3 months of rHuEPO therapy at doses of 50 IU/kg three times/week and 2 weeks after rHuEPO withdrawal. For each test glucose, immunoreactive insulin (IRI) and C peptide (C-p) plasma values were measured, and glucose constant decay, whole IRI (area IRI) and C-p area C-p) production, insulinogenic index, and insulin resistance index were calculated. After 3 months of rHuEPO therapy, the glucose constant decay increased significantly, area IRI, area C-p, and insulin resistance index decreased significantly, and the insulinogenic index did not change. No correlations were found between changes in hemoglobin values and changes in glucose metabolism parameters. Acute rHuEPO administration and rHuEPO withdrawal had no effect on glucose metabolism, despite significant changes in plasma erythropoietin levels. Long-term rHuEPO therapy improves glucose metabolism in maintenance hemodialysis patients significantly, mainly by reduction of insulin resistance. Neither anemia correction nor a direct effect of rHuEPO on some metabolic steps seem to be responsible of these effects.

Topics: Adult; Aged; C-Peptide; Erythropoietin; Female; Glucose; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Recombinant Proteins; Renal Dialysis; Time Factors

Insulin sensitivity and cardiovascular risk profile were examined in 20 healthy, nonobese, middle-aged men who were long-term users of nicotine-containing chewing gum and in 20 matched control subjects who did not use nicotine.. Long-term use of nicotine-containing chewing gum was associated with insulin resistance and hyperinsulinemia. The degree of insulin sensitivity correlated negatively to the extent of nicotine use measured as plasma cotinine levels.. These findings suggest that nicotine is the major constituent in cigarette smoke that leads to insulin resistance, metabolic abnormalities associated with the insulin resistance syndrome, and increased cardiovascular morbidity. Thus, the use of nicotine replacement therapy during smoking cessation should be transient and limited.

Topics: Adult; C-Peptide; Cotinine; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Nicotine

Topics: Acanthosis Nigricans; Aged; Aged, 80 and over; C-Peptide; Diabetes Mellitus, Type 2; Female; Humans; Insulin; Insulin Resistance; Syndrome

There has been no simultaneous evaluation of different aspects of insulin action in ageing. We studied 12 elderly (77 +/- 2 years) and 12 young (26 +/- 1 years) subjects with normal glucose tolerance and matched for sex, body mass index, lean body mass (LBM), blood pressure and physical activity, using a euglycaemic-hyperinsulinaemic clamp at about 350 pmol L-1 in combination with [3H]-glucose infusion. In the elderly group, hepatic glucose production was normal, fasting serum insulin and C-peptide were significantly increased (P = 0.001) and glucose utilization (34.4 +/- 2.4 vs. 44.4 +/- 3.2 mumol kg-1 LBM min-1, P = 0.02) and the percentage maximal suppression of C-peptide (58 +/- 6% vs. 79 +/- 5%, P = 0.02) during the clamp were reduced. Fasting plasma free fatty acid (FFA) and glycerol levels were similar in the two groups, but their percentage maximal suppression during the clamp was reduced in the elderly group (FFA 45 +/- 5% vs. 77 +/- 6%, P = 0.001; glycerol 43 +/- 5% vs. 76 +/- 3%, P = 0.001). Branched-chain amino acids (valine, leucine, isoleucine) and glucagon levels were similar in the two groups, both while fasting and during the clamp. Thus, insulin resistance in ageing appears selective on glucose utilization, inhibition of lipolysis and feedback inhibition of the B-cell secretion.

Topics: Adult; Age Factors; Aged; Amino Acids, Branched-Chain; Blood Glucose; C-Peptide; Fatty Acids; Female; Glucose; Glycerol; Humans; Insulin; Insulin Resistance; Male

In order to study the relationships between obesity, serum uric acid, insulin secretion and insulin resistance in female subjects, we evaluated serum C-peptide and glucose-induced insulin utilization (euglycemic hyperinsulinemic clamp) in 16 obese (8 nonhyperuricemic and 8 hyperuricemic) and 10 nonobese control subjects. Baseline C-peptide levels were significantly higher in hyperuricemic compared to both nonhyperuricemic obese subjects and controls (P < 0.001). M values, a measure of glucose disposal and insulin sensitivity, were significantly lower in hyperuricemic obese compared to nonhyperuricemic obese subjects and controls (P < 0.001) and, for all subjects were inversely correlated with the serum uric acid values (r = -0.821, P < 0.001). In conclusion, in this group of subjects the serum uric acid values were directly related to insulin resistance independently of age, sex, excess body weight, fat distribution and blood pressure.

