piperidines and Glucose-Intolerance

SCO-267 is a full agonist of the free fatty acid receptor 1 (GPR40), which regulates the secretion of islet and gut hormones. In this phase 1 study, we aimed to evaluate the clinical profile of single and multiple once-daily oral administration of SCO-267 in healthy adults and patients with diabetes. Plasma SCO-267 concentration was seen to increase in a dose-dependent manner after administration, and its plasma exposure was maintained for 24 h. Repeated dose did not alter the pharmacokinetic profile of SCO-267 in healthy adults. SCO-267 was generally safe and well tolerated at all evaluated single and multiple doses. Single and repeated doses of SCO-267 stimulated the secretion of insulin, glucagon, glucagon-like peptide 1, glucose-dependent insulinotropic polypeptide, and peptide YY in healthy adults. Furthermore, a single dose of SCO-267 stimulated the secretion of these hormones, decreased fasting hyperglycemia, and improved glycemic control during an oral glucose tolerance test in patients with diabetes, without inducing hypoglycemia. This study is the first to demonstrate the clinical effects of a GPR40 full agonist. SCO-267 is safe and well tolerated and exhibits once-daily oral dosing potential. Its robust therapeutic effects on hormonal secretion and glycemic control make SCO-267 an attractive drug candidate for the treatment of diabetes.

Topics: Adult; Aged; Blood Glucose; Diabetes Mellitus, Type 2; Double-Blind Method; Gastrointestinal Hormones; Glucose Intolerance; Glucose Tolerance Test; Glycemic Control; Humans; Insulin Secretion; Islets of Langerhans; Japan; Male; Middle Aged; Piperidines; Pyridines; Receptors, G-Protein-Coupled; Young Adult

The experimental aim of this study was to determine whether ET-1-mediated vasoconstrictor tone is elevated in adult humans with impaired fasting blood glucose concentrations, independent of other cardiovascular risk factors.. Forearm blood flow (FBF: plethysmography) responses to intra-arterial infusion of selective ETA receptor blockade (BQ-123: 100 nmol/min for 60 min) and non-selective ETA/B blockade (BQ-123 + BQ-788: 50 nmol/min for 60 min) were determined in 28 middle-aged, sedentary adults (17 M/11 F): 14 with normal fasting blood glucose (age: 57 ± 2 yr; 6 F/8 M; BMI: 29.2 ± 0.9 kg/m(2); glucose: 4.9 ± 0.1 mmol/L) and 14 impaired fasting blood glucose (58 ± 1 yr; 5 F/9 M; 29.6 ± 1.1 kg/m(2); 5.8 ± 0.1 mmol/L) concentrations.. Selective ETA receptor blockade elicited a significantly greater (∼20%) increase in FBF in the impaired fasting glucose adults compared with the normoglycemia controls. ETA/B blockade resulted in a further 2-fold increase (P < 0.05) in FBF above that elicited by ETA receptor antagonism in the impaired fasting glucose but not normal fasting glucose adults. There was a positive correlation between fasting blood glucose levels and the peak vascular responses to ETA (r = 0.44; P < 0.05) and ETA/B (r = 0.62; P < 0.05) blockade. No other anthropometric, hemodynamic or metabolic variable was correlated with the blood flow responses to ET-1 receptor blockade.. ET-1-mediated vasoconstrictor tone is elevated in adults with impaired fasting blood glucose concentrations, independent of other cardiometabolic risk factors. Enhanced ET-1 system activity may underlie endothelial vasomotor dysfunction and increased cardiovascular risk in adults with impaired fasting blood glucose concentrations.

Topics: Antihypertensive Agents; Blood Glucose; Cardiovascular Diseases; Endothelin A Receptor Antagonists; Endothelin B Receptor Antagonists; Endothelin-1; Fasting; Female; Glucose Intolerance; Humans; Infusions, Intra-Arterial; Male; Middle Aged; Oligopeptides; Peptides, Cyclic; Piperidines; Plethysmography; Risk Factors; Sedentary Behavior; Vasoconstriction

The efficacy and safety of the new drug, BGP-15, were compared with placebo in insulin-resistant patients in a 28-day dose-ranging study. Forty-seven nondiabetic patients with impaired glucose tolerance were randomly assigned to 4 weeks of treatment with 200 or 400 mg of BGP-15 or placebo. Insulin resistance was determined by hyperinsulinemic euglycemic clamp technique and homeostasis model assessment method, and beta-cell function was measured by intravenous glucose tolerance test. Each BGP-15 dose significantly increased whole body insulin sensitivity (M-1, p=0.032), total body glucose utilization (M-2, p=0.035), muscle tissue glucose utilization (M-3, p=0.040), and fat-free body mass glucose utilization (M-4, p=0.038) compared to baseline and placebo. No adverse drug effects were observed during treatment. BGP-15 at 200 or 400 mg significantly improved insulin sensitivity in insulin-resistant, nondiabetic patients during treatment compared to placebo and was safe and well-tolerated. This was the first clinical study demonstrating the insulin-sensitizing effect of a molecule, which is considered as a co-inducer of heat shock proteins.

