LOW-DENSITY-LIPOPROTEIN BINDING TO MONOLAYER-CULTURES OF HEPATOCYTES ISOLATED FROM HAMSTERS FED DIFFERENT DIETARY FATTY-ACIDS

(i) The aim of these studies was to investigate the effect of dietary cholesterol and dietary fat on the expression of the hepatic low density lipoprotein (LDL) receptor. (ii) Low density lipoprotein (LDL) binding to monolayer cultures of hepatocytes isolated from hamsters fed different amounts of cholesterol and fats was measured. (iii) Hepatocytes isolated from hamsters fed a low cholesterol diet (< 0.008% w/w) specifically bound LDL and this binding increased with time in culture. By comparison, LDL binding to hepatocytes isolated from hamsters fed 0.12% (w/w) cholesterol was lower and there was no time dependent increase. Intermediate levels of binding were seen for hepatocytes from hamsters fed 0.06% (w/w) cholesterol. (iv) In hamsters fed 10% (w/w) fat in the presence of 0.06% (w/w) cholesterol, significantly more LDL receptors were expressed by hepatocytes from animals fed safflower oil compared to those isolated from lard or olive oil fed animals. (v) The reduced LDL cholesterol concentrations frequently observed for hamsters fed polyunsaturated fatty acids thus reflects an increase in the number of LDL receptors expressed in the liver. However, other explanations are needed for the effects of monounsaturated fatty acids.