Insulin and the Fate of Pyruvate in the Diabetic

A previous report dealt with the action of insulin on the fate of the 3 carbon atoms of lactate in the liver of the alloxan-diabetic rat (1). It was shown that insulin decreased the oxidation of the crand P-carbons of added lactate to COz and stimulated, in a pronounced manner, the incorporation of these 2 carbon atoms, as an intact unit, into fatty acids. In assessing the significance of these findings, we assumed that the fate of the LYand P-carbons of lactate was identical with that of the corresponding carbons of pyruvate. The validity of our assumption with respect to the a-carbon is borne out by the findings presented here. It is shown that the fate of the a-carbon of pyruvate in the liver of the insulin-treated and untreated alloxan-diabetic rat parallels that of the corresponding carbon of lactate.