nateglinide and repaglinide

Glinides, including repaglinide, nateglinide and mitiglinide, are a type of fasting insulin secretagogue that could help to mimic early-phase insulin release, thus providing improved control of the postprandial glucose levels. Glinides stimulate insulin secretion by inhibiting ATP-sensitive potassium channels in the pancreatic β-cell membrane. Although glinides have been widely used clinically and display excellent safety and efficacy, the response to glinides varies among individuals, which is partially due to genetic factors involved in drug absorption, distribution, metabolism and targeting. Several pharmacogenomic studies have demonstrated that variants of genes involved in the pharmacokinetics or pharmacodynamics of glinides are associated with the drug response. Polymorphisms of genes involved in drug metabolism, such as CYP2C9, CYP2C8 and SLCO1B1, may influence the efficacy of glinides and the incidence of adverse effects. In addition, Type 2 diabetes mellitus susceptibility genes, such as KCNQ1, PAX4 and BETA2, also influence the efficacy of glinides. In this article, we review and discuss current pharmacogenomics researches on glinides, and hopefully provide useful data and proof for clinical application.

Topics: Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Inactivation, Metabolic; Insulin; Insulin Secretion; Insulin-Secreting Cells; Isoindoles; KATP Channels; Nateglinide; Pharmacogenetics; Phenylalanine; Piperidines

Type 2 diabetes mellitus (T2DM) is characterized by multiple pathophysiologic abnormalities. With time, multiple glucose-lowering medications are commonly required to reduce and maintain plasma glucose concentrations within the normal range. Type 2 diabetes mellitus individuals also are at a very high risk for microvascular complications and the incidence of heart attack and stroke is increased two- to three-fold compared with non-diabetic individuals. Therefore, when selecting medications to normalize glucose levels in T2DM patients, it is important that the agent not aggravate, and ideally even improve, cardiovascular risk factors (CVRFs) and reduce cardiovascular morbidity and mortality. In this review, we examine the effect of oral (metformin, sulfonylureas, meglitinides, thiazolidinediones, DPP4 inhibitors, SGLT2 inhibitors, and α-glucosidase inhibitors) and injectable (glucagon-like peptide-1 receptor agonists and insulin) glucose-lowering drugs on established CVRFs and long-term studies of cardiovascular outcomes. Firm evidence that in T2DM cardiovascular disease can be reversed or prevented by improving glycaemic control is still incomplete and must await large, long-term clinical trials in patients at low risk using modern treatment strategies, i.e., drug combinations designed to maximize HbA1c reduction while minimizing hypoglycaemia and excessive weight gain.

Topics: Carbamates; Clinical Trials as Topic; Coronary Artery Disease; Cyclohexanes; Diabetes Mellitus, Type 2; Diabetic Angiopathies; Dipeptidyl-Peptidase IV Inhibitors; Glucagon-Like Peptide-1 Receptor; Glycoside Hydrolase Inhibitors; Humans; Hypoglycemic Agents; Insulin; Metformin; Nateglinide; Phenylalanine; Piperidines; Sodium-Glucose Transport Proteins; Sulfonylurea Compounds; Thiazolidinediones; Treatment Outcome

Insulin secretagogues promote insulin release by binding to sulfonylurea receptors on pancreatic β-cells (SUR1). However, these drugs also bind to receptor isoforms on cardiac myocytes (SUR2A) and vascular smooth muscle (SUR2B). Binding to SUR2A/SUR2B may inhibit ischaemic preconditioning, an endogenous protective mechanism enabling cardiac tissue to survive periods of ischaemia. This study was designed to identify insulin secretagogues that selectively bind to SUR1 when given at therapeutic doses.. Using accepted systematic review methods, three electronic databases were searched from inception to 13 June 2011. Original studies measuring the half-maximal inhibitory concentration (IC(50)) for an insulin secretagogue on K(ATP) channels using standard electrophysiological techniques were included. Steady-state concentrations (C(SS)) were estimated from the usual oral dose and clearance values for each drug.. Data were extracted from 27 studies meeting all inclusion criteria. IC(50) values for SUR1 were below those for SUR2A/SUR2B for all insulin secretagogues and addition of C(SS) values identified three distinct patterns. The C(SS) for gliclazide, glipizide, mitiglinide and nateglinide lie between IC(50) values for SUR1 and SUR2A/SUR2B, suggesting that these drugs bind selectively to pancreatic receptors. The C(SS) for glimepiride and glyburide (glibenclamide) was above IC(50) values for all three isoforms, suggesting these drugs are non-selective. Tolbutamide and repaglinide may have partial pancreatic receptor selectivity because IC(50) values for SUR1 and SUR2A/SUR2B overlapped somewhat, with the C(SS) in the midst of these values.. Insulin secretagogues display different tissue selectivity characteristics at therapeutic doses. This may translate into different levels of cardiovascular risk.

Topics: Animals; ATP-Binding Cassette Transporters; Carbamates; Cardiovascular Diseases; Cricetinae; Cyclohexanes; Diabetes Mellitus, Type 2; Gliclazide; Glipizide; Glyburide; Humans; Hypoglycemic Agents; Ischemic Preconditioning, Myocardial; Isoindoles; Mice; Muscle, Smooth, Vascular; Myocytes, Cardiac; Nateglinide; Phenylalanine; Piperidines; Potassium Channels, Inwardly Rectifying; Rats; Receptors, Drug; Risk Factors; Sulfonylurea Compounds; Sulfonylurea Receptors; Tolbutamide

Organic anion-transporting polypeptide 1B1 (OATP1B1; gene: SLCO1B1) is an influx transporter expressed on the sinusoidal membrane of human hepatocytes, where it mediates the uptake of its substrates from blood into liver. In vitro, the SLCO1B1 c.521T>C (p.Val174Ala) single-nucleotide polymorphism (SNP) has been associated with reduced and the c.388A>G (p.Asn130Asp) SNP with both enhanced and reduced transport activity of OATP1B1. In vivo in humans, the c.521C allele (present in SLCO1B1*5 and *15 haplotypes) is associated with decreased hepatic uptake and increased plasma concentrations of several OATP1B1 substrates. The SLCO1B1*1B (c.388G-c.521T) haplotype is associated with enhanced hepatic uptake and decreased plasma concentrations of some OATP1B1 substrates. The SLCO1B1 c.521CC genotype has been associated with an about 60-190% increased, and the SLCO1B1*1B/*1B genotype with an about 30% decreased area under the plasma concentration-time curve of repaglinide. Moreover, SLCO1B1 polymorphism can affect the extent of interaction between OATP1B1 inhibitors and repaglinide. Accordingly, SLCO1B1 genotyping may help in choosing the optimal starting dose of repaglinide. In Chinese individuals, the SLCO1B1 c.521C allele has been associated with increased plasma concentrations of nateglinide, but the association could not be replicated in Caucasians. SLCO1B1 genotype has had no effect on the pharmacokinetics of rosiglitazone, pioglitazone or their metabolites. The hepatic uptake of metformin is mediated by organic cation transporters 1 and 3, and the liver is not important for the elimination or action of the dipeptidylpeptidase 4 inhibitors sitagliptin, vildagliptin and saxagliptin. Therefore, SLCO1B1 polymorphism unlikely affects the response to these antidiabetics. Possible effects of SLCO1B1 polymorphism on sulfonylureas remain to be investigated.

Topics: Administration, Oral; Alleles; Carbamates; Cyclohexanes; Genotype; Haplotypes; Humans; Hypoglycemic Agents; Liver-Specific Organic Anion Transporter 1; Nateglinide; Organic Anion Transporters; Phenylalanine; Pioglitazone; Piperidines; Polymorphism, Genetic; Rosiglitazone; Thiazolidinediones

The purpose of this study is to evaluate efficacy and safety of nateglinide tablet administration in comparison with those of repaglinide tablet as control on treating type 2 diabetes mellitus in China. Pooled-analysis with analysis of covariance (ANCOVA) method was applied to assess the efficacy and safety based on original data collected from four independent randomized clinical trials with similar research protocols. However meta-analysis was applied based on the outcomes of the four studies. The results by meta-analysis were comparable to those obtained by pooled-analysis. The means of HbA(1c), and fasting blood glucose in both the nateglinide and repaglinide groups were reduced significantly after 12 weeks duration but no statistical differences in reduction between the two groups. The adverse reaction rates were 9.89 and 6.51% in the nateglinide and repaglinide groups respectively, with the rate difference showing no statistical significance, and the Odds Ratio of adverse reaction rate (95% confidence interval) was 1.59 (0.99, 2.55). Both nateglinide and repaglinide administration have similarly significant effects on reducing HbA(1c) and FBG. However, the adverse reaction rate in the nateglinide group is higher than that in the latter using repaglinide but no statistical significance difference as revealed in the four clinical trials detailed below.

Topics: Carbamates; China; Cyclohexanes; Diabetes Mellitus, Type 2; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Male; Middle Aged; Nateglinide; Phenylalanine; Piperidines

Topics: alpha-Galactosidase; Biguanides; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Combinations; Drug Therapy, Combination; Humans; Hypoglycemic Agents; Insulin; Nateglinide; Phenylalanine; Piperidines; Pyrazines; Sitagliptin Phosphate; Sulfonylurea Compounds; Thiazolidinediones; Triazoles

This review describes the current knowledge on drug-drug and food-drug interactions with repaglinide and nateglinide. These two meglitinide derivatives, commonly called glinides, have been developed for improving insulin secretion of patients with type 2 diabetes mellitus. They are increasingly used either in monotherapy or in combination with other oral antihyperglycaemic agents for the treatment of type 2 diabetes. Compared with sulfonylureas, glinides have been shown to (i) provide a better control of postprandial hyperglycaemia, (ii) overcome some adverse effects, such as hypoglycaemia, and (iii) have a more favourable safety profile, especially in patients with renal failure. The meal-related timing of administration of glinides and the potential influence of food and meal composition on their bioavailability may be important. In addition, some food components (e.g. grapefruit juice) may cause pharmacokinetic interactions. Because glinides are metabolised via cytochrome P450 (CYP) 3A4 isoenzyme, they are indeed exposed to pharmacokinetic interactions. In addition to CYP3A4, repaglinide is metabolised via CYP2C8, while nateglinide metabolism also involves CYP2C9. Furthermore, both compounds and their metabolites may undergo specialised transport/uptake in the intestine, another source of pharmacokinetic interactions. Clinically relevant drug-drug interactions are those that occur when glinides are administered together with other glucose-lowering agents or compounds widely coadministered to diabetic patients (e.g. lipid-lowering agents), with drugs that are known to induce (risk of lower glinide plasma levels and thus of deterioration of glucose control) or inhibit (risk of higher glinide plasma levels leading to hypoglycaemia) CYP isoenzymes concerned in their metabolism, or with drugs that have a narrow efficacy : toxicity ratio. Pharmacokinetic interactions reported in the literature appear to be more frequent and more important with repaglinide than with nateglinide. Rifampicin (rifampin) reduced repaglinide area under the plasma concentration-time curve (AUC) by 32-85% while it reduced nateglinide AUC by almost 25%. Reported increases in AUCs with coadministration of drugs inhibiting CYP isoenzymes never exceeded 80% for repaglinide (except with ciclosporin and with gemfibrozil) and 50% for nateglinide. Ciclosporin more than doubled repaglinide AUC (+144%), a finding that should raise caution when using these two drugs in combination. The most im

Topics: Anti-Bacterial Agents; Area Under Curve; Biological Availability; Biotransformation; Carbamates; Cyclohexanes; Cytochrome P-450 Enzyme Inhibitors; Cytochrome P-450 Enzyme System; Drug Administration Schedule; Drug Interactions; Enzyme Induction; Enzyme Inhibitors; Fasting; Food-Drug Interactions; Humans; Hypoglycemic Agents; Intestinal Absorption; Nateglinide; Phenylalanine; Piperidines; Postprandial Period

In type 2 diabetes mellitus, impairment of insulin secretion is an important component of the disease. Meglitinide analogues are a class of oral hypoglycaemic agents that increase insulin secretion, in particular, during the early phase of insulin release.. The aim of this review was to assess the effects of meglitinide analogues in patients with type 2 diabetes mellitus.. We searched several databases including The Cochrane Library, MEDLINE and EMBASE. We also contacted manufacturers and searched ongoing trials databases, and the American Diabetes Association (ADA) and European Association for the Study of Diabetes (EASD) websites.. We included randomised controlled, parallel or cross-over trials comparing at least 10 weeks of treatment with meglitinide analogues to placebo, head-to-head, metformin or in combination with insulin.. Two authors independently extracted data and assessed trial quality.. Fifteen trials involving 3781 participants were included. No studies reported the effect of meglitinides on mortality or morbidity. In the eleven studies comparing meglitinides to placebo, both repaglinide and nateglinide resulted in a reductions in glycosylated haemoglobin (0.1% to 2.1% reduction in HbA1c for repaglinide; 0.2% to 0.6% for nateglinide). Only two trials compared repaglinide to nateglinide (342 participants), with greater reduction in glycosylated haemoglobin in those receiving repaglinide. Repaglinide (248 participants in three trials) had a similar degree of effect in reducing glycosylated haemoglobin as metformin. Nateglinide had a similar or slightly less marked effect on glycosylated haemoglobin than metformin (one study, 355 participants). Weight gain was generally greater in those treated with meglitinides compared with metformin (up to three kg in three months). Diarrhoea occurred less frequently and hypoglycaemia occurred more frequently but rarely severely enough as to require assistance.. Meglitinides may offer an alternative oral hypoglycaemic agent of similar potency to metformin, and may be indicated where side effects of metformin are intolerable or where metformin is contraindicated. However, there is no evidence available to indicate what effect meglitinides will have on important long-term outcomes, particularly mortality.

