Regulation of gonadotrophin secretion in male mice from birth to adulthood. Response to LRH injection, castration and testosterone replacement therapy.

Plasma LH and FSH concentrations were determined by radioimmunoassay in male mice from birth to adulthood after LRH injection, castration and testosterone replacement therapy. Except at birth for LH, LRH significantly increased circulating levels of both gonadotrophins at all stages studied. It is suggested that a change in the pituitary LH response to LRH occurs around puberty and perhaps represents the time of initiation of pubertal processes.

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).