Topics: Adult; Double-Blind Method; Drug-Related Side Effects and Adverse Reactions; Female; Glucose; Glucose Intolerance; Humans; Hypoglycemic Agents; Insulin; Insulin Resistance; Male; Middle Aged; Oximes; Piperidines; Placebos; Young Adult

Impaired glucose tolerance (IGT) is associated with increased cardiovascular risk. The pathophysiological mechanisms linking post-challenge hyperglycemia to accelerated atherosclerosis, however remain to be elucidated.. A prospective, open, randomised, cross-over study was performed to investigate the effect of 2 mg repaglinide on hyperglycemia and endothelial function during an oral glucose tolerance test (75 g glucose) in 12 subjects with diagnosed IGT. Blood samples for determination of plasma glucose were drawn fasting, 1 and 2 hours after glucose ingestion. Endothelial function was assessed by measuring flow-mediated dilatation (FMD) of the brachial artery with high-resolution ultrasound.. Administration of repaglinide resulted in a significant reduction of plasma glucose at 2 hours (172.8+/-48.4 vs. 138.3+/-41.2 mg/dl; p < 0.001). The flow-mediated dilatation (FMD) 2 hours after the glucose-load was significantly reduced in comparison to fasting in the control group (6.21+/-2.69 vs. 7.98+/-2.24 %; p = 0.028), whereas after theadministration of repaglinide the FMD was not significantly different to fasting values (7.24+/-2.57 vs. 8.18+/-2.93 %; p = n.s.). Linear and logistic regression analysis revealed that only the change of glucose was significantly correlated to the change of FMD observed (p < 0.001). Regression analysis after grouping for treatment and time confirmed the strong negative association of the changes of plasma glucose and FMD and indicate that the effect of repaglinide observed is based on the reduction glycemia.. In subjects with IGT, the endothelial dysfunction observed after a glucose challenge is related to the extent of hyperglycemia. Reduction of hyperglycemia by repaglinide reduces endothelial dysfunction in a glucose dependent manner.

Topics: Aged; Blood Glucose; Carbamates; Cross-Over Studies; Endothelium, Vascular; Female; Glucose Intolerance; Glucose Tolerance Test; Humans; Male; Middle Aged; Piperidines; Prospective Studies; Vascular Diseases

Cisapride is used widely for the treatment of diabetic gastroparesis. There is some evidence that cisapride may influence insulin secretion. The aim of this study was to evaluate the effect of cisapride on plasma concentrations of glucose, insulin and C-peptide in response to oral and intravenous glucose loads. Twelve normal subjects took cisapride and placebo, each for 10 days using a randomized, double-blind, crossover design. In each treatment phase, the plasma glucose, insulin and C-peptide response to intravenous (0.5 g/kg) and oral (75 g) glucose loads was evaluated on separate days. Gastric emptying of the oral glucose load was also measured. After the intravenous glucose load, plasma concentrations of C-peptide were higher (P< 0.01) on cisapride when compared with placebo (e.g. peak C-peptide 2.08+/-0.25 nmol/L vs 1.78+/-0.22 nmol/L, P< 0.01) while there was no significant difference in plasma glucose or insulin. Cisapride had no effect on the rate of gastric emptying of the oral glucose load. Mean plasma concentrations of insulin and C-peptide were higher after oral glucose on cisapride than placebo, but these differences were not significantly different. These observations indicate that cisapride may increase glucose-stimulated insulin secretion.

Topics: Administration, Oral; Adult; C-Peptide; Cisapride; Female; Gastrointestinal Agents; Glucose; Glucose Intolerance; Glucose Tolerance Test; Humans; Injections, Intravenous; Insulin; Male; Osmolar Concentration; Piperidines; Reference Values

Metabolic inflammation is an essential event in obesity-induced diabetes and insulin resistance. In obesity, an increasing number of macrophages recruited into visceral adipose tissues undergo significant M. Newborn mice were subcutaneously (s.c.) injected with monosodium glutamate (MSG) to establish a diabetes model. After 24 weeks, the MSG obese mice were divided into three groups and treated with piperine (40 mg/kg/day), metformin (150 mg/kg/day) and vehicle for 10 successive weeks, respectively.. The obesity model was successfully established, as the body weight, insulin resistance, fasting blood glucose (FBG) and dyslipidemia were significantly increased. The 10-week administration of piperine to the obese mice not only significantly decreased the elevated FBG (Model: 6.45 ± 0.41 mM; Piperine: 4.72 ± 0.44 mM, p < 0.01), serum TC (Model: 5.66 ± 0.66 mM; Piperine: 3.55 ± 0.30 mM, p < 0.01) and TG (Model: 1.41 ± 0.08 mM; Piperine: 0.94 ± 0.05 mM, p < 0.001), but also enhanced the glucose infusion rate in the hyperglycemic clamp experiment. Meanwhile, piperine improved glucose intolerance and insulin resistance in MSG obese mice. Piperine markedly decreased the total and differential white blood cell (WBC) count, the serum levels of lipopolysaccharide (LPS) and pro-inflammatory cytokines such as galectin-3 (Gal-3) and interleukin-1β (IL-1β). Furthermore, piperine clearly down-regulated the mRNA levels of pro-inflammatory cytokines and the protein levels of M. Piperine served as an immunomodulator for the treatment of obesity-related diabetes through its anti-inflammatory effects, which might be achieved by inhibiting macrophages M

Topics: Adipose Tissue; Alkaloids; Animals; Benzodioxoles; Body Weight; Cytochrome P-450 Enzyme Inhibitors; Cytokines; Female; Flavoring Agents; Glucose Intolerance; Inflammation; Insulin Resistance; Macrophages; Mice; Mice, Inbred C57BL; Mice, Obese; Obesity; Piperidines; Polyunsaturated Alkamides; Sodium Glutamate

Cannabinoid type 1 receptor (CB1R) inhibition tends to be one of the promising strategies for the treatment of obesity and other related metabolic disorders. Although CB1R inhibition may cause adverse psychiatric effects including depression and anxiety, the investigation of the role of peripheral CB1R on weight loss and related metabolic parameters are urgently needed. We first explored the effect of rimonabant, a selective CB1R antagonist/inverse agonist, on some metabolic parameters in high fat-diet (HFD)-induced obesity in mice. Then, real-time PCR and electrophysiology were used to explore the contribution of high voltage-activated Ca2+ channels (HVACCs), especially Cav1.1, on rimonabant's effect in skeletal muscle (SM) in HFD-induced obesity. Five-week HFD feeding caused body weight gain, and decreased glucose/insulin tolerance in mice compared to those in the regular diet group (P<0.05), which was restored by rimonabant treatment compared to the HFD group (P<0.05). Interestingly, HVACCs and Cav1.1 were decreased in soleus muscle cells in the HFD group compared to the control group. Daily treatment with rimonabant for 5 weeks was shown to counter such decrease (P<0.05). Collectively, our findings provided a novel understanding for peripheral CB1R's role in the modulation of body weight and glucose homeostasis and highlight peripheral CB1R as well as Cav1.1 in the SM as potential targets for obesity treatment.