Topics: Benzamides; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Metformin; Nateglinide; Phenylalanine; Piperidines; Randomized Controlled Trials as Topic

[symbol: see text] Nateglinide (Starlix-Novartis) and [symbol: see text] repaglinide (NovoNorm-Novo Nordisk) are two of a new class of orally active antidiabetic drugs, the meglitinides. They have a rapid-onset and short-lasting stimulating effect on insulin secretion. Both are licensed for combination therapy with metformin in patients with type 2 diabetes mellitus who are inadequately controlled by maximally tolerated doses of metformin alone. In addition, repaglinide is licensed for use as monotherapy in patients with type 2 diabetes whose hyperglycaemia can no longer be controlled satisfactorily by diet, weight reduction and exercise. Here we discuss whether repaglinide and nateglinide offer worthwhile advantages in the management of patients with type 2 diabetes.

Topics: Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Double-Blind Method; Humans; Hypoglycemic Agents; Nateglinide; Phenylalanine; Piperidines; Randomized Controlled Trials as Topic; Treatment Outcome

Topics: 1-Deoxynojirimycin; Acarbose; Aged; Blood Glucose; Carbamates; Contraindications; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Enzyme Inhibitors; Fasting; Follow-Up Studies; Germany; Glucosamine; Glyburide; Glycated Hemoglobin; Glycoside Hydrolase Inhibitors; Humans; Hypoglycemia; Hypoglycemic Agents; Imino Pyranoses; Insulin; Metformin; Middle Aged; Nateglinide; Obesity; Patient Compliance; Phenylalanine; Pioglitazone; Piperidines; Practice Guidelines as Topic; Risk Factors; Rosiglitazone; Sulfonylurea Compounds; Thiazolidinediones; Time Factors

The expression meglitinide analogs was introduced in 1995 to cover new molecules proposed as non-sulfonylurea insulinotropic agents and displaying structural analogy with meglitinide, such as repaglinide, nateglinide, and mitiglinide. Meglitinide analogs display, as judged by conformation analysis, a U-shaped configuration similar to that of antihyperglycemic sulfonylureas such as glibenclamide (glyburide) and glimepiride. In rat pancreatic islets incubated in the presence of 7.0 mmol/L D-glucose, repaglinide and mitiglinide demonstrate comparable concentration-response relationships for stimulation of insulin release, with a threshold value < 10 nmol/L and a maximal secretory response at about 10 nmol/L. Several findings indicate that meglitinide analogs provoke the closing of adenosine triphosphate-sensitive potassium channels, with subsequent gating of voltage-sensitive calcium channels. The effects of meglitinide analogs upon the binding of [3H]glibenclamide to islet cells membranes reinforces this concept. At variance, however, with other meglitinide analogs, the ionic and secretory response to repaglinide (10 micromol/L) is not rapidly reversible in perifused rat islets. In experiments conducted in vivo in control and diabetic rats, repaglinide provokes a greater and more rapid increase in plasma insulin concentration and an earlier fall in glycemia than glibenclamide or glimepiride. Onset of effect is also more rapid and duration of effect shorter with nateglinide versus glibenclamide. In clinical studies, single or repeated daily administration of repaglinide increased plasma insulin concentration in a dose-dependent manner, with an incremental peak reached about 2 hours after repaglinide intake. Plasma concentrations of repaglinide are about 5.0 microg/L 2-2.5 hours after oral intake of the drug. Despite the slow reversibility of repaglinide action in vitro, this drug offers advantages over glibenclamide in terms of the possible occurrence of hypoglycemia if a meal is missed. In volunteers receiving a single oral dose of nateglinide (120mg) 10 minutes before a standardized 800 Kcal breakfast, the plasma insulin concentration was higher 5, 10, and 20 minutes after meal intake than when they received a single dose of repaglinide (0.5 or 2.0mg) or placebo 10 minutes before breakfast. Peak plasma concentrations of nateglinide were reached within 2 hours in most volunteers. Peak plasma concentrations of mitiglinide were reached 30 minutes after a sing

Topics: Animals; Benzamides; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Nateglinide; Phenylalanine; Piperidines

Existing oral insulin secretagogues, sulphonylureas, are associated with hyperinsulinaemia, risk of hypoglycaemia and weight gain. Furthermore, they are not able to offer durable glycaemic control in patents with type 2 diabetes and are associated with progressive decline of beta-cell function. New insulin secretagogues offer an exciting opportunity. Repaglinide, the first prandial glucose regulator, now has convincing data that, compared to sulphonylurea use, it has a lower risk of hypoglycaemia. When used in a flexible dosing regime in a large cohort of patients, it is associated with better glycaemic control, a reduction in HbA1c, weight loss and improved quality of life compared to sulphonylureas. Early data shows the possibility of an effective combination with night time isophane insulin with significant falls in HbA1c and lower doses of insulin required. Nateglinide is an amino acid derivative. It again acts directly on the pancreatic beta-cell. Because of its very short duration of action, and the fact that it appears to secrete insulin in a glucose-dependent manner, it appears to secrete insulin in the closest way to that seen in a person without diabetes. Early data, both in monotherapy and in combination with metformin, show that it is an effective agent in terms of lowering HbA1c, has a low risk of hypoglycaemia and potentially less risk of significant weight gain. These characteristics mean that it may be the ideal agent to be used very early in the disease process, or even in subjects with impaired glucose tolerance, in whom early-phase insulin response is already lost. However these concepts, at the present time, are unproven.

Topics: Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Glycated Hemoglobin; Humans; Hyperglycemia; Hyperinsulinism; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Nateglinide; Phenylalanine; Piperidines; Postprandial Period; Sulfonylurea Compounds; United Kingdom

Topics: Adenosine Triphosphate; Animals; ATP-Binding Cassette Transporters; Calcium Channels; Carbamates; Cyclohexanes; Exocytosis; Humans; Hypoglycemic Agents; Indoles; Insulin; Insulin Secretion; Islets of Langerhans; Isoindoles; Nateglinide; Organ Specificity; Phenylalanine; Piperidines; Potassium Channels; Potassium Channels, Inwardly Rectifying; Receptors, Drug; Sulfonylurea Receptors

Increasingly, type 2 diabetes takes a toll on public health and healthcare costs in the United States. Although the remedy for this growing problem is very complex, two critical components of its control are prevention and effective therapy. Progress in diabetes prevention is likely to take decades. But fortunately, growth in our understanding of what occurs in this chronic disease has led to advances in the pharmacologic options aimed at decreasing hyperglycemia, the main clinically measurable metabolic consequence of diabetes. In this article, Drs Ahmann and Riddle provide an overview of the oral agents now available for the treatment of diabetes and discuss the clinical factors that help determine when to use which medication and what outcome to expect.

Topics: Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Monitoring; Drug Therapy, Combination; Glycoside Hydrolases; Humans; Hypoglycemic Agents; Metformin; Nateglinide; Phenylalanine; Piperidines; Receptors, Cytoplasmic and Nuclear; Sulfonylurea Compounds; Transcription Factors

The loss of early insulin secretion appears to be a critical event in the deterioration in glucose tolerance during the development of type 2 diabetes. There is therefore a strong rationale for developing new antidiabetic agents aimed at restoring or replacing early prandial insulin secretion and thereby curbing mealtime glucose excursions in patients with type 2 diabetes. Four such new agents are either now available (repaglinide and nateglinide) or in clinical development (KAD-1229 and BTS 67 582). Preclinical studies suggest that each of these new insulinotropic agents share a common receptor/effector mechanism with the sulfonylureas (SUs) but that each may have distinct characteristics that differentiate them from the SUs and from each other. Nateglinide and KAD-1229 clearly stimulate biphasic insulin secretion in vitro and in vivo and their effects are rapidly reversible, whereas the effects of repaglinide and BTS 67 582 are prolonged well beyond their removal from perfusion media in vitro or their clearance in vivo. Available data from human studies indicate that the pharmacokinetics of repaglinide and nateglinide are similar, i.e., they are both rapidly absorbed and eliminated, but consistent with findings from animal studies, the insulinotropic and glucose-lowering effects of repaglinide are slower in onset and more prolonged than those of nateglinide. Repaglinide and nateglinide have been shown to be safe and well-tolerated in patients with type 2 diabetes and to produce clinically-meaningful reductions of HbA1c, both alone and in combination with agents with complementary modes of action (e.g., metformin and thiazolidinediones). Because these new agents can potentially bring patients to near normoglycemia without an undue risk of hypoglycemia, they are important additions to the therapeutic armamentarium.

Topics: Animals; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Glucose; Guanidines; Humans; Hypoglycemic Agents; Indoles; Insulin; Insulin Secretion; Isoindoles; Nateglinide; Phenylalanine; Piperidines

Presentation of six drugs: clopidogrel, raloxifene, mecillinam, natiglinide and repaglinide, pneumococcal conjugate vaccine. For each, positive and negative arguments, questions on hold and rating.

Topics: Amdinocillin; Carbamates; Clopidogrel; Cyclohexanes; Drug Interactions; Humans; Hypoglycemic Agents; Nateglinide; Patient Selection; Penicillins; Phenylalanine; Piperidines; Platelet Aggregation Inhibitors; Pneumococcal Vaccines; Raloxifene Hydrochloride; Safety; Selective Estrogen Receptor Modulators; Ticlopidine

The loss of early-phase insulin secretion is an important and early event in the natural history of type 2 diabetes. Because a normal pattern of insulin secretion is essential for the effective control of postprandial metabolism, a rational basis for the development of agents that target early-phase insulin release exists. Conventional oral hypoglycaemic agents do not target, or adequately control, postprandial glycaemia. The emergence of new classes of oral agent with a more specific mode of action provides, for the first time, an opportunity to restore early-phase insulin release. One such drug class is the meglitinide analogues (repaglinide, nateglinide, and mitiglinide). These drugs are ideally suited for combination use with metformin. They could also prove effective in combination with a thiazolidinedione, a drug class that targets insulin resistance. Exogenous insulin is frequently required in the late management of type 2 diabetes. However, one hope for newer combinations of diabetic drugs is that the functional life of the beta cell can be extended, thereby delaying the need for insulin injections.

Topics: Adult; Animals; Benzamides; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Nateglinide; Phenylalanine; Piperidines; Rats

The complications of diabetes mellitus, arising from inadequate glycemic control, have serious consequences for society as well as individuals. It is now urged that tight glycemic control be the goal for all patients, regardless of type of diabetes. Unfortunately, hypoglycemia can be a consequence of this aggressive approach. Treatment with a combination of agents and improved therapies are needed to maintain glycemic balance in patients. A better understanding of the pathophysiology of diabetes has yielded many treatment options based on various mechanisms of action. The sulfonyluereas, repaglinide, metformin, acarbose and the thiazolidinediones are effective in decreasing fasting plasma glucose levels, but their limitations may include adverse effects, such as weight gain and hypoglycemia, and an inability to modify some of the important comorbidities of diabetes. Therapies aimed at treating mealtime hyperglycemia are gaining attention. One promising investigational agent in this category is nateglinide. Early data suggest that its rapid onset and short duration of action result in increased early mealtime insulin release, reduced mealtime glucose excursions, and improved glycemic control.

Topics: Acarbose; Administration, Oral; Blood Glucose; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Combinations; Drug Therapy, Combination; Glycated Hemoglobin; Humans; Hypoglycemia; Hypoglycemic Agents; Insulin; Insulin Secretion; Insulin-Secreting Cells; Metformin; Nateglinide; Phenylalanine; Piperidines; Randomized Controlled Trials as Topic; Thiazolidinediones; United States; Weight Gain

A central finding of the UKPDS was that in type 2 diabetic patients, tight glycemic control with HbA1c targets as close to the normal range as possible must be achieved to further reduce diabetes related-complications, -mortality, and -cardiovascular disease, highlighting the need for new, optimized treatment strategies. With a focus on clinical efficacy, this paper discusses the results from the 20 major therapeutical trials published in the years 1997-1999, that evaluated the new insulinsensitizing thiazolidinediones Rosiglitazone and Pioglitazone and the new insulin-releasing potassium channel blockers Repaglinide and Nateglinide. While for Nateglinide, promising, but only preliminary data is available at current, Rosiglitazone, Pioglitazone, and Repaglinide have been shown appropriate for both mono- and combination therapy with current standard drug treatment of type 2 diabetes. Similar to the known, older antidiabetic drugs, the new agents discussed have comparable blood glucose lowering potentials with a dose-related capacity of 0.5 to 1.5% HbA1c reduction. These beneficial effects were both seen in drug-naive patients previously treated with diet only and in combination therapies where patients had previous antidiabetic standard drug treatment suggesting effectiveness of glitazones and glinides also in more advanced stages of the disease. Problems with adverse effects appeared minor although long-range implications of weight gain, edema, lowering of hemoglobin, increase of total cholesterol for the glitazones, and hypoglycemia for glinides warrant further consideration. What becomes clear from the variety of most recent mono- and combination treatment studies with as much as five different classes of antidiabetic drugs is that individually tailored therapies that recognize quality of life parameters and target the predominant features of metabolic pathology (such as early postprandial versus fasting hyperglycemia, degree of insulin resistance, progressive loss of 1-cell function) may become a feasible goal in the future.

