Blockade of hp-GRF-40-induced GH release in normal men by a cholinergic muscarinic antagonist.
In five healthy young men, pretreatment with the cholinergic muscarinic antagonist pirenzepine (0.6 mg/kg iv) almost completely abolished the rise in plasma growth hormone (GH) elicited by an iv bolus injection of 1 microgram/kg human pancreatic GH-releasing factor 1-40 (hp-GRF-40). These data demonstrate that cholinergic receptor sites involved in GH-releasing mechanisms do not interact with GRF-secreting structures in the central nervous system. A mechanism mediated via hypothalamic release of somatostatin or, alternatively, a direct pituitary site of action, can be postulated for the blocking effect of pirenzepine.
D000328:Adult; D001570:Benzodiazepinones / Q000494:pharmacology*; D013006:Growth Hormone / Q000097:blood*; D013007:Growth Hormone-Releasing Hormone / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D006801:Humans; D008297:Male; D010276:Parasympatholytics / Q000494:pharmacology*; D010446:Peptide Fragments / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D010890:Pirenzepine
D001570:Benzodiazepinones; D010276:Parasympatholytics; D010446:Peptide Fragments; C036893:somatotropin releasing factor 40; D010890:Pirenzepine; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone