The Development of Cyclic Pituitary—Gonadal Function in Adolescent Females

Serum concentrations of FSH, LH, estradiol, progesterone and testosterone were measured at 2–3-day intervals for 35 days in 1 prepubertal girl, 3 pubertal premenarchal girls, 1 girl at menarche and 2 girls who were 6 and 9 months postmenarche. No hormone rhythms were seen before puberty. Random episodic fluctuations in FSH, estradiol and testosterone appeared in early puberty. The girl studied at menarche showed an apparent 11-day estradiol rhythm, with peaks to 12 ng/100 ml unaccompanied by changes in gonadotropin concentration. The post-menarchal girls both showed adult-type estradiol peaks followed by a midcycle FSH/LH peak of ovulatory magnitude. In 1 the cycle was anovulatory; in the other an abbreviated luteal progesterone rise occurred. A midcycle testosterone rise was seen in both. These patterns suggest that the development of mature pituitary-ovarian hormone interrelationships may involve a stage during which there are regular fluctuations in ovarian estrogen secretion; these later could become of sufficient magnitude and duration to induce an ovulatory LH surge.