Effects of fatty acid esters of cheno- and ursodeoxycholic acids on gallstone formation in hamsters.

Fatty acid esters (at the 7 position) of chenodeoxycholic (CDCA) and ursodeoxycholic (UDCA) acids have been tested for their effects on formation and dissolution of gallstones in hamsters. The free bile acids were fed at a level of 0.2% of the diet and esters were fed at equimolar levels. The earlier finding that CDCA does not affect gallstone formation in hamsters fed the Dam and Christensen diet were confirmed. The acetic, butyric and lauric acid esters of CDCA had a very slight inhibitory effect on lithogenesis but CDCA 7 oleate and linoleate completely inhibited gallstone formation. UDCA and its 7 oleate inhibited both formation and progression of gallstones. The observed effects are probably a function of the form of the bile acid and not of the esterifying acid. The observation that ethyl oleate has a slight litholytic effect suggests that the acid moiety of the ester may exert a slight influence.