Participation of cholinergic muscarinic receptors in glucagon- and arginine-mediated growth hormone secretion in man.

To investigate the participation of cholinergic receptors in glucagon- and arginine-induced GH and PRL secretion, glucagon (1 mg, sc) and arginine (30 mg over 30 min) were administered to a group of normal subjects. On a different occasion, both tests were repeated after premedication with 40 mg pirenzepine, a muscarinic blocker, given iv 5 min before the test substances. Pirenzepine completely suppressed the glucagon- and arginine-induced GH rise in all subjects. The PRL response to arginine was not altered by pirenzepine. The results suggest that cholinergic muscarinic receptors regulate the GH response to glucagon and arginine in man.