Conversion of cholesterol injected into man to cholestanol via a 3-ketonic intermediate.

Cholesterol-3-(3)H,4-(14)C was injected intravenously in man and its transformation to cholestanol was studied. From the (3)H: (14)C ratios in cholestanol isolated from blood, evidence for the participation of a ketonic intermediate in the conversion was obtained. In a second subject given cholestanol-3-(3)H,4-(14)C the (3)H: (14)C ratios in blood sterols remained unchanged for as long as 1 wk after the injection, which showed that cholestanol did not lose tritium by interconversion with cholestanone.