Topics: Animals; Blood Glucose; Body Weight; Calcium Channels; Calcium Channels, L-Type; Cannabinoid Receptor Antagonists; Diet, High-Fat; Glucose Intolerance; Insulin Resistance; Male; Mice, Inbred C57BL; Models, Animal; Muscle, Skeletal; Obesity; Piperidines; Pyrazoles; Receptor, Cannabinoid, CB1; Rimonabant

Glucagon-like peptide-1 (GLP-1), an incretin hormone, is released from intestinal L cells in response to nutrient ingestion. Dipeptidyl peptidase-4 (DPP-4) rapidly degrades the active form of GLP-1 to an inactive form in the bloodstream. The present study aimed to investigate the role of serotonin (5-HT)1B receptors in the regulation of plasma active GLP-1 levels and glucose tolerance under DPP-4 inhibition.. C57BL6J mice treated with or without alogliptin, a highly selective DPP-4 inhibitor, for 4 days were intraperitoneally injected with either saline, the 5-HT1B/2C receptor agonist meta-chlorophenylpiperazine (mCPP) at 2.5mg/kg and 5mg/kg or the selective 5-HT1B receptor agonist CP94253 at 2.5mg/kg and 5mg/kg, and food-deprived after treatment. An hour later, plasma active GLP-1 levels were determined. Also, a glucose tolerance test was done by injecting D-glucose (2g/kg) following the injection of saline or CP94253 (5mg/kg) in mice treated with alogliptin.. Intraperitoneal injection of mCPP (2.5 and 5mg/kg) or CP94253 (2.5 and 5mg/kg) in mice treated with alogliptin for 4 days significantly increased plasma active GLP-1 levels compared with saline controls in mice that were food-deprived after the injections. While intraperitoneal injection of either mCPP or CP94253 alone had no significant effect on plasma active GLP-1 levels, the injection of CP94253 improved glucose tolerance in mice treated with alogliptin compared with saline.. These findings suggest that pharmacological stimulation of 5-HT1B receptors enhances the increases in plasma active GLP-1 induced by DPP-4 inhibition independently of feeding and also improves glucose tolerance in mice.

Topics: Administration, Oral; Animals; Dipeptidyl Peptidase 4; Dipeptidyl-Peptidase IV Inhibitors; Dose-Response Relationship, Drug; Drug Therapy, Combination; Food-Drug Interactions; Glucagon-Like Peptide 1; Glucose Intolerance; Injections, Intraperitoneal; Insulin; Insulin Secretion; Insulin-Secreting Cells; Male; Mice, Inbred C57BL; Piperazines; Piperidines; Pyridines; Receptor, Serotonin, 5-HT1B; Serotonin 5-HT1 Receptor Agonists; Up-Regulation; Uracil

Effects of cannabinoid receptor 1 (CB1R) blockade were observed by comparing 9-day and 6-week SR141716 treatments in monosodium glutamate (MSG)-induced hypometabolic and hypothalamic obesity (HO) in rats for the first time and molecular mechanisms were investigated. Compared with normal rats, the MSG rats display typical symptoms of the metabolic syndrome, i.e., excessive abdominal obesity, hypertriglyceridemia, hyperinsulinemia, insulin resistance, and hepatic steatosis, but with lower food intake. Although both the 9-day and 6-week treatments with the specific CB1R antagonist SR141716 effectively lowered body weight, intraperitoneal adipose tissue mass, serum triglyceride (TG), and insulin level, the effect of chronic treatment is more impressive. Moreover, serum cholesterol, free fatty acids (FFA), fasted and postprandial blood glucose, and insulin insensitivity were more effectively improved by 6-week exposure to SR141716, whereas hypophagia was only effective within the initial 2 weeks. In addition, hepatic steatosis as well as hepatic and adipocyte morphology was improved. Western blot analysis revealed that the markedly increased CB1R expression and decreased insulin receptor (INR) expression in liver and adipose tissues were effectively corrected by SR141716. Consistent with this, deregulated gene expression of lipogenesis and lipolysis as well as glucose metabolic key enzymes were also restored by SR141716. In conclusion, based on present data we found that: (1) alteration of the hypothalamus in MSG rats leads to a lower expression of INR in crucially insulin-targeted tissues and hyperinsulinemia that was reversed by SR141716, (2) the abnormally increased expression of CB1R in liver and adipose tissues plays a vital role in the pathophysiological process of MSG rats, and (3) chronic CB1R blockade leads to a sustained improvement of the metabolic dysfunctions of MSG rats.

