Some studies on ascorbic acid metabolism in hydrazine-treated rats.

The metabolism of ascorbic acid was studied in hydrazine-treated rats. Hydrazine was administered i.p. at a dose of 1.28 mg/day (20% LD50) for each 100 g body weight for 7 days. Hydrazine administration at the present dose did not appear to have an effect on the total ascorbic acid level of liver, kidney, spleen and testis. The adrenal and plasma total ascorbic acid levels were, however, elevated. The activity of liver D-glucuronoreductase and that of liver and kidney dehydroascorbatases were diminished after hydrazine administration. The changes in the activities of liver enzymes were accompanied by a fall in the reduced ascorbic acid level and an elevation in the dehydroascorbic acid level. The uronolactonase activity of liver, on the other hand, remained independent of hydrazine treatment. It has been suggested that hydrazine treatment at the present dose reduced the biosynthesis of L-ascorbic acid from D-glucuronolactone as substrate. In spite of diminished synthesis, the normal level of total ascorbic acid in the liver of hydrazine-treated rats was maintained by reducing the degradation of L-ascorbic acid. The rise in the plasma total ascorbic acid level after hydrazine treatment was ascribed to reduced catabolism and urinary excretion of ascorbic acid, while the elevation in adrenal total ascorbic acid level might result from increased uptake of ascorbic acid by the gland from blood or from nonfunctional accumulation.