Heparin-induced release of lipase activity in the human forearm: an immunological study

Low doses of heparin were injected into the brachial artery of three volunteers. The lipase activities in the deep vein of the same forearm, draining mainly muscle tissue, and in the artery were monitored over a 10-min period. Lipase activity, rapidly released by heparin in the deep vein, was immunologically similar to lipoprotein lipase (E.C. 3.1.1.3), i.e. (1) it did not react with antiserum against human post-heparin plasma hepatic lipase and (2) it was inhibited by an antiserum against bovine milk lipoprotein lipase, which cross reacts with human post-heparin plasma lipoprotein lipase. The evidence that human muscle contains lipoprotein lipase is discussed.