Topics: Adipose Tissue; Animals; Animals, Newborn; Cannabinoid Receptor Antagonists; Fatty Liver; Female; Glucose Intolerance; Hyperlipidemias; Insulin Resistance; Liver; Male; Obesity; Piperidines; Pyrazoles; Rats; Rats, Wistar; Receptor, Cannabinoid, CB1; Receptor, Insulin; Rimonabant; Sodium Glutamate

Although the presence of cannabinoid type 1 (CB1) receptor in islets has been reported, the major contributor to the protective effect of rimonabant on islet morphology is unknown. We determined whether the protective effect of rimonabant on pancreatic islet morphology is valid in established diabetes and also whether any effect was independent of decreased food intake.. After diabetes was confirmed, Otsuka Long-Evans Tokushima Fatty rats, aged 32 weeks, were treated with rimonabant (30 mg/kg/d, rimonabant group) for 6 weeks. Metabolic profiles and islet morphology of rats treated with rimonabant were compared with those of controls without treatment (control group), a pair-fed control group, and rats treated with rosiglitazone (4 mg/kg/d, rosiglitazone group).. Compared to the control group, rats treated with rimonabant exhibited reduced glycated albumin levels (p<0.001), islet fibrosis (p<0.01), and improved glucose tolerance (p< 0.05), with no differences from the pair-fed control group. The retroperitoneal adipose tissue mass was lower in the rimonabant group than those of the pair-fed control and rosiglitazone groups (p<0.05). Rimonabant, pair-fed control, and rosiglitazone groups showed decreased insulin resistance and increased adiponectin, with no differences between the rimonabant and pair-fed control groups.. Rimonabant had a protective effect on islet morphology in vivo even in established diabetes. However, the protective effect was also reproduced by pair-feeding. Thus, the results of this study did not support the significance of islet CB1 receptors in islet protection with rimonabant in established obesity-associated type 2 diabetes.

Topics: Adiponectin; Adiposity; Animals; Cell Proliferation; Diabetes Mellitus, Type 2; Eating; Glucose Intolerance; Insulin Resistance; Insulin-Secreting Cells; Male; Piperidines; Pyrazoles; Rats; Rats, Inbred OLETF; Receptor, Cannabinoid, CB1; Rimonabant; Rosiglitazone; Thiazolidinediones

Adiponectin secreted from adipocytes binds to adiponectin receptors AdipoR1 and AdipoR2, and exerts antidiabetic effects via activation of AMPK and PPAR-α pathways, respectively. Levels of adiponectin in plasma are reduced in obesity, which causes insulin resistance and type 2 diabetes. Thus, orally active small molecules that bind to and activate AdipoR1 and AdipoR2 could ameliorate obesity-related diseases such as type 2 diabetes. Here we report the identification of orally active synthetic small-molecule AdipoR agonists. One of these compounds, AdipoR agonist (AdipoRon), bound to both AdipoR1 and AdipoR2 in vitro. AdipoRon showed very similar effects to adiponectin in muscle and liver, such as activation of AMPK and PPAR-α pathways, and ameliorated insulin resistance and glucose intolerance in mice fed a high-fat diet, which was completely obliterated in AdipoR1 and AdipoR2 double-knockout mice. Moreover, AdipoRon ameliorated diabetes of genetically obese rodent model db/db mice, and prolonged the shortened lifespan of db/db mice on a high-fat diet. Thus, orally active AdipoR agonists such as AdipoRon are a promising therapeutic approach for the treatment of obesity-related diseases such as type 2 diabetes.

Topics: Adenylate Kinase; Adiponectin; Adipose Tissue, White; Administration, Oral; Animals; Diabetes Mellitus, Type 2; Diet, High-Fat; Drug Evaluation, Preclinical; Dyslipidemias; Enzyme Activation; Glucose Intolerance; Inflammation; Insulin Resistance; Liver; Longevity; Mice; Mitochondria; Muscle Fibers, Skeletal; Muscles; Obesity; Oxidative Stress; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Piperidines; PPAR alpha; Receptors, Adiponectin; Signal Transduction; Small Molecule Libraries; Transcription Factors; Triglycerides

Rimonabant is a cannabinoid CB1 receptor antagonist. Other CB1 antagonists have biphasic effects on blood glucose levels following acute administration. We therefore tested the effects of rimonabant on glucose tolerance following acute administration.. We tested the effects of oral and intracerebroventricular administration of rimonabant on blood glucose and gastrointestinal transit in mice following oral and intravenous glucose challenge.. We found a dose-dependent increase in blood glucose from oral doses of rimonabant of 3 mg/kg and above. WIN55,212-2 (3 mg/kg), a cannabinoid receptor agonist, did not influence blood glucose in the presence or absence of rimonabant. Rimonabant did not induce release of glucose from isolated rat hepatocytes or modify serum insulin concentration in mice. Intracerebroventricular administration of rimonabant caused increases in blood glucose and gastrointestinal transit, suggesting a central nervous system site of action. Increases in blood glucose by rimonabant were partially blocked by the dopamine receptor antagonist haloperidol and significantly blocked by the 5-hydroxytryptophan(5-HT) depleting agent p-CPA and the 5-HT 3 receptor antagonist ondansetron.. Rimonabant causes dose-dependent increase in glucose profile upon glucose challenge partially mediated by the central nervous system control of gastrointestinal carbohydrate absorption through pathways that are modulated by both 5-HT and dopamine.

Topics: Administration, Oral; Animals; Benzoxazines; Blood Glucose; Dopamine Antagonists; Eating; Fenclonine; Glucose; Glucose Intolerance; Haloperidol; Hepatocytes; Infusions, Intraventricular; Insulin; Male; Mice; Morpholines; Naphthalenes; Ondansetron; Piperidines; Pyrazoles; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Receptors, Dopamine; Receptors, Serotonin; Rimonabant; Serotonin Antagonists

G-protein coupled receptor 26 (GPR26) is a brain-specific orphan GPCR with high expression in the brain region that controls satiety. Depletion of GPR26 has been shown to increase fat storage in C. elegans, whereas GPR26 deficiency in the hypothalamus is associated with high genetic susceptibility to the onset of obesity in mice. However, the metabolic function of GPR26 in mammals remains elusive. Herein, we investigated a role of GPR26 in regulating energy homeostasis by generating mice with targeted deletion of the GPR26 gene. We show that GPR26 deficiency causes hyperphagia and hypometabolism, leading to early onset of diet-induced obesity. Accordingly, GPR26 deficiency also caused metabolic complications commonly associated with obesity, including glucose intolerance, hyperinsulinemia, and dyslipidemia. Moreover, consistent with hyperphagia in GPR26 null mice, GPR26 deficiency significantly increased hypothalamic activity of AMPK, a key signaling event that stimulates appetite. In further support of a regulatory role of GPR26 in satiety, GPR26 knockout mice also demonstrate hypersensitivity to treatment of rimonabant, an endocannabinoid receptor-1 antagonist commonly used to treat obesity by suppressing appetite in humans. Together, these findings identified a key role of GPR26 as a central regulator of energy homeostasis though modulation of hypothalamic AMPK activation.

