Chronic exercise training alters kinetic properties of rat skeletal muscle and myocardial lactate dehydrogenase.

10 weeks of treadmill running dramatically altered the kinetic properties of lactate dehydrogenase (EC 1.1.1.27) in skeletal muscle and myocardium in the rat. These changes, including Vmax, Km and optimal concentrations for pyruvate and lactate, indicate that exercise training induces the formation of H-isozyme in skeletal muscle and M-isozyme in the heart and represent metabolic adaptations of these tissues to chronic aerobic exercise.