Topics: Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Nateglinide; Phenylalanine; Pioglitazone; Piperidines; Rosiglitazone; Thiazoles; Thiazolidinediones

Type 2 diabetes mellitus is a complex heterogenous metabolic disorder in which peripheral insulin resistance and impaired insulin release are the main pathogenetic factors. The rapid response of the pancreatic beta-cells to glucose is already markedly disturbed in the early stages of type 2 diabetes mellitus. The consequence is often postprandial hyperglycaemia, which seems to be extremely important in the development of secondary complications, especially macrovascular disease. Therefore one of the main aims of treatment is to minimise blood glucose oscillations and attain near-normal glycosylated haemoglobin levels. Meglitinide analogues belong to a new family of insulin secretagogues which stimulate insulin release by inhibiting ATP-sensitive potassium channels of the beta-cell membrane via binding to a receptor distinct from that of sulphonylureas (SUR1/KIR 6.2). The pharmacokinetic and pharmacodynamic properties of repaglinide, the first drug of these new antihyperglycaemic agents on the market, and of nateglinide, which will be available soon, differ markedly from the currently used sulphonylureas [mainly glibenclamide (glyburide) and glimepiride]. Repaglinide and nateglinide are absorbed rapidly, stimulate insulin release within a few minutes, are rapidly metabolised in the liver and are mainly excreted in the bile. Therefore, following preprandial administration of these drugs, insulin is more readily available during and just after the meal. This leads to a significant reduction in postprandial hyperglycaemia without the danger of hypoglycaemia between meals. The short action of these compounds and biliary elimination makes repaglinide and nateglinide especially suitable for patients with type 2 diabetes mellitus who would like to have a more flexible lifestyle, need more flexibility because of unplanned eating behaviour (e.g. geriatric patients) or in whom one of the other first-line antidiabetic drugs, i.e. metformin, is strictly contraindicated (e.g. nephropathy with creatinine clearance < or = 50 ml/min). Meglitinide analogues act synergistically with metformin and thiazolidinediones (pioglitazone and rosiglitazone) and can be also combined with long-acting insulin (NPH insulin at bedtime). Therefore, these drugs enrich the palette of antidiabetic drugs and make the treatment more flexible and better tolerated, which both add to better metabolic control and support the empowerment and compliance of the patient. However, this will only be the

Topics: Benzamides; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Glyburide; Humans; Hypoglycemic Agents; Molecular Structure; Nateglinide; Phenylalanine; Piperidines

Topics: Carbamates; Chromans; Cyclohexanes; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Insulin Resistance; Metformin; Nateglinide; Phenylalanine; Piperidines; Thiazoles; Thiazolidinediones; Troglitazone

Topics: Administration, Oral; Carbamates; Cyclohexanes; Diabetes Mellitus; Dose-Response Relationship, Drug; Glucose; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Nateglinide; Phenylalanine; Piperidines; Receptors, Cytoplasmic and Nuclear; Thiazoles; Thiazolidinediones; Transcription Factors

Two novel oral hypoglycaemic agents, NN623 and A4166, have been developed and are now in phase II clinical trial. Both agents have several common characteristics from sulphonylureas. NN623 is a stereoisomer of derivatives of benzoic acid and A4166 is also a stereoisomer of phenylalanine derivative. The predominant mechanism of the action is thought to be like sulphonylureas. Both NN623 and A4166 occupy, at least partly, a common receptor site with glibenclamide and close the ATP-dependent K+ channel. They are rapidly absorbed from the intestine and are eliminated mainly into the bile. NN623 is about 10 times more potent in hypoglycaemic action than glibenclamide and 100 times more than A4166 in terms of dosage. When 1.0 mg NN623 or 60 mg A4166 was given orally in the post-absorptive state to healthy volunteers, both agents evoked hypoglycaemia by 40 min. The duration of hypoglycaemia after NN623 was longer than after A4166 by about 1 hour. The effect of food on their bioavailability is similar. Food has marked influence on the absorption of both drugs and on their efficacy. When 1 mg of NN623 or 60 mg of A4166 was administered just before the meal, Tmax of NN623 and A4166 was 34 +/- 18 min and 18 +/- 6 min, while T1/2 was 0.64 +/- 0.12 h and 0.98 +/- 0.06 h, respectively. The postprandial rise in plasma glucose was reduced at 45 min and thereafter over 4-h after 1.0 mg NN623 and at 30 min to 90 min after 60 mg A4166. Plasma insulin levels rose more than those after placebo from 30 to 90 min after NN623 and at 20 to 40 min after A4166. Both agents stimulated insulin release much more in the postprandial than in the fasting state. There was no difference in the bioavailability after 5 or 7 days of administration. However, when administered immediately after the meal, the absorption of both drugs was delayed and the rise in plasma absorption was not suppressed until 60 min after the meal. Both fasting and postprandial hyperglycaemia were reduced after 1 to 4 weeks of premeal treatment with 0.5 mg NN623 or 60 mg A4166 in subjects with NIDDM. Plasma glucose levels were decreased over 4 h after NN623 and over 1 h after A4166. The meal-induced insulin response was almost doubled by NN623 over 2 h and 1 h by A4166. There was no difference in the bioavailability after breakfast between the first and last administrations of both drugs. In conclusion, a rapid rise in plasma insulin levels is associated with the suppression of postprandial hyperglycaemia.

Topics: Administration, Oral; Biological Availability; Blood Glucose; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Glyburide; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Intestinal Absorption; Molecular Structure; Nateglinide; Phenylalanine; Piperidines; Reference Values; Stereoisomerism

The purpose of this study is to evaluate efficacy and safety of nateglinide tablet administration in comparison with those of repaglinide tablet as control on treating type 2 diabetes mellitus in China. Pooled-analysis with analysis of covariance (ANCOVA) method was applied to assess the efficacy and safety based on original data collected from four independent randomized clinical trials with similar research protocols. However meta-analysis was applied based on the outcomes of the four studies. The results by meta-analysis were comparable to those obtained by pooled-analysis. The means of HbA(1c), and fasting blood glucose in both the nateglinide and repaglinide groups were reduced significantly after 12 weeks duration but no statistical differences in reduction between the two groups. The adverse reaction rates were 9.89 and 6.51% in the nateglinide and repaglinide groups respectively, with the rate difference showing no statistical significance, and the Odds Ratio of adverse reaction rate (95% confidence interval) was 1.59 (0.99, 2.55). Both nateglinide and repaglinide administration have similarly significant effects on reducing HbA(1c) and FBG. However, the adverse reaction rate in the nateglinide group is higher than that in the latter using repaglinide but no statistical significance difference as revealed in the four clinical trials detailed below.

Topics: Carbamates; China; Cyclohexanes; Diabetes Mellitus, Type 2; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Male; Middle Aged; Nateglinide; Phenylalanine; Piperidines

Organic anion transporting polypeptide 1B1 (OATP1B1), encoded by SLCO1B1, is an influx transporter expressed on the sinusoidal membrane of human hepatocytes. The aim of this study was to investigate whether the SLCO1B1*1B haplotype affects the pharmacokinetics and pharmacodynamics of repaglinide and nateglinide.. Eight healthy volunteers with the SLCO1B1*1B/*1B genotype and 16 with the SLCO1B1*1A/*1A genotype ingested a single 0.5-mg dose of repaglinide and, after a washout period of 1 week, a single 60-mg dose of nateglinide. Plasma repaglinide and nateglinide and blood glucose concentrations were measured for 7 h.. The AUC(0-infinity) and Cmax of repaglinide were 32% (P=0.007) and 24% lower (P=0.056) in the individuals with the SLCO1B1*1B/*1B genotype than in those with the SLCO1B1*1A/*1A genotype. The mean blood glucose concentration from 0 to 7 h after repaglinide intake was 10% higher in the SLCO1B1*1B/*1B participants than in the SLCO1B1*1A/*1A participants (P=0.007). The Cmax of nateglinide occurred earlier in the SLCO1B1*1B/*1B participants than in the SLCO1B1*1A/*1A participants (P=0.004), but no differences were seen in the other pharmacokinetic variables of nateglinide.. The SLCO1B1*1B/*1B genotype is associated with reduced plasma concentrations of repaglinide, consistent with an enhanced hepatic uptake by OATP1B1, but has limited effects on the pharmacokinetics of nateglinide.

Topics: Administration, Oral; Adult; Area Under Curve; Blood Glucose; Carbamates; Cyclohexanes; Female; Haplotypes; Humans; Hypoglycemic Agents; Liver-Specific Organic Anion Transporter 1; Male; Nateglinide; Organic Anion Transporters; Phenylalanine; Piperidines; Time Factors

Thirty-two healthy volunteers with different SLCO1B1 genotypes ingested a 0.5-mg dose of repaglinide and 60-mg dose of nateglinide with a washout period of 1 week. Participants with SLCO1B1 c.521CC genotype (n = 4) had a 59% (P = 0.001) or 72% (P < 0.001) greater mean area under the plasma repaglinide concentration-time curve (AUC(0-infinity)) than participants with c.521TC (n = 12) or c.521TT (n = 16) genotypes. The AUC(0-infinity) of repaglinide metabolites M2 and M4 were 112% (P = 0.004) and 81% (P = 0.002) larger in participants with c.521CC genotype than in those with c.521TT genotype, but no differences existed in the pharmacokinetics of M1. Maximum decrease in blood glucose concentration correlated with repaglinide AUC(0-infinity) (r = 0.412, P = 0.019). SLCO1B1 polymorphism had no significant effect on the pharmacokinetics or pharmacodynamics of nateglinide or its M7 metabolite. Thus, in contrast to repaglinide, the disposition of nateglinide is unaffected by the SLCO1B1 c.521T>C polymorphism.

Topics: Analysis of Variance; Area Under Curve; Aryl Hydrocarbon Hydroxylases; Blood Glucose; Carbamates; Chromatography, Liquid; Cyclohexanes; Cytochrome P-450 CYP2C8; Cytochrome P-450 CYP2C9; Dose-Response Relationship, Drug; Genotype; Half-Life; Humans; Hypoglycemic Agents; Liver-Specific Organic Anion Transporter 1; Metabolic Clearance Rate; Molecular Structure; Nateglinide; Organic Anion Transporters; Pharmacogenetics; Phenylalanine; Piperidines; Polymorphism, Single Nucleotide; Tablets; Tandem Mass Spectrometry

To evaluate the efficacy of nateglinide vs. repaglinide in blood glucose (BG) control and the effect on insulin resistance and beta-Cell function in patients with type 2 diabetes.. A randomized controlled double-blind and double-dummy multicentre clinical trial was conducted. A total of 230 Chinese patients with type 2 diabetes were enrolled in five clinical centres. The patients were divided randomly into group A [repaglinide 1.0 mg three times daily (t.i.d.), n = 115] or group B (nateglinide 90 mg t.i.d., n = 115). At baseline and end of the 12-week clinical trial, standard mixed meal tolerance tests were performed.. A total of 223 patients (96.9%) completed the trial. There was no significant difference between repaglinide and nateglinide groups in the effects of reducing fasting blood glucose (FBG), 30-, 60- and 120-min BG during 12 weeks (p > 0.05). At week 12, no significant difference was shown between the two groups in BG or haemoglobin A(1c) (HbA(1c)) (p > 0.05). However, the effect on HbA(1c) in repaglinide group was stronger than that in nateglinide group (p < 0.05). After 12-week treatment, area under the curve (AUC) of BG decreased (p < 0.05), and AUC of insulin and C-peptide (CP) increased in both groups (p < 0.05). The effects of nateglinide on AUC of BG, insulin and CP were similar to that of repaglinide (p > 0.05). There was no significant difference between the two groups in AUC of BG, insulin or CP in week 12 (p > 0.05). Furthermore, homeostasis model assessment of insulin resistance (HOMA-IR) and beta-cell function indexes measured by HOMA-beta, DeltaI(30)/DeltaG(30) and (DeltaI(30)/DeltaG(30))/HOMA-IR were improved significantly in both groups during 12 weeks (p < 0.05). The effects of improving HOMA-IR and beta-cell function indexes in nateglinide group were comparable with that of repaglinide group (p > 0.05).. The efficacy of repaglinide and nateglinide in FBG, postprandial glucose excursion and early-phase insulin secretion is similar. But the effect of repaglinide 1.0 mg t.i.d. on HbA(1c) is stronger than that of nateglinide 90 mg t.i.d.. This trial had shown that nateglinide and repaglinide could comparably improve insulin sensitivity and beta-cell function.

Topics: Adult; Age of Onset; Aged; Area Under Curve; Asian People; Blood Glucose; Carbamates; China; Cyclohexanes; Diabetes Mellitus, Type 2; Double-Blind Method; Humans; Insulin; Insulin Secretion; Insulin-Secreting Cells; Middle Aged; Nateglinide; Phenylalanine; Piperidines

To compare the efficacy of nateglinide with repaglinide in the treatment of type 2 diabetes mellitus.. Forty-six type 2 diabetic patients were randomly treated with repaglinide (group A, 1.0 mg tid, n=23) or nateglinide (group B, 90.0 mg tid, n=23). The trial consisted of a 4-week equilibrated period followed by 12 weeks of treatment course.. In group A, the fasting blood glucose (FBG) and 30-, 60-, 120- min postprandial blood glucose (PBG), as well as hemoglobin A1c were decreased significantly (P<0.05). In group B, the 60-min and 120-min PBG decreased remarkably (P<0.05), but FBG, 30-min PBG and A1c decreased with no statistical significance (P>0.05). After 12 weeks treatment, the 30-, 60-, 120-min postprandial insulin level, area under the curve of insulin and C peptide (0 to 120 min) increased in both groups (P<0.05). No significant difference was found between the effects of repaglinide and nateglinide on early phase insulin secretion.. The glucose lowering effect of repaglinide at a dosing level of 1.0 mg tid was better than that of nateglinide 90 mg tid on fasting blood glucose and A1c during 12 weeks treatment period, yet the insulinotropic effects of the two drugs were similar.

