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...

INTRODUCTION Hypertension is a major risk factor for cardiovascular diseases. In adults, high sodium intake is associated with elevated blood pressure. In children, experimental studies have shown that reducing sodium intake can reduce blood pressure. However, their external validity is limited, notably because the sodium reduction was substantial and not applicable in a real-life setting. Obse...

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...

Vanadate, at concentrations between 0.5 and 2 mM, rapidly decreased the basal level of P-enolpyruvate carboxykinase (GTP) (EC 4.1.1.32) mRNA and blocked the dibutyryl cyclic AMP (Bt2cAMP)-induced increase in enzyme mRNA in both FTO-2B and H4IIE rat hepatoma cells. The concentration of vanadate necessary to inhibit the expression of this gene was similar to that required for the vanadate-mediate...

To determine the role of protein phosphorylation in neutrophil activation, electropermeabilized cells were treated with vanadate, a phosphatase inhibitor. Micromolar concentrations of vanadate elicited a NADPH-dependent burst of oxygen utilization in permeabilized, but not in intact cells, indicating an intracellular site of action. Stimulation of oxygen consumption by vanadate was reversible, ...

High-affinity vanadate transport systems have not heretofore been identified in any organism. Anabaena variabilis, which can fix nitrogen by using an alternative V-dependent nitrogenase, transported vanadate well. The concentration of vanadate giving half-maximum V-nitrogenase activity when added to V-starved cells was about 3 x 10(-9) M. The genes for an ABC-type vanadate transport system, vup...