We examined the effect of genetic polymorphisms of proteins regulating intrahepatic processing of apolipoprotein B-100 (apoB) and the supply of neutral lipids to the liver on the hepatic secretion of very low density lipoprotein (VLDL) apoB in obesity. Hepatic secretion of very low density apolipoprotein B-100 (VLDL apoB) was measured using an infusion of [1-(13)C]leucine in 29 obese men. Isoto...

Twenty two subjects (9 males, 13 females) were fed a fat-rich meal (1 g of fat/kg body weight). Triglyceride-rich lipoproteins (TRL) were isolated by ultracentrifugation (d less than 1.006 g/ml) from blood drawn 0, 3, 6, 9, and 12 hr after the meal. Plasma triglyceride increased then decreased postprandially, while plasma apoA-I and apoB concentrations decreased. TRL triglyceride, TRL total pro...

Fatty liver is prevalent in apolipoprotein B (apoB)-defective familial hypobetalipoproteinemia (FHBL). Similar to humans, mouse models of FHBL produced by gene targeting (apob(+/38.9)) manifest low plasma cholesterol and increased hepatic triglycerides (TG) even on a chow diet due to impaired hepatic VLDL-TG secretive capacity. Because apoB truncations shorter than apoB48 are expressed in the i...

OBJECTIVE proprotein convertase subtilisin/kexin type 9 (PCSK9) negatively regulates the low-density lipoprotein (LDL) receptor (LDLR) in hepatocytes and therefore plays an important role in controlling circulating levels of LDL-cholesterol. To date, the relationship between PCSK9 and metabolism of apolipoprotein B (apoB), the structural protein of LDL, has been controversial and remains to be ...

OBJECTIVE The Apolipoprotein-related Mortality Risk (AMORIS) study concluded that the apolipoprotein (apo)B/apoA-I ratio was the best predictor of coronary heart disease (CHD) risk. We have compared the pairwise combinations of total cholesterol, triglycerides (TGs), apoB, high density lipoprotein (HDL) cholesterol, low density lipoprotein cholesterol, and apoA-I on CHD risk prediction in middl...

g-Tocotrienol (g-T3), a naturally occurring analog of tocopherol (vitamin E), has been shown to have a hypocholesterolemic effect in animals and humans. Unlike tocopherol, it has also been shown to reduce plasma apoB levels in hypercholesterolemic subjects. The aim of this study was to define the mechanism of action of g-T3 on hepatic modulation of apoB production using cultured HepG2 cells as ...

Cultured hepatocytes from rats fed a low fat, chow diet (LF) or diets rich in fish oil (FO, 20% v/w) or olive oil (OO, 20%, v/w) were used to determine how the intracellular metabolism and secretion of apolipoproteins (apo)B-100 and B-48 respond to in vivo and in vitro manipulations of fatty acid esterification, storage, secretion, and oxidation. Hepatocytes from the FO- and OO-fed rats had hig...

The purpose of the present study was to examine the regulation of levels of apolipoprotein B (apoB) mRNA and its protein by cytokines in HepG2 cells. A dose-dependent increase in apoB mRNA levels was observed in the presence of either interleukin-1beta (IL-1beta) or IL-6 alone. This increase occurred as early as 1 h after IL-1beta or IL-6 stimulation. Exogenous addition of IL-1beta (5 ng/ml) an...

Studies of truncated apoB peptides in human subjects with familial hypobetalipoproteinemia, as well as of puromycin-generated spectra of nascent apoB peptides in rat and hamster liver, suggest that a minimum size is required for N-terminal fragments of apoB to be efficiently assembled into full-sized VLDL. We report here results of experiments undertaken to examine this phenomenon in greater de...