Topics: Adult; Blood Glucose; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Double-Blind Method; Female; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Male; Middle Aged; Nateglinide; Phenylalanine; Piperidines

A randomized, parallel-group, open-label, multicenter 16-week clinical trial compared efficacy and safety of repaglinide monotherapy and nateglinide monotherapy in type 2 diabetic patients previously treated with diet and exercise.. Enrolled patients (n = 150) had received treatment with diet and exercise in the previous 3 months with HbA(1c) >7 and < or =12%. Patients were randomized to receive monotherapy with repaglinide (n = 76) (0.5 mg/meal, maximum dose 4 mg/meal) or nateglinide (n = 74) (60 mg/meal, maximum dose 120 mg/meal) for 16 weeks. Primary and secondary efficacy end points were changes in HbA(1c) and fasting plasma glucose (FPG) values from baseline, respectively. Postprandial glucose, insulin, and glucagon were assessed after a liquid test meal (baseline, week 16). Safety was assessed by incidence of adverse events or hypoglycemia.. Mean baseline HbA(1c) values were similar in both groups (8.9%). Final HbA(1c) values were lower for repaglinide monotherapy than nateglinide monotherapy (7.3 vs. 7.9%). Mean final reductions of HbA(1c) were significantly greater for repaglinide monotherapy than nateglinide monotherapy (-1.57 vs. -1.04%; P = 0.002). Mean changes in FPG also demonstrated significantly greater efficacy for repaglinide than nateglinide (-57 vs. -18 mg/dl; P < 0.001). HbA(1c) values <7% were achieved by 54% of repaglinide-treated patients versus 42% for nateglinide. Median final doses were 6.0 mg/day for repaglinide and 360 mg/day for nateglinide. There were 7% of subjects treated with repaglinide (five subjects with one episode each) who had minor hypoglycemic episodes (blood glucose <50 mg/dl) versus 0 patients for nateglinide. Mean weight gain at the end of the study was 1.8 kg in the repaglinide group as compared with 0.7 kg for the nateglinide group.. In patients previously treated with diet and exercise, repaglinide and nateglinide had similar postprandial glycemic effects, but repaglinide monotherapy was significantly more effective than nateglinide monotherapy in reducing HbA(1c) and FPG values after 16 weeks of therapy.

Topics: Biomarkers; Body Mass Index; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Diet, Diabetic; Exercise; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Male; Middle Aged; Nateglinide; Phenylalanine; Piperidines; Time Factors

An open-label, parallel-group, randomized, multicenter trial was conducted to compare efficacy and safety of repaglinide versus nateglinide, when used in a combination regimen with metformin for treatment of type 2 diabetes.. Enrolled patients (n = 192) had HbA(1c) >7% and < or =12% during previous treatment with a sulfonylurea, metformin, or low-dose Glucovance (glyburide < or =2.5 mg, metformin < or =500 mg). After a 4-week metformin run-in therapy period (doses escalated to 1,000 mg b.i.d.), patients were randomized to addition of repaglinide (n = 96) (1 mg/meal, maximum 4 mg/meal) or nateglinide (n = 96) (120 mg/meal, reduced to 60 mg if needed) to the regimen for 16 weeks. Glucose, insulin, and glucagon were assessed after a liquid test meal at baseline and week 16.. Final HbA(1c) values were lower for repaglinide/metformin treatment than for nateglinide/metformin (7.1 vs. 7.5%). Repaglinide/metformin therapy showed significantly greater mean reductions of HbA(1c) (-1.28 vs. -0.67%; P < 0.001) and of fasting plasma glucose (FPG) (-39 vs. -21 mg/dl; P = 0.002). Self-monitoring of blood glucose profiles were significantly lower for repaglinide/metformin before breakfast, before lunch, and at 2:00 A.M. Changes in the area under the curve of postprandial glucose, insulin, or glucagon peaks after a test meal were not significantly different for the two treatment groups during this study. Median final doses were 5.0 mg/day for repaglinide and 360 mg/day for nateglinide. Safety assessments were comparable for the two regimens.. The addition of repaglinide to metformin therapy resulted in reductions of HbA(1c) and FPG values that were significantly greater than the reductions observed for addition of nateglinide.

Topics: Area Under Curve; Blood Glucose; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Female; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Insulin; Male; Metformin; Middle Aged; Nateglinide; Phenylalanine; Piperidines; Postprandial Period; Safety

This study was designed to compare the pharmacodynamic effects of single doses of nateglinide (A-4166), repaglinide, and placebo on mealtime insulin secretion and glycemic control in healthy subjects.. Fifteen healthy volunteers participated in this open-label five-period crossover study. They received single 10-min preprandial doses of 120 mg nateglinide, 0.5 or 2 mg repaglinide, or placebo or 1 min preprandially of 2 mg repaglinide. Subjects received each dose only once, 48 h apart. Pharmacodynamic and pharmacokinetic assessments were performed from 0 to 12 h postdose.. Nateglinide induced insulin secretion more rapidly than 2 and 0.5 mg repaglinide and placebo (10 min preprandial), with mean rates of insulin rise of 2.3, 1.3, 1.15, and 0.8 microU x ml(-1) x min(-1), respectively, over the 0- to 30-min postmeal interval. After peaking, insulin concentrations decreased rapidly in the nateglinide-treated group and were similar to placebo within 2 h postdose. After 2 mg repaglinide, peak insulin concentrations were delayed and returned to baseline more slowly than with nateglinide treatment. Nateglinide treatment produced lower average plasma glucose concentrations in the 0- to 2-h postdose interval than either dose of repaglinide and placebo (P < 0.05 vs. 0.5 mg repaglinide and placebo). Plasma glucose concentrations returned more rapidly to predose levels with nateglinide treatment than with either dose of repaglinide. Treatment with repaglinide produced a sustained hypoglycemic effect up to 6 h postdose.. In this single-dose study in nondiabetic volunteers, nateglinide provided a more rapid and shorter-lived stimulation of insulin secretion than repaglinide, resulting in lower meal-related glucose excursions. If similar results are observed in diabetes, nateglinide may produce a more physiological insulin secretory response with the potential for a reduced risk of postabsorptive hypoglycemia.

Topics: Adolescent; Adult; Blood Glucose; Body Mass Index; Body Weight; Carbamates; Cross-Over Studies; Cyclohexanes; Female; Food; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Kinetics; Male; Middle Aged; Nateglinide; Phenylalanine; Piperidines; Placebos; Time Factors

Two novel oral hypoglycaemic agents, NN623 and A4166, have been developed and are now in phase II clinical trial. Both agents have several common characteristics from sulphonylureas. NN623 is a stereoisomer of derivatives of benzoic acid and A4166 is also a stereoisomer of phenylalanine derivative. The predominant mechanism of the action is thought to be like sulphonylureas. Both NN623 and A4166 occupy, at least partly, a common receptor site with glibenclamide and close the ATP-dependent K+ channel. They are rapidly absorbed from the intestine and are eliminated mainly into the bile. NN623 is about 10 times more potent in hypoglycaemic action than glibenclamide and 100 times more than A4166 in terms of dosage. When 1.0 mg NN623 or 60 mg A4166 was given orally in the post-absorptive state to healthy volunteers, both agents evoked hypoglycaemia by 40 min. The duration of hypoglycaemia after NN623 was longer than after A4166 by about 1 hour. The effect of food on their bioavailability is similar. Food has marked influence on the absorption of both drugs and on their efficacy. When 1 mg of NN623 or 60 mg of A4166 was administered just before the meal, Tmax of NN623 and A4166 was 34 +/- 18 min and 18 +/- 6 min, while T1/2 was 0.64 +/- 0.12 h and 0.98 +/- 0.06 h, respectively. The postprandial rise in plasma glucose was reduced at 45 min and thereafter over 4-h after 1.0 mg NN623 and at 30 min to 90 min after 60 mg A4166. Plasma insulin levels rose more than those after placebo from 30 to 90 min after NN623 and at 20 to 40 min after A4166. Both agents stimulated insulin release much more in the postprandial than in the fasting state. There was no difference in the bioavailability after 5 or 7 days of administration. However, when administered immediately after the meal, the absorption of both drugs was delayed and the rise in plasma absorption was not suppressed until 60 min after the meal. Both fasting and postprandial hyperglycaemia were reduced after 1 to 4 weeks of premeal treatment with 0.5 mg NN623 or 60 mg A4166 in subjects with NIDDM. Plasma glucose levels were decreased over 4 h after NN623 and over 1 h after A4166. The meal-induced insulin response was almost doubled by NN623 over 2 h and 1 h by A4166. There was no difference in the bioavailability after breakfast between the first and last administrations of both drugs. In conclusion, a rapid rise in plasma insulin levels is associated with the suppression of postprandial hyperglycaemia.

Topics: Administration, Oral; Biological Availability; Blood Glucose; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Glyburide; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Intestinal Absorption; Molecular Structure; Nateglinide; Phenylalanine; Piperidines; Reference Values; Stereoisomerism

A rapid and simple method to measure oral hypoglycemic agents is essential in the evaluation of a patient with spontaneous hypoglycemia. As a result, a robust high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for the qualitative detection of first-generation sulfonylureas (e.g., chlorpropamide, tolazamide, and tolbutamide), second-generation sulfonylureas (e.g., glimepiride, glipizide, and glyburide), meglitinides (e.g., repaglinide, nateglinide), and thiazolidinediones (e.g., rosiglitazone and pioglitazone). HPLC involved a C8 column and MS/MS was used in electrospray ionization (ESI) positive mode. Identification of all compounds was made using various multiple-reaction monitoring (MRMs). Isotopic labeled chlorpropamide-d4, glimepiride-d5, glyburide-d11, nateglinide-d5, repaglinide-ethyl-d5, rosiglitazone-d3, and zomepirac were used as the internal standards. The cutoffs for each drug were as follows: chlorpropamide 100 ng/mL, tolazamide 50 ng/mL, tolbutamide 20 ng/mL, glimepiride 20 ng/mL, glipizide 5 ng/mL, glyburide 5 ng/mL, repaglinide 5 ng/mL, rosiglitazone 20 ng/mL, pioglitazone 20 ng/mL, and nateglinide 5 ng/mL.

Topics: Chlorpropamide; Chromatography, High Pressure Liquid; Chromatography, Liquid; Glipizide; Glyburide; Humans; Hypoglycemic Agents; Nateglinide; Pioglitazone; Rosiglitazone; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry; Tolazamide; Tolbutamide

Polypharmacy in type 2 diabetes is an issue of major concern as the prescription of multiple medi-cations for the management of diabetes-associated comorbidities can lead to drug-to-drug interactions, which can pose serious risks to patients' health. Within this context, the development of bioanalytical methods for monitoring the therapeutic levels of antidiabetic drugs is notably useful to ensure patients' safety. In the present work, a liquid chromatography-mass spectrometry method for the quantitation of pioglitazone, repaglinide, and nateglinide in human plasma is described. Sample preparation was performed by fabric phase sorptive extraction (FPSE), and hydrophilic interaction liquid chromatography (HILIC) was implemented for the chromatographic separation of the analytes, using a ZIC®-cHILIC analytical column (150 × 2.1 mm, 3 µm) under isocratic elution. The mobile phase consisted of 10 mM ammonium formate aqueous solution (pH = 6.5)/ acetonitrile, 10/90 v/v, and was pumped at a flow rate of 0.2 mL min

Topics: Chromatography, High Pressure Liquid; Chromatography, Liquid; Diabetes Mellitus, Type 2; Drug Monitoring; Humans; Hydrophobic and Hydrophilic Interactions; Nateglinide; Pioglitazone; Spectrometry, Mass, Electrospray Ionization

Serious hypoglycemia is a major adverse event associated with insulin secretagogues. Previous studies have suggested a potential relationship between angiotensin-converting enzyme inhibitors (ACEIs) used with sulfonylureas and serious hypoglycemia, and widely used drug compendia warn of this potential drug-drug interaction. We investigated the association between serious hypoglycemia and concomitant use of ACEIs in patients receiving insulin secretagogues, using the self-controlled case series design and Medicaid claims data from 5 US states linked to Medicare claims from 1999-2011. The exposure of interest was active prescription for ACEIs during insulin secretagogue or metformin (negative control object drug) episodes. The outcome was hospital presentation for serious hypoglycemia, identified by discharge diagnosis codes in inpatient and emergency department claims (positive predictive value ~ 78-89%). We calculated confounder-adjusted rate ratios (RRs) and 95% confidence internals (CIs) of outcome occurrence during ACEI-exposed vs. ACEI-unexposed time using conditional Poisson regression. The RRs for ACEIs were not statistically elevated during observation time of glipizide (RR, 1.06; CI, 0.98-1.15), glyburide (RR, 1.05; CI, 0.96-1.15), repaglinide (RR, 1.15; CI, 0.94-1.41), or metformin (RR, 1.02; CI, 0.97-1.06); but was modestly elevated with glimepiride (RR, 1.23; CI, 1.11-1.37) and modestly reduced with nateglinide (RR, 0.73; CI, 0.56-0.96). The overall pattern of results do not suggest that ACEIs used with insulin secretagogues were associated with increased rates of serious hypoglycemia, with the possible exception of glimepiride.

