Precursor of 27-nor-5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 24,25-pentol in man.

Cholesterol was shown to be the precursor of 27-nor-5 beta-cholestane-3 alpha, 7 alpha, 12 alpha, 24,25-pentol which is the major bile alcohol in human urine. 4-[14C]-Labelled cholesterol and beta-sitosterol were administered to patients with primary biliary cirrhosis. Urine was extracted with Amberlite XAD-2 and sterol glucuronides and bile acid conjugates were isolated by ion exchange chromatography on Lipidex-DEAP. Following hydrolysis and further purification on Lipidex-DEAP, the C26 bile alcohol and methyl esters of cholic and chenodeoxycholic acids were isolated by HPLC. The specific radioactivity of the C26-pentol was the same as that of cholic acid after administration of [14C]-cholesterol. In contrast, little if any radioactivity could be detected in the C26-pentol after administration of labelled beta-sitosterol.