Classification of patients with GH deficiency (GHD) according to the response to GH-RH

Abstract

Synthetic GH-RH-1-44 was administered in a dose of 1 mcg/1 Kg to 3 normal adolescents with short stature and to 17 patients with GHD (hGH response to ITT and clonidine < 2 ng/ml). In the normal subjects the peak response of plasma hGH to GH-RH was 100, 20 and 19 ng/ml. In the GHD patients 3 patterns of response were observed: a) Good response (n=5), 18±1.9 ng/ml, i.e. GHD of hypothalamic origin; b) Partial response (n=4), 4.25±0.4 ng/ml, i.e. GHD of hypothalamic origin, possibly with a pituitary component; c) No response (n=8), 1.3±0.3 ng/ml, i.e. GHD of pituitary origin. It remains to be established whether a partial response of GH to one bolus of GH-RH may in certain patients be due to a longstanding GH-RH deficiency, with the possibility of its unmasking following repeated injections and the consequent synthesis of sufficient GH for its release.