Topics: Administrative Claims, Healthcare; Aged; Aged, 80 and over; Angiotensin-Converting Enzyme Inhibitors; Carbamates; Databases, Factual; Diabetes Mellitus, Type 2; Drug Interactions; Female; Glipizide; Glyburide; Humans; Hypoglycemia; Hypoglycemic Agents; Insulin; Male; Medicaid; Metformin; Middle Aged; Nateglinide; Pharmacoepidemiology; Piperidines; Secretagogues; Sulfonylurea Compounds; United States

During diabetes human serum albumin (HSA), an important drug transport protein, can be modified by agents such as glyoxal (Go) and methylglyoxal (MGo) to form advanced glycation end-products. High-performance affinity microcolumns and zonal elution competition studies were used to compare interactions by the anti-diabetic drugs repaglinide and nateglinide with normal and Go- or MGo-modified HSA at Sudlow sites I and II of this protein. Both drugs had their strongest binding at Sudlow site II for the normal and modified forms of HSA. The association equilibrium constants at this site for repaglinide and nateglinide with normal HSA were 6.1 (± 0.2) × 10

Topics: Carbamates; Chromatography, Affinity; Glycosylation; Glyoxal; Humans; Nateglinide; Piperidines; Protein Binding; Pyruvaldehyde; Serum Albumin; Serum Albumin, Human

To assess the association of metformin monotherapy with the risk of all-cause deaths and cardiovascular deaths and events in type 2 diabetes patients in real clinical practice.. This retrospective, observational study comprised patients with type 2 diabetes initially treated with metformin or nonmetformin monotherapy over 2011-2016. Data were extracted from the National Healthcare Big Data database in Fuzhou, China. Propensity score matching (PSM) was performed, matching each patient on metformin to one on nonmetformin in terms of a set of covariates. The primary endpoint was all-cause death, and secondary endpoints were cardiovascular death, heart failure, and heart failure hospitalization. Covariate-adjusted associations of metformin use with all the endpoints were assessed by Cox proportional hazards models.. Among 24,099 patients, 5491 were initially treated with metformin and 18,608 with nonmetformin. PSM yielded 5482 patients in each cohort. During a median follow-up of 2.02 years, we observed 110 and 211 deaths in the metformin and nonmetformin groups, respectively. Metformin was significantly associated with reduced risk of all-cause death (adjusted hazard ratio (aHR) 0.52, 95% confidence interval (CI) 0.39-0.69), cardiovascular death (aHR 0.63, 95% CI 0.43-0.91), and heart failure (aHR 0.61, 95% CI 0.52-0.73), whereas the reduced risk in heart failure hospitalization was not statistically significant (aHR 0.70, 95% CI 0.47-1.02).. In this analysis of electronic health record data from a large database in China, metformin as first-line monotherapy greatly reduced the risk of all-cause death, cardiovascular death, and heart failure in diabetes patients as compared with nonmetformin medications.

Topics: Aged; Benzamides; Carbamates; Cardiovascular Diseases; Cause of Death; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Female; Glycoside Hydrolase Inhibitors; Heart Failure; Hospitalization; Humans; Hypoglycemic Agents; Male; Metformin; Middle Aged; Mortality; Nateglinide; Piperidines; Proportional Hazards Models; Retrospective Studies; Sulfonylurea Compounds; Thiazolidinediones

This nested case-control study evaluated the potential interaction between repaglinide and clopidogrel. Cases were defined by inpatient admissions or emergency department visits due to hypoglycemia. Concomitant use of repaglinide and clopidogrel within 3 days before the hypoglycemic event was the exposure of interest. For each case, up to four controls were randomly selected and matched by age, sex, type of glinide used (repaglinide or nateglinide), and time since cohort entry to the index date. Hypoglycemic risk was estimated by conditional logistic regressions. Concomitant use of repaglinide and clopidogrel was associated with an increased risk of hypoglycemia compared with repaglinide alone (adjusted odds ratio: 2.42; 95% confidence interval: 1.75-3.35). No significant associations were found with the two negative control object drug concomitants: nateglinide and clopidogrel and repaglinide and aspirin (without clopidogrel use). Our study suggests drug interaction between clopidogrel and repaglinide is clinically relevant and could increase the risk for hypoglycemia.

Topics: Aged; Aspirin; Carbamates; Case-Control Studies; Clopidogrel; Drug Interactions; Female; Humans; Hypoglycemia; Hypoglycemic Agents; Male; Middle Aged; Nateglinide; Piperidines; Platelet Aggregation Inhibitors

The antidiabetic drugs glibenclamide, repaglinide, and nateglinide are well-known substrates for hepatic uptake transporters of the organic anion transporting polypeptide (OATP) family and metabolizing enzymes of the cytochrome P450 (CYP) 2C subfamily. The systemic exposure of these drugs varies substantially among individuals, impacted by genetic polymorphisms of transporters and metabolizing enzymes as well as drug-drug interactions. The use of the conventional in vitro-in vivo extrapolation (IVIVE) method was found to underestimate their hepatic intrinsic clearance (CL

Topics: Albumins; Carbamates; Cytochrome P-450 Enzyme System; Glyburide; HEK293 Cells; Hepatocytes; Humans; Hypoglycemic Agents; Liver; Liver-Specific Organic Anion Transporter 1; Metabolic Clearance Rate; Microsomes, Liver; Models, Biological; Nateglinide; Piperidines; Solute Carrier Organic Anion Transporter Family Member 1B3

Drug-drug interactions with insulin secretagogues are associated with increased risk of serious hypoglycemia in patients with type 2 diabetes. We aimed to systematically screen for drugs that interact with the five most commonly used secretagogues-glipizide, glyburide, glimepiride, repaglinide, and nateglinide-to cause serious hypoglycemia.. We screened 400 drugs frequently coprescribed with the secretagogues as candidate interacting precipitants. We first predicted the drug-drug interaction potential based on the pharmacokinetics of each secretagogue-precipitant pair. We then performed pharmacoepidemiologic screening for each secretagogue of interest, and for metformin as a negative control, using an administrative claims database and the self-controlled case series design. The overall rate ratios (RRs) and those for four predefined risk periods were estimated using Poisson regression. The RRs were adjusted for multiple estimation using semi-Bayes method, and then adjusted for metformin results to distinguish native effects of the precipitant from a drug-drug interaction.. We predicted 34 pharmacokinetic drug-drug interactions with the secretagogues, nine moderate and 25 weak. There were 140 and 61 secretagogue-precipitant pairs associated with increased rates of serious hypoglycemia before and after the metformin adjustment, respectively. The results from pharmacokinetic prediction correlated poorly with those from pharmacoepidemiologic screening.. The self-controlled case series design has the potential to be widely applicable to screening for drug-drug interactions that lead to adverse outcomes identifiable in healthcare databases. Coupling pharmacokinetic prediction with pharmacoepidemiologic screening did not notably improve the ability to identify drug-drug interactions in this case.

Topics: Area Under Curve; Carbamates; Cyclohexanes; Databases, Factual; Diabetes Mellitus, Type 2; Drug Interactions; Glipizide; Glyburide; Humans; Hypoglycemia; Hypoglycemic Agents; Medical Informatics; Nateglinide; Pharmacoepidemiology; Phenylalanine; Piperidines; Sulfonylurea Compounds

Meglitinides (nateglinide and repaglinide) are widely used oral drugs for the treatment of type II diabetes mellitus. In the present study, the effects of meglinitides administered supraspinally on kainic acid (KA)-induced hippocampal neuronal cell death and hyperglycemia were studied in ICR mice. Mice were pretreated intracerebroventricularly (i.c.v.) with 30 μg of nateglinide and repaglinide for 10 min and then, mice were administered i.c.v. with KA (0.1 μg). The neuronal cell death in the CA3 region in the hippocampus was assessed 24h after KA administration and the blood glucose level was measured 30, 60, and 120 min after KA administration. We found that i.c.v. pretreatment with repaglinide attenuated the KA-induced neuronal cell death in CA3 region of the hippocampus and hyperglycemia. However, nateglinide pretreated i.c.v. did not affect the KA-induced neuronal cell death and hyperglycemia. In addition, KA administered i.c.v. caused an elevation of plasma corticosterone level and a reduction of the plasma insulin level. Furthermore, i.c.v. pretreatment with repaglinide attenuated KA-induced up-regulation of plasma corticosterone level. Furthermore, i.c.v. administration of repaglinide alone increased plasma insulin level and repaglinide pretreated i.c.v. caused a reversal of KA-induced hypoinsulinemic effect. Our results suggest that supraspinally administered repaglinide, but not nateglinide, exerts a protective effect against the KA-induced neuronal cells death in CA3 region of the hippocampus. The neuroprotective effect of repaglinide appears to be mediated by lowering the blood glucose level induced by KA.

Topics: Animals; Blood Glucose; CA3 Region, Hippocampal; Carbamates; Cell Death; Corticosterone; Cyclohexanes; Excitatory Amino Acid Agonists; Hypoglycemic Agents; Infusions, Intraventricular; Insulin; Kainic Acid; Male; Mice; Mice, Inbred ICR; Nateglinide; Neurons; Phenylalanine; Piperidines

In Germany, coverage decisions in the statutory health insurance (SHI) system are based on the principles of evidence-based medicine. Recently, an evidence assessment by the Institute for Quality and Efficiency in Health Care (IQWiG) of the oral antidiabetics of the glinide class showed that their long-term benefit is not proven. Accordingly, the responsible Federal Joint Committee (G-BA) decided to exclude glinides from prescription in the SHI system. This was, however, objected to by the Ministry of Health, which is charged with legal supervision. We use this case to illustrate the path from evidence assessments to coverage decisions in Germany against the background of the latest health reform, which has changed the legal requirements for evidence assessments and the ensuing coverage decisions.

Topics: Carbamates; Cost Control; Cost-Benefit Analysis; Costs and Cost Analysis; Cyclohexanes; Diabetes Mellitus; Eligibility Determination; Evidence-Based Medicine; Germany; Health Care Reform; Health Policy; Humans; Hypoglycemic Agents; Insurance Coverage; Nateglinide; National Health Programs; Phenylalanine; Piperidines; Prescription Drugs; Reimbursement Mechanisms; Technology Assessment, Biomedical

Meglitinides (repaglinide and nateglinide) are insulin secretagogues used to treat diabetes mellitus. We present a case of hypersensitivity reaction to repaglinide in a 61-year-old man who developed a maculopapular rash 5 days after treatment. Skin prick tests including repaglinide (0.5 g/mL) and patch tests (0.05% in pet and saline) were performed, and the results were negative. A blind oral challenge test with repaglinide was performed and the therapeutic dose was subsequently taken at home every 24 hours for 7 days. The result was positive with a delayed reaction at day 3. A punch biopsy of the skin lesions revealed drug-induced exanthema. The clinical manifestations, the latency period, the reappearance of cutaneous lesions after rechallenge, and the histopathology report of the skin biopsy suggest a type IV mechanism.

Topics: Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Hypersensitivity; Erythema; Exanthema; Humans; Hypoglycemic Agents; Male; Middle Aged; Nateglinide; Patch Tests; Phenylalanine; Piperidines

Topics: Administration, Oral; Biguanides; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Dipeptidyl-Peptidase IV Inhibitors; Drug Combinations; Drug Therapy, Combination; Glycoside Hydrolase Inhibitors; Humans; Hypoglycemic Agents; Nateglinide; Phenylalanine; Piperidines; Sulfonylurea Compounds

Hypoglycaemia is an acute complication associated with intensive treatment of patients with diabetes mellitus. This complication poses a major challenge in diabetes management. Furthermore, severe hypoglycaemia may be life threatening. Although hypoglycaemia is more often associated with insulin treatment, oral hypoglycaemic agents have the potential to trigger hypoglycaemia.. The aim of this study was to quantify the incidence of hypoglycaemic events and to describe the pattern of these incident events during the first 9 months of treatment with four oral antidiabetic drugs, rosiglitazone, pioglitazone, nateglinide and repaglinide, prescribed in general practice in England.. We used data collected for prescription-event monitoring (PEM) studies of rosiglitazone, pioglitazone, nateglinide and repaglinide. PEM is an observational, non-interventional, incept cohort study. Observation time for each patient and incidence rate (IR) per 1000 patient-years of treatment for hypoglycaemia was calculated for each drug cohort. Smoothed hazard estimates were plotted over time. Case/non-case analysis was performed to describe and compare patients who had at least one hypoglycaemic event in the first 9 months of treatment with those who did not.. The total number of patients included in the analysis was 14,373, 12,768, 4,549 and 5,727 in rosiglitazone, pioglitazone, nateglinide and repaglinide cohorts, respectively. From these, 276 patients experienced at least one episode of hypoglycaemia. The IR was between 50% and 100% higher in patients receiving treatment with meglitinides compared with those treated with the thiazolidinediones (TZDs) [IR = 9.94, 9.64, 15.71 and 20.32 per 1,000 patient-years for rosiglitazone, pioglitazone, nateglinide and repaglinide, respectively]. The plot of the hazard function and the estimated shape parameter from the Weibull regression model showed that pioglitazone, nateglinide and repaglinide had non-constant (decreasing) hazards over time, whereas the hazard for rosiglitazone-treated patients was approximately constant over time. Nateglinide and repaglinide had similar shape hazard function, indicating a significantly higher number of hypoglycaemic episodes shortly after starting treatment. For women treated with TZDs, hypoglycaemia was reported more frequently than for men.. This analysis shows that the frequency of reported hypoglycaemia within the study cohorts was relatively low. The rates of hypoglycaemia were not equal between drug classes. Treatment with nateglinide or repaglinide was characterized by a higher incidence of hypoglycaemia at the beginning of treatment. Further investigation is necessary to assess whether women treated with TZDs are more prone to hypoglycaemia than men. Findings from this study should be taken into account with other clinical and pharmacoepidemiological studies.

