Further studies of the effects of intravenous infusion or intramuscular injection of gonadotropin-releasing hormone during childhood and adolescence.

To provide data on the readily releasable pools of pituitary gonadotropins and to compare routes of administration, gonadotropin-releasing hormone (Gn-RH, 100 micrograms) was administered to 135 endocrinologically normal children and adolescents by continuous intravenous 3-hour infusion or by acute intramuscular injection. The Gn-RH infusion resulted in a significant four- and sevenfold increase in serum luteinizing hormone (LH) values in prepubertal subjects and pubertal males, respectively. A 14-fold increment, biphasic in appearance, occurred in pubertal females. Gn-RH-induced serum follicle-stimulating hormone (FSH) increases were greater in females than in males. Following intramuscular injection of Gn-RH, a monophasic increment of serum LH and FSH occurred. LH rises were greater in pubertal than in prepubertal children and greater in females than in males. FSH increments were greater in females than in males, prepubertal being slightly greater than pubertal. Urinary gonadotropin excretion mirrored the changes in the serum samples. These results in the largest reported group of normal children generally confirm those of previous reports except for the greater Gn-RH-evoked releasable LH in pubertal females than in males.