Isolation of 5 alpha-cholestane-3 beta, 7 alpha-diol from bile of patients with cerebrotendinous xanthomatosis. Inefficiency of this steroid as a precursor to cholestanol.
Cerebrotendinous xanthomatosis is a rare, inherited disease characterized by defective bile acid biosynthesis as well as by accumulation of cholesterol and cholestanol. The mechanism behind the accumulation of cholestanol is unknown. Using combined gas chromatography-mass spectrometry, 5 alpha-cholestane-3 beta, 7 alpha-diol could be identified as a minor component in bile from two such patients. There were no significant amounts of this steroid in bile from control subjects. Most probably, the 5 alpha-cholestan-3 beta, 7 alpha-diol found is formed from 7 alpha-hydroxy-4-cholesten-3-one in the liver. 7 alpha-Hydroxy-1-cholesten-3-one, being a normal intermediate in bile acid biosynthesis, is known to accumulate in the liver and bile of patients with cerebrotendinous xanthomatosis, due to a defect of the mitochondrial 26-hydroxylase. The possibility was tested that (7 beta-3H)-labeled 5 alpha-cholestane-3 beta, 7 alpha-diol could be converted into cholestanol by a direct 7 alpha-dehydroxylation in the intestine. This conversion did not occur in rabbits, however, regardless of whether the labelled steroid was administered orally or intracoecally. It is concluded that 5 alpha-cholestane-3 beta, 7 alpha-diol is of little or no importance as a precursor to cholestanol in rabbits. Most probably, this is also the case in patients with cerebrotendinous xanthomatosis.
D000818:Animals; D001646:Bile / Q000378:metabolism*; D001647:Bile Acids and Salts / Q000096:biosynthesis; D001927:Brain Diseases / Q000378:metabolism; D004083:Cholestanol / Q000096:biosynthesis* / Q000378:metabolism; D002784:Cholesterol / Q000031:analogs & derivatives*; D006801:Humans; D011817:Rabbits; D013710:Tendons; D014973:Xanthomatosis / Q000378:metabolism*
D001647:Bile Acids and Salts; D004083:Cholestanol; D002784:Cholesterol