[Biochemical and morphological parameters of rats subjected to intensive physical effort].

Lactate dehydrogenase activity was determined in the liver and skeletal muscle and types of muscle fibers were studied in m.gastrocnemius of male rats subjected to intensive physical exercise. In the skeletal muscle LDH4+5 isozymes activity and percent of white muscle fibers were increased. No changes in LDH activity and morphological parameters were found in the liver.