Topics: Adult; C-Peptide; Female; Glucose Clamp Technique; Humans; Insulin; Insulin Resistance; Insulin Secretion; Obesity; Uric Acid

To analyse the relationship between age, glucose tolerance, beta-cell function, and insulin sensitivity in preclinical states of non-insulin-dependent (Type 2) diabetes mellitus (NIDDM), we have done a cross-sectional, age-stratified analysis of 86 non-diabetic first-degree relatives of NIDDM patients and 49 controls with similar age, sex, and BMI. A 5 mg kg ideal body weight-1 min-1 for 60 min of continuous infusion of glucose with model assessment (CIGMA) of serum glucose and C-peptide values at the end of the infusion was used to determine glucose tolerance and beta-cell function. Insulin sensitivity was estimated by modelling basal serum glucose and insulin values. Relatives and controls were divided into tertiles on the basis of age. Relatives had higher basal (5.3 vs 5 mmol l-1, p = 0.02) and achieved serum glucose (9.1 vs 8.4 mmol l-1, p = 0.01), lower beta-cell function (128 vs 145%, p = 0.007), and lower insulin sensitivity (37 vs 43%, p = 0.002). Beta-cell function declined with age in relatives (from 139% in young subjects to 134% in intermediate subjects and to 111% in older subjects, p = 0.002) and this decline was associated with an increase in basal serum glucose (from 5.1 to 5.3 and to 5.7 mmol l-1, p = 0.000) and achieved glucose (from 8.3 to 9.1 and to 9.3 mmol l-1, p = 0.038), without significant changes in insulin sensitivity. These trends were observed even after the exclusion of subjects with mild glucose intolerance. We conclude that both beta-cell dysfunction and insulin resistance are present in first-degree relatives of NIDDM. The progression of beta-cell dysfunction and glucose intolerance with age suggests that beta-cell dysfunction is the key factor in the apparition and progression of the disease.

Topics: Adolescent; Adult; Blood Glucose; C-Peptide; Cross-Sectional Studies; Diabetes Mellitus, Type 2; Female; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Male; Middle Aged; Nuclear Family; Prediabetic State; Reference Values

To determine the time course of changes in insulin action and secretion that occur early during the development of obesity, we studied children before the onset of puberty. The reason for choosing the prepubertal stage of development is that it is metabolically characterized by both a high sensitivity to insulin and low glucose stimulated insulin responses. Fifteen obese preadolescents (8 male/7 female, age 10 +/- 0.4 years, body mass index (BMI) 31 +/- 1.2 kg/m2 Tanner Stage I) with a duration of obesity of less than 5 years and 10 non-obese preadolescents (6 male/4 female, age 10 +/- 0.4 years, BMI 18 +/- 0.9 kg/m2) matched for gender were studied. In a cross-sectional analysis, we compared responses in obese preadolescents, with those in obese adolescents and obese adults with a longer duration of obesity. The euglycaemic hyperinsulinaemic clamp with 1-13C-glucose (Hot Ginf) and indirect calorimetry were used to quantitate insulin action and the hyperglycaemic clamp used to assess beta-cell function. Insulin-stimulated glucose uptake measured at two physiological levels of hyperinsulinaemia (approximately 180 and 480 pmol) was reduced by 20 and 45% in all three groups of obese compared to non-obese subjects (p < 0.01). Defects in oxidative and non-oxidative glucose metabolism were observed in all three groups of obese subjects at the higher insulin infusion rate. The ability of insulin to inhibit lipid oxidation was impaired in all three obese groups at both levels of hyperinsulinaemia. Increases in basal and glucose-stimulated insulin levels during the hyperglycaemic clamp mirrored the reductions in glucose uptake during the insulin clamp in all obese groups. These results indicate that insulin resistance and hyperinsulinaemia co-exist in preadolescent children with moderate to severe obesity.

