Two procedures were used to isolate hepatocytic Golgi fractions from rat liver. One procedure yields a light Golgi fraction (GF1 + 2) and the other "intact" stacks of cisternae. Triglyceride fatty acids in nascent very low density lipoproteins (VLDL) were labeled by injection of [3H]palmitate intravenously, and radiolabeled lipoproteins were injected as markers of potentially contaminating endo...

The plasma lipoproteins and "particles"' fall into four major groups. As defined by paper electrophoresis (3) these are the beta, alpha, and pre-beta lipoproteins, and chylomicrons. The latter two are rich in glyceride and very low in density (< 1.006, Sf > 20). It is now common to reserve the term chylomicrons for the relatively large particles that arise in the gut from exogenous or ingested ...

In this investigation in cultured human fibroblasts, an attempt was made to determine the optimal metabolism of apolipoprotein (apo) B-100 lipoproteins from normolipidemic human subjects. We supplemented culture systems containing 125I-lipoproteins with exogenous recombinant or plasmatic apo E-3. Very low density lipoprotein (VLDL) fractions I, II, and III, and low density lipoproteins (LDL) we...

Low density lipoproteins (LDL) in blood plasma and their immediate precursors are generally thought to be the major atherogenic lipoproteins. The initial indications that LDL are formed from very low density lipoproteins (VLDL) were obtained more than 25 years ago (1, 2), yet even today the precise mechanism of LDL formation from VLDL is unknown. During the last 15 years the processes of interc...

Recombination of low and very low density lipoproteins (VLDL and LDL) from normal subjects with plasma from patients with non-insulin-dependent diabetes mellitus significantly increased the reduced rate of transfer of cholesteryl ester to these lipoproteins, which is characteristic of diabetic plasma, whereas diabetic VLDL and LDL reduced cholesteryl ester transfer rates in normal plasma. VLDL ...

Endotoxemia stimulates many physiologic responses including disturbances in lipid metabolism. We hypothesized that this lipemia may be part of a defensive mechanism by which the body combats the toxic effects of circulating endotoxin. We tested the effects of mixtures of endotoxin, lipoproteins, and lipoprotein-free plasma and determined the ability of varying concentrations of human very low d...

Plasma-derived lipid transfer protein (LTP) facilitates the transfer of cholesteryl ester and triglyceride between all lipoproteins. Kinetic models of the transfer event have suggested that transfer is facilitated through the physical interaction (binding) of LTP with its lipoprotein substrate. Such binding has been observed previously between LTP and high density lipoprotein (HDL), but not bet...

The triacylglycerol content of chylomicrons and VLDL (very-low-density lipoprotein) compete for the same lipolytic pathway in the capillary beds. Although chylomicron triacylglycerols appear to be the favoured substrate for lipoprotein lipase, VLDL particles compete in numbers. Methods to quantify the specific triacylglycerol removal from VLDL and chylomicrons may involve endogenous labelling o...

The incorporation of labeled amino acids into the peptides of very low density lipoproteins (VLDL) and high density lipoproteins (HDL) secreted by perfused rat liver was studied using a Ringer-albumin solution in the perfusate in place of serum to diminish exchange of peptides between VLDL and HDL. Among the lipoproteins, the greatest release of protein, greatest incorporation of amino acid, an...

In this study we have investigated the effects of very low density lipoprotein (VLDL) lipolysis on the removal of radiolabeled apolipoprotein C-II and apolipoprotein C-III-1 from in vitro lipolyzed lipoproteins. Lipolysis was carried out in vitro using lipoprotein lipase purified from bovine milk, and mixtures with or without plasma. Lipoproteins were isolated by ultracentrifugation and by gel ...