In the mouse beta-cell, glucose generates large amplitude oscillations of the cytosolic-free Ca(2+) concentration ([Ca(2+)](i)) that are synchronous to insulin release oscillations. To examine the role played by [ Ca(2+)](i) oscillations in the process of insulin release, we examined the effect of plasma membrane Ca(2+)-ATPase (PMCA) overexpression on glucose-induced Ca(2+) oscillations and ins...

1. Concentrations of cyclic AMP (adenosine 3':5'-cyclic monophosphate) and rates of insulin release were measured in islets of Langerhans isolated from rat pancreas and incubated for various times in the presence of glucose, 3-isobutyl-1-methylxanthine, caffeine, theophylline, adrenaline and diazoxide. 2. Caffeine and theophylline produced small but significant increases in both cyclic AMP and ...

Glucose-induced inhibition of Ca(++) extrusion from the beta-cell may contribute to the rise in cytosol Ca(++) that leads to insulin release. To study whether interference with Na/Ca exchange is involved in this inhibition the effects of glucose were compared to those of ouabain. This substance inhibits Na/K ATPase, decreases the transmembrane Na(+) gradient in islets, and thus interferes with ...

1. 3-Phenylpyruvate caused a dose-related stimulation of insulin release from rat pancreatic islets deprived of exogenous nutrient or incubated in the presence of 5.6 or 8.3 mM-D-glucose. 2. 3-Phenylpyruvate inhibited insulin release evoked by high concentrations of D-glucose (16.7 or 27.8 mM) or 4-methyl-2-oxopentanoate (10.0 mM). This inhibitory effect appeared to be attributable to impairmen...

1. The effects of azaserine and nicotinamide, agents which inhibit and stimulate hepatic NAD synthesis respectively, on the content of NAD+ and NADH in isolated rat islets of Langerhans incubated in vitro were studied. The effects of these compounds on the rates of insulin release, from isolated islets incubated in vitro, in response to various secretagogues were also measured. 2. Preincubation...

Objective: The present study aimed to develop and characterize Chitosan coated Alginate Nanocapsules loaded with M-Insulin Concanavalin A Complex for glucose-responsive delivery. Methods: Preformulation studies were performed on the Insulin human recombinant prepared by ionic gelation method chitosan using electrostatic attraction. formulation variables optimized Box-Behnken design (BBD) help o...

background: the modern dairy cows, due to intensive selection for higher milk production during past decades, have become more resistant to insulin. accompanied with dmi depression in per parturient dairy cow, insulin resistance may lead to a massive release of non-esterified fatty acids (nefa) to bloodstream which might act as a start point for development of other diseases. objectives: the pu...

Leucine is the only physiologic amino acid that can stimulate insulin release by itself, and a great deal of evidence suggests that leucine does this by allosterically activating glutamate dehydrogenase (GDH). GDH catalyzes the oxidative deamination of endogenous glutamate, which is present at a high concentration in the pancreatic b-cell. Studies that support this role of leucine include the f...

To ascertain whether prostaglandins (PG) may play a role in the secretion of glucagon and in an attempt to elucidate the conflicting observations on the effects of PG on insulin release, the isolated intact rat pancreas was perfused with solutions containing 1.1 x 10(-9) to 1.8 x 10(-5)m PGE2. In the presence of 5.6 mM glucose significant increments in portal venous effluent levels of glucagon ...

context: over the last few decades, extensive efforts have been made worldwide to develop nanomedicine delivery systems, especially via oral route for antidiabetic drugs. absorption of insulin is hindered by epithelial cells of gastrointestinal tract, acidic gastric ph and digestive enzymes. evidence acquisition: recent reports have identified and explained the beneficial role of several struct...