Human intestinal sulphation of lithocholate: A new site for bile acid metabolism

The liver and intestinal lumen are both important sites in the entero-hepatic circulation of bile salts. Lithocholate, a secondary bile acid and a potent hepatotoxin is probably detoxified in man predominantly by hepatic sulphation. Other sites may also be important. Because steroid sulphating enzymes exist throughout the gastrointestinal tract we have examined the invitro lithocholate sulphation capacity of healthy and diseased ileal and colonic mucosal samples using radio-isotope tracer techniques. Lithocholate sulphation was demonstrated in healthy and diseased ileal mucosa but not in the colonic mucosal samples studied. This new site for lithocholate metabolism acts as a further protective mechanism to prevent toxic unsulphated lithocholate reaching the liver. These findings suggest that the intestinal mucosa may have an important role in the metabolism of other bile acids.