June 2004 Volume 49 Issue 2 If GIP and GLP-1 are missing or inactive, the release of insulin is reduced, and a higher rise in blood glucose levels will therefore be expected. In people with Type 2 diabetes, the hormone GIP no longer acts on insulin release and/or blood glucose.The exact reasons are not known.2 In contrast, GLP-1 is able to normalize the levels of blood glucose in Type 2 diabete...

The release of insulin from pancreatic islets requires negative regulation to ensure low levels of insulin release under resting conditions, as well as positive regulation to facilitate robust responsiveness to conditions of elevated fuel or glucose. The first phase of release involves the plasma-membrane fusion of a small pool of granules, termed the readily releasable pool; these granules are...

Diphenylhydantoin (DPH), which is clinically used in the treatment of epilepsy, inhibits glucose-induced insulin release from pancreatic islets by a mechanism that remains unknown. In the present study, DPH is shown to suppress glucose-induced insulin release concentration-dependently. In dynamic experiments, 20 microm DPH suppressed 16.7 mm glucose-induced biphasic insulin release. DPH also su...

The cytoplasmic Ca2+ concentration ([Ca2+]i) and insulin release were measured simultaneously in mouse pancreatic islets cultured overnight. [Ca2+]iwas 105 nM and insulin release 3 pmol ⋅ g-1 ⋅ s-1at 3 mM glucose. An increase to 7 mM glucose reduced [Ca2+]itransiently, whereas insulin release doubled and was pulsatile with a frequency of 0.47 min-1. [Ca2+]i oscillations with similar frequency a...

OBJECTIVE Insulin activates several processes potentially dangerous for the arterial wall and hyperinsulinemia might be atherogenic. However, other insulin effects are protective for the vessel wall and thus anti-atherogenic. Aim of this study was to investigate whether insulin effects on potentially pro-atherogenic and anti-atherogenic processes were differently affected in cells from insulin-...

Acute insulin secretion determines the efficiency of glucose clearance. Moreover, impaired acute insulin release is characteristic of reduced glucose control in the prediabetic state. Incretin hormones, which increase β-cell cAMP, restore acute-phase insulin secretion and improve glucose control. To determine the physiological role of the cAMP-dependent protein kinase (PKA), a mouse model was d...

Nitric oxide (NO) produced by islet constitutive NO synthase (cNOS) is a putative modulator of islet hormone secretion. We show here for the first time that the release of insulin induced byl-arginine orl-homoarginine is inhibited and that of glucagon stimulated in parallel with the rate of islet NO production. It was found thatl-homoarginine was ≈25-30% less potent thanl-arginine as an insulin...

BACKGROUND Type 2 diabetes often displays hyperlipidemia. We examined palmitate effects on pancreatic islet function in relation to FFA receptor GPR40, NO generation, insulin release, and the PPARgamma agonistic thiazolidinedione, rosiglitazone. PRINCIPAL FINDINGS Rosiglitazone suppressed acute palmitate-stimulated GPR40-transduced PI hydrolysis in HEK293 cells and insulin release from MIN6c ...