Sterol metabolism in the rat: effect of alcohol on sterol metabolism in two strains of rats.

Abstract

Sterol metabolism studies using a combination of isotopic and chromatographic procedures were carried out in two strains of rats fed 5% ethanol (36% of calories) in the diet. Feeding ethanol to the Fisher rat over 17 days produced no significant changes in body weight. Cholesterol levels in various tissues were elevated in the ethanol-fed group: plasma cholesterol, +61%; liver cholesterol, +47%; and bile cholesterol, +57%. The alcohol-fed Fisher rat showed several changes in sterol metabolism over controls: fecal acidic steroid output, +13%; fecal neutral sterol output, +51%; endogenous neutral sterol output, +107%; cholesterol turnover, +54%; and cholesterol balance, +18%. Ethanol feeding to the Sprague Dawley rat showed similar differences between ethanol-fed vs. control rats. Cholesterol levels were significantly elevated in plasma (+35%) and in the liver (+81%). Sterol metabolism data showed the following differences (alcohol vs. control): fecal acidic steroid output, +9%; fecal neutral sterol output, +17%; endogenous neutral sterol output, +72%; cholesterol turnover, +33%; and cholesterol balance +13%. The Fisher rat maintained almost constant weight throughout the experimental period and is a preferable strain for sterol balance studies using liquid diets. A major finding of these experiments was the increased concentration of cholesterol in liver, plasma, and bile in both strains of rats. The sterol balance measurements indicated that this tissue accumulation of cholesterol was due to enhanced cholesterol synthesis as well as inhibition of bile acid syntheses.