We studied the interstitial fluid concentration of two lipid-metabolizing enzymes (lipoprotein lipase and hepatic triacylglycerol lipase) to determine their importance in interstitial modification of filtered lipoproteins. Despite the use of a very sensitive lipase assay (1 nmol of fatty acid release/ml/hr), lipase activities in plasma and in peripheral and skeletal muscle lymph from control do...

Rat hepatocytes in monolayer culture were preincubated for 19 h with 1 microM-dexamethasone, and the incubation was continued for a further 23 h with [14C]oleate, [3H]glycerol and 1 microM-dexamethasone. Dexamethasone increased the secretion of triacylglycerol into the medium in particles that had the properties of very-low-density lipoproteins. The increased secretion was matched by a decrease...

Primary cultures of estrogen-induced chick parenchymal liver cells have been used to study the assembly of the apolipoprotein and glycerolipid constituents of hepatic very low density lipoprotein (VLDL). Liver cell monolayers in serum-free medium were pulse-labeled for 2.5 min with either [3H]leucine or [3H]glycerol and were then chased for 4 h. The kinetics of secretion of VLDL 3H-apolipoprote...

Excess fatty acids and sterols are stored as triacylglycerols and sterol esters in specialized cellular organelles, called lipid droplets. Understanding what determines the cellular amount of neutral lipids and their packaging into lipid droplets is of fundamental and applied interest. Using two species of fission yeast, we show that cycling cells deficient in the function of the ER-resident CD...

Defective control of lipid metabolism leading to lipotoxicity causes insulin resistance in skeletal muscle, a major factor leading to diabetes. Here, we demonstrate that perilipin (PLIN) 5 is required to couple intramyocellular triacylglycerol lipolysis with the metabolic demand for fatty acids. PLIN5 ablation depleted triacylglycerol stores but increased sphingolipids including ceramide, hydro...

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...

Studies on the hydrodynamic properties of human milk bile salt-activated lipase (BAL) indicated that it is a monomer with molecular weight of 107,000. The presence of taurocholate (1 mM) did not lead to an association of the enzyme. The enzyme had a basal activity with trioctanoylglycerol and with shorter chain, but not with longer chain, monoacid triacylglycerols. Based on kinetic analyses, we...