Topics: Adolescent; Adult; C-Peptide; Calorimetry, Indirect; Child; Cohort Studies; Cross-Sectional Studies; Dose-Response Relationship, Drug; Fatty Acids, Nonesterified; Female; Glucose; Glucose Clamp Technique; Humans; Hyperinsulinism; Insulin; Insulin Resistance; Lipid Metabolism; Male; Obesity; Oxidation-Reduction; Time Factors

We examined the association between psychosocial stress-related variables and insulin resistance syndrome (IRS) risk-factor clustering. In 90 middle-aged male volunteers, psychosocial stress-related variables, defined as feelings of excessive tiredness and as personality and behavioral factors reflecting a stress-inducing life-style (type A behavior, hostility, and anger), were significantly correlated with the hyperinsulinemia, hyperglycemia, dyslipidemia, hypertension, increased abdominal obesity, and increased plasminogen activator inhibitor-1 (PAI-1) antigen comprising the IRS. The correlations remained significant after adjusting for body mass index (BMI), age, educational level, smoking status, alcohol consumption, and physical activity. However, the different stress-related factors reflected different risk-factor clustering profiles. Type A behavior was associated with normotension and a normal metabolic profile (canonical r = .50, chi2(36) = 59.1, P = .008). Hostility was related to elevated systolic blood pressure (SBP) and elevated triglycerides (TGs) (canonical r = .38, chi2(14) = 23.2, P = .052), whereas feelings of excessive tiredness were related to abdominal obesity, augmented glycemic responses to glucose ingestion, dyslipidemia, and increased PAI-1 antigen (canonical r = .39, chi2(24) = 36.8, P = .046). Although hostility and feelings of excessive tiredness have partly overlapping but clearly different clinical and metabolic correlates, their combination represents a full-blown IRS. Thus, even though insulin resistance is presumably to some extent genetically determined, these results suggest that considering psychosocial stress may be beneficial in understanding IRS risk-factor clustering.

Topics: Adult; Anthropometry; Blood Glucose; C-Peptide; Humans; Insulin; Insulin Resistance; Life Style; Male; Middle Aged; Risk Factors; Stress, Psychological

The relation between the C-peptide concentration in twenty-four-hour urine specimens and atherogenic risk factors was investigated in 38 patients with noninsulin-dependent diabetes mellitus in an attempt to determine the significance of urine C-peptide in diagnosing "syndrome X," which is characterized by insulin resistance. Weak positive correlations between twenty-four-hour urine C-peptide concentration and body mass index, systolic blood pressure (BP), diastolic BP, serum total cholesterol, and serum triglyceride were detected. A weak negative correlation was also apparent between urine C-peptide and serum high-density lipoprotein (HDL). The body mass index and serum triglyceride of patients with urine C-peptide excretion of > 100 micrograms/day were significantly higher than those in patients with normal urine C-peptide excretion (< 100 micrograms/day) (P < 0.01 and P < 0.02, respectively). Systolic BP, diastolic BP, serum total cholesterol, and serum HDL did not differ significantly between the two groups of patients. Results indicate that twenty-four-hour urine C-peptide concentration is of significance in determining whether a patient has a tendency to insulin resistance but has only limited value as a quantitative measure of endogenous insulin secretion.

Topics: Adult; Aged; Aged, 80 and over; Arteriosclerosis; Body Mass Index; C-Peptide; Diabetes Mellitus, Type 2; Female; Humans; Insulin Resistance; Male; Microvascular Angina; Middle Aged; Risk Factors; Triglycerides

