Oxidative processes in hypervitaminosis A in albino rats

Abstract

Albino rats were made hypervitaminotic A by feeding 30,000 iu of vitamin A daily by mouth; the effect of this hypervitaminosis was compared with a similar pair-fed group. Food consumption and body weight gain were reduced. Study of liver and kidney slices shows that the latter manifest no significant increase in oxygen consumption in presence of succinate or acetate. There is slight increase in O2 consumption in brain homogenates. Liver homogenate shows 15.2% inhibition with succinate and 5.6% with ascorbate oxidation. Liver homogenate shows 19.3% inhibition of succinate dehydrogenase activity by Thunberg technique with methylene blue indicator. It is concluded that hypervitaminosis A inhibits liver respiration by affecting the dehydrogenase, or any immediate step following it, and the cytochrome c-cytochrome oxidase end of the succinoxidase system is little affected.