Effects of heparin infusion on plasma lipoproteins in subjects with lipoprotein lipase deficiency

The role of heparin‐releasable hepatic endothelial lipase (HL) in human plasma lipoprotein metabolism was investigated by examining the effects of intravenous infusion of heparin (180 units/kg over 2 h) in 8 subjects with primary extrahepatic lipoprotein lipase deficiency. In addition to reducing the triglyceride concentration in very low‐density lipoproteins, heparin‐induced release of HL reduced the phopholipid and protein concentrations in the HDL 2 subclass of high‐density lipoprotein (by 28% and 36% respectively, mean values) and simultaneously increased the HDL 3 phospholipid concentration (by 23%), providing the first in vivo evidence for a function of HL in the interconversion of the major HDL subfractions in man.