Increased lithogenicity of the bile after jejunoileal bypass in the rat.

Increased formation of biliary calculi is a complication of jejunoileal bypass (JIB) in man. We investigated the biliary lipid composition and bile flow rate in the rat 42 days after a JIB or sham operation. In the bile of the bypassed rats, the percentage cholesterol saturation and the concentration of phospholipids were significantly increased, while the concentration of bile acids and the lithogenic index (bile acids + phospholipids/cholesterol) were markedly decreased. The concentrations of cholesterol in the bile and in the liver were unchanged. These results suggest an increase in lithogenicity of the bile with decreased bile flow after JIB in the rat.