To define the role of insulin in blood pressure regulation, the hormone's action on renal sodium handling, potassium balance, pressor reactivity, and the release of catecholamines and aldosterone are summarized. Insulin-stimulated renal sodium reabsorption induces expansion of the extracellular volume, increase in cardiac output, and ultimately, hypertension. On the other hand, the insulin-indu...

MacDonald MJ, Longacre MJ, Stoker SW, Brown LJ, Hasan NM, Kendrick MA. Acetoacetate and -hydroxybutyrate in combination with other metabolites release insulin from INS-1 cells and provide clues about pathways in insulin secretion. Am J Physiol Cell Physiol 294: C442–C450, 2008. First published December 26, 2007; doi:10.1152/ajpcell.00368.2007.—Mitochondrial anaplerosis is important for insulin ...

The insulin-releasing ability and uptake characteristics of non-metabolizable, transport-specific amino acids were studied in an in vitro system, using microdissected pancreatic islets with more than 9 ° O//o/~-cells. Among the four stereoisomers of 2-aminobicyclo(2,2,i)heptane-2-carboxylic acid (BCH), only the b(-) form stimulated insulin release. This isomer is known as a specific substrate f...

Sulfonylurea and glinide drugs display different effects on insulin granule motion in single beta-cells in vitro. We therefore investigated the different effects that these drugs manifest towards insulin release in an in vivo long-term treatment model. Diabetic GK (Goto-Kakizaki) rats were treated with nateglinide, glibenclamide or insulin for 6 weeks. Insulin granule motion in single beta-cell...

Polymeric delivery systems based on nanoparticles have emerged as a promising approach for peroral insulin delivery. The aim of the present study was to investigate the release of insulin nanoparticulate systems and ex vivo studies. The nanoparticles were prepared by the ion gelation method. Particle size distribution, zeta potential, and polydispersity index of the nanoparticles were determine...

BACKGROUND Insulin secretion is a complex and highly regulated process. It is well established that cytoplasmic calcium is a key regulator of insulin secretion, but how elevated intracellular calcium triggers insulin granule exocytosis remains unclear, and we have only begun to define the identities of proteins that are responsible for sensing calcium changes and for transmitting the calcium si...

Type 2 diabetes mellitus (T2DM) is characterized by the inability of the pancreatic β-cells to secrete enough insulin to meet the demands of the body. Therefore, research of potential therapeutic approaches to treat T2DM has focused on increasing insulin output from β-cells or improving systemic sensitivity to circulating insulin. In this study, we examined the role of the A(1) receptor in gluc...

Insulin (100 ~tU/ml) stimulated protein synthesis and PGF2~ release in isolated rabbit muscle, but had little effect on the rate of protein degradation. The effect of insulin persisted for at least 5 h after removal of the hormone. Indomethacin, added at the start of the incubation, inhibited the stimulatory effect of insulin on protein synthesis and PGF2~ release, but did not block the binding...

Introduction: Ghrelin is a peptide hormone secreted from the stomach with both endocrine and paracrine effects. Ghrelin and its mRNA as well as growth hormone (GH) secretagogue receptor mRNAs are expressed in the pancreas and islet cells and regulate insulin release. Also the immounoreactivity of ghrelin is proved to be high in the hypothalamus and parts of the brain responsible for the re...

We discovered that two physiologically occurring metabolic intermediates, glyceraldehyde phosphate and succinate, are potent insulin secretagogues. No other glycolytic intermediate besides glyceraldehyde phosphate was insulinotropic. Succinate, when added to islets as either its monomethyl or dimethyl ester to increase its cellular permeability, was also insulinotropic. In islets, as in other c...