アルコールならびに食事組成のコレステロール・胆汁酸代謝に及ぼす影響 ： 催胆石性胆汁生成との関連において

Abstract

This experiment was designed to define the effect of ethanol ingestion on cholesterol and bile acid metabolism in the liver as well as lithogenicity of bile in rats fed with different diets. HMG-CoA reductase and cholesterol 7α-hydroxylase activities were significantly decreased in rats fed with high-fat diet compared with those fed with standard diet. These reductions were more marked in the latter enzyme than in the former. In rats fed with high-protein diet, both enzyme activities were significantly elevated, and these elevations were more marked in the latter than in the former. Ingestion of ethanol decreased HMG-CoA reductase and 7α-hydroxylase activities, and these decreases were more marked in the latter than in the former in rats fed with standard and high-protein diets compared with pair-fed controls. However, ingestion of ethanol elevanted both enzyme activities in rats fed with high-fat diet compared with pair-fed controls, and this elevation was greater for HMG-CoA reductase than for 7α-hydroxylase. Dietary composition did not affect hepatic cholesterol ester hydrolase activities, but high-fat diet with ethanol decreased those activities compared with pair-fed control. Hepatic total cholesterol content increased in rats fed with high-fat diet, and decreased in rats fed with high-protein diet compared with those fed with standard diet. Administration of ethanol showed a tendency to increase hepatic total and esterified cholesterol contents in all dietary groups. The increases were particularly remarkable in rats fed with high-fat diet. High-protein diet remarkably increased cholesterol solubility in bile, however, high-fat diet diminished cholesterol solubility compared with standard diet. Ethanol showed a tendency to diminish cholesterol solubility in bile in all dietary groups, particularly in rats fed with high-fat diet. These results indicated that the effect of ethanol on cholesterol and bile acid metabolism depends on dietary composition, and high-protein and low-fat diet intake is effective to prevent gallstone formation facilitated by alcohol ingestion.