THE EFFECTS OF FEEDING A SATURATED FAT-RICH DIET ON ENZYMES OF CHOLESTEROL-METABOLISM IN THE LIVER, INTESTINE AND AORTA OF THE HAMSTER

The effects of two dietary treatments on parameters of cholesterol metabolism were studied. Hamsters were maintained on diets containing 2% (w/w) cholesterol or 20% (w/w) hydrogenated coconut oil for 4 weeks. Both diets induced a hypercholesterolaemia. The effects of the two treatments on hepatic and intestinal acyl-CoA : cholesterol acyltransferase activity and 3-hydroxy-3-methylglutaryl-CoA reductase activity were measured. As expected, cholesterol feeding stimulated cholesterol esterification and inhibited cholesterol synthesis. Saturated fat-feeding had no effect on cholesterol synthesis but markedly inhibited cholesterol esterification in both liver and intestine. The diet-induced hypercholesterolaemia was strongly correlated with an increase in acyl-CoA : cholesterol acyltransferase activity in the aorta. A stronger negative correlation was obtained with the HDL/LDL ratio and acyl-CoA : cholesterol acyltransferase activity. In contrast, the hypercholesterolaemia induced by feeding either of the two diets tended to increase aortic uptake of cholesterol and hence acyl-CoA : cholesterol acyltransferase activity. We suggest that the changes in cholesterol esterification correlate well with the expected flux of cholesterol into each tissue. © 1990.