title: A quantitative evaluation of the conversion of 25-hydroxycholesterol to bile acids in man.
abstract: The present study was directed toward providing additional information in man on the nature of a potential alternative pathway to cholic acid not involving an initial 7 alpha-hydroxylation of cholesterol. Two bile fistula patients and one normal subject each received 25-hydroxy[G-3H]cholesterol; [14C]cholic and [14C]chenodeoxycholic acids were also simultaneously administered to one bile fistula patient and normal subject. The labeled 25-hydroxycholesterol was found to be poorly converted to primary bile acids by all three patients; the range of conversion was 9.7 to 18.9%. Cholic acid was favored over chenodeoxycholic acid by a margin of about 1.4/1. It is concluded that a pathway to primary bile acid via the 25-hydroxylation of cholesterol is of minor importance under conditions of normal or accelerated synthesis in man.
mesh_terms: D001646:Bile / Q000378:metabolism*; D001647:Bile Acids and Salts / Q000096:biosynthesis*; D001658:Biliary Fistula / Q000378:metabolism; D002250:Carbon Radioisotopes; D002635:Chenodeoxycholic Acid / Q000378:metabolism; D002793:Cholic Acids / Q000378:metabolism; D005260:Female; D006801:Humans; D006888:Hydroxycholesterols / Q000378:metabolism*; D007700:Kinetics; D011865:Radioisotope Dilution Technique; D014316:Tritium
chemical_list: D001647:Bile Acids and Salts; D002250:Carbon Radioisotopes; D002793:Cholic Acids; D006888:Hydroxycholesterols; D002635:Chenodeoxycholic Acid; D014316:Tritium; C007997:25-hydroxycholesterol