Plasma kinetics of lipoprotein lipase and hepatic lipase activities induced by heparin and a low molecular weight heparin fragment

Intravenous injections of conventional heparin and a low molecular weight heparin fragment (LMWH, mean molecular weight 4000-6000) were given to six male volunteers at doses of 10, 50 and 100 U (antiFXa)/kg body wt. The plasma kinetics of lipoprotein lipase (LPL) and hepatic lipase (HL) were analysed. The peak values, as well as the accumulated release of LPL activity, were dose dependent and were twice as high after heparin as after LMWH. The plasma half-life of LPL activity followed first order kinetics and was similar for both heparin preparations when given in comparable doses. The peak values and the plasma half-life of HL activity were the same for heparin and LMWH in the clinically relevant doses (50 and 100 U (antiFXa)/kg). Compared with LMWH, the total release of HL was twice as large after the heparin injections, possibly due to mobilization of an additional enzyme pool by the conventional heparin. It is concluded that the use of LMWH as an anticoagulant is associated with a lower plasma lipolytic activity than with standard heparin.