Ontogeny of the secretory pattern of LH and FSH in male mice during sexual maturation.

Plasma LH and FSH concentrations were measured in male mice at 10-day intervals from 1 to 90 days and at 2-day intervals between 20 and 40 days. The skewed distribution and variability of LH concentrations observed in mice aged 20 to 90 days suggests that LH is released in an episodic fashion. Mean levels of LH and baseline concentrations increased significantly from infantile (1-20 days) to adult age (50-90 days). Pulsatile discharges of LH appeared to start at 22 days, and their frequency increased from 9.6% (prepubertal stage: 20-30 days) to 31.6% (pubertal stage: 30-40 days). In contrast, for FSH no evidence of pulsatile secretion was found, and mean levels increased 5-fold from the infantile to the peripubertal stage, and adult levels were then attained.