Diagnostic value of growth hormone-releasing hormone test in children and adolescents with idiopathic growth hormone deficiency.

Average growth hormone (GH) peaks following an i.v. growth hormone releasing hormone (GHRH) 1-29 stimulation test were significantly lower in 48 children and adolescents with GH deficiency (GHD) than in 20 age-matched controls (15.2 + 12.7 vs 37.5 + 28.1 ng/ml, 2 P less than 0.001). Twelve patients exhibited a low GH peak (less than 5 ng/ml), 27 demonstrated a normal response (greater than 10 ng/ml) and 9 showed an intermediate rise in plasma GH (5-10 ng/ml). Six of the 12 patients with low GH response to the first GHRH stimulation failed to respond to two other tests immediately before and after a 1 week priming with s.c. GHRH. These subjects with subnormal GH increase at repeat testing had total GHD (TGHD) and multiple pituitary hormone deficiency (MPHD) and had suffered from perinatal distress. On the contrary, 26 of 27 patients with normal GH response to the first test had isolated GHD and only a minority (8/27) had signs of perinatal distress. It is concluded that perinatal injuries primarily damage pituitary structures and that a pituitary defect more probably underlies more severe forms (TGHD and MPHD) of GHD.