Topics: Administration, Oral; Adult; Adverse Drug Reaction Reporting Systems; Carbamates; Cohort Studies; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Monitoring; Drug Prescriptions; Female; Humans; Hypoglycemia; Hypoglycemic Agents; Incidence; Male; Middle Aged; Nateglinide; Phenylalanine; Pioglitazone; Piperidines; Rosiglitazone; Sex Factors; Thiazolidinediones

To investigate the different effects between sulfonylurea (SU) and glinide drugs in insulin secretion, pancreatic beta-cells were repeatedly stimulated with SU (glimepiride) or glinide (mitiglinide). Total internal reflection fluorescent (TIRF) microscopy revealed that secondary stimulation with glimepiride, but not glucose and mitiglinide, failed to evoke fusions of insulin granules although primary stimulation with glucose, glimepiride, and mitiglinide induced equivalent numbers of exocytotic responses. Glimepiride, but not glucose and mitiglinide, induced abnormally sustained [Ca(2+)](i) elevations and reductions of docked insulin granules on the plasma membrane. Our data suggest that the effect of glinide on insulin secretory mechanisms is similar to that of glucose.

Topics: Animals; Calcium; Carbamates; Cell Fusion; Cells, Cultured; Cyclohexanes; Exocytosis; Glucose; Hypoglycemic Agents; Insulin; Insulin Secretion; Insulin-Secreting Cells; Mice; Mice, Inbred C57BL; Microscopy, Fluorescence; Nateglinide; Phenylalanine; Piperidines; Sulfonylurea Compounds

Topics: Carbamates; Cyclohexanes; Glipizide; Humans; Hyperglycemia; Hyperlipidemias; Hypoglycemic Agents; Nateglinide; Phenylalanine; Piperidines; Postprandial Period; Sulfonylurea Compounds

The role of K(ATP) channels in the antiarrhythmic effect of Escherichia coli endotoxin-induced nitric oxide synthase (iNOS) was examined in an anesthetised rat model of myocardial ischemia and reperfusion arrhythmia by using glibenclamide (1 mg kg(-1)), nateglinide (10 mg kg(-1)) and repaglinide (0.5 mg kg(-1)). Endotoxin (1 mg kg(-1)) was administered intraperitoneally 4 h before the occlusion of the left coronary artery and glibenclamide, nateglinide or repaglinide was administered 30 min before coronary artery occlusion. We also evaluated the effects of K(ATP) channel blockers and nonselective K(+) channel blocker tetraethylammonium (TEA) on cardiac action potential configuration in the atria obtained from endotoxemic rats. The mean arterial blood pressure of rats receiving endotoxin was lower during both the occlusion and reperfusion periods. Endotoxin significantly reduced the total number of ectopic beats and the duration of ventricular tachycardia. Glibenclamide, but not nateglinide and repaglinide, prevented the hypotension and antiarrhythmic effects of endotoxin. Atria obtained from endotoxin-treated rats had prolonged action potential duration. This effect was abolished with pretreatment of iNOS inhibitors, l-canavanine and dexamethasone and perfusion of glibenclamide, but not with TEA and non-sulfonylurea drug, nateglinide. We demonstrated that glibenclamide inhibits the antiarrhythmic effect of endotoxin and this effect does not appear to involve K(ATP) channels.

Topics: Action Potentials; Adenosine Triphosphate; Animals; Arrhythmias, Cardiac; Blood Pressure; Carbamates; Cyclohexanes; Disease Models, Animal; Drug Interactions; Endotoxemia; Glyburide; Heart Atria; Heart Conduction System; Lipopolysaccharides; Male; Myocardial Ischemia; Nateglinide; Phenylalanine; Piperidines; Potassium Channel Blockers; Potassium Channels; Rats; Rats, Sprague-Dawley; Tachycardia, Ventricular; Tetraethylammonium; Time Factors; Ventricular Fibrillation; Ventricular Premature Complexes

ATP-sensitive K(+) (K(ATP)) channels are composed of pore-forming subunits (Kir6.x) and of regulatory subunits, the sulfonylurea receptors (SURx). Subtypes of K(ATP) channels are expressed in different organs. The sulfonylureas and glinides (insulinotropes) close the K(ATP) channel in pancreatic beta-cells and stimulate insulin secretion. The insulinotrope binding site of the pancreatic channel (Kir6.2/SUR1) consists of two overlapping (sub)-sites, site A, located on SUR1 and containing Ser1237 (which in SUR2 is replaced by Tyr1206), and site B, formed by SUR1 and Kir6.2. Insulinotropes bind to the A-, B-, or A + B-site(s) and are grouped accordingly. A-ligands are highly selective in closing the pancreatic channel, whereas B-ligands are nonselective and insensitive to the mutation S1237Y. We have examined the binding of insulinotropes representative of the three groups in [(3)H]glibenclamide competition experiments to determine the contribution of Kir6.x to binding affinity, the effect of the mutation Y1206S in site A of SUR2, and the subtype selectivity of the compounds. The results show that the bipartite nature of the SUR1 binding site applies also to SUR2. Kir6.2 as part of the B-site may interact directly or allosterically with structural elements common to all insulinotropes, i.e., the negative charge and/or the adjacent phenyl ring. The B-site confers a moderate subtype selectivity on B-ligands. The affinity of B-ligands is altered by the mutation SUR2(Y1206S), suggesting that the mutation affects the binding chamber of SUR2 as a whole or subsite A, including the region where the subsites overlap.

Topics: Amino Acid Substitution; Animals; ATP-Binding Cassette Transporters; Binding Sites; Binding, Competitive; Carbamates; Cell Line; Cyclohexanes; Dose-Response Relationship, Drug; Glyburide; Hypoglycemic Agents; KATP Channels; Ligands; Mice; Molecular Structure; Nateglinide; Phenylalanine; Piperidines; Potassium Channels; Potassium Channels, Inwardly Rectifying; Protein Binding; Radioligand Assay; Rats; Receptors, Drug; Sulfonylurea Compounds; Sulfonylurea Receptors; Transfection

Loss of beta-cell mass and function raises a concern regarding the application of sulfonylureas for the treatment of type 2 diabetes because previous studies have shown that agents that cause closure of inwardly rectifying K(+) sulfonylurea receptor subtype of ATP-sensitive potassium channels, such as tolbutamide and glibenclamide, induce apoptosis in beta-cell lines and rodent islets. Therefore, we investigated the effect of the new insulin secretagogues, repaglinide and nateglinide, and the sulfonylurea, glibenclamide, on beta-cell apoptosis in human islets. Human islets from six organ donors were cultured onto extracellular matrix-coated plates and exposed to glibenclamide, repaglinide, or nateglinide. The doses of the three compounds were chosen according to detected maximal effects, i.e. efficacy. Exposure of human islets for 4 h to 0.1 and 10 microm glibenclamide induced a 2.09- and 2.46-fold increase in beta-cell apoptosis, respectively, whereas repaglinide (0.01 and 1 microm) did not change the number of apoptotic beta-cells. At low concentration (10 microm), nateglinide did not induce beta-cell apoptosis. However, at high concentration of 1000 microm, it induced a 1.49-fold increase in the number of apoptotic beta-cells. Prolonged exposure for 4 d of the islets to the secretagogues induced beta-cell apoptosis. The increase was of 3.71- and 4.4-fold at 0.1 and 10 microm glibenclamide, 2.37- and 3.8-fold at 0.01 and 1 microm repaglinide, and of 3.2- and 4.6-fold at 10 and 1000 microm nateglinide, respectively. Glibenclamide at 0.1-10 nm (doses that were less efficient on insulin secretion) did not induce beta-cell apoptosis after 4 h incubation as well as 0.1 nm after 4 d incubation. However, 1 and 10 nm glibenclamide for 4 d induced a 2.24- and 2.53-fold increase in beta-cell apoptosis, respectively. Taken together, closure of the inwardly rectifying K(+) sulfonylurea receptor subtype of ATP-sensitive potassium channels induces beta-cell apoptosis in human islets and may precipitate the decrease in beta-cell mass observed in patients with type 2 diabetes.

Topics: Adult; Aged; Apoptosis; Calcium; Carbamates; Cells, Cultured; Cyclohexanes; Dose-Response Relationship, Drug; Glyburide; Humans; Hypoglycemic Agents; Insulin; Islets of Langerhans; Middle Aged; Nateglinide; Phenylalanine; Piperidines

To design and synthesize new compounds of prandial glucose regulator with more simple structure.. The target compounds were synthesized from diethyl succinate and benzaldehyde or 4-fluorobenzaldehyde by four-step reactions. Thus 18 compounds were synthesized. Their structures were comfirmed by NMR, MS and IR.. Seventeen compounds had different hypoglycemic activity in mice, among them, 9 compounds had higher hypoglycemic activity and 6 compounds had character of prandial glucose regulator.. Part of the compounds have higher hypoglycemic activity deserve to be further investigated.

Topics: Animals; Benzylidene Compounds; Blood Glucose; Carbamates; Cyclohexanes; Hypoglycemic Agents; Indoles; Isoindoles; Mice; Molecular Structure; Nateglinide; Phenylalanine; Piperidines; Structure-Activity Relationship; Succinates

As an example application of the CORE Diabetes Model in type 2 diabetes, we simulated the cost-effectiveness of repaglinide/metformin combination therapy versus nateglinide/metformin for treatment of individuals with type 2 diabetes with an inadequate response to sulphonylurea, metformin, or fixed dose glyburide/metformin.. The CORE Diabetes Model was used to simulate long-term outcomes for a cohort of individuals with type 2 diabetes treated with either repaglinide/metformin or nateglinide/metformin. HbA1c changes for each regimen were taken from a comparative study. At the end of the study, changes in HbA1c from baseline were -1.28% points and -0.67% points for repaglinide/metformin and nateglinide/metformin, respectively. Median final doses were 5.0 mg/day for repaglinide, 360 mg/day for nateglinide and 2000 mg/day metformin in each treatment arm. Costs were calculated as the annual costs for drugs plus costs of complications (US Medicare perspective) over a 30-year period. Life expectancy (LE) and quality-adjusted life expectancy (QALE) were calculated. Outcomes and costs were discounted at 3% annually.. With repaglinide/metformin, improved glycaemic control led to projected decreases in complication rates, improvement of LE and QALE by 0.15 and 0.14 years respectively, and total cost savings of 3,662 dollars/person over the 30-year period. Repaglinide/metformin had a 96% probability that the incremental costs per quality-adjusted life year gained would be 20,000 dollars or less, and a 66% probability that repaglinide/metformin would be cost-saving compared to nateglinide/metformin. Sensitivity analyses supported the validity and reliability of the results.. In the health economic context, repaglinide/metformin combination was dominant to nateglinide/metformin. The CORE Diabetes Model is a tool to help third-party reimbursement payers identify treatments for type 2 diabetes that are good value for money.

Topics: Carbamates; Cohort Studies; Computer Simulation; Cost of Illness; Cost-Benefit Analysis; Cyclohexanes; Decision Support Systems, Clinical; Diabetes Complications; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Female; Glycated Hemoglobin; Health Care Costs; Humans; Male; Metformin; Middle Aged; Models, Econometric; Nateglinide; Outcome Assessment, Health Care; Phenylalanine; Piperidines; Quality-Adjusted Life Years

Topics: Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Administration Schedule; Eating; Humans; Hypoglycemic Agents; Nateglinide; Phenylalanine; Piperidines

This study sought first to compare the pharmacodynamics and pharmocokinetics of two rapid-onset, rapidly-reversible insulinotropic agents, nateglinide and repaglinide, in pre-diabetic Cynomolgus monkeys and second to use these agents to assess the metabolic effects of early insulin secretion on prandial glucose control.. First, equipotent doses of nateglinide (20 mg/kg) and repaglinide (0.1 mg/kg) or vehicle were given intragastrically to overnight-fasted ketamine-anesthetized pre-diabetic Cynomolgus monkeys and samples were obtained for measurement of plasma glucose, insulin, glucagon, NEFA and drug concentrations. Second, nateglinide, repaglinide or vehicle were administered 10 min before a glucose-supplemented liquid meal and prandial glucose and insulin profiles were compared.. Although oral administration of nateglinide and repaglinide elicited similar maximum increments of plasma insulin (+403 and +448 pmol/l, respectively), the effects of nateglinide were more rapidly manifest and less prolonged. With nateglinide, insulin increased within 10 min and returned to baseline within 50 min. After repaglinide, the first increase occurred at 30 min and insulin concentrations remained increased for 3.5 h post-dose. When given 10 min before a meal, nateglinide increased early, but not total insulin release (AUC(0-210)=108 vs 150 nmol/l min for nateglinide and vehicle, respectively) and reduced prandial glucose excursions by 78%. Repaglinide increased total insulin release (AUC(0-210)=298 nmol/l min) and reduced glucose excursions by 53%.. Nateglinide is more rapid-acting and rapidly-reversible than is repaglinide. By restoring a more physiologic insulin profile, nateglinide is more effective than repaglinide in controlling prandial glucose excursions with less hyperinsulinaemia.

