Hepatic lipase-deficient subjects in the Ontario kindred are compound heterozygotes for hepatic lipase mutations (Ser267-->Phe and Thr383-->Met). Cholesteryl ester-rich beta-very-low-density lipoprotein (beta-VLDL) accumulates in plasma and such subjects have premature atherosclerosis. To determine a possible mechanism, we hypothesized that hepatic lipase-deficient beta-VLDL, homozygous for apo...

These studies were undertaken to determine the kinetic characteristics of high density lipoprotein (HDL) apo AI and cholesteryl ester transport in the hamster in vivo. Saturable HDL apo AI transport was demonstrated in the kidneys, adrenal glands, and liver. Saturable HDL cholesteryl ester transport was highest in the adrenal glands and liver. In the liver and adrenal glands, maximal transport ...

The effect of cholesteryl oleate on the lipoprotein lipase-catalyzed hydrolysis of trioleoylglycerol was determined in monolayers of egg phosphatidylcholine at a constant surface pressure of 24 mN m-1. The phospholipid monolayers contained 1.0 to 7.5 mol % trioleoylglycerol and various amounts (0 to 20 mol %) of cholesteryl oleate. The initial rates of trioleoylglycerol hydrolysis were determin...

Net mass transfer of lipids was measured in plasma from fasted, normolipidemic subjects. The plasma was incubated, and lipoproteins were subsequently separated by polyanion precipitation or density gradient ultracentrifugation. Total cholesterol, unesterified cholesterol, and triglycerides were measured in the isolated lipoprotein fractions. The rate of cholesterol esterification was measured s...

Lecithin-cholesterol acyltransferase (LCAT) catalyzes the intravascular synthesis of lipoprotein cholesteryl esters by converting cholesterol and lecithin to cholesteryl ester and lysolecithin. LCAT is unique in that it catalyzes sequential reactions within a single polypeptide sequence, a phospholipase A2 reaction followed by a transacylation reaction. In this report we find that LCAT mediates...

Administration of estrogen to cholesterol-fed rabbits dramatically retarded arterial lesion development despite its lack of effect on plasma cholesterol concentration and on lipoprotein patterns. Cholesteryl ester influx into the aortic wall was also much lower in the estrogen-treated animals and paralleled the aortic cholesterol content in treated and untreated animals; the fraction of aortic ...

The mechanisms of hydrolysis and accumulation of cholesteryl oleate-lipid droplets prepared in vitro were studied in acid cholesteryl-esterase-deficient fibroblasts (GM00863, GM03111). Acid cholesteryl esterase activity was reduced in both GM00863 and GM03111 (8.9% and 17.4% of the normal level, respectively), while neutral cholesteryl esterase activity was highly stimulated in GM03111. The hyd...

Mouse peritoneal macrophages take up acetylated human low density lipoprotein by receptor-mediated endocytosis, hydrolyze its cholesteryl esters in lysosomes, and re-esterify the cholesterol in the cytoplasm. The re-esterified cholesterol accumulates as cytoplasmic lipid droplets that resemble the droplets seen in “foam cells” of atherosclerotic lesions. In the present studies, we have investig...

Lymph chylomicrons labeled with 14C-cholesterol and plasma very low and intermediate density lipoproteins (d less than 1.019) labeled with 3H-cholesterol were injected simultaneously into recipient cholesterol-fed rabbits. The cholesteryl ester of chylomicron origin (14C) found in the tissues 1 to 4 hours after the injection is the sum of both direct and indirect uptake of chylomicron cholester...

The relationship of cholesteryl ester hydrolysis to the physical state of the cholesteryl ester in J774 murine macrophages was explored in cells induced to store cholesteryl esters either in anisotropic (ordered) inclusions or isotropic (liquid) inclusions. In contrast to other cell systems, the rate of cholesteryl ester hydrolysis was faster in cells containing anisotropic inclusions than in c...