Journal of Lipid Research, Vol 26, 403-417, Copyright © 1985 by Lipid Research, Inc.
Effects of the degree of saturation of dietary fat on the hepatic production of lipoproteins in the African green monkey
FL Johnson, RW St. Clair and LL Rudel
The cholesteryl ester content of plasma low density lipoproteins (LDL) in
monkeys has previously been shown to be related to the rate of hepatic
cholesterol secretion and cholesteryl ester content of newly secreted
lipoproteins in the isolated perfused liver. In the present studies,
African green monkeys were fed diets containing cholesterol and 40% of
calories as either butter or safflower oil in order to determine the
effects of saturated versus polyunsaturated dietary fat on hepatic
lipoprotein secretion. The rate of cholesterol accumulation in liver
perfusates was correlated with the size of the donor's plasma LDL, but for
any rate, a smaller plasma LDL was found in donor animals of the safflower
oil group than in those of the butter group. Hepatic very low density
lipoproteins (VLDL) were smaller in the safflower oil group but contained
more cholesteryl ester and fewer triglyceride molecules per particle than
those from the butter group. Livers from the safflower oil group contained
more cholesteryl ester and less triglyceride than those from the butter
group. The cholesteryl ester percentage composition of hepatic VLDL
resembled that of the liver in each group. The data show that dietary
polyunsaturated fat decreased plasma LDL size even though it increased the
cholesteryl ester content of lipoproteins secreted by the liver. Therefore,
intravascular formation of plasma LDL from hepatic precursor lipoproteins
appears to include the removal of relatively greater amounts of cholesteryl
esters from the precursor lipoproteins in polyunsaturated fat-fed animals.