Turnover rates of D-isoascorbic acid and L-ascorbic acid in guinea pig organs

Abstract

To elucidate the mode of action of D-isoascorbic acid (IAA) in exerting vitamin C activity for guinea pigs, it was necessary to determine the turnover rate of this ascorbic acid in their organs as well as its effect on the turnover of L-ascorbic acid (AA). Guinea pigs were saturated with either IAA or AA, and the organ contents of the isomers were determined at different intervals of depletion. In a second experiment, guinea pigs previously saturated with AA were injected intraperitoneally with L-ascorbic-1-14C acid. Twenty-four hours after injection, L-ascorbic-1-14C acid was measured in the organs of some of the animals; three groups were formed with the other animals: group 1 was fed with a diet deficient in vitamin C, group 2 with the diet plus 0.1% AA, and group 3 with the diet plus 2% IAA. The L-ascorbic-1-14C acid content of the organs was determined on different days. It was found that the rate of IAA turnover was much more rapid than that of AA in all organs. Furthermore, IAA increased rather than decreased the turnover of AA.