Plasma growth hormone (GH) responses to single and repetitive subcutaneous administration of GH releasing factor (hpGRF-44) in normal and GH deficient children.

Synthetic human pancreatic GRF (hpGRF-44) was administered sc to 8 normal children with short stature and 11 patients with GH deficiency. After a dose of 100-200 micrograms hpGRF-44, mean plasma GH levels reached a peak at 15 min of 27.2 +/- 6.4 (+/- SE) ng/ml in normal children. However the responses were variable and peak plasma GH varied from 10.1 to 56.5 ng/ml. Eight of 11 patients with idiopathic GH deficiency did not respond to sc administration of 100-300 micrograms hpGRF-44. However, a plasma GH increase of more than 5 ng/ml occurred in 2 patients and to twice the basal level in 1 patient. Their GH values were 14.3, 5.2 and 3.4 ng/ml, respectively. After repetitive administration of hpGRF-44 (200 micrograms, twice a day) sc for 5 consecutive days, 2 of 8 patients restored their responsiveness, but the remaining patients did not show GH rise in response to both sc and iv bolus administration of hpGRF-44. Repetitive hpGRF-44 administrations for 5 days had no effect on somatomedin-C production.