Reinvestigation of the diabetogenic effect of dehydroascorbic acid.

To investigate the diabetogenic effect of pure dehydroascorbic acid, male Wister- and Sprague-Dawley rats received i.v. injections of the substance. No hyperglycemia and no decreased glucose tolerance were found. I.v. administration of the hydrolysis products of dehydroascorbic acid and of a solution containing monodehydroascorbate likewise did not increase blood glucose values. It is concluded that in previously performed experiments not dehydroascorbic acid itself but one or several impurities might have produced hyperglycemia in the rat. The electron transfer proteins tested (ascorbate:ferricytochrome b5 oxidoreductase, cytochrome b5, NADH:ferricytochrome b5 oxidoreductase, NADH:monodehydroascorbate oxidoreductase), which might participate in the reduction of dehydroascorbic acid, could not be induced in liver microsomes from Wistar rats by the injection of dehydroascorbic acid, its hydrolysis products, or monodehydroascorbate.