Retinol in cholesterol biosynthesis: effect on lipid metabolism

Abstract

Physiologically tolerable doses of carotenoids in oil, (palm oil) or the feeding of its equivalent in pre-formed vitamin A to experimental animal, had provided sufficient evidence to lead to the proposal that, the administration of vitamin A triggers off a series of metabolic reactions all of which can be traced to the biosynthesis of cholesterol in which the vitamin has been previously reported to be involved. An increase in fatty acid oxidation which showed up as lack of increase in plasma glyceride levels in the vitamin A fed animals was suggested. The livers and kidneys of these animals revealed high levels of lipids. Cholesterol was found to be responsible for these increases in the tissue lipids. Highly significant positive correlations were found to exist between the cholesterol and tbe lipid levels and also between lipid and vitamin A levels in these tissues. It was therefore concluded that the effects of vitamin A are mediated through its involvement in cholesterol biosynthesis