Bile Acids

Abstract 5α-Cholestan-3β-ol-4-14C (0.2 to 0.4 mg, 107 dpm) was administered intraperitoneally to rats made hyperthyroid by daily subcutaneous injections of l-thyroxine (250 µg per kg per day) for a period of 4 weeks prior to cannulation of the bile ducts. The bile secreted over 17 postoperative days contained 72% of the administered 14C. Bile from the first 2 days was hydrolyzed, and the free bile acids were separated by acetic acid partition chromatography. Of the chromatographed 14C, 38% was associated with dihydroxy acids, 48% with cholic acid, and 9% with more polar fractions. The metabolite in the first zone was separated from known acids by repeated chromatography of the methyl esters and identified by dilution with synthetic allochenodeoxycholic acid. The synthetic material was prepared from methyl chenodeoxycholate by conversion to methyl 3-keto-7α-hydroxy-5α-cholanoate with Raney nickel, followed by catalytic reduction, and its structure was supported by mass spectral studies of the acid and its derivatives.