[Inhibition of growth hormone (GH) response to GHRH in diabetes mellitus type 1 after blockade of the cholinergic system with pirenzepine].

The effect of pirenzepine, a peripheric cholinergic antagonist, on GHRH-induced GH secretion was studied in 10 type I diabetic subjects and 8 healthy controls. GH response was significantly greater in diabetics than in the healthy controls (p < 0.02) with peak values of 59.6 and 15.9 ng/ml, respectively. Pirenzepine 20 mg in given 15 min before GHRH inhibited GH response in both groups. In diabetics GH response calculated as area under curve (AUC) was inhibited from 3666 to 260 ng/ml. min (p < 0.001) and in the controls from 831 to 255 ng/ml. min (p < 0.05). The great efficacy of pirenzepine in inhibiting GH hypersecretion in type I diabetes may find a clinical application in future.