Topics: Animals; Blood Glucose; Carbamates; Cyclohexanes; Fatty Acids, Nonesterified; Food; Glucagon; Hypoglycemic Agents; Insulin; Insulin Secretion; Kinetics; Macaca fascicularis; Male; Nateglinide; Phenylalanine; Piperidines

Topics: Administration, Oral; Carbamates; Cyclohexanes; Diabetes Mellitus; Glipizide; Humans; Hypoglycemic Agents; Insulin; Insulin Secretion; Nateglinide; Phenylalanine; Piperidines; Sulfonylurea Compounds

Topics: Adiponectin; Blood Glucose; Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Humans; Hypoglycemic Agents; Intercellular Signaling Peptides and Proteins; Nateglinide; Phenylalanine; Piperidines; Proteins; Sulfonylurea Compounds

Topics: Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Glycated Hemoglobin; Humans; Hypoglycemic Agents; Metformin; Nateglinide; Phenylalanine; Piperidines

Repaglinide and nateglinide represent a new class of insulin secretagogues, structurally unrelated to sulphonylureas, that were developed for the treatment of type 2 diabetes. The inhibitory effect of these drugs was investigated on recombinant wild-type and mutant Kir6.2/SUR1 channels expressed in HEK293 cells. Nateglinide and repaglinide dose-dependently inhibited whole-cell Kir6.2/SUR1 currents with half-maximal inhibitory concentration (IC(50)) values of 800 and 21 nmol/l, respectively. Mutation of serine 1237 in SUR1 to tyrosine (S1237Y) abolished tolbutamide and nateglinide block, suggesting that these drugs share a common point of interaction on the SUR1 subunit of the ATP-sensitive K(+) channel. In contrast, repaglinide inhibition was unaffected by the S1237Y mutation (IC(50) = 23 nmol/l). Radioligand binding studies revealed a single high-affinity binding site for [(3)H]repaglinide on membranes prepared from HEK293 cells expressing wild-type (equilibrium dissociation constant [K(D)] = 0.40 nmol/l) or mutant (K(D) = 0.31 nmol/l) Kir6.2/SUR1 channels. Nateglinide and tolbutamide displaced [(3)H]repaglinide binding to wild-type channels with IC(50) values of 0.7 and 26 micro mol/l, respectively, but produced <10% displacement of [(3)H]repaglinide bound to mutant channels. This is consistent with the idea that binding of nateglinide and tolbutamide, but not repaglinide, is abolished by the SUR1[S1237Y] mutation and that the binding site for repaglinide is not identical to that of nateglinde/tolbutamide. These results are discussed in terms of a conformational analysis of the drug molecules.

Topics: ATP-Binding Cassette Transporters; Binding, Competitive; Carbamates; Cell Line; Cyclohexanes; Drug Interactions; Electrophysiology; Humans; Islets of Langerhans; Nateglinide; Phenylalanine; Piperidines; Potassium Channels; Potassium Channels, Inwardly Rectifying; Receptors, Drug; Sulfonylurea Receptors; Tolbutamide

Good glucose control is a prerequisite for the prevention of long-term complications in type 2 diabetics. In recent years, two new groups of substances have been approved for the oral treatment of type 2 diabetes: glinides and glitazones. The former are short-acting agents that promote insulin secretion and offer an alternative to the sulfonylureas, in particular in patients with irregular eating habits and high postprandial glucose peaks. The glitazones improve one of the disorders underlying type 2 diabetes, insulin resistance. They are used in particular in patients who are inadequately controlled with a sulfonylurea or metformin and who show insulin resistance. Both groups of substances are a useful addition to the antidiabetic drug armamentarium. Endpoint studies involving these substances have, however, not yet been performed.

Topics: Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Humans; Hypoglycemic Agents; Insulin; Nateglinide; Phenylalanine; Pioglitazone; Piperidines; Rosiglitazone; Thiazoles; Thiazolidinediones; Treatment Outcome

To investigate the hormonal and cellular selectivity of the prandial glucose regulators, we have undertaken a series of experiments, in which we characterised the effects of repaglinide and nateglinide on ATP-sensitive potassium ion (KATP) channel activity, membrane potential and exocytosis in rat pancreatic alpha-cells and somatotrophs. We found a pharmacological dissociation between the actions on KATP channels and exocytosis and suggest that compounds that, unlike repaglinide, have direct stimulatory effects on exocytosis in somatotrophs and alpha- and beta-cells, such as sulphonylureas and nateglinide, may have a clinically undesirable general stimulatory effect on cells within the endocrine system.

Topics: Animals; Carbamates; Cyclohexanes; Electrophysiology; Exocytosis; Hypoglycemic Agents; Islets of Langerhans; Membrane Potentials; Nateglinide; Phenylalanine; Piperidines; Postprandial Period; Potassium Channels; Rats

Topics: Carbamates; Cyclohexanes; Diabetes Mellitus, Type 2; Drug Therapy, Combination; Humans; Hypoglycemic Agents; Metformin; Nateglinide; Phenylalanine; Piperidines

Nateglinide is a novel insulinotropic agent for the treatment of type 2 diabetes. It is a D-phenylalanine derivative, chemically distinct from repaglinide and sulphonylureas (glyburide or glimepiride). Although each agent is known to stimulate insulin release via the signaling cascade initiated by closure of ATP-dependent K+ (K(ATP)) channels in pancreatic beta-cells, the pharmacological effect of nateglinide is reportedly fast-acting, short-lasting, sensitive to ambient glucose and more resistant to metabolic inhibition. The aim of the present study was to elucidate the molecular mechanism(s) underlying the distinct properties of the insulinotropic action of nateglinide. By using the patch-clamp methods, we comparatively characterized the potency and kinetics of the effect of these agents on K(ATP) channels in rat beta-cells at normal vs. elevated glucose and under physiological condition vs. experimentally induced metabolic inhibition. Our results demonstrated that the mode of the action of nateglinide on K(ATP) current was unique in (a) glucose dependency; (b) increased potency and efficacy under ATP depletion and uncoupling of mitochondrial oxidative phosphorylation than physiological condition; (c) substantially more rapid onset and offset kinetics. The data provide mechanistic rationale for the unique in vivo and ex vivo activity profile of nateglinide and may contribute to reduced hypoglycemic potential associated with excessive insulin secretion.

Topics: Adenosine Triphosphate; Animals; Carbamates; Cyclohexanes; Dose-Response Relationship, Drug; Glucose; Glyburide; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Kinetics; Male; Membrane Potentials; Nateglinide; Phenylalanine; Piperidines; Potassium Channel Blockers; Potassium Channels; Rats; Rats, Sprague-Dawley; Sulfonylurea Compounds; Time Factors

GH causes insulin resistance, impairs glycemic control and increases the risk of vascular diabetic complications. Sulphonylureas stimulate GH secretion and this study was undertaken to investigate the possible stimulatory effect of repaglinide and nateglinide, two novel oral glucose regulators, on critical steps of the stimulus-secretion coupling in single rat somatotrophs.. Patch-clamp techniques were used to record whole-cell ATP-sensitive K(+) (K(ATP)) and delayed outward K(+) currents, membrane potential and Ca(2+)-dependent exocytosis. GH release was measured from perifused rat somatotrophs.. Both nateglinide and repaglinide dose-dependently suppressed K(ATP) channel activity with half-maximal inhibition being observed at 413 nM and 13 nM respectively. Both compounds induced action potential firing in the somatotrophs irrespective of whether GH-releasing hormone was present or not. The stimulation of electrical activity by nateglinide, but not repaglinide, was associated with an increased mean duration of the action potentials. The latter effect correlated with a reduction of the delayed outward K(+) current, which accounts for action potential repolarization. The latter effect had a K(d) of 19 microM but was limited to 38% inhibition. When applied at concentrations similar to those required to block K(ATP) channels, nateglinide in addition potentiated Ca(2+)-evoked exocytosis 3.3-fold (K(d)=3 microM) and stimulated GH release 4.5-fold. The latter effect was not shared by repaglinide. The stimulation of exocytosis by nateglinide was mimicked by cAMP and antagonized by the protein kinase A inhibitor Rp-cAMPS.. Nateglinide stimulates GH release by inhibition of plasma membrane K(+) channels, elevation of cytoplasmic cAMP levels and stimulation of Ca(2+)-dependent exocytosis. By contrast, the effect of repaglinide was confined to inhibition of the K(ATP) channels.

Topics: Animals; Calcium; Carbamates; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Cyclohexanes; Delayed Rectifier Potassium Channels; Exocytosis; Growth Hormone; Growth Hormone-Releasing Hormone; Hypoglycemic Agents; Male; Membrane Potentials; Nateglinide; Patch-Clamp Techniques; Phenylalanine; Piperidines; Pituitary Gland; Potassium; Potassium Channel Blockers; Potassium Channels; Potassium Channels, Voltage-Gated; Rats; Rats, Sprague-Dawley

Chronic exposure of pancreatic islets to sulfonylureas (SUs) is known to impair the ability of islets to respond to subsequent acute stimulation by SUs or glucose. Nateglinide (NAT) is a novel insulinotropic agent with a primarily site of action at beta-cell K(ATP) channels, which is common to the structurally diverse drugs like repaglinide (REP) and the SUs. Earlier studies on the kinetics, glucose-dependence and sensitivity to metabolic inhibitors of the interaction between NAT and K(ATP) channels suggested a distinct signaling pathways with NAT compared to REP, glyburide (GLY) or glimepiride (GLI). To obtain further evidence for this concept, the present study compared the insulin secretion in vitro from rat islets stimulated acutely by NAT, GLY, GLI or REP at equipotent concentrations during 1-hr static incubation following overnight treatment with GLY or tolbutamide (TOL). The islets fully retained the responsiveness to NAT stimulation after prolonged pretreatment with both SUs, while their acute response to REP, GLY, and GLI was markedly attenuated, confirming the desensitization of islets. The insulinotropic efficacy of NAT in islets desensitized to SUs may result from a distinct receptor/effector mechanism, which contributes to the unique pharmacological profile of NAT.

Topics: Animals; Carbamates; Cyclohexanes; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Male; Nateglinide; Phenylalanine; Piperidines; Rats; Rats, Sprague-Dawley; Sulfonylurea Compounds

Nateglinide, a novel D-phenylalanine derivative, stimulates insulin release via closure of K(ATP) channels in pancreatic beta-cell, a primary mechanism of action it shares with sulfonylureas (SUs) and repaglinide. This study investigated (1) the influence of ambient glucose levels on the insulinotropic effects of nateglinide, glyburide and repaglinide, and (2) the influence of the antidiabetic agents on glucose-stimulated insulin secretion (GSIS) in vitro from isolated rat islets. The EC50 of nateglinide to stimulate insulin secretion was 14 microM in the presence of 3 mM glucose and was reduced by 6-fold in 8 mM glucose and by 16-fold in 16 mM glucose, indicating a glucose-dependent insulinotropic effect. The actions of glyburide and repaglinide failed to demonstrate such a glucose concentration-dependent sensitization. When tested at fixed and equipotent concentrations (approximately 2x EC50 in the presence of 8 mM glucose) nateglinide and repaglinide shifted the EC50s for GSIS to the left by 1.7 mM suggesting an enhancement of islet glucose sensitivity, while glimepiride and glyburide caused, respectively, no change and a right shift of the EC50. These data demonstrate that despite a common basic mechanism of action, the insulinotropic effects of different agents can be influenced differentially by ambient glucose and can differentially influence the islet responsiveness to glucose. Further, the present findings suggest that nateglinide may exert a more physiologic effect on insulin secretion than comparator agents and thereby have less propensity to elicit hypoglycemia in vivo.

Topics: Animals; Carbamates; Cyclohexanes; Glucose; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Kinetics; Male; Nateglinide; Phenylalanine; Piperidines; Rats; Rats, Sprague-Dawley; Sulfonylurea Compounds

Abnormal beta-cell function, characterized as the inability of the beta-cell to mount a rapid secretory response to glucose, is a well-established pathology of type 2 diabetes mellitus. These studies were designed to demonstrate the importance of early insulin release on the control of meal-induced glucose excursions by capitalizing on the significant pharmacodynamic differences between several oral insulin secreting agents.. Male Sprague Dawley fitted with indwelling jugular cannulas were used to compare the pharmacodynamic profiles of nateglinide (Nateg), glipizide (Glip) and repaglinide (Repag) through frequent blood samples following the administration of these compounds via oral gavage. In similar animals which were pretrained to consume their daily food intake in two discrete 45-min meals, the effects of compound induced changes in pre-meal, meal and post-meal insulin profiles on glycaemic control were assessed through frequent blood sampling following the administration of these compounds 10 min prior to a 30-min meal.. There were significant pharmacodynamics differences between the three oral agents tested and the time to elicit peak insulin secretory responses increased from Nateg (4 min) to Repag (10 min) to Glip (45 min). During the meal tolerance test, glibenclamide did not increase pre-meal insulin levels and glucose excursions paralleled those in the control. Conversely, the other three agents, at doses that produced hypoglycaemic responses of similar magnitude, all increased early insulin release (Delta AUC(-15 to 3 min) = 0.5 +/- 0.01, 1.6 +/- 0.4, 3.6 +/- 0.0, 1.2 +/- 0.1 and 1.73 +/- 0.4 nmol/min, for control, Nateg at 60 and 120 mg/kg, Glip and Repag, respectively) and curbed glucose excursions during the meal at varying rates and degrees (Delta AUC(0--30 min) = 39 +/- 6, 8 +/- 7, 5 +/- 7, - 1 +/- 8 and - 3 +/- 8 mmol/min for control, Nateg at 60 and 120 mg/kg, Glip and Repag, respectively). However, unlike Nateg, the longer duration of action of Repag and Glip elicited sustained post-meal relative hypoglycaemia.. These data support the impact of early and rapid insulin release in the control of prandial and post-meal glycaemia and demonstrate that a short anticipatory burst of insulin, restricted to the beginning of a meal, provides a clear metabolic advantage and prevents post-meal hypoglycaemic episodes when compared to a greater but reactive insulin exposure that follows a meal-induced increase in glucose excursion.

