Studies on lipid metabolism of cholesterol fed rats Part I Metabolism of liver tissue

In order to elucidate the effect of dietary cholesterol on lipid metabolism in rat liver, the author investigated the change of hepatic lipid biosynthesis in cholesterol fed rats by measuring the I-(14)C acetate incorporation into lipids. The cholesterol feeding did not have any effect on serum lipid levels. Hepatic cholesterol biosynthesis from acetate was markedly suppressed by cholesterol feeding, which indicates that there is a feedback regulation system in the cholesterol biosynthesis in rat liver. The cholesterol feeding increased both fatty acid biosynthesis and monounsaturation of long chain fatty acids. Concerning the percent composition of liver and serum fatty acids, an increase in oleic acid and decrease in arachidonic acid were observed after cholesterol feeding. The same pattern of lipid metabolism was observed in in vivo experiments as well as in in vitro experiments: