Inhibition of cholesterol biosynthesis by cholic acid

¹ Edsel B. Ford Institute for Medical Research, Henry Ford Hospital, Detroit, Michigan

The effects of dietary cholic acid on free, total and ester cholesterol levels in liver and serum, and on the relative rates of incorporation of acetate-1-C¹⁴ and mevalonic acid-2-C¹⁴ were investigated in the rat. Cholic acid caused equally significant increases in free and ester liver cholesterol. No significant changes were found in serum cholesterol levels. The incorporation rate of acetate-1-C¹⁴ into liver and serum cholesterol was inhibited by 65% when cholic acid was fed to rats, while the inhibition of mevalonic acid-2-C¹⁴ incorporation was 25%. It is suggested that cholic acid inhibits cholesterol biosynthesis between mevalonic acid and cholesterol, or retards the entire series of reactions between acetate and cholesterol.