Lactic dehydrogenase activities of rat heart and skeletal muscle after exercise and training.

Abstract

Forty-eight male albino rats were used in an investigation of the immediate and chronic effects of exercise on the lactic dehydrogenase activity of heart and skeletal muscle. The animals were allocated into two equal groups; one group was trained for 5 weeks and the remaining rats served as untrained controls. The training program consisted of an initial 30-min. swim which was extended to 60 min.by increasing the swim time 5 min. each day. Water temperature in the exercise tank was maintained at 35 C. Half of the trained and untrained animals were sacrificed 24 hr. after the last training session. The remaining rats were exercised for 30 min. immediately prior to sacrifice. On an absolute weight basis, the trained animals had heavier adrenals than the untrained controls but lighter spleens and heart ventricles. Analysis of regressed organ weights adjusted for differences in final body weights revealed that the trained animals had heavier adrenals than the controls and that the rats which were exercised prior to sacrifice had lighter spleens. Training produced a significant increase in LDH activity of the heart ventricles whereas skeletal muscle activity decreased. Exercise did not produce any change in LDH activity of either heart or skeletal muscle.