The effects of vanadate (Na3VO4) on pancreatic B-cell function were studied in normal mouse islets. Vanadate did not affect basal insulin release but potentiated the effect of 7-30 mM glucose at concentrations of 0.1-1 mM. This effect was progressive and slowly reversible. It was abolished by omission of extracellular Ca2+ but unaffected by blockers of adrenergic or muscarinic receptors. Compar...

The interaction of vanadate with the (Na' + K')st imulated ATPase from electric organ was investigated using the acid quench-flow technique. A t 21"C, incubation of the enzyme with 1.3 to 1.6 p~ vanadate in the presence of 75 m~ Na' and 25 mM K' strongly inhibits phosphorylation by ATP. Enzyme activity remaining under these conditions shows no change in the apparent rates of phosphorylation or...

Semicarbazide-sensitive amine oxidase (SSAO) is highly expressed in adipose cells, and substrates of SSAO, such as benzylamine, in combination with low concentrations of vanadate strongly stimulate glucose transport and GLUT4 recruitment in 3T3-L1 and rat adipocytes. Here we examined whether acute and chronic administration of benzylamine and vanadate in vivo enhances glucose tolerance and redu...

The properties of the basal Ca2+ influx (measured using cells labelled with 45Ca2+) in intact human red blood cells (RBC) were compared with those of 45Ca2+ influx induced by vanadate. The basal Ca2+ influx was not sensitive to inhibitors of vanadate-induced Ca2+ influx such as the HS-reagent p-chloromercuribenzoate and low concentrations of Cu2+, and also the sensitivity to nifedipine was sign...

The formation of transition state mimics of phosphoryl transfer reactions with the metal oxoanion vanadate is a powerful technique in macromolecular crystallography. The tendency of vanadate to form pentacovalent complexes exhibiting trigonal bipyramidal geometry makes this compound a close approximation of the transition state for such reactions. In many cases, vanadate complexes provide the m...

Decavanadate induced rat liver mitochondrial depolarization at very low concentrations, half-depolarization with 39 nM decavanadate, while it was needed a 130-fold higher concentration of monomeric vanadate (5 microM) to induce the same effect. Decavanadate also inhibits mitochondrial repolarization induced by reduced glutathione in vitro, with an inhibition constant of 1 microM, whereas no eff...

Adipocytes route internalized insulin through two major pathways, a degradative pathway and a retroendocytotic pathway. To examine whether sorting of incoming insulin-receptor complexes can be altered, we assessed the effect of vanadate on the intracellular processing of both insulin and insulin receptors. After cells were pretreated with vanadate (1 mM for 30 min at 37 degrees C), 125I-insulin...

HYPOTHESIS Fibroblasts, not myofibroblasts, are responsible for wound contraction. Only myofibroblasts express a smooth muscle actin for which vanadate blocks its expression. Wound contraction in vanadate-treated rats will proceed normally in the absence of myofibroblasts. DESIGN Laboratory study using rats. METHODS Wound healing in rats receiving vanadate parenterally, an inhibitor of tyro...

Vanadate ions, low-molecular-weight phosphate analogues, mimic most of the rapid actions of insulin in various cell types. When administered orally to diabetic hyperglycemic rats, vanadate reaches the circulation, mimics insulin stimulation of glucose uptake and metabolism, and leads to normoglycemic and partial anabolic states. In addition, vanadate restores tissue responsiveness to insulin an...

Amylase activity and mRNA abundance are reduced to less than 1% of normal levels in diabetic rat pancreas. Administration of vanadate in drinking water restored normal amylase activity and amylase mRNA levels. These results demonstrate an effect of vanadate on pancreatic acinar cells and suggest that vanadate can mimic the effect of insulin on transcription of the pancreatic amylase gene.