Polyvanadate acts at the level of plasma membranes through aadrenergic receptor and affects cellular calcium distribution and some oxidation activities.

The activities of calcium-stimulated respiration, calcium uptake, a-glycerophosphate 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 a−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 a-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.

Increase in hepatic ubiquinone on administration of diethylhexyl phthalate to the rat.

It is shown for the first time that the content of ubiquinone of liver increases (2·5 fold) on dietary administration of the widely-used industrial plasticizer diethylhexyl phthalate to the rat. The increase is localized almost entirely in mitochondria in which the concentration of the quinone per mg protein is 1·7 times the control. Incorporation of the radioactive precursor (acetate) reveals that the biosynthesis of ubiquinone is increased in the livers of plasticizer-administered animals. The rate of degradation is not altered.