This study investigated the role of muscarinic cholinergic receptors in regulating growth hormone (GH) secretion in acromegalic patients. The trial involved eight subjects who received GH-releasing factor (GRF 1-29) and thyrotropin-releasing hormone (TRH) tests, with and without pirenzepine, a muscarinic antagonist. The results showed that muscarinic cholinergic blockade did not
