Peripheral plasma concentrations of LH, FSH, prolactin and GH from birth to puberty in male and female mice.

Circulating concentrations of plasma LH, FSH, prolactin and GH in male and female mice were measured twice daily (12:00 and 24:00 h) by radioimmunoassay from birth to puberty. FSH concentrations in females were higher than in males from birth to about 16 days of age, then values in males rose while those in females fell. Prolactin levels in both sexes were low then increased slightly toward puberty with midnight levels being higher in the males and lower in the females. LH concentrations were relatively low in both sexes until Days 7-8 of age then showed distinct fluctuations. The fluctuations of GH in both sexes seemed to correspond to fluctuations in LH.