To investigate whether insulin resistance and microalbuminuria are associated in non-insulin-dependent diabetes mellitus (NIDDM).. Insulin sensitivity was assessed using a hyperinsulinemic euglycemic clamp in 11 normoalbuminuric and 9 microalbuminuric NIDDM patients matched for sex, age, body composition, glycemic control, diabetes duration, and therapy.. Isotopically determined glucose disposal was similar in normo- and microalbuminuric patients in the basal state (mean +/- SD; 3.30 +/- 1.01 vs. 3.46 +/- 0.82 mg.kg lean body mass [LBM]-1.min-1; NS) and during hyperinsulinemia (7.16 +/- 2.65 vs. 6.63 +/- 2.88 mg.kg LBM-1.min-1;NS). No difference was observed in nonoxidative glucose disposal or lipid oxidation. Endogenous glucose production was equally suppressed by insulin (-0.08 +/- 0.99 vs. 0.30 +/- 1.12 mg.kg-1 LBM.min-1; NS). Glucose oxidation tended to be lower in the normoalbuminuric patients in the basal state (1.16 +/- 0.37 vs. 1.41 +/- 0.36 mg.kg LBM-1.min-1) and during hyperinsulinemia (2.35 +/- 0.72 vs. 2.90 +/- 0.77 mg.kg LBM-1.min-1; both P < 0.15). Urinary albumin excretion rate correlated with the insulin-stimulated glucose oxidation rate (r = 0.59, P = 0.0064), and a similar trend was seen in the basal state (r = 0.42, P = 0.063). Protein oxidation was higher in normoalbuminuric patients (1.6 +/- 0.5 vs. 1.0 +/- 0.4 mg.kg LBM-1.min-1; P = 0.017) and correlated inversely with albuminuria (r = -0.70, P = 0.0007). Serum growth hormone increased during insulin infusion; however, the increase was significantly greater in microalbuminuric patients. Plasma lipoproteins, maximal aerobic capacity, and 24-h ambulatory blood pressure were similar in the two groups.. Basal and insulin-stimulated glucose uptakes are comparable in carefully matched normo- and microalbuminuric NIDDM patients, and glucose oxidation may be positively related to albuminuria. The inverse relation between protein oxidation and albuminuria may be due to higher growth hormone levels during daily life perturbations in glucose in microalbuminuric patients.

Topics: Albuminuria; Blood Glucose; Body Composition; C-Peptide; Calorimetry; Circadian Rhythm; Diabetes Mellitus, Type 2; Diastole; Female; Fructosamine; Glucose; Glucose Clamp Technique; Glycated Hemoglobin; Glycolysis; Heart Rate; Hexosamines; Humans; Infusions, Intravenous; Insulin; Insulin Resistance; Male; Middle Aged; Oxidation-Reduction; Reference Values; Regression Analysis; Systole; Tritium

The acute effects of hyperinsulinemia on androgen homeostasis and a possible association of androgens to insulin sensitivity, serum lipids and lipoproteins and to lipid oxidation were examined in 19 healthy males (27 +/- 1 yrs, body mass index 24 +/- 1 kg/m2). In each subject, a 240 min euglycemic hyperinsulinemic clamp was performed and glucose and lipid oxidation were determined by indirect calorimetry. During hyperinsulinemia serum sex hormone-binding globulin (SHBG) concentration decreased by 5% (P < 0.01), insulin-like growth factor binding protein (IGFBP-1) by 88% (P < 0.001) and dehydroepiandrosterone sulphate (DHEAS) by 12% (P < 0.001), with no change in total or free testosterone concentrations. In the basal state, IGFBP-1 and C-peptide were inversely related (r = -0.54, P < 0.05). Fasting concentrations of serum free testosterone (r = 0.59, P < 0.01) and DHEAS (r = 0.47, P < 0.05) correlated positively with serum free fatty acid (FFA) concentrations during hyperinsulinemia, but not with fasting FFA level. Lipid oxidation rate in the basal state correlated positively to the decline in SHBG (r = 0.61, P < 0.01) and DHEAS concentrations (r = 0.62, P < 0.01) during hyperinsulinemia. While the fasting serum high density lipoprotein cholesterol level correlated positively with the insulin-induced decline in DHEAS level (r = 0.58, P < 0.01), no associations were found between serum androgens and total cholesterol, low density lipoprotein cholesterol or triglyceride concentrations. Insulin sensitivity was not related to SHBG, IGFBP-1, DHEAS or testosterone concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Acute Disease; Adult; Androgens; C-Peptide; Dehydroepiandrosterone; Dehydroepiandrosterone Sulfate; Homeostasis; Humans; Hyperinsulinism; Insulin Resistance; Insulin-Like Growth Factor Binding Protein 1; Lipid Peroxidation; Male; Sex Hormone-Binding Globulin; Somatomedins; Testosterone

