A study on the relationship between l-ascorbic acid and purine metabolism in vivo.

A recent finding from this laboratory indicated that the incubation in vitro of purified xanthine oxidase with trace amounts of l-ascorbic acid resulted in a marked inhibition of the enzymatic activity (1, 2). Since the physiological mode’of action of Z-ascorbic acid is still obscure, it seemed desirable to determine whether ascorbic acid would, in the intact animal, exert a similar effect on xanthine oxidase. Should ascorbic acid inhibit xanthine oxidase in viva, animals receiving high ascorbic acid supplements should produce uric acid and allantoin at a diminished rate. Therefore, this problem was studied by supplementing guinea pigs with varying dosages of ascorbic acid and measuring the liver xanthine oxidase activity, the rates of urinary uric acid and allantoin excretion, and the blood uric acid and allantoin levels in each animal.