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 spite of much progress in understanding the mechanisms of lipoprotein metabolism at the cellular level, much less is known quantitatively about what actually occurs in vivo. A new tool for understanding the catabolic fates of lipoproteins in vivo is the use of noncatabolizable ligands for labeling proteins. These ligands are incorporated into cells with the labeled protein. The protein is ca...

A rapid method for the separation and quantitation of unesterified cholesterol and cholesteryl esters by high-performance liquid chromatography is described. All of the cholesteryl esters typically present in plasma were resolved on Zorbax ODS reversed-phase columns using a linear gradient of water (3%-0%) in acetonitrile-tetrahydrofuran 65:35 (v/v) as eluting solvent. Results obtained by this ...

The precursor-product relationship of very low density (VLDL) and low density lipoproteins (LDL) was studied. VLDL obtained from normal (NTG) and hypertriglyceridemic (HTG) subjects was fractionated by zonal ultracentrifugation and subjected to in vitro lipolysis. The individual subfractions and their isolated lipolysis products, as well as IDL and LDL, were rigorously characterized. A striking...

Patients with acute hepatitis and chronic alcoholic liver disease had decreased net serum cholesterol esterifying activity (CEA) which correlated positively with the percentages and concentrations of cholesteryl esters in their serum. These cholesterol parameters also correlated negatively with serum bilirubin concentrations, but bilirubin added to sera in vitro failed to influence CEA. The dec...

Mast cell granule remnants contain heparin proteoglycans and bind low density lipoproteins (LDL). Phagocytosis of such LDL-coated remnants by smooth muscle cells of synthetic phenotype (s-SMC) leads to cellular accumulation of LDL-derived cholesteryl esters (Wang et al. 1995. Arterioscler. Thromb. Vasc. Biol. 15: 801-810). In the present study, we investigated the pathway by which granule remna...

The cholesteryl esters of very low density lipoproteins become labeled when human plasma is incubated with cholesterol-(14)C. The relative order of magnitude of the specific activity of the cholesteryl esters of the major lipoprotein fractions is: high density lipoproteins >> very low density lipoproteins > low density lipoproteins. This pattern of labeling is similar to that found by others in...

The rate of secretion of apoB-100-containing lipoprotein particles by HepG2 cells is determined to an important extent by post-translational mechanisms, the mass of neutral lipids clearly playing a role in this process. Our previous data indicated that cholesteryl ester might influence the proportion of newly synthesized apoB-100 molecules that are incorporated into nascent lipoproteins rather ...

Two fluorescent cholesteryl esters, cholesteryl cis-parinarate and cholestatrienyl oleate, have been incorporated into human serum low density lipoprotein (LDL) by two alternative procedures. The core location of the incorporated cholesterol esters and the surface location of cis-parinaric acid and cholestatrienol are verified by fluorescence energy transfer. In these LDL preparations, the inco...

Lipid transfer activities from human plasma have been characterized to determine whether triglyceride and cholesteryl ester transfer proteins are identical. After sequential purification by phenyl-Sepharose, CM-cellulose, chromatofocusing, and gel filtration, both triglyceride and cholesteryl ester transfer activities were purified approximately 15,000-fold compared to lipoprotein-deficient pla...