We have studied the effects of first and second generation sulphonylureas on the release of insulin and neuropeptide tyrosine (NPY) from hamster insulinoma tumour (HIT T15) cells and isolated rat islets. In the presence of 5.5 mmol/l glucose all sulphonylureas stimulated insulin release from the HIT cells (P<0.01 ANOVA, n> or =4) but only glibenclamide (GLIB, 10 micromol/l) stimulated the relea...

Insulin-induced vasodilatation is sensitive to nitric oxide (NO) synthase (NOS) inhibitors. However, insulin is unable to relax isolated arteries or to activate endothelial NOS in endothelial cells. Since insulin can enhance platelet endothelial NOS activity, we determined whether insulin-induced vasodilatation can be attributed to a NO-dependent, platelet-mediated process. Insulin failed to re...

OBJECTIVE Several transient receptor potential (TRP) channels are expressed in pancreatic beta cells and have been proposed to be involved in insulin secretion. However, the endogenous ligands for these channels are far from clear. Here, we demonstrate the expression of the transient receptor potential ankyrin 1 (TRPA1) ion channel in the pancreatic beta cells and its role in insulin release. T...

β-cells release hexameric Zn2+-insulin into the extracellular space, but monomeric Zn2+-free insulin appears to be the only biologically active form. The mechanisms implicated in dissociation of the hexamer remain unclear, but they seem to be Zn2+ concentration-dependent. In this study, we investigate the influence of albumin binding to Zn2+ on Zn2+-insulin dissociation into Zn2+-free insulin a...

Nutrient augmentation of Ca(2+)-triggered insulin release occurs in an ATP-sensitive K(+) (K(ATP)) channel--independent manner. Here, using rat islets, we explored the possibility of the K(ATP) channel-independent nutrient triggering of insulin release. In the presence of 250 micromol/l diazoxide, simultaneous application of forskolin and 16.7 mmol/l glucose strongly stimulated insulin release:...

BACKGROUND The concept of closed-loop control of glucose, in which continuous glucose sensing is coupled to a fully automated insulin delivery device, without human input, has been an attractive idea for diabetes management. This study presents a new class of hybrid nanogels that can integrate glucose sensing and glucose-responsive insulin release into a single nano-object. METHODS Zinc oxide...

Glucose stimulation of insulin release involves closure of ATP-sensitive K+ channels, depolarization, and Ca2+ influx in B cells. Mouse islets were used to investigate whether glucose can still regulate insulin release when it cannot control ATP-sensitive K+ channels. Opening of these channels by diazoxide (100-250 mumol/liter) blocked the effects of glucose on B cell membrane potential (intrac...

Objective(s): The purpose of this study is about the preparation and evaluation of nanoparticles composed of thiolated methylated pyridinyl chitosan (TMPC) which are made P.E.C method, for bucal drug delivery of insulin.Materials and Methods: First of all have to synthesize methylated pyridinyl chitosan and then for (TMPC) L-cysteine should be attached to methylated pyridinyl chitosan by the fo...

Microencapsulation of insulin has been difficult, due to the high sensitivity of insulin to the harsh conditions that can occur during the microencapsulation process. We have developed a method of preparing insulin-loaded microcapsules by using a monoaxial ultrasonic atomizer to form microdroplets of insulin in aqueous solution surrounded by poly(lactic-co-glycolic acid) (PLGA) solution. Admini...

The number of adult individuals with insulin-treated diabetes mellitus (DM) is steadily increasing worldwide. main local complications insulin injection are lipohypertrophies (LHs), i.e., subcutaneous nodules consisting aggregates macro-adipocytes and fibrin. These result from errors repeatedly made by patients while injecting insulin. Despite being very common, LH lesions/nodules due to incorr...