In the present study, we investigated the mechanisms that regulate apolipoprotein B-100 (apoB) secretion in response to the change of intracellular cholesteryl ester contents by adding low density lipoprotein (LDL) and an inhibitor of 3-hydroxy-3-methylglutaryl-CoA reductase (pravastatin) in rabbit hepatocyte culture system. LDL caused a significant dose-dependent increase in apoB secretion. On...

BACKGROUND Plasma lipoproteins are important determinants of atherosclerosis. Apolipoprotein (apo) B is a large, amphipathic glycoprotein that plays a central role in human lipoprotein metabolism. Two forms of apoB are produced from the APOB gene by a unique posttranscriptional editing process: apoB-48, which is required for chylomicron production in the small intestine, and apoB-100, required ...

Apolipoprotein B (apoB) metabolism was investigated in 20 men with plasma triglyceride 0.66-2.40 mmol/l and plasma cholesterol 3.95-6. 95 mmol/l. Kinetics of VLDL(1) (S(f) 60-400), VLDL(2) (S(f) 20-60), IDL (S(f) 12-20), and LDL (S(f) 0;-12) apoB were analyzed using a trideuterated leucine tracer and a multicompartmental model which allowed input into each fraction. VLDL(1) apoB production vari...

The acute effects of intravenous heparin administration (50 U/kg body weight) on apolipoprotein (apo)B-48 and apoB-100-containing lipoproteins in relation to postheparin lipase activities were studied in ten healthy normolipidemic volunteers. Five subjects returned to receive sham injections with saline. Lipoproteins were separated from plasma by density gradient ultracentrifugation at baseline...

Primary hepatocytes cultured in a medium supplemented with amino acids and lipogenic substrates responded to increased extracellular glucose by increasing the secretion of VLDL apoB. This effect was accompanied by an increased secretion of VLDL triacylglycerol (TAG) derived from endogenous stores. Glucose also stimulated intracellular TAG mobilization via the TAG lipolysis/esterification cycle....

Primary hepatocytes cultured in a medium supplemented with amino acids and lipogenic substrates responded to increased extracellular glucose by increasing the secretion of VLDL apoB. This effect was accompanied by an increased secretion of VLDL triacylglycerol (TAG) derived from endogenous stores. Glucose also stimulated intracellular TAG mobilization via the TAG lipolysis/esterification cycle....

BACKGROUND Oxidized phospholipids (OxPL) are pro-inflammatory. We evaluated whether changes in plasma levels of OxPL associated with apolipoprotein B-100 (apoB-100) reflect changes in OxPL content in atherosclerotic plaques during dietary-induced atherosclerosis progression and regression. METHODS AND RESULTS OxPL content was measured in plasma and immunohistochemically in aortic plaques with...

Hepatic accumulation of lipid substrates perturbs apolipoproteinB-100 (apoB) metabolism in insulin-resistant, obese subjects and may account for increased risk of cardiovascular disease. In a placebo-controlled trial, we examined the independent and combined effects of decreasing cholesterol synthesis with atorvastatin (40 mg/day) and triglyceride synthesis with fish oils (4 g/day) on apoB kine...

The ATPase associated with various cellular activities (AAA-ATPase) p97 (p97) has been implicated in the retrotranslocation of target proteins for delivery to the cytosolic proteasome during endoplasmic reticulum-associated degradation (ERAD). Apolipoprotein B-100 (apoB-100) is an ERAD substrate in liver cells, including the human hepatoma, HepG2. We studied the potential role of p97 in the ERA...

Lipid esters stored in cytoplasmic lipid droplets (CLDs) of hepatocytes are used to synthesize very low-density lipoproteins (VLDLs), into which apolipoprotein B (ApoB) is integrated cotranslationally. In the present study, by using Huh7 cells, derived from human hepatoma and competent for VLDL secretion, we found that ApoB is highly concentrated around CLDs to make “ApoB-crescents.” ApoB-cresc...