Exercise-induced changes of reactivity of different types of muscle on glycogenolytic effect of adrenaline.

In the investigations presented it was found that the glycogenolytic effect of adrenaline in the skeletal muscle of resting rats depends on the type of muscle: the hormone exerts the least effect in the white muscle and the greatest effect in the intermediate one. There was a cumulative effect of adrenaline in a dose of 0.1 mg/kg and exercise on the glycogen level in the white muscle. In the red and intermediate muscles the exercise-induced glycogen depletion rate was very rapid and no additional effect of adrenaline on glycogen level was observed. No repletion of glycogen in the white muscle occurred during the first 3 h of the post-exercise recovery, and adrenaline further decreased the glycogen level in this muscle. In the red and intermediate muscles full repletion of glycogen took place already during the first hour of recovery. A dose of 0.1 mg/kg adrenaline had no effect on the glycogen repletion rate in the red muscle and only partly inhibited it in the intermediate muscle. A dose of 0.5 mg/kg adrenaline prevented the glycogen repletion in both types of muscles. During the exercise as well as during the post-exercise recovery the hyperglycemic effect of adrenaline was decreased.