Bile acids. XXXII. Allocholic acid, a metabolite of allochenodeoxycholic acid in bile fistula rats.

3p-3H-Allochenodeoxycholic acid was administered by stomach tube to rats with bile fistulas. Bile collected during the first 21 hours contained 53 to 59% of the administered 3H. After hydrolysis and separation of the free bile acids by acetic acid partition chromatography, 95% of the chromatographed 3H was recovered as the unchanged acid, but 0.3% and 4.5% appeared in two trihydroxy acid regions. At least 85% of the latter material was identified as allocholic acid. One of the metabolites in the former fraction appeared to be a.llohyocholic acid. These results show a distinct difference in the metabolism of the 5aand 5P-cholanic acids and demonstrate for the first time the 12a-hydroxylation of a cholanic acid nucleus in the rat.