Exercise training has a heparin-like effect on lipoprotein lipase activity in muscle

Abstract

Lipoprotein lipase (LPL) is anchored with high affinity to heparan sulphate proteoglycans on the luminal surface of the capillary endothelium. The levels of pre-heparin perfusate LPL activity increased from 16 ± 1 to 145 ± 6 U/hindlimb (ninefold increase) in hindlimb muscle of exercise-trained rats measured immediately after the last bout of work. At the same time, post-heparin perfusate LPL activity decreased from 63 ± 2 to 13 ± 1 U/hindlimb (p < 0.001). These results provide evidence that exercise-training has a heparin-like effect on capillary-bound LPL. The total amount of LPL (i.e., pre-heparin perfusate plus post-heparin perfusate) was twofold greater in the hindlimb of the trained animals versus the controls. The effect of exercise on muscle LPL activity appears to last for as long as 5 days after cessation of exercise. Serum triglycerides were reduced 38% and plasma free fatty acids increased fourfold. These results provide evidence that training increases the capacity to remove triglycerides from circulation.Key words: lipoprotein lipase, skeletal muscle, exercise, serum triglycerides, heparin.