Plasma lipoprotein cholesterol levels in rats fed a diet enriched in cholesterol and cholic acid

To investigate the effects of dietary cholesterol and cholic acid on plasma cholesterol levels, rats fed a cholesterol-free diet or a diet enriched in cholesterol (0.5% or 1%) with or without cholic acid supplementation were studied for 4 weeks. Although 0.5% cholesterol supplementation showed no effect on plasma total cholesterol and LDL-cholesterol levels in rats fed a diet without cholic acid treatment, the addition of dietary cholic acid caused an increase in plasma total cholesterol, LDL-cholesterol and VLDL-cholesterol levels in rats fed a cholesterol-rich diet. There was no significant change in HDL-cholesterol levels among the dietary groups. Rats fed a diet enriched in cholesterol have increased liver total lipids and total cholesterol contents. In addition, lower liver lipid peroxide concentration was found in rats fed a cholesterol-rich diet when compared with those fed the control diet. It is interesting that cholic acid supplementation led to an increase in hepatic cholesterol content and a decrease in liver lipid peroxide concentration in rats fed a cholesterol-rich diet. Results from this study suggest that dietary cholesterol and cholic acid might play an important role in regulation of lipid metabolism in rats.