Studies on cholesterol metabolism in the diabetic rat

Abstract

Plasma and hepatic cholesterol levels were determined in rats with severe alloxan diabetes. Significant hypercholesterolemia and elevated hepatic cholesterol content were found, suggesting an expansion of the cholesterol pool in this experimental model. To elucidate the mechanisms leading to cholesterol accumulation, the biliary excretion of cholesterol and bile salts, the pool size and turnover of the trihydroxycholanic acid fraction, and the rate of cholesterol absorption were studied in alloxan diabetic rats. The results of this study indicate that in these animals (1) the biliary excretion of cholesterol and bile salts was significantly increased, and this penomenon was corrected by the administration of insulin; (2) the pool of the trihydroxycholanic acid fraction was expanded, and its rate of daily synthesis was higher than in control animals; and (3) cholesterol absorptive rates were significantly increased. These observations demonstrate that cholesterol conversion into bile salts is enhanced in the alloxan diabetic rat, and suggest that the expansion of its cholesterol pool can be partly due to an increased rate of cholesterol absorption.