Pirenzepine Decreases Basal and Stimulated GH Secretion in Patients with Type 2 (Non-Insulin-Dependent) Diabetes Mellitus

Summary

Growth hormone (GH) hypersecretion has been described in diabetes mellitus and seems to be involved in the pathogenesis of diabetes complications. As piren-zepine (PZ), a cholinergic muscarinic antagonist, is able to inhibit GH hypersecretion in insulindependent diabetes mellitus (IDDM), we investigated whether PZ is also able to inhibit spontaneous and stimulated GH-release in noninsulin-dependent diabetes mellitus (NIDDM). Ten non-obese wellcontrolled patients with NIDDM underwent in random order the following three double-blind one week treatments: placebo (PL), PZ at low dose (PL in the morning plus PZ 50 mg at 22 h) or high dose (PZ 50 mg at 8 h plus l00 mg at 22 h). Pirenzepine administration significantly (p<0.05) decreased nocturnal GH release after both low and high dose (AUC, PL vs PZ: 107.3±26.5 vs 48.3±10.5 and 57.6±9.6 μg/L/h, respectively). The GH response to arginine infusion was significantly inhibited by PZ at high dose (AUC, 147.1 ±48.8 vs 444.7+194.3 μg/L/h, p<0.01), but not at low dose. Glucose, insulin, glucagon and somatostatin responses to arginine infusion were not changed by pirenzepine treatment. In conclusion, the muscarinic blockade by PZ is able to inhibit the spontaneous and stimulated GH secretion also in NIDDM without affecting insulin secretion.

Key words

Growth Hormone - Pirenzepine - Non-Insulin-Dependent-Diabetes Mellitus - Somatostatin - Insulin