Expression of lipoprotein lipase (LPL) by the macrophage has been proposed to promote foam cell formation and atherosclerosis, primarily on the basis of in vitro studies. LPL-deficient mice might provide a model for testing the role of LPL secretion by the macrophage in an in vivo system. Unfortunately, homozygous deficiency of LPL in the mouse is lethal shortly after birth. Because the fetal l...

Lipoprotein lipase (LPL) is the enzyme responsible for hydrolysis of circulating triglyceride-rich lipoproteins and is important for storage of adipocyte lipid. To study the regulation of LPL synthetic rate in adipose tissue, primary cultures of isolated rat adipocytes were pulse-labeled with [35S]methionine, and LPL was immunoprecipitated with an LPL-specific antibody. A pulse-chase experiment...

Lipoprotein lipase (LPL), synthesized in muscle and fat, hydrolyzes plasma triglycerides primarily while bound to luminal endothelial cell surfaces. To obtain information about the movement of LPL from the basal to the luminal endothelial cell surface, we studied the transport of purified bovine milk LPL across bovine aortic endothelial cell monolayers. 125I-labeled LPL (125I-LPL) added to the ...

Lipoprotein lipase (LPL) is a key enzyme in lipoprotein metabolism, and has been hypothesized to exert either pro- or anti-atherogenic effects, depending on its localization. Decreased plasma LPL activity is associated with the high triglyceride (TG);-low HDL phenotype that is often observed in patients with premature vascular disease. In contrast, in the vessel wall, decreased LPL may be assoc...

Lipoprotein lipase (LPL) is a key enzyme for fatty acid and lipoprotein metabolism in muscle. However, the effect of aging on LPL regulation in skeletal muscle is unknown. We report the effect of aging on LPL regulation in the soleus (red oxidative postural) muscle and the tibialis anterior (white glycolytic non-weight-bearing) muscle in 4- and 24-mo-old Fischer 344 rats and 18- and 31-mo-old F...

Lipoprotein lipase (LPL; EC 3.1.1.34) may promote atherogenesis by producing remnant lipoproteins on the endothelial surface and by acting on lipoproteins in the artery wall. In vitro, smooth muscle cells and macrophages synthesize LPL, but in human carotid lesions only a few smooth muscle cells were reported to contain LPL protein. Endothelial cells do not synthesize LPL in vitro, but in norma...

We investigated, in the present study, the role of reactive oxygen intermediates (ROI) in the control of macrophage lipoprotein lipase (LPL) secretion. Exposure of murine macrophages to increasing concentrations of hydrogen peroxide (H2O2) resulted in enhanced basal LPL production and mRNA levels. The increase of LPL production was reduced in the presence of antioxidants. Oxidant stress also mo...

To study the mechanism of lipoprotein lipase (LPL) regulation by exercise, we recruited 16 healthy athletes to undergo a 2-wk period of detraining. Fasting fat and muscle biopsies were performed both before and after the detraining period. In muscle, detraining resulted in a decrease in LPL activity in both the heparin-releasable (HR) (-45%, P < 0.05) and cellular (extractable [EXT]) (-75%, P <...

Hypertriglyceridemia of sepsis is associated with suppressed tissue lipoprotein lipase (LPL) activities. We investigated the effect of sepsis on lipoprotein lipase gene expression in epididymal fat and soleus muscle from control and septic rats in the fasted and fed state. After 24 h of sepsis, LPL activity decreased significantly in epididymal fat from fasted rats by 45% along with a 57% reduc...