THE IN VITRO METABOLISM OF DESMOSTEROL WITH ADRENAL AND LIVER PREPARATIONS*

Abstract

The metabolism of C14-labeled 24-dehydrocholesterol (desmosterol) and cholesterol was compared with in vitro liver and adrenal preparations from triparanol fed mice and rats. Both sterols were biosynthetically prepared from 2-Cl4-mevalonic acid. The reactions studied included the oxidation of the terminal carbons of the sterol side- chain to CO2 by mouse liver mitochondria, and the conversion of sterol to steroid hormones by rat adrenal gland homogenates. Similar yields of CO2, and of steroid hormones, were obtained with each of the 2 sterol substrates, demonstrating that they were quantitatively comparable as substrates in these in vitro enzyme systems. These results confirm a previous in vivo study (J. clin. Invest. 1962, 41, 962) which suggested that desmosterol was similar to cholesterol in its ability to serve as a precursor for bile acids and for steroid hormones in patients on triparanol therapy.