Topics: Adiposity; AMP-Activated Protein Kinases; Animals; Diet; Dyslipidemias; Energy Metabolism; Enzyme Activation; Gene Silencing; Gene Targeting; Glucose Intolerance; Hyperinsulinism; Hyperphagia; Hypothalamus; Mice; Mice, Inbred C57BL; Obesity; Phosphorylation; Piperidines; Pyrazoles; Receptor, Cannabinoid, CB1; Receptors, G-Protein-Coupled; Rimonabant; Weight Loss

Fat Aussie mice (foz/foz) are morbidly obese, glucose intolerant and have liver steatosis that develops into steatohepatitis on a high-fat diet. The cannabinoid 1 receptor (CB1) antagonist SR141716 has been shown to improve obesity-associated metabolic complications in humans and rodent models. The aim of this study was to assess the effect of SR141716 in foz/foz mice.. Male wildtype (WT) and foz/foz mice were fed a chow or high-fat diet (45% saturated fat). Vehicle or SR141716 (10 mg kg(-1) per day) was administered in jelly once daily for 4 weeks from 4 months of age.. Foz/foz mice were obese but had less epididymal adipose tissue mass than fat-fed WT mice despite being significantly heavier. Liver weight was increased by twofold in foz/foz compared with WT mice and showed significant steatogenesis associated with impaired liver function. Foz/foz and fat-fed WT mice were glucose intolerant as determined by oral glucose tolerance test. In chow-fed foz/foz mice, SR141716 reduced body weight, liver weight, reversed hepatosteatosis and glucose intolerance. Subcutaneous white adipose tissue gene expression of the macrophage-specific marker Cd68 reflected the improvements in the metabolic status by SR141716 in these mice.. The results are consistent with the hypothesis that foz/foz mice have defective lipid metabolism, are unable to adequately store fat in adipose tissue but instead sequester fat ectopically in other metabolic tissues (liver) leading to insulin resistance and hepatic steatosis associated with inflammation. Our findings suggest that SR141716 can improve liver lipid metabolism in foz/foz mice in line with improved insulin sensitivity and adipose tissue inflammation.

Topics: Adipose Tissue; Animals; Diet, High-Fat; Disease Models, Animal; Fatty Liver; Glucose Intolerance; Glucose Tolerance Test; Inflammation; Insulin Resistance; Lipid Metabolism; Liver; Male; Mice; Obesity, Morbid; Piperidines; Pyrazoles; Receptor, Cannabinoid, CB1; Rimonabant

Dipeptidyl peptidase-IV (DPP-IV) is the primary inactivator of glucoregulatory incretin hormones, and DPP-IV inhibitors are expected to become a useful new class of anti-diabetic agent. The aim of the present study is to characterize the chronic in vivo profile of the DPP-IV inhibitor ASP8497. In streptozotocin-nicotinamide-induced diabetic mice, ASP8497 was administered orally for 3 weeks at 1, 3, or 10 mg/kg once daily, which improved the hemoglobin A(1c), non-fasting plasma insulin, fasting blood glucose levels, glucose intolerance, and lipid profiles (plasma triglyceride, non-esterified fatty acid and total cholesterol) with neutral effect on body weight. The pancreatic insulin content and hepatic phosphoenolpyruvate carboxykinase (PEPCK) activity recovered dose-dependently in ASP8497-treated groups. These results revealed that ASP8497 was successful in improving glycemic control and metabolic parameters in streptozotocin-nicotinamide-induced diabetic mice. It is therefore suggested that ASP8497 may be a potential agent for the treatment of type 2 diabetes.

Topics: Administration, Oral; Animals; Diabetes Mellitus, Experimental; Dipeptidyl-Peptidase IV Inhibitors; Drug Evaluation, Preclinical; Glucose Intolerance; Glycated Hemoglobin; Hypoglycemic Agents; Insulin Resistance; Lipids; Male; Mice; Mice, Inbred ICR; Niacinamide; Piperidines; Pyrrolidines; Streptozocin

The present study investigated the antidiabetic effects of the dipeptidyl peptidase (DPP)-IV inhibitors ASP8497 and vildagliptin, and the sulfonylureas glibenclamide and gliclazide in streptozotocin-nicotinamide-induced mildly diabetic mice. A single administration of ASP8497 and vildagliptin significantly improved glucose tolerance by increasing plasma insulin and glucagon-like peptide-1 levels. In addition, a single administration of glibenclamide and gliclazide also caused significant improvement in glucose tolerance with an accompanying increase in the plasma insulin level. Subsequently, the effects of a 1-week chronic daily dosing of DPP-IV inhibitors and sulfonylureas were investigated. All drugs significantly improved glucose tolerance on day 1 of chronic daily dosing. After 1 week of chronic daily dosing, the DPP-IV inhibitors caused a significant improvement in glucose tolerance similar to those observed on day 1 by increasing the plasma insulin and glucagon-like peptide-1 levels. In contrast, the sulfonylureas had no significant improving or insulinotropic effect. Furthermore, ASP8497 also had an antihyperglycemic effect and improved pancreatic histopathologic lesions in a 4-week chronic daily dosing study. These results suggest that chronic daily dosing of sulfonylureas had virtually no antidiabetic effects because of marked attenuation of the insulinotropic action in streptozotocin-nicotinamide-induced mildly diabetic mice. In contrast, the antidiabetic efficacy of DPP-IV inhibitors, including ASP8497, did not change even after chronic daily dosing; therefore, DPP-IV inhibitors are useful as a therapeutic agent for impaired glucose tolerance and type 2 diabetes mellitus.

