The response of plasma
growth hormone (GH) to
insulin-induced hypoglycaemia (IIH) and
arginine infusion (AI) was studied in 22 young males (ages 8 to 17 years) with short atature and absent or delayed sexual maturation, before and after
androgen administration. During initial evaluation, 5 patients had blunted GH response to IIH, 12 responded subnormally to AI and 4 failed to respond normally to either stimulus. These same studies were repeated in each patient following
androgen administration. The source of
androgen was as follows: a) 5 days of
testosterone propionate (25 mg intramuscularly daily) in 20 patients. b)
Methyltestosterone, 10 mg t.i.d. orally for four days in the other 2 subjects. In almost every case,
androgen administration resulted in raising the levels of fasting GH and enhancement of the GH responses to IIH and AI was observed. Patients manifesting subnormal GH responses to these stimuli before
androgen consistently demonstrated a normal response when challenged with identical stimuli during
androgen administration. Growth velocities during the year following these studies were significantly increased in most instances and the growth spurts correlated well with the progression of sexual maturation. Sustained improvement in the GH responses to IIH and AI were uniformly observed in 3 patients when repetitive studies were performed 8 to 12 months later during spontaneous advancing sexual development. The results indicate that brief
androgen administration can be helpful in delineating the cause of growth retardation in boys with short stature and delayed sexual maturation, particularly when the diagnosis of
isolated growth hormone deficiency is suspected. They also offer prognostic value in determining growth potential in this same group of young males.