Effect of denervation and cocainization on activity of creatine synthesizing enzyme and phosphorylase in skeletal muscle

Abstract

Creatine synthesizing enzyme and phosphorylase were determined in the gastrocnemius of the rat, and effects of epinephrine, norepinephrine, cocaine and denervation on them were studied. Denervation caused decrease of activity of the creatine synthesizing enzyme and increase of phosphorylase activity. Cocaine (1 x 10^–4 and 3 x 10^–4) exerted denervation-like action on both enzyme systems. Epinephrine (2 x 10^–5) increased the activity of creatine synthesizing enzyme in the normal muscle, but it did not affect the enzyme activity of the denervated muscle. Conversely, norepinephrine (2 x 10^–5) increased the enzyme activity of the denervated muscle but it did not affect that of the normal muscle significantly. Epinephrine (20 µg i.p.) and norepinephrine (100 µg i.p.) increased the phosphorylase activity ratio, and the former was more potent than the latter. Neither drug affected the enzyme in the denervated muscle.