Liver and plasma malic dehydrogenase activities in the exercised rat.

Abstract

Nikkila et al(1) have reported increased activity of serum malic dehydrogenase (MDH), and of other enzymes, as a consequence of exercise in untrained subjects and, to a lesser extent, in trained athletes Gardner et al (2) have reported similar observations with human subjects, noting a relationship of degree and duration of exercise (treadmill) with serum enzyme levels; training per se did not alter basal enzyme activities. More recently, we have reported (3) that liver and plasma MDH activities were increased in rats made to swim for 2 hours. Repeated daily exercise (training) caused an increased basal MDH activity in liver but not plasma; in the trained rat, a 2-hour swimming exercise did not elicit a further elevation of MDH activity in liver nor did it elicit an elevation in plasma. Neither acute nor repeated exercise caused any alteration in liver or plasma glutamic-pyruvate transaminase activities.The lack of unanimity in observations from several laboratories on effects of exercise on enzyme activi...