Vanadate inactivated rat hepatocyte glycogen synthase and activated glycogen phosphorylase in a dose- and time-dependent manner. These effects were observed in hepatocytes from both fasted as well as fed rats. When rat hepatocytes were preincubated with [32P]phosphate and then with vanadate, and the 32P-labeled glycogen synthase was specifically immunoprecipitated, it was observed that vanadate...

Insulin has recently been reported to function as a complete mitogen for SV40 large T antigen-transformed 3T3 T-cells, designated CSV3-1, but not for nontransformed 3T3 T-cells (H. Wang and R. E. Scott, J. Cell. Physiol., 147: 102-110, 1991). It is now reported that sodium orthovanadate mimics this effect of insulin. For example, when exposed to 1-5 microM vanadate, most predifferentiation grow...

Vanadate activated rat adipocyte glycogen synthase similarly to insulin in a dose- and time-dependent manner. No additional effect was observed when insulin and vanadate were added together. Vanadate also partially counteracted the effect of epinephrine to activate rat adipocyte glycogen phosphorylase similarly to insulin. Inhibition of Na+K+ATPase or stimulation of hydrogen peroxide generation...

The plasma membrane ATPase of Neurospom cmsa, which is believed to function as an electrogenic proton pump, is extremely sensitive to inhibition by vanadium in the +5 oxidation state (vanadate). At pH 6.7 (the pH optimum of the ATPase), inhibition is half-maximal between 0.45 and 1.0 PM vanadate, depending upon the ionic composition of the reaction medium. Inhibition also depends upon pH, with ...

The present study was undertaken to test the hypothesis that the toxicity and carcinogenicity of vanadium might arise from elevation of reactive oxygen species leading to activation of the transcription factor activator protein-1 (AP-1). The AP-1 transactivation response has been implicated as causal in transformation responses to phorbol esters and growth factors. To investigate the possible a...

The interaction of vanadium in the +5 oxidation state (vanadate) with purified dog kidney Na+ and K+-stimulated adenosine trlphosphatase [(Na,K)-ATPase] has been studied using equilibrium binding, steady state kinetics, and measurements of relaxation kinetics. Vanadate binds to one high affinity site (Kl = 4 no) and one low afinity site (Kz = 0.5 pM) per enzyme molecule (Le. per ouabain binding...

It has been shown that the combination of benzylamine or tyramine and low concentrations of vanadate markedly stimulates glucose transport in rat adipocytes by a mechanism that requires semicarbazide-sensitive amine oxidase (SSAO) activity and H(2)O(2) formation. Here we have further analysed the insulin-like effects of the combination of SSAO substrates and vanadate and we have studied the sig...

The plasma membrane ATPase of Neurospom cmsa, which is believed to function as an electrogenic proton pump, is extremely sensitive to inhibition by vanadium in the +5 oxidation state (vanadate). At pH 6.7 (the pH optimum of the ATPase), inhibition is half-maximal between 0.45 and 1.0 PM vanadate, depending upon the ionic composition of the reaction medium. Inhibition also depends upon pH, with ...

Vanadate at doses from 10(-4.5) to 10(-3) M caused a dose-dependent contraction of the rat aorta in vitro. Aortas of Dahl salt-hypertension sensitive (S) rats responded to vanadate with a greater contraction than Dahl salt-hypertension resistant (R) rats. In contrast, S and R aortic responses to depolarization with potassium were equal, and responses to norepinephrine were less in S than R. The...

Ca2+ + Mg2+-dependent ATPase from sarcoplasmic reticulum was inhibited by preincubation with vanadate. When the inhibited enzyme was preincubated in the presence of vanadate and assayed in its absence, a slow reactivation process was observed. This slow, hysteretic, process was exploited to study the influence of Ca2+ and ATP on the dissociation of vanadate. Ca2+ alone slowly displaced vanadate...