Effect of Pituitary Hormones, Cortisone and Adrenalectomy on Some Aspects of Neuromuscular Function and Acetylcholine Synthesis

Abstract

Hypophysectomy decreased the ability of muscle to maintain the amplitude of action potential unaltered during repetitive indirect stimulation of the nerve, and a decreased synthesis of acetylcholine by nerve. During expts. of short duration only a mild dysfunction of the muscle and a severe dysfunction of the nerve could be demonstrated. ACTH restored the neuromuscular system of hypophysectomized animals to normal. ACTH increased the ability of brain of nonoperated and hypophysectomized animals to synthesize acetylcholine. Cortisone induced qualitatively similar but quantitatively less effect than did ACTH. Thyrotropic hormone, thyroxine and growth hormone induced an additional impairment of the maintenance of action potential of muscle during direct and indirect stimulation in nonoperated and hypophysectomized animals whereas pitocin and pitressin had no effect. Salt-treated adrenalectomized animals showed a more marked dysfunction of the muscle than did the hypophysectomized animals but synthesis of acetylcholine by brain was not impaired except after exposure to prolonged stress.