Effect of Cholesterol on Hepatic Phospholipid Metabilism in Rats Fed a Diet Containing Fish Oil and Beef Tallow

The influence of dietary cholesterol on phospolipid metabolism in rat liver microsmes was studied in rats fed a diet containing fish oil(FO) or beef tallow (BT). The hepatic phospholipid content decreased wherease gepatic triglyceride and cholesterol increased significantly in both groups after cholestered supplementation. Plasma concentrations of phospholipid and traiglyceride increased with cholesterol supplement in both groups while cholesterol decreased only moderately in the FO group. Dietary cholesterol affected microsomal phosphiolpids in liver ; the proportation of phosphatidylcholine decreased in the FO group, an d it also slightly decreased in the BT group at the expense of phosphatidylethanolamine. The activity of CTP : phospocholine cytidylytransferase , the rate-limiting enzyme of phosphatidylcholine synthesis, increased inhepatic mocrosomes whreas it decreased in hepatic cytosol of both groups by cholesterol supplementation. In conclusion, these indicated that the dietary cholesterol profoundly influences phospholipid metabolism in the rat liver.