Topics: Animals; Blood Glucose; Carbamates; Cyclohexanes; Food; Glipizide; Glucagon; Insulin; Insulin Secretion; Male; Nateglinide; Phenylalanine; Piperidines; Rats; Rats, Sprague-Dawley

Novel insulinotropic agent nateglinide stimulates insulin via binding to sulfonylurea receptor and closing the ATP-dependent K+ (K(ATP)) channels in pancreatic beta-cells, leading to an increase in [Ca(2+)](i) for exocytosis. The voltage-dependent Ca(2+) channel and the delayed rectifier K+ (Kv) channels are also present in beta-cells and their activities determine the configuration of action potential and hence contribute to the regulation of [Ca(2+)](i) and insulin secretion. This study, by using the patch-clamp method in whole cell configuration, comparatively characterized the direct effects of sulfonylurea receptor ligands including nateglinide, glyburide, and repaglinide on Kv and Ca(2+) channels. Each agent inhibited Kv currents in a concentration-dependent manner with effective concentration range two to three orders higher than that for blocking K(ATP) channels. A marginal stimulation of Ca(2+) current was observed with all drugs, while repaglinide at concentration greater than 300 nM inhibited Ca(2+) current. The direct effects of these antidiabetic agents on Kv and Ca(2+) channels may act concertedly with their primary action on K(ATP) channels in regulating [Ca(2+)](i) and the stimulus-secretion coupling.

Topics: Animals; Calcium Channels; Carbamates; Cyclohexanes; Dose-Response Relationship, Drug; Electric Stimulation; Glyburide; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Male; Membrane Potentials; Nateglinide; Patch-Clamp Techniques; Phenylalanine; Piperidines; Potassium Channels; Rats; Rats, Sprague-Dawley

Nateglinide (A-4166) is an amino acid derivative with insulinotrophic action in clinical development for treatment of type 2 diabetes. The aim of this study was to determine whether nateglinide's interaction at the K(ATP) channel/sulfonylurea receptor underlies its more rapid onset and shorter duration of action in animal models. Binding studies were carried out with membranes prepared from RIN-m5F cells and HEK-293 cells expressing recombinant human sulfonylurea receptor 1 (SUR1). The relative order for displacement of [(3)H]glibenclamide in competitive binding experiments with RIN-m5F cell membranes was glibenclamide > glimepiride > repaglinide > glipizide > nateglinide > L-nateglinide > tolbutamide. The results with HEK-293/recombinant human SUR1 cells were similar with the exception that glipizide was more potent than repaglinide. Neither nateglinide nor repaglinide had any effect on the dissociation kinetics for [(3)H]glibenclamide, consistent with both compounds competitively binding to the glibenclamide-binding site on SUR1. Finally, the inability to measure [(3)H]nateglinide binding suggests that nateglinide dissociates rapidly from SUR1. Direct interaction of nateglinide with K(ATP) channels in rat pancreatic beta-cells was investigated with the patch-clamp method. The relative potency for inhibition of the K(ATP) channel was repaglinide > glibenclamide > nateglinide. Kinetics of the inhibitory effect on K(ATP) current showed that the onset of inhibition by nateglinide was comparable to glibenclamide but more rapid than that of repaglinide. The time for reversal of channel inhibition by nateglinide was also faster than with glibenclamide and repaglinide. These results suggest that the unique characteristics of nateglinide are largely the result of its interaction at the K(ATP) channel.

Topics: Animals; ATP-Binding Cassette Transporters; Binding, Competitive; Carbamates; Cell Membrane; Cell Separation; Cells, Cultured; Cyclohexanes; Glucose; Glyburide; Glycosyltransferases; Humans; Hypoglycemia; Hypoglycemic Agents; In Vitro Techniques; Insulin; Islets of Langerhans; KATP Channels; Kinetics; Male; Membrane Proteins; Nateglinide; Patch-Clamp Techniques; Phenylalanine; Piperidines; Potassium Channel Blockers; Potassium Channels; Potassium Channels, Inwardly Rectifying; Rats; Rats, Sprague-Dawley; Repressor Proteins; Saccharomyces cerevisiae Proteins; Sulfonylurea Compounds

Nateglinide (NAT) stimulates insulin secretion from pancreatic beta-cells by closing K(ATP) channels. Because K(ATP) channels are widely distributed in cardiovascular (CV) tissues, we assessed the tissue specificity of NAT by examining its effect on K(ATP) channels in enzymatically isolated rat beta-cells, rat cardiac myocytes, and smooth muscle cells from porcine coronary artery and rat aorta with the patch-clamp method. The selectivity of known antidiabetic agents glyburide (GLY) and repaglinide (REP) was also studied for comparison. NAT was found to inhibit K(ATP) channels in the cells from porcine coronary artery and rat aorta with IC(50)s of 2.3 and 0. 3 mM, respectively, compared with 7.4 microM in rat beta-cells, indicating a respective 311- and 45-fold selectivity (p <.01) for beta-cells. With an IC(50) of 5.0 nM in beta-cells, REP displayed an approximately 16-fold (p <.05) selectivity for beta-cells over both types of vascular cells. GLY was nonselective between vascular and beta-cells. At equipotent concentrations (2x respective IC(50)s in beta-cells), NAT, GLY, and REP all caused 62% reduction of pancreatic K(ATP) current but a respective 39, 55, and 66% inhibition of cardiac K(ATP) current. These data collectively indicate that NAT, when compared with GLY and REP, at concentrations effective in stimulating insulin secretion is least likely to cause detrimental CV effects via blockade of CV K(ATP) channels.

Topics: Animals; Aorta, Thoracic; Carbamates; Cardiovascular System; Coronary Vessels; Cyclohexanes; Glyburide; Heart; Hypoglycemic Agents; Islets of Langerhans; Male; Muscle, Smooth, Vascular; Nateglinide; Phenylalanine; Piperidines; Potassium Channels; Potassium Channels, Inwardly Rectifying; Rats; Rats, Sprague-Dawley; Swine

The effects of the two prandial glucose regulators, repaglinide and nateglinide, on ATP-sensitive K(+) (K(ATP)) channel activity, membrane potential and exocytosis in single rat pancreatic A-cells were investigated using the patch-clamp technique. K(ATP) channel activity was reversibly blocked by repaglinide (K(d)=22 nM) and nateglinide (K(d)=410 nM) and this was associated with membrane depolarisation and initiation of electrical activity. The effect of repaglinide and nateglinide on stimulation of glucagon secretion by direct interference with the exocytotic machinery was investigated by the use of capacitance measurements. Nateglinide, but not repaglinide, at concentrations similar to those required to block K(ATP) channels potentiated Ca(2+)-evoked exocytosis 3-fold. In alphaTC1-9 glucagonoma cells addition of nateglinide, but not repaglinide, was associated with stimulation of glucagon secretion. These results indicate that the fast-acting insulin secretagogue nateglinide is glucagonotropic primarily by stimulating Ca(2+)-dependent exocytosis.

Topics: Animals; ATP-Binding Cassette Transporters; Calcium; Carbamates; Cyclohexanes; Eating; Electrophysiology; Exocytosis; Glucagon; Glucose; Hypoglycemic Agents; In Vitro Techniques; Islets of Langerhans; KATP Channels; Kinetics; Male; Nateglinide; Patch-Clamp Techniques; Phenylalanine; Piperidines; Potassium Channel Blockers; Potassium Channels; Potassium Channels, Inwardly Rectifying; Rats; Rats, Inbred Lew; Stimulation, Chemical

Several meglitinide analogs are currently under investigation as potential insulinotropic tools for the treatment of noninsulin-dependent diabetes. The present study aimed to further insight into the effect of these agents on the secretion of insulin, glucagon, and somatostatin by the isolated perfused pancreas. Both repaglinide (0.01 microM) and A-4166 (1.0 microM) stimulated insulin and somatostatin release, but failed to affect glucagon output, from pancreases exposed to 5.6 mM D-glucose. The secretory response of the B- and D-cells to the hypoglycemic agents was much less marked than that caused by a rise in hexose concentration from 5.6-16.7 mM. Although repaglinide was tested at a concentration a hundred times lower than that of A-4166, the drug-induced increase in both insulin and somatostatin secretion persisted for a longer time after exposure to repaglinide, than to A-4166. The relevance of these findings to the use of meglitinide analogs as antidiabetic agents is double. First, they document that these drugs, although enhancing both insulin and somatostatin release, do not provoke an undesirable stimulation of glucagon secretion. Second, they indicate that even at a very low concentration, repaglinide provokes a protracted insulinotropic action, thus suggesting that the reversibility of the secretory response to this or other meglitinide analogs represents an intrinsic molecular attribute, unrelated to either their biological potency or the relative extent of B-cell stimulation.

Topics: Animals; Benzamides; Blood Glucose; Carbamates; Cyclohexanes; Female; Glucagon; Hypoglycemic Agents; Insulin; Insulin Secretion; Islets of Langerhans; Nateglinide; Perfusion; Phenylalanine; Piperidines; Rats; Rats, Wistar; Somatostatin

The insulinotropic action of the meglitinide analogues KAD-1229, A-4166 and repaglinide was examined in rat pancreatic islets deprived of exogenous nutrient or incubated in the presence of nutrient secretagogues such as D-glucose and the methyl esters of pyruvic acid, succinic acid and glutamic acid. The meglitinide analogues exerted little effect on insulin release in the absence of exogenous nutrient or in the presence of methyl pyruvate. They caused obvious stimulation of insulin output in the presence of D-glucose, dimethyl succinate or dimethyl glutamate. It is proposed, therefore, that suitable esters of dicarboxylic nutrients could be used to potentiate the secretory response to meglitinide analogues in non-insulin-dependent diabetes mellitus.

Topics: Animals; Carbamates; Cells, Cultured; Cyclohexanes; Glucose; Glutamates; Hypoglycemic Agents; Indoles; Insulin; Insulin Secretion; Islets of Langerhans; Isoindoles; Nateglinide; Phenylalanine; Piperidines; Pyruvates; Rats; Succinates

Non-sulfonylurea hypoglycemic agents of the meglitinide family such as S3075, repaglinide, KAD-1229, and A-4166, were found to display a comparable U-shaped conformation by molecular modelling, with hydrophobic cycles placed at the extremity of each branch and a peptidic bond placed at the bottom of the U. A comparable conformation was observed with the hypoglycemic sulfonylureas glibenclamide and glimepiride. A different conformation with a greater distance between the hydrophobic cycles at the extremity of each branch was found, however, with the biologically inactive enantiomers of A-4166 and repaglinide and the poorly efficient insulinotropic agent meglitinide. The identification of a common conformation of these hypoglycemic agents may help in the design of highly active compounds and provide an imprint of their postulated target receptor on the pancreatic B-cell plasma membrane.

Topics: Benzamides; Carbamates; Cyclohexanes; Drug Design; Glyburide; Hypoglycemic Agents; Indoles; Isoindoles; Molecular Conformation; Nateglinide; Phenylalanine; Piperidines; Stereoisomerism; Structure-Activity Relationship; Sulfonylurea Compounds

At normal extracellular K+ concentration (5 mM), the meglitinide analogues A-4166, KAD-1229, repaglinide and S3075, all tested at a 10 mu M concentration, markedly enhanced insulin release evoked by 6 mM D-glucose in isolated rat pancreatic islets. They failed, however, to augment the much higher rate of insulin release evoked by D-glucose in islets exposed to a high K+ concentration (30 mM). Under the latter conditions, the potent diazoxide analogue BPDZ-44 (50 mu M) did not exert any sizeable effect upon insulin release. Even at normal K+ concentration, BPDZ-44 (50 mu M), which suppressed glucose-stimulated insulin release, only caused a partial inhibition of the insulinotropic action of A-4166 and failed to affect significantly insulin secretion in the presence of KAD-1229, repaglinide or S3075. These findings argue against the view that meglitinide analogues could affect cytosolic Ca2+ activity independently of the closing of ATP-sensitive K+ channels. The present results also indicate that, with the possible exception of A-4166 which in the least potent secretagogue in this series, meglitinide analogues are able, like hypoglycemic sulphonylureas, to fully protect ATP-sensitive K+ channels against their activation by BPDZ-44.

Topics: Animals; Benzamides; Carbamates; Cyclohexanes; Female; Hypoglycemic Agents; Indoles; Insulin; Insulin Secretion; Islets of Langerhans; Isoindoles; Nateglinide; Phenylalanine; Piperidines; Potassium; Rats

The insulinotropic action of meglitinide was compared to that of its analogs S 3075, A-4166, KAD-1229 and repaglinide. None of these hypoglycemic agents significantly enhanced insulin output from rat pancreatic islets incubated for 90 min in the absence of exogenous nutrient. However, all these agents, when tested at a 10 microM concentration, augmented insulin release evoked by either 7 mM D-glucose or 10 microM succinic acid monomethyl ester (SAM). In this respect, meglitinide was a less efficient secretagogue than the other non-sulfonylurea hypoglycemic agents. Moreover, in the presence of 7 mM D-glucose, the lowest concentration of the drug required to cause a significant increase in insulin output decreased from about 1.0 microM for meglitinide to 0.1 microM with A-4166, KAD-1229 or repaglinide and even close to 10 nM in the case of S 3075. The concentration-response relationship thus yielded the following hierarchy, S 3075 > KAD-1229 = repaglinide > A-4166 > meglitinide, there being a difference of more than two orders of magnitude between the weakest and most potent agent.

Topics: Animals; Benzamides; Carbamates; Cyclohexanes; Female; Glucose; Hypoglycemic Agents; In Vitro Techniques; Indoles; Insulin; Insulin Secretion; Islets of Langerhans; Isoindoles; Molecular Structure; Nateglinide; Phenylalanine; Piperidines; Rats; Structure-Activity Relationship; Succinates