Women with the diagnosis of gestational diabetes mellitus (GDM) are at a greater risk for developing diabetes in later life. This raises the question in which time span, to what extent and on which pathophysiological basis disorders of carbohydrate metabolism are to be expected post partum. Therefore 28 former gestational diabetes patients (GDM) were compared to 35 control patients, who had shown no irregularities in the oral glucose tolerance test during pregnancy. The follow-up study took place 5 years after the screening during pregnancy. The Wilcoxon Test for random samples revealed significantly higher blood sugar levels in the GDM group compared to the control group at 0.1 h and 2 h (median: 0 h 96 mg % vs 91 mg %; 1 h 155 mg % vs 126 mg %; 2 h 117 mg % vs 105 mg %; p < 0,05). Whereas no differences were apparent for fasting insulin, the values of the GDM group showed a markedly higher insulin level (Wilcoxon Test: p < 0.05) after 1 h (median: 74 microU/ml vs 56 microU/ml), 2 h (median: 60 microU/ml vs 38 microU/ml) and 3 h (median: 50 microU/ml vs 33 microU/ml). The serum level of C-peptide responded accordingly 2 h (median: 6.7 ng/ml vs 5.4 ng/ml; p = 0.04) and 3 h (median: 5.9 ng/ml vs 4.9 ng/ml; p = 0.04) after an oral glucose load.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; C-Peptide; Diabetes Mellitus, Type 2; Female; Follow-Up Studies; Glucose Tolerance Test; Glycated Hemoglobin; Humans; Hyperglycemia; Insulin Resistance; Pregnancy; Pregnancy in Diabetics; Reference Values

We report 34 patients (aged 5-18 years) with acute (n = 26) or chronic (n = 1) leukemia, non-Hodgkin's lymphoma (n = 3) or severe aplastic anemia (n = 4) evaluated for pancreatic beta-cell function 9 months to 10.2 years after autologous (n = 19) or allogeneic (n = 15) BMT. Before BMT, all patients received cytotoxic drugs, combined with total body irradiation (TBI) in 24 cases or thoracoabdominal irradiation (TAI) in 4 children. Patients were investigated for fasting blood glucose (FBG), HbA1C, anti-insulin (IAA) and islet cell antibodies (ICA), first-phase insulin response (FPIR) and insulinemia/glycemia (I/G) ratio on i.v. glucose tolerance test (GTT) and C-peptide response after glucagon 1 mg i.v. Results were compared with those obtained in 21 age- and sex-matched controls. None of the patients or controls had IAA and/or ICA. FBG and HbA1C were normal in all children. In the patients, glycemia on i.v. GTT was similar to controls whereas insulin levels I/G ratio and FPIR were significantly higher in patients than in controls, as well as C-peptide levels. We divided the patients on the basis of the radiotherapy into group I with TBI (n = 18), group II with TAI (n = 4) and group III who were not irradiated (n = 4). The I/G ratio, FPIR on i.v. GTT and C-peptide response were significantly higher in group I compared with the other two groups and controls. The increased insulin and C-peptide levels in our patients with normal glycemia might be interpreted as a state of insulin resistance, more evident in patients who received TBL.

Topics: Adolescent; Anemia, Aplastic; Antineoplastic Combined Chemotherapy Protocols; Autoantibodies; Blood Glucose; Bone Marrow Transplantation; C-Peptide; Child; Child, Preschool; Female; Glucagon; Glycated Hemoglobin; Growth Hormone; Humans; Hypogonadism; Hypothyroidism; Insulin; Insulin Resistance; Insulin Secretion; Islets of Langerhans; Leukemia; Lymphoma, Non-Hodgkin; Male; Prospective Studies; Radiation Injuries; Radioisotope Teletherapy; Whole-Body Irradiation

The tissue sensitivity to insulin was evaluated using the hyperinsulinemic euglycemic clamp technique in a 44-year old male with Werner's syndrome associated with diabetes mellitus. In addition, the autophosphorylation of insulin receptors and the number of autophosphorylated insulin receptors were measured in his erythrocytes by a new enzyme-linked immunosorbent assay. He had an increased serum insulin level (30.5 microU/ml) in addition to hyperglycemia (226 mg/dl), suggesting that he had insulin-resistant diabetes mellitus. A clamp study revealed that his insulin-stimulated glucose disposal rate (2.80 mg/kg/min) was comparable to that in noninsulin-dependent diabetes mellitus (4.14 +/- 1.94 (SD) mg/kg/min, n = 23). The number of autophosphorylated insulin receptors per 300 microliters of erythrocytes was also identical to that in normal control subjects. In addition, the autophosphorylation of insulin receptors determined at six different insulin concentrations was within the normal range, even when it was expressed as per 300 microliters of erythrocytes as well as per unit receptor. These results demonstrate that insulin resistance in the patient with Werner's syndrome is caused by a defect that cannot be detected by means employed in this study, and suggest that the defect is present at the steps distal to the autophosphorylation of tyrosine kinase of insulin receptors.

