Metabolism of beta-muricholic acid in the hamster and prairie dog.

The metabolism of beta-muricholic acid was investigated in the prairie dog and the hamster. Intravenous infusion into bile fistula hamsters showed that beta-muricholic acid was extracted by the liver and secreted into the bile (> 85% in 1 h). Hepatic extraction of this compound and cholic acid in the prairie dog was not as rapid as in the hamster. In the bile of the prairie dog, most (93%) of the administered beta-muricholic acid was present as the taurine conjugate. In the hamster, 28% of infused beta-muricholic acid was secreted in unconjugated form, 43% as the taurine conjugate, and 22% as the glycine conjugate. In both species, the administered compound underwent little biotransformation. After intraduodenal injection of [6 alpha-3H]-labeled beta-muricholic acid into bile fistula hamsters, the bile acid was rapidly secreted into the bile; more than 80% of the administered radioactivity was recovered in 3 h. In the prairie dog, biliary recovery after intraduodenal administration of either beta-muricholic acid (43% in 3 h) or cholic acid (22% in 3 h) was slower than in the hamster. After intragastric administration, more than 80% of beta-muricholic acid was recovered unchanged in feces of both animal species.