To study the cardioprotective effects of vanadate on ischemia-reperfusion (I/R) injury, isolated rat hearts perfused at constant flow were subjected to global ischemia for 30 min followed by reperfusion for 30 min. In this experimental model, I/R markedly decreased ventricular developed pressure and increased end-diastolic pressure. Pretreatment of hearts with 4 microM vanadate attenuated I/R-i...

The disruption of endoplasmic reticulum function leads to an accumulation of unfolded proteins, which results in endoplasmic reticulum stress. In the present study, we investigated the effect of vanadate on such stress. Endoplasmic reticulum stress increased glucose-regulated protein 78 (GRP78) and CCAAT/enhancer-binding protein homologous protein (CHOP) expressions in glial cell cultures. We f...

Endothelial cells possess constitutive or inducible cyclo-oxygenase (COX) isoenzymes for prostacyclin production, but the mechanisms for their expression are largely unknown. We found that vanadate, an inhibitor of protein-tyrosine phosphatases, induced the expression of two COX isoenzyme mRNAs in human umbilical vein endothelial cells (HUVEC) in a time- and dose-dependent manner. Vanadate also...

The effects of orthovanadate on the uptake of sucrose by Ricinus cotyledons and on sucrose-coupled proton influx were measured in order to gain insight into the relationship to the plasma membrane proton pump. Vanadate had no effect on short-term sucrose uptake. In longterm experiments (>30 min) sucrose uptake was progressively inhibited, but only at high external sucrose concentrations. Vanada...

Carotenoids, Chlorella fusca, Chlorophylls, Iron Stress, Vanadate The pigment composition of Chlorella fusca has been investigated in the absence and in presence of vanadate and during iron stress. 1. Fe-deficiency generally decreases algal pigment content without change of the ratio chloro­ phyll a/b. 2. A twofold vanadate induced increase of the chlorophylls is accompanied by a similar enhanc...

We investigated the effect of ammonium vanadate (vanadate) on ATP-induced increases in intracellular calcium ion level ([Ca(2+)](i)) of human umbilical vein endothelial cells (HUVEC) by fluorescence confocal microscopic imaging using the Ca(2+)-sensitive probe Calcium Green 1/AM. The ATP analogue 2-methylthio-ATP (2meS-ATP), at 10 microM, significantly increased the [Ca(2+)](i) of HUVEC, and th...

Insulin resistance is a common phenomenon in obesity and type 2 diabetes (1). It has been demonstrated that, among other factors, acutely elevated free fatty acids can induce insulin resistance in both peripheral tissues and liver (2). Free fatty acids also reduce insulin binding and degradation, and exert an important modulating effect on insulin action in isolated rat hepatocytes (3). They ca...

Sodium orthovanadate (vanadate) inhibits the DNA-binding activity of p53, but its precise effects on p53 function have not been examined. Here, we show that vanadate exerts a potent antiapoptotic activity through both transcription-dependent and transcription-independent mechanisms relative to other p53 inhibitors, including pifithrin (PFT) alpha. We compared the effects of vanadate to PFTalpha...

Vanadate and peroxovanadate (pV), potent inhibitors of tyrosine phosphatases, mimic several of the metabolic actions of insulin. Here we compare the mechanisms for the anti-lipolytic action of insulin, vanadate and pV in rat adipocytes. Vanadate (5 mM) and pV (0.01 mM) inhibited lipolysis induced by 0.01-1 microM isoprenaline, vanadate being more and pV less efficient than insulin (1 nM). A los...