Cholinergic mediation in dermorphin-induced growth hormone secretion in man

The effects of pirenzepine (P), a cholinergic muscarinic antagonist, on growth hormone (GH) and prolactin (PRL) response to dermorphin (D) were studied in a group of 7 healthy men. D produced clear elevations in GH and PRL levels. P completely blocked the GH-releasing activity of D, whereas it did not alter the PRL-releasing activity. These results indicate that GH-releasing action of D is mediated via the central cholinergic nervous system in man.