Topics: Adult; Blood Glucose; C-Peptide; Diabetes Mellitus; Enzyme-Linked Immunosorbent Assay; Erythrocytes; Humans; Insulin; Insulin Resistance; Male; Phosphorylation; Receptor, Insulin; Werner Syndrome

Inasmuch as previous studies have obtained conflicting results on the contribution of obesity to insulin resistance in noninsulin-dependent diabetes mellitus (NIDDM), we studied 10 nonobese and 10 obese NIDDM patients with the isoglycemic-(approximately 10 mmol/L)-hyperinsulinemic clamp (two insulin infusions of 4 and 40 mU/m-2 min-1), combined with [3-3H]glucose infusion and indirect calorimetry. As compared with nonobese patients, obese NIDDM patients had higher baseline peripheral and estimated portal plasma insulin concentrations (113 +/- 18 vs. 46 +/- 3 pmol/L and 288 +/- 53 vs. 98 +/- 6 pmol/L, respectively; P < 0.05) and less suppressed endogenous insulin production during clamp. Hepatic glucose production was greater in obese than in nonobese patients (basal, 16 +/- 1.1 vs. 12 +/- 0.5 mumol/kg-1 fat-free mass (FFM) min-1; clamp, 5.7 +/- 0.5 vs. 2.8 +/- 0.2 mumol/kg-1 FFM min-1, P < 0.05). Glucose utilization increased to a lesser extent in obese than in nonobese patients (49 +/- 5 vs. 73 +/- 7 mumol/kg-1 FFM min-1, P < 0.05) during clamp because of a lower increase in nonoxidative glucose metabolism (30 +/- 5 vs. 50 +/- 7 mumol/kg-1 FFM min-1, P < 0.05). Plasma free fatty acid concentrations and rates of lipid oxidation were greater in obese (P < 0.05) patients and correlated with hepatic glucose production (r = 0.79 and 0.50, P < 0.05). In conclusion, obesity exaggerates hepatic as well as extra-hepatic insulin resistance in NIDDM. The impaired inhibition of pancreatic beta-cell function by exogenous insulin contributes to exaggerated hyperinsulinemia in obese NIDDM.

Topics: Blood Glucose; C-Peptide; Diabetes Mellitus; Diabetes Mellitus, Type 2; Energy Metabolism; Fatty Acids, Nonesterified; Female; Glucose Clamp Technique; Glycolysis; Humans; Infusions, Intravenous; Insulin; Insulin Resistance; Liver; Male; Middle Aged; Obesity; Portal System; Regression Analysis

Congenital muscle fiber type disproportion myopathy (CFTDM) is a chronic, nonprogressive muscle disorder characterized by universal muscle hypotrophy and growth retardation. Histomorphometric examination of muscle shows a preponderance of smaller than normal type 1 fibers and overall fiber size heterogeneity. Concomitant endocrine dysfunctions have not been described. We report the findings of altered insulin secretion and insulin action in two brothers affected with CFTDM and glucose intolerance as well as in their nonconsanguineous glucose-tolerant parents. Results are compared with those of six normoglycemic control subjects. All study participants underwent an oral glucose tolerance test to estimate insulin secretion. The oldest boy and his parents volunteered for studies of whole-body insulin sensitivity consisting of a 4-h euglycemic hyperinsulinemic clamp in combination with indirect calorimetry. Insulin receptor function and glycogen synthase (GS) activity and expression were examined in biopsies of vastus lateralis muscle. Despite a 45-90-fold increase in both fasting and postprandial serum insulin levels, both CFTDM patients had diabetes mellitus. Clamp studies revealed that the oldest boy had severe insulin resistance of both liver and peripheral tissues. The impaired insulin-stimulated glucose disposal to peripheral tissues was primarily due to reduced nonoxidative glucose metabolism. These changes were paralleled by reduced basal values of muscle GS total activity, allosterical activation of GS by glucose-6-phosphate, GS protein, and GS mRNA. The father expressed a lesser degree of insulin resistance, and studies of muscle insulin receptor function showed a severe impairment of receptor kinase activity. In conclusion, CFTDM is a novel form of severe hyperinsulinemia and insulin resistance. Whether insulin resistance is causally related to the muscle disorder awaits to be clarified.

