Plasma Lipoprotein Metabolism in Familial Lecithin: Cholesterol Acyltransferase Deficiency

Three series of experiments have been performed to study plasma lipoprotein metabolism in familial lecithin: cholesterol acyltransferase deficiency. In one series diets that contained little or no long chain triglyceride decreased the concentrations of several of the lipoproteins, particularly including the large unesterified cholesterol- and lecithin-rich lipoproteins in the class of d 1.019–1.063 g/ml. In the second series of experiments post-heparin lipolytic activity was found to increase the concentrations of the same low density lipoproteins in vivo. In the third series of experiments incubation with lecithin: cholesterol acyltransferase in vitro was found to decrease the unesterified cholesterol and lecithin of the large low density lipoproteins and to increase the cholesteryl ester of normal-sized very low, low, and high density lipoproteins. These findings are compatible with the concept that the large low density lipoproteins accumulate in the patients' plasma because chylomicron surface lipids are disposed of abnormally in the absence of lecithin: cholesterol acyltransferase.