Growth-hormone releasing factor and clonidine in children with constitutional growth delay. Evidence for defective pituitary growth hormone reserve.
Six male prepubertal children with constitutional growth delay (CGD), and a subnormal growth hormone (GH) response to insulin hypoglycemia, and four normal prepubertal children were given in different occasions 1 microgram/Kg iv synthetic hpGRF-40 or a single oral dose of 0.15 mg/m2 clonidine (Clon), an effective growth hormone (GH) secretagogue. In the normal children brisk and clear-cut GH rises were detected in plasma after hpGRF-40 (peak GH levels at 15-30 min) or clonidine (peak GH levels 60-90 min). In CGD children hpGRF-40 induced a biphasic response, e.g. a slight increase in plasma GH at 15 min followed by a delayed and erratic GH rise occurring 45-120 min post-injection. Also the GH response to Clon was sluggish and delayed and peak plasma GH levels were attained only 90-180 min post-drug administration. These data indicate that the CGD children of our study have a defect in the pituitary GH reserve.
D002648:Child; D003000:Clonidine / Q000494:pharmacology; D006130:Growth Disorders / Q000503:physiopathology*; D013006:Growth Hormone / Q000378:metabolism*; D013007:Growth Hormone-Releasing Hormone; D006801:Humans; D008297:Male; D010446:Peptide Fragments; D012636:Secretory Rate / Q000187:drug effects
D010446:Peptide Fragments; C036893:somatotropin releasing factor 40; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone; D003000:Clonidine