Topics: Adolescent; Adult; Base Sequence; Blood Glucose; C-Peptide; Child; Diabetes Complications; Female; Glucose; Glucose Clamp Technique; Glucose Tolerance Test; Humans; Insulin; Insulin Resistance; Insulin Secretion; Lipid Metabolism; Male; Molecular Sequence Data; Muscle Fibers, Skeletal; Muscles; Muscular Diseases; Oxidation-Reduction; Proinsulin

Increased lipoprotein(a) [Lp(a)] concentrations have been recognized as a risk factor for coronary heart disease. Little data exists on the relationship of Lp(a) concentrations to insulin resistance.. We examined insulin resistance (as determined by the euglycemic clamp) together with indirect calorimetry in relation to Lp(a) concentrations, apolipoprotein(a) [apo(a)] molecular weight, and apo(a) phenotype in 87 normoglycemic men.. Lp(a) concentrations were significantly related to total (r = 0.225) and nonoxidative (r = 0.256) whole-body glucose disposal. These results suggest a positive but weak association between insulin sensitivity (restricted to the nonoxidative whole-body glucose disposal) and Lp(a) concentrations. However, after adjustment for apo(a) molecular weight [which accounts for some of the genetic influences on Lp(a) levels], total and nonoxidative body glucose disposal were not significantly related to Lp(a) concentrations.. Normoglycemic insulin-resistant subjects do not have elevated Lp(a) concentrations.

Topics: Apolipoproteins; Apoprotein(a); Blood Glucose; Body Mass Index; C-Peptide; Calorimetry; Cholesterol; Cholesterol, HDL; Cholesterol, LDL; Fasting; Glucose; Glucose Clamp Technique; Humans; Insulin; Insulin Resistance; Lipoprotein(a); Male; Middle Aged; Phenotype; Triglycerides

To investigate the relationship between gonadal function, insulin and psychosocial stress in middle-aged men.. A population-based, cross-sectional, observational study.. Glostrup Hospital, Copenhagen, Denmark.. Four hundred and thirty-nine males, all aged 51 years.. Body-mass index (BMI), waist-to-hip ratio (WHR), insulin, C-peptide, free testosterone, luteinizing hormone (LH), lipids, fibrinogen, lung function tests (FVC, FEV1, PEF), blood pressure, a self-administered questionnaire with questions on psychosocial variables, lifestyle and self-rated health.. Free testosterone correlated inversely (P < 0.05) with weight, BMI, WHR, and fibrinogen, and positively with FEV1. An independent correlation between free testosterone and insulin (P < or = 0.03), but not with C-peptide, was seen after controlling for BMI and WHR. Subjects with low levels of free testosterone, or those in the lowest quintile of the distribution of the hypogonadal index (HI: free testosterone/LH), showed a cluster of negative psychosocial variables, and psychological as well as health-related problems. Furthermore, hypogonadal men had lower (P < 0.05) levels of FEV1, peak flow and FVC, but higher (P < 0.01) levels of fibrinogen and higher pulse pressure than men with normal gonadal function. This gradient of variables, relative to HI, was not seen for possible confounders like BMI, WHR, and tobacco or alcohol consumption.. Psychosocial stress may be associated with a process of premature ageing in middle-aged males, corresponding to a hypogonadal state as well as to indirect signs of increased insulin resistance.

