Change in bile composition during gallstone formation in gerbils.

Mongolian gerbils form cholesterol gallstones when fed with chow supplemented with cholesterol and cholic acid. The change in bile composition accompanying gallstone formation was found to consist of an increase of the cholesterol fraction at the expense of the bile acid fraction of the total sum of bile acids and lipids. The five animals models for gallstone formation on which reliable information regarding bile composition is now available, were compared. A similar change was found in all five models while the phospholipid fraction showed a tendency to higher values. In all five models the bile acid/phospholipid ratio decreases when gallstones are induced.