Effect of Synthetic Luteinizing Hormone-Releasing Factor on Serum Testosterone and Gonadotropins in Prepubertal, Pubertal and Adult Males

Following the acute intravenous injection of synthetic luteinizing hormone-releasing factor (LRF), plasma testosterone rises to peak levels by 4 hr and increases significantly (p = .02) in adult and pubertal males but not in prepubertal males. The mean maximal increase above basal testosterone levels ±sem in ng/100 ml was 132 ± 31 in 10 adult males, 52 ± 13 in 18 pubertal males, and 0.9 ± 2 in 8 prepubertal males. There was a positive correlation (p < 0.01) between basal plasma testosterone levels and maximal increase in testosterone prior to and during puberty. The magnitude of LH release following LRF was correlated with the testosterone responses in each group: The mean maximal increase in LH and the mean maximal increase in testosterone in adult males > pubertal males > prepubertal males. We conclude that an ordered, sequential maturation of the hypothalamic → pituitary gonadotropin → gonadal axis presages the onset of puberty in man.