Acute and chronic effects of ethanol on biliary secretion of bilirubin and bile acids.

Rats treated acutely with ethanol showed a significant increase in biliary bilirubin secretion and in serum bilirubin levels (compared to saline treated controls); no difference was found in bile acid secretion. In rats fed ethanol chronically (36% of total energy for 4-6 weeks) there was a significant increase in the secretion of bilirubin and bile acids when compared to pair fed controls. We observed this effect either in the presence or in the absence of alcohol in the blood at the time of the experiment. The presence of ethanol in the blood, however, resulted in higher biliary and serum bilirubin levels. The increase in bile acid secretion involved selectively di- (but not tri-) hydroxy bile acids. Since increased secretion of unconjugated bilirubin favors pigment gallstones formation, it can be postulated that ethanol contributes to the pathogenesis of cholelithiasis by enhancing the biliary secretion of the pigment.