Differential diagnosis between hypothalamic and pituitary hGH deficiency with the aid of synthetic GH-RH 1-44.

Synthetic GH-RH 1-44 administered as an intravenous bolus (1 microgram/kg) evoked a marked hGH rise (greater than 20 ng/ml) in three children with constitutional short stature and in two of eight children diagnosed as having hGH deficiency by insulin hypoglycaemia and/or clonidine tests. As judged by the intensity of the hGH response to the dose employed and the peak time, GH-RH 1-44 may be as potent as GH-RH 1-40 in children. It is concluded that GH-RH is an important addition to the endocrine armamentarium, providing the means for differentiation between hypothalamic and pituitary hGH deficiency in a simple test which is devoid of side effects.