Topics: Blood Pressure; Body Mass Index; C-Peptide; Cohort Studies; Cross-Sectional Studies; Denmark; Genitalia, Male; Gonadal Steroid Hormones; Humans; Insulin; Insulin Resistance; Male; Middle Aged; Regression Analysis; Respiratory Function Tests; Stress, Psychological; Surveys and Questionnaires

In overweight women with polycystic ovary syndrome (PCOS), increased insulin resistance has been observed. Since abdominal obesity is associated with impaired fibrinolytic capacity and elevated levels of plasminogen activator inhibitor (PAI-1) and since PAI-1 seems to be related to insulin resistance, we investigated the possible effects of dietary intervention on lipids, fibrinolysis, coagulation, and insulin sensitivity in obese PCOS women. Nine women aged 22 to 39 years (median weight, 97 kg) ate a protein-rich very-low-calorie diet (VLCD) (Nutrilett, Nycomed Pharma, Oslo, Norway; 421 kcal/d) for 4 weeks (part 1). After significant reductions of body fat (13%, P < .01), two of nine women achieved regular menstruation and became pregnant. Six of the remaining women continued on a conventional low-calorie diet (1,000 to 1,500 kcal/d) for the next 20 weeks (part 2), during which time they were generally able to preserve the body fat loss obtained in part 1 of the study. During part 1, significant reductions of total serum cholesterol (29%, P = .001) and fasting triglyceride ([TG] 31%, P < .05) levels were observed, as well as significant reductions of fasting glucose (6%, P < .05) and insulin (20%, P < .05). Insulin sensitivity (glucose disposal rate [GDR]) was increased by 93% (P < .05). After finishing part 2, insulin sensitivity was still significantly increased (86%, P < .05) and PAI-1 activity was significantly reduced (54%, P < .05). Moreover, overall fibrinolytic activity was significantly improved (serum D-dimer concentration increased by 75%, P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adipose Tissue; Adult; Blood Glucose; Body Mass Index; Body Weight; C-Peptide; Diet, Reducing; Factor VII; Female; Fibrinogen; Fibrinolysis; Hemostasis; Humans; Insulin; Insulin Resistance; Lipids; Obesity; Plasminogen Activator Inhibitor 1; Polycystic Ovary Syndrome; Sex Hormone-Binding Globulin; Testosterone; Time Factors; Tissue Plasminogen Activator

An increased risk of ischemic heart disease in men with the Lewis blood group phenotype Le(a-b-) has been reported. It has been suggested that the Le(a-b-) phenotype is a genetic marker of the insulin resistance syndrome. To examine whether Le(a-b-) confers the insulin resistance syndrome, we studied a random sample of unrelated healthy young white men and women living in Copenhagen (n = 380, 18 to 32 years). All individuals had their insulin sensitivity estimated using Bergman's minimal model (intravenous glucose in combination with tolbutamide) and systolic blood pressure (SBP) was measured with a London School of Hygiene Sphygmomanometer. A number of anthropometric measurements including body mass index (BMI, kilograms/meters squared) and biochemical characteristics were performed. The Lewis blood group typing was carried out on erythrocytes. Twenty-one men had the Le(a-b-) phenotype. Compared to all other men (N = 165), the Le(a-b-) men had a significantly higher SBP (6 mm Hg, P = .0024). They also had higher values of BMI (8%, P = .016), total body fat mass (25%, P = .015), fasting values of serum insulin (32%, P = .006), serum C-peptide (20%, P = .029), and plasma glucose (8%, P = .003). The fasting values of serum lipids, plasminogen activator inhibitor (PAI-1) activity, tissue plasminogen activator (t-PA) antigen, and insulin sensitivity did not differ between Le(a-b-) men and men with other Lewis phenotypes. Altogether 194 women participated in the study of which 21 women had the Le(a-b-) phenotype. Except for a lower PAI-1 activity (45%, P = .044), no values differed between Le(a-b-) women and women with other Lewis phenotypes. The women were also stratified according to use of oral contraceptives. Le(a-b-) women using oral contraceptives (N = 8) had a significantly lower plasma level of fasting PAI-1 activity (P = .029) and t-PA antigen (P = .004) compared to women using oral contraceptives without the Le(a-b-) phenotype (N = 42). Our data support the hypothesis that Le(a-b-) men exhibit features of the insulin resistance syndrome, including higher levels of BMI, SBP, and fasting levels of serum insulin and plasma glucose. In young women no signs of the insulin resistance syndrome were found in subjects with the Le(a-b-) phenotype.

Topics: Adolescent; Adult; Blood Glucose; C-Peptide; Cardiovascular Diseases; Female; Genetic Markers; Humans; Insulin; Insulin Resistance; Lewis Blood Group Antigens; Life Style; Male; Risk Factors; Sex Factors; Syndrome