COMPARISON OF THE POTENTIATING EFFECT OF PYRIDOSTIGMINE, ARGININE ANDPROPRANOLOL ON THE GHRH-INDUCED GH RELEASE IN SHORT CHILDREN

The effect of pyridostigmine (60 mg orally), arginine (0.5 g/kg iv) an d propranolol (PROP, 40 mg orally) on GHRH (1 mug/kg iv) - induced GH release was studied in seven short children. Pyridostigmine and argini ne induced a similar potentiating effect on GHRH-induced GH rise (Peak , mean +/- SEM: 56.9 +/- 12.8 and 48.6 +/- 8.5 mu/L, respectively vs 1 2.3 +/- 1.6 mug/L; p < 0.05). Combination of GHRH with propranolol ind uced an increase of GH that was significant only with regard to peak ( 28.9 +/- 8.4 mug/L) but not to AUC. However, GH rises observed after G HRH combined with PD or ARG did not significantly differ from that rec orded after coadministration of GHRH and PROP both for peak and AUC. O ur results confirm that pyridostigmine and arginine have a striking po tentiating effect on the GHRH-induced GH rise in children and show tha t the tests with GHRH + PD and GHRH + ARG are more reliable than that with GHRH + PROP to explore the secretory capacity of somatotroph cell s.