Acetone powders of a 20,000g pellet fraction from spinach leaves (Spinacia oleracea L.) synthesized [4-(14)C]cholesteryl esters when incubated with [4-(14)C]cholesterol. The reaction was inhibited by digitonin. There was a reciprocal relationship between the decline of label in cholesterol and its incorporation into cholesteryl ester, indicating that free cholesterol was the direct precursor fo...

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...

The clear cell form of renal cell carcinoma is known to derive its histologic appearance from accumulations of glycogen and lipid. We have found that the most consistently stored lipid form is cholesteryl ester. Clear cell cancer tissue contained 8-fold more total cholesterol and 35-fold more esterified cholesterol than found in normal kidney. Cholesteryl ester appeared to be formed intracellul...

A cholesteryl de-esterifying enzyme found in partially purified preparations of alpha toxin produced by the Wood 46 strain on Staphylococcus aureus has been separated from other staphylococcal proteins and from alpha toxin by isoelectric focusing and gel filtration. Preparations of alpha toxin from Bi-Gel P-60 columns and of the cholesteryl esterase from Bio-Gel P-200 columns showed a high degr...

Baboons from some families have a higher concentration of plasma high density lipoproteins (HDL) on a chow diet and accumulate large HDL (HDL1) when challenged with a high cholesterol and high saturated fat (HCHF) diet. HDL1 from high HDL1 animals contained more (1.5-fold) cholesteryl ester than HDL (HDL2 + HDL3) from high or low HDL1 animals. HDL from high HDL1 baboons had lower triglyceride c...

Beta very low density lipoproteins (B-VLDL) from cholesterol-fed animals and from patients with Type III hyperlipoproteinemia are internalized by a receptor-mediated process in mouse macrophages. Once internalized, the cholesteryl esters of B-VLDL are hydrolyzed in lysosomes, and the released cholesterol is re-esterified, resulting in a massive accumulation of cholesteryl esters. In the present...

Lovastatin has been shown to reduce cholesterol esterification in cholesterol-loaded human macrophages. Surprisingly, in nonloaded macrophages, lovastatin produces the opposite effect, lowering free cholesterol and increasing cholesteryl ester levels, as measured by high-performance liquid chromatography. In cholesterol-loaded cells, lovastatin reduced the cholesteryl esters of unsaturated but ...

Normal human plasma HDL was applied to a column of heparin-Sepharose in the presence of MnCl(2) and three fractions were obtained by stepwise elution with increasing NaCl concentrations: a non-retained fraction (NR, 78% of protein) and two retained fractions (R(1) and R(2), 18 and 2.5% of protein, respectively). Both unesterified and esterified cholesterol increased from NR to R(1) to R(2) but ...

Chylomicrons containing labeled cholesterol, mainly (70%) present as cholesteryl ester, were injected intravenously into intact rats, and samples of liver were obtained 27-210 min later. Most (58-75%) of the injected label was recovered in the liver after 27-75 min. Hepatic uptake occurred without hydrolysis of the labeled cholesteryl ester. In separate experiments, in vitro perfusion of livers...

While the content of fatty streaks and fibrous plaques has been extensively studied in autopsied specimens, little is known about the lipid composition of advanced human atherosclerotic plaques requiring surgical removal. We have analyzed free cholesterol, cholesteryl ester, and the cholesteryl ester fatty acid content in 19 carotid and 7 femoral obliterative plaques obtained at endarterectomy....