Abstract
Bio-potency of vitamin A of fish liver oil was estimated from their maleic value according to Ames et al. As the results, maleic value of raw liver oil and distilled fish liver oil were about 35, and relative bio-potency about 65% for all-trans isomer of vitamin A. But from view point of effect of distillation and freshness of liver oil, relative bio-potency of vitamin A of fish liver oil was considered to be more than 90%. Isomerization of synthetic vitamin A in oil was observed under storage and radiation of ultra violet light, and its bio-potency recognized to show sometimes below 75%. It was observed in vivo that the type of vitamin A storaged in, liver was hardly influenced by distribution of isomer of vitamin A adminstered, as well as by ratio of distribution of vitamin A isomer in feed. Decrease of maleic value in liver in vitro was found under addition of “slow reacting isomer”. Isomerization of vitamin A on the wall of intestine was not remarkable. Relation between bio-potency of vitamin A shown by growth of rat and maleic value of vitamin A source was exsamined, and only within the specific range of dosing of vitamin A the above relation was observed.
