SUMMARY It is well known that muscarinic cholinergic blockade either reduces or abolishes stimulated GH release in normal subjects. In this study we have investigated whether cholinergic muscarinic blockade could reduce the GH responses...
moreSUMMARY It is well known that muscarinic cholinergic blockade either reduces or abolishes stimulated GH release in normal subjects. In this study we have investigated whether cholinergic muscarinic blockade could reduce the GH responses to G R F 1-29 and TRH in acromegalic subjects. Eight acromegalic subjects underwent two G R F tests (GRF 1-29, 1 pg/kg i.v.) with and without pirenzepine (0.6 mg/kg, i.v.). A further four of these patients received TRH (200 pg/kg, i.v.) on separate occasions with and without pirenzepine (0.6 mg/kg, i.v.). Cholinergic muscarinic blockade did not alter the GH responses to G R F and TRH in patients with acromegaly. These findings are in contrast with previous data reported on the effects of cholinergic blockade on stimulated GH levels in normal subjects and in patients with type I diabetes mellitus and are compatible with the view that somatotroph adenomas are functionally disconnected from hypothalamic control mechanisms.