Topics: Animals; Blood Glucose; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Gliclazide; Glucagon-Like Peptide 1; Glucose Intolerance; Glyburide; Hypoglycemic Agents; Insulin; Male; Mice; Mice, Inbred ICR; Niacinamide; Piperidines; Pyrrolidines; Sulfonylurea Compounds

Islet cell adaptation to insulin resistance in type 2 diabetes mellitus may be due in part to increased stimulation of beta cells by the autonomic nervous system. The parasympathetic neurotransmitter acetylcholine (ACh) mediates insulin release via M3 muscarinic receptors on islet beta cells. The vesicular ACh transporter (VAChT) receptor correlates with cholinergic activity in vivo. The positron emission tomography (PET) radiotracer (+)-4-[18F]fluorobenzyltrozamicol ([18F]FBT) binds to the VAChT receptor on presynaptic cholinergic neurons and can be quantified by PET. In this study, we utilize [18F]FBT PET to demonstrate pancreatic cholinergic activity before and after dextrose infusion in nonhuman primates with normal (NGT) and impaired (IGT) glucose tolerance.. Seven adult female vervet (Chlorocebus aethiops) monkeys were maintained on an atherogenic Western diet. They were divided into two groups: four with NGT and three with IGT. Each subject underwent [18F]FBT PET twice: first, a baseline PET under fasting conditions; and second, PET under fasting conditions but after intravenous infusion of dextrose solution. Quantitative analysis of pancreatic uptake at 60 min post-injection was performed.. There was no difference in pancreatic uptake of [18F]FBT on baseline scans between the two groups. Pancreatic uptake of [18F]FBT increased in every subject after dextrose infusion (P = 0.03). On post-dextrose PET scans, pancreatic uptake of [18F]FBT was significantly higher in IGT subjects compared with NGT subjects (P = 0.03). The post-dextrose to pre-dextrose uptake ratios were higher in IGT subjects (P = 0.08).. Acute increases in pancreatic cholinergic activity in vivo were detected in the pancreata of nonhuman primates with NGT and IGT after intravenous dextrose infusion on [18F]FBT PET. In subjects with IGT, this activity was significantly higher, suggesting increased autonomic nervous system stimulation of the pancreatic islets in insulin-resistant subjects.

Topics: Animals; Blood Glucose; Chlorocebus aethiops; Female; Fluorine Radioisotopes; Fluorobenzenes; Glucose Intolerance; Insulin; Piperidines; Positron-Emission Tomography; Primates; Reference Values; Triglycerides

It has been recently reported that blockade of type 1 cannabinoid (CB1) receptors by specific antagonists or genetic manipulation alleviates dyslipidaemia, hyperglycaemia and insulin resistance in animal models of obesity and type 2 diabetes. However, the precise role of adipokines in the insulin-sensitising effects of the CB1 antagonist rimonabant is not clear.. ob/ob mice were treated with different doses of rimonabant and then subjected to an oral glucose tolerance test. The expression of different adipokines in white adipose tissue was analysed by quantitative real-time PCR.. Rimonabant (30 mg/kg) significantly inhibited body weight and fat pad weight gain (P < 0.05) and improved glucose tolerance. Gene expression analysis indicated that tumour necrosis factor-alpha, visfatin and retinol binding protein-4 were downregulated in the adipose tissue of ob/ob mice treated with rimonabant compared with controls, whereas adiponectin was significantly upregulated.. Rimonabant-mediated alteration of adipokines in white adipose tissues may play a role in improving insulin sensitivity in obese animals.

Topics: Adipokines; Adiponectin; Adipose Tissue; Adipose Tissue, White; Animals; Anti-Obesity Agents; Blood Glucose; Body Weight; Down-Regulation; Female; Gene Expression; Glucose Intolerance; Glucose Tolerance Test; Insulin; Insulin Resistance; Leptin; Mice; Mice, Knockout; Models, Animal; Nicotinamide Phosphoribosyltransferase; Obesity; Organ Size; Piperidines; Pyrazoles; Receptor, Cannabinoid, CB1; Retinol-Binding Proteins, Plasma; Reverse Transcriptase Polymerase Chain Reaction; Rimonabant; RNA, Messenger; Tumor Necrosis Factor-alpha

GIP receptor antagonism with (Pro3)GIP protects against obesity, insulin resistance, glucose intolerance and associated disturbances in mice fed high-fat diet. Furthermore, cannabinoid CB1 receptor antagonism with AM251 reduces appetite and body weight gain in mice. The present study has examined and compared the effects of chronic daily administrations of (Pro3)GIP (25 nmol/kg body weight), AM251 (6 mg/kg body weight) and a combination of both drugs in high-fat fed mice. Daily i.p. injection of (Pro3)GIP, AM251 or combined drug administration over 22 days significantly (P<0.05 to <0.01) decreased body weight compared with saline-treated controls. This was associated with a significant (P<0.05 to <0.01) reduction of food intake in mice treated with AM251. Plasma glucose levels and glucose tolerance were significantly (P<0.05) lowered by 22 days (Pro3)GIP, AM251 or combined drug treatment. These changes were accompanied by a significant (P<0.05) improvement of insulin sensitivity in all treatment groups. In contrast, AM251 lacked effects on glucose tolerance, metabolic response to feeding and insulin sensitivity in high-fat mice when administered acutely. These data indicate that chemical blockade of GIP- or CB1-receptor signaling using (Pro3)GIP or AM251, respectively provides an effective means of countering obesity and related abnormalities induced by consumption of high-fat energy-rich diet. AM251 lacks acute effects on glucose homeostasis and there was no evidence of a synergistic effect of combined treatment with (Pro3)GIP.

Topics: Animals; Appetite; Area Under Curve; Blood Glucose; Body Weight; Dietary Fats; Drug Evaluation, Preclinical; Drug Interactions; Eating; Female; Gastric Inhibitory Polypeptide; Glucose Intolerance; Glucose Tolerance Test; Injections, Intraperitoneal; Insulin; Insulin Resistance; Mice; Obesity; Piperidines; Pyrazoles; Receptor, Cannabinoid, CB1

We investigated the effect of rimonabant on inflammation and enhanced platelet reactivity in type 2 diabetic Zucker rats, an experimental model of impaired glucose tolerance and the metabolic syndrome.. Rimonabant (10 mg kg(-1) by gavage) was fed for 2 weeks to 3-month-old male obese Zucker rats as an impaired glucose tolerance model and for 10 weeks to 6-month-old male obese Zucker rats as a model of the metabolic syndrome. RANTES (Regulated upon Activation, Normal T cell Expressed, and Secreted) and MCP-1 (monocyte chemotactic protein-1) serum levels were determined by ELISA. Leukocyte populations were quantitatively assessed using a veterinary differential blood cell counter. Platelet activation was assessed by flow-cytometry, platelet aggregation, and adhesion of isolated platelets to immobilized fibrinogen.. RANTES and MCP-1 serum levels were increased in obese vs lean Zucker rats and significantly reduced by long-term treatment with rimonabant, which slowed weight gain in rats with the metabolic syndrome. Neutrophils and monocytes were significantly increased in young and old obese vs lean Zucker rats and lowered by rimonabant. Platelet-bound fibrinogen was significantly enhanced in obese vs lean Zucker rats of both age, and was reduced by rimonabant. Platelets from obese rats were more sensitive to thrombin-induced aggregation and adhesion to fibrinogen, which were both attenuated by rimonabant therapy.. We demonstrate positive modulation of circulating neutrophil and monocyte numbers, reduced platelet activation and lower RANTES and MCP-1 levels by rimonabant in Zucker rats. This may potentially contribute to a reduction of cardiovascular risk.

Topics: Animals; Anti-Inflammatory Agents; Chemokine CCL2; Chemokine CCL5; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Flow Cytometry; Glucose Intolerance; Inflammation Mediators; Leukocyte Count; Leukocytes; Lipids; Male; Metabolic Syndrome; Piperidines; Platelet Activation; Platelet Adhesiveness; Platelet Aggregation; Platelet Aggregation Inhibitors; Platelet Count; Pyrazoles; Rats; Rats, Zucker; Receptor, Cannabinoid, CB1; Rimonabant; Time Factors; Weight Gain

Endothelin (ET)-1 is a vasoconstrictor and proinflammatory peptide that may inhibit glucose uptake. The objective of the study was to investigate if ET (selective ET(A) and dual ET(A)+ET(B)) receptor blockade improves insulin sensitivity in patients with insulin resistance and coronary artery disease.. Seven patients (aged 58 +/- 2 years) with insulin resistance and coronary artery disease completed three hyperinsulinemic-euglycemic clamp protocols: a control clamp (saline infusion), during ET(A) receptor blockade (BQ123), and during combined ET(A) (BQ123) and ET(B) receptor blockade (BQ788). Splanchnic blood flow (SBF) and renal blood flow (RBF) were determined by infusions of cardiogreen and p-aminohippurate.. Total-body glucose uptake (M) differed between the clamp protocols with the highest value in the BQ123+BQ788 clamp (P < 0.05). The M value corrected by insulin was higher in the BQ123+BQ788 than in the control clamp (P < 0.01) or the BQ123 clamp (P < 0.05). There was no difference between the control clamp and the BQ123 clamp. Mean arterial pressure did not change during the control clamp, whereas it decreased during both the BQ123 (P < 0.01) and BQ123+BQ788 (P < 0.05) clamps. RBF increased and renal vascular resistance decreased in the BQ123+BQ788 clamp (P < 0.05) but not in the BQ123 clamp. There was no change in SBF in either clamp.. Dual ET(A)+ET(B) receptor blockade acutely enhances insulin sensitivity in patients with insulin resistance and coronary artery disease, indicating an important role for endogenous ET-1.

Topics: Antihypertensive Agents; Blood Glucose; Blood Pressure; Coronary Disease; Diabetes Mellitus, Type 2; Endothelin Receptor Antagonists; Glucose Clamp Technique; Glucose Intolerance; Heart Rate; Humans; Insulin; Insulin Resistance; Middle Aged; Obesity; Oligopeptides; Peptides, Cyclic; Piperidines

Ghrelin, through action on its receptor, GH secretagogue receptor type 1a (GHS-R1a), exerts a variety of metabolic functions including stimulation of appetite and weight gain and suppression of insulin secretion. In the present study, we examined the effects of novel small-molecule GHS-R1a antagonists on insulin secretion, glucose tolerance, and weight loss. Ghrelin dose-dependently suppressed insulin secretion from dispersed rat islets. This effect was fully blocked by a GHS-R1a antagonist. Consistent with this observation, a single oral dose of a GHS-R1a antagonist improved glucose homeostasis in an ip glucose tolerance test in rat. Improvement in glucose tolerance was attributed to increased insulin secretion. Daily oral administration of a GHS-R1a antagonist to diet-induced obese mice led to reduced food intake and weight loss (up to 15%) due to selective loss of fat mass. Pair-feeding experiments indicated that weight loss was largely a consequence of reduced food intake. The impact of a GHS-R1a antagonist on gastric emptying was also examined. Although the GHS-R1a antagonist modestly delayed gastric emptying at the highest dose tested (10 mg/kg), delayed gastric emptying does not appear to be a requirement for weight loss because lower doses produced weight loss without an effect on gastric emptying. Consistent with the hypothesis that ghrelin regulates feeding centrally, the anorexigenic effects of potent GHS-R1a antagonists in mice appeared to correspond with their brain exposure. These observations demonstrate that GHS-R1a antagonists have the potential to improve the diabetic condition by promoting glucose-dependent insulin secretion and promoting weight loss.

