Intestinal absorption of lithocholate and its sulfate and glucuronide in rats.

The absorption of lithocholate and its sulfate and glucuronide in rat jejunum and terminal ileum was studied. Tracer amounts of radiolabelled bile acids were administered to the ligated intestinal segments, and their absorption was monitored by biliary excretion through a bile duct catheter. Absorption of lithocholate was faster in the terminal ileum than in the jejunum. Although the sulfation reduced lithocholate absorption in the jejunum, it did not affect lithocholate absorption in the terminal ileum. This was due to the Na+-dependency of ileal absorption of lithocholate-sulfate assessed by perfusion studies. In contrast, the glucuronidation markedly reduced lithocholate absorption both in the jejunum and the terminal ileum. These findings indicate that the glucuronidation is more effective than sulfation in detoxifying lithocholate as far as the prevention of its intestinal absorption is concerned.