Evolution of the menstrual pattern of gonadotrophin