title: Transformation of chenodeoxycholic acid to ursodeoxycholic acid in patients with Crohn's disease.
abstract: In vivo 7 beta-epimerization of chenodeoxycholic acid to ursodeoxycholic acid and the role of 7-ketolithocholic acid as an intermediate in this biotransformation were studied in 11 patients with Crohn's disease and in 5 healthy volunteers. The incorporation of deuterium into biliary ursodeoxycholic acid and 7-ketolithocholic acid was determined by computed gas chromatography-mass fragmentography after ingestion of a dideuterated chenodeoxycholic acid, chenodeoxycholic-11,12-d2 acid. The incorporation of deuterium into ursodeoxycholic acid increased to a peak level at 48 h in the patients with Crohn's disease, but was delayed in healthy volunteers. In 8 patients and 2 healthy controls there were small amounts of 7-ketolithocholic acid in bile. The incorporation of deuterium into 7-ketolithocholic acid was confirmed in only 2 patients and the peak level was noted at 48 h. These observations suggest that 7-ketolithocholic acid is an intermediate of this biotransformation in patients with Crohn's disease.
mesh_terms: D000293:Adolescent; D000328:Adult; D001646:Bile / Q000032:analysis; D001647:Bile Acids and Salts / Q000032:analysis; D002635:Chenodeoxycholic Acid / Q000378:metabolism*; D003424:Crohn Disease / Q000378:metabolism*; D003840:Deoxycholic Acid / Q000031:analogs & derivatives*; D003903:Deuterium; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D008095:Lithocholic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D014580:Ursodeoxycholic Acid / Q000378:metabolism*
chemical_list: D001647:Bile Acids and Salts; D003840:Deoxycholic Acid; D002635:Chenodeoxycholic Acid; C023020:7-ketolithocholic acid; D008095:Lithocholic Acid; D014580:Ursodeoxycholic Acid; D003903:Deuterium