Polyvanadate acts at the level of plasma membranes through α-adrenergic receptor and affects cellular calcium distribution and some oxidation activities

The activities of calcium-stimulated respiration, calcium uptake, α-glycero-phosphate dehydrogenase and rates of oxidation in state 3 and of H2O2 generation, were found to increase and that of pyruvate dehydrogenase decrease in mitochondria isolated from livers of rats administered intraperitoneally or perfused with polyvanadate. Phenoxybenzamine, an antagonist of α-adrenergic receptor, effectively prevented these changes. It was also found that perfusion of the liver with polyvanadate reproduced one of the best characterized events of α-adrenergic activation-stimulation of protein kinase C in plasma membrane accompanied by its decrease in cytosol. These experiments indicate for the first time the α-adrenergic mimetic action of polyvanadate.