To understand the mechanism responsible for maternal hyperlipidemia, 25 healthy pregnant women were studied longitudinally during the three trimesters of gestation and at post-partum, and 11 were studied again at post-lactation. Triglyceride and cholesterol levels increased with gestation in all the lipoprotein fractions. However, the greatest change appeared in low density (LDL) and high densi...

Lipoprotein lipase forms an enzyme-substrate complex with fat emulsions in the presence of serum lipoproteins. Lipoproteins of very low density and high density have this property, but the former are much more active per unit weight of protein. In this investigation, the activity, expressed as quantity giving half-maximal rate of production of free fatty acids, of specific glycopeptides isolate...

As part of the avian reproductive effort, large quantities of triglyceride-rich very-low-density lipoprotein (VLDL) particles are transported by receptor-mediated endocytosis into the female germ cells. Although the oocytes are surrounded by a layer of granulosa cells harbouring high levels of active lipoprotein lipase, non-lipolysed VLDL is transported into the yolk. This is because VLDL parti...

Lipoprotein lipase has been identified in extracts of adipose tissue and heart and seems to be identical to the lipase that appears in plasma after the injection of a polyanion (cf. 1,2). The most unique characteristic of this lipase is its specificity for triglycerides in the form of a natural or synthetic lipoprotein complex. This paper describes investigations on the specificity of lipoprote...

Insulin regulation of lipoprotein lipase was studied in fully differentiated 3T3-Ll fat cells. Insulin at low concentrations (10e7 to 10-l’ M) elicited a rapid and maximal increase (-lo-fold) in lipoprotein lipase release from the cells to the medium within 30 min and caused a 2to lo-fold increase in total cellular lipoprotein lipase activity over a a-day period. Insulin had no effect on cell l...

IN ADDITION to its anticoagulant action, heparin initiates the release of lipoprotein lipase into the blood. This lipolytic enzyme has the capacity to reduce the turbidity of lipemic plasma and hence has become known also as "clearing factor." Its clearing action occurs from the hydrolysis of triglyceride contained in chylomicrons and other lipoprotein particles.' Studies in animals have sugges...

The nature of the lipolytic activity released from chicken livers perfused with Krebs-Ringer buffer (pH 7.0) containing heparin (50 or 10 U/ml), fraction V albumin (3%), and glycerol (20%) was investigated. The nonrecirculating perfusates contained both previously described NaCl-resistant "liver lipase" as well as an apoLp-Gluactivated lipoprotein lipase (LPL). Crude perfusate lipolytic activit...

The purpose of this study was to determine the threshold of exercise energy expenditure necessary to change blood lipid and lipoprotein concentrations and lipoprotein lipase activity (LPLA) in healthy, trained men. On different days, 11 men (age, 26.7 +/- 6.1 yr; body fat, 11.0 +/- 1.5%) completed four separate, randomly assigned, submaximal treadmill sessions at 70% maximal O2 consumption. Dur...

Lipoprotein lipase (LPL) is a key factor determining the clearance of triglycerides from the circulation. The enzyme activity is tissue-specifically regulated by insulin, but it is not clear yet how insulin regulates the total LPL activity in the circulation. To answer such question, we measured LPL activity using the intravenous fat tolerance test (IVFTT) that was carried out 1 h before as wel...