Effect of ethanol on cholesterol and bile acid metabolism.

Ethanol feeding increased significantly levels of hepatic esterified cholesterol and serum free and esterified cholesterol in rats. Incorporation of intraperitoneally administered [(14)C]acetate into cholesterol was significantly increased. Labeling of cholesterol was also enhanced in liver slices from animals pretreated with ethanol and incubated with [(14)C]-acetate. Ethanol consumption prolonged the half-excretion time of labeled cholic or chenodeoxycholic acids, increased slightly the pool size, and decreased daily excretion. By contrast, supplementation of the diet with cholesterol shortened the half-excretion time, did not modify pool size, and increased daily excretion. When ethanol and cholesterol feeding were combined, the effects of ethanol prevailed and there was suppression of the adaptive changes in bile acid metabolism induced by cholesterol feeding. There was also a greater accumulation of esterified cholesterol in the liver than that produced by cholesterol alone, ethanol administration alone, or the summation of both effects. Thus, cholesterol accumulation produced by ethanol feeding is associated with both enhanced cholesterogenesis and decreased bile acid excretion. Both mechanisms may play a role, but the latter is probably predominant in these studies in which cholesterol accumulation was markedly enhanced by the addition of cholesterol to the ethanol-containing diet.