[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.

Effect of exercise on glycogen level in muscles and liver in rats.

The effect of exercise of glycogen level in skeletal muscles and liver was studied in Wistar rats. The previously untrained animals were subjected to one-time exercise in form of swimming in water at 32 degrees C for 10, 20 and 30 min. The glycogen level in the muscles (in g per 100 g of tissue) fell down during the first 10 minutes of the exercise by a mean value of 0.

The effect of short-lasting intensive physical exercise on ATP content in the rat muscles and liver.

Using the method of column chromatography the content of adenyl nucleoptides in the muscle and liver homogentates was determined in the rats subjected to short-lasting, intensive physical exercise. Following the exercise a slight increase in AMP and a decrease in ATP levels were found in the liver. In the muscles the levels of AMP and ADP increased while the level of ATP decreased markedly.