HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Boberg, K. M. Articles by Bjorkhem, I. Search for Related Content PubMed PubMed Citation Articles by Boberg, K. M. Articles by Bjorkhem, I. Social Bookmarking                      What's this?

Journal of Lipid Research, Vol 31, 1083-1088, Copyright © 1990 by Lipid Research, Inc.

ARTICLES

Apparent lack of conversion of sitosterol into C24-bile acids in humans

KM Boberg, K Einarsson and I Bjorkhem
Institute of Clinical Biochemistry, University of Oslo, Rikshospitalet, Norway.

The metabolic fate of intravenously administered [4-14C]sitosterol was studied in two healthy subjects. In marked contrast to the results of a previous investigation with [22,23-3H]sitosterol, no detectable labeled C24-bile acid products appeared in bile. The first and rate-limiting step in the conversion of cholesterol into bile acids is catalyzed by the liver microsomal cholesterol 7 alpha-hydroxylase. When incubated with human liver microsomes, no detectable 7 alpha-hydroxylation of sitosterol could be demonstrated. This was the case also when using liver microsomes from two subjects treated with cholestyramine, in which case the rate of 7 alpha-hydroxylation of cholesterol was increased three- to sixfold. In order to bypass the rate-limiting step, the metabolic fate of 3H-labeled 7 alpha-hydroxysitosterol was studied in two volunteers. In this case there was a significant conversion into acid products in bile (18-32% excreted in bile during the first 17 h). Although part of the labeled products had chromatographic properties similar to those of cholic acid and chenodeoxycholic acid, further analysis showed that none of the products was identical to chenodeoxycholic acid and only traces at the most could be identical to cholic acid. The results suggest that healthy human subjects, in similarity with other mammalian species studied, have little or no capacity to convert sitosterol into the normal C24-bile acids.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				S Kidambi and S B Patel Sitosterolaemia: pathophysiology, clinical presentation and laboratory diagnosis J. Clin. Pathol., May 1, 2008; 61(5): 588 - 594. [Abstract] [Full Text] [PDF]

				J. J. Clarenbach, M. Reber, D. Lutjohann, K. von Bergmann, and T. Sudhop The lipid-lowering effect of ezetimibe in pure vegetarians J. Lipid Res., December 1, 2006; 47(12): 2820 - 2824. [Abstract] [Full Text] [PDF]

				T Sudhop, Y Sahin, B Lindenthal, C Hahn, C Luers, H K Berthold, and K von Bergmann Comparison of the hepatic clearances of campesterol, sitosterol, and cholesterol in healthy subjects suggests that efflux transporters controlling intestinal sterol absorption also regulate biliary secretion Gut, December 1, 2002; 51(6): 860 - 863. [Abstract] [Full Text] [PDF]

				T. Sudhop, D. Lutjohann, A. Kodal, M. Igel, D. L. Tribble, S. Shah, I. Perevozskaya, and K. von Bergmann Inhibition of Intestinal Cholesterol Absorption by Ezetimibe in Humans Circulation, October 8, 2002; 106(15): 1943 - 1948. [Abstract] [Full Text] [PDF]

				B. Lindenthal, T. Sudhop, P. Schiedermaier, M. Agnan, T. Sauerbruch, and K. von Bergmann Serum plant sterols and biliary cholesterol secretion in humans: studies with ursodeoxycholic acid J. Lipid Res., July 1, 2002; 43(7): 1072 - 1077. [Abstract] [Full Text] [PDF]

				J. Plat, H. Brzezinka, D. Lutjohann, R. P. Mensink, and K. von Bergmann Oxidized plant sterols in human serum and lipid infusions as measured by combined gas-liquid chromatography-mass spectrometry J. Lipid Res., December 1, 2001; 42(12): 2030 - 2038. [Abstract] [Full Text] [PDF]

				M. Norlin, A. Toll, I. Björkhem, and K. Wikvall 24-Hydroxycholesterol is a substrate for hepatic cholesterol 7{alpha}-hydroxylase (CYP7A) J. Lipid Res., October 1, 2000; 41(10): 1629 - 1639. [Abstract] [Full Text]

				G. M. B. Berger, R. J. Pegoraro, S. B. Patel, P. Naidu, L. Rom, H. Hidaka, A. D. Marais, A. Jadhav, R. P. Naoumova, and G. R. Thompson HMG-CoA reductase is not the site of the primary defect in phytosterolemia J. Lipid Res., May 1, 1998; 39(5): 1046 - 1054. [Abstract] [Full Text]