Developmental changes in serum luteinizing hormone, follicle stimulating hormone and androgen levels in males of two inbred mouse strains.

A comprehensive developmental study of serum LH, FSH and androgen concentrations was carried out in male mice of two inbred strains. Gonadotropic hormone (GTH) levels rose 10-15 days prior to the pubertal increase in serum androgen with FSH preceding LH in this regard. In both strains GTH titer rose to a peak at 30 or 35 days and then steadily declined to adult levels which were strain-specific. Serum androgen was detected at low, relatively steady levels until the pubertal increase between 30 and 50 days postpartum. The results are interpreted as supporting the hypothesis that a shift in feedback sensitivity, occurring at about 20 days of age, may be involved in the onset of puberty in the male mouse.