Topics: Animals; Appetite; Appetite Depressants; Cells, Cultured; Drug Evaluation, Preclinical; Ghrelin; Glucose Intolerance; Hypoglycemic Agents; Male; Mice; Mice, Inbred C57BL; Models, Biological; Piperidines; Quinazolinones; Rats; Rats, Sprague-Dawley; Rats, Wistar; Receptors, Ghrelin; Weight Loss

We have previously established a nonobese diabetes mouse model characterized by moderate hyperglycemic levels, like those usually occurring in human type 2 diabetes. As oxidative stress is considered a major mechanism of progressive beta-cell damage in diabetes, we tested in this model the protective effects of a new low-molecular-weight antioxidant, namely, bis(1-hydroxy-2,2,6,6-tetramethyl-4-piperidinyl)decandioate dihydrochloride (IAC).. Diabetes was induced in C57Bl/6J mice by streptozotocin (STZ) and nicotinamide (NA) administration. Two weeks later, STZ-NA mice were treated for 5 weeks with different doses of IAC (15 or 30 mg/kg per day intraperitoneally) and monitored for glycemia, insulinemia, glucose tolerance, and pancreatic insulin content.. Streptozotocin-NA mice showed moderate hyperglycemia, hypoinsulinemia, glucose intolerance, growth impairment, and markedly reduced pancreatic insulin content (22% of controls). IAC-treated STZ-NA mice showed clear-cut reduction of hyperglycemia and attenuation of glucose intolerance, associated to higher residual pancreatic insulin content with respect to untreated diabetic animals. Plasma nitrotyrosine levels (an index of oxidative stress), enhanced 3-fold in diabetic mice, were significantly reduced by IAC treatment. Significant correlations were found between plasma nitrotyrosine values and either blood glucose levels or pancreatic insulin content.. In the STZ-NA diabetic mouse model, the new antioxidant, IAC, improves diabetic metabolic alterations, likely by counteracting beta-cell dysfunction and loss associated with oxidative stress.

Topics: Animals; Antioxidants; Blood Glucose; Body Weight; Diabetes Mellitus, Experimental; Diabetes Mellitus, Type 2; Dose-Response Relationship, Drug; Esters; Fatty Acids, Nonesterified; Glucose Intolerance; Glucose Tolerance Test; Hyperglycemia; Hypoglycemic Agents; Insulin; Male; Mice; Mice, Inbred C57BL; Molecular Weight; Niacinamide; Oxidative Stress; Pancreas; Piperidines; Streptozocin; Time Factors; Tyrosine

Recent reports have described the presence of cannabinoid CB1 receptors in pancreatic islets. Here we show that administration of the endogenous cannabinoid anandamide or the selective cannabinoid CB1 receptor agonist Arachidonyl-2'-chloroethylamide (ACEA) results in glucose intolerance after a glucose load. This effect is reversed by the selective cannabinoid CB1 receptor antagonist N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251). These results suggest that targeting cannabinoid CB1 receptors may serve as new therapeutic alternatives for metabolic disorders such as diabetes.

Topics: Animals; Arachidonic Acids; Blood Glucose; Cannabinoid Receptor Modulators; Endocannabinoids; Glucose Intolerance; Male; Piperidines; Polyunsaturated Alkamides; Pyrazoles; Rats; Rats, Wistar; Receptor, Cannabinoid, CB1

Topics: Anti-Obesity Agents; Cardiovascular Diseases; Dyslipidemias; Glucose Intolerance; Humans; Obesity; Overweight; Piperidines; Pyrazoles; Rimonabant; Weight Loss

To estimate the prevalence, awareness, treatment and control of hypertension in a Canarian population; and their relationship with the glucose tolerance categories.. From a population of 6355 subjects over 29 years old, 690 were chosen in a random sampling. Blood pressure measurements, a standard oral glucose tolerance test (excluding known diabetic patients), and a questionnaire on diabetes and hypertension history and medication use was performed.. The total prevalence of hypertension was 50.3%; 62.0% of the hypertensive subjects were aware of their condition; 60.6% had their diastolic and 11.0% their systolic blood pressure controlled and 8.6% had both. For diabetic, glucose intolerant and normoglycemic subjects, the respective prevalences of hypertension were 79.4, 60.2 and 43.1% (higher in diabetic subjects, P < 0.001); the awareness of hypertension was 66.7, 61.8 and 59.5% (differences not significant); systolic blood pressure control was 4.8, 14.7 and 13.7% (lower in diabetic subjects, P = 0.017 versus glucose intolerant and P = 0.011 versus normoglycemic subjects); diastolic blood pressure control was 50.4, 72.1 and 63.2% (lower in diabetic subjects, P = 0.004 versus glucose intolerant and P = 0.025 versus normoglycemic subjects). There were no differences in the number and type of antihypertensive drugs among the different glucose tolerance categories.. Blood pressure was comparable in our population and in other European populations. The prevalence of hypertension was higher, the awareness was similar, and control was worse in diabetic than in non-diabetic subjects; the drug treatment pattern was not different.

Topics: Adrenergic alpha-Antagonists; Adrenergic beta-Antagonists; Adult; Aged; Angiotensin-Converting Enzyme Inhibitors; Antihypertensive Agents; Awareness; Blood Pressure; Calcium Channel Blockers; Diabetes Mellitus; Diastole; Diuretics; Drug Therapy, Combination; Female; Glucose Intolerance; Humans; Hypertension; Male; Middle Aged; Piperidines; Prevalence; Spain; Systole; Treatment Outcome