Showing papers on "Endothelial lipase published in 1987"

Lipoprotein Lipases, Lipoproteins and Tissue Lipids in Rats Fed Fish Oil or Coconut Oil

Abstract: The effect of fish oil and coconut oil on plasma lipoproteins and lipoprotein-catabolizing enzymes [lipoprotein lipase (LPL) and hepatic endothelial lipase (HL)] was studied in rats. Male rats were fed for 4 wk purified diets containing equienergetic, amounts of either coconut oil (group A), coconut oil:fish oil, 50:50 (group B) or fish oil (group C). Whole plasma triacylglycerol, cholesterol and phospholipid concentrations were appreciably lower in group C than in group A, mainly due to a fall in very low density lipoprotein (VLDL) and subgroup 2 of high density lipoprotein (HDL2), with less consistent changes in LDL and HDL3. VLDL components of group B were also considerably lower than corresponding ones in group A. LPL and HL activities were about 50% lower in groups B and C than in group A. Increased hepatic triacylglycerol and cholesterol concentrations were observed in groups B and C. It is suggested that the decrease in LPL and HL activity of fish oil-fed rats may be an adaptive response to the low concentration of the substrate (triacylglycerols) for these enzymes.

Metabolic Determinants of Plasma High-Density Lipoprotein Concentration in Humans

Abstract: Interest in the metabolic factors which collectively determine the concentration and composition of high-density lipoprotein (HDL) has been stimulated by the evidence that HDL cholesterol is an independent predictor of coronary heart disease risk. HDL participates in the transport of all major lipids in plasma - cholesterol, phospholipids and triglycerides. Its metabolism is complex and, although still incompletely understood, appears to include the following events: the synthesis and secretion of apoproteins AI and All by the liver and small intestine; the transfer of cholesterol and phospholipids from cell membranes, and from the surface coats of lipolyzed triglyc-eride-rich lipoproteins, to HDL; the esterification of HDL cholesterol by plasma lecithin:cholesterol acyltransferase (LCAT); the transfer of cholesteryl esters and triglycerides between HDL and other lipoproteins by the lipid-transfer protein; the hydrolysis of HDL phospholipid by hepatic endothelial lipase; and the receptor-mediated catabolism of HDL particles by hepatocytes, macrophages and other cells (1). The extent to which each of these processes influences plasma HDL concentration in man has been little explored.

Lipolysis and Lipoprotein Metabolism

Abstract: The intravascular metabolism of lipoproteins represents a complex interplay between enzymatic reactions, nonenzymatic transfer of lipoprotein components between lipoprotein particles, and receptor-mediated uptake of lipoprotein particles in various organs. Three lipases, hormone-sensitive lipase (HSL), lipoprotein lipase (LPL), and hepatic lipase (HL) represent important points of regulation in lipoprotein metabolism and are consequently major determinants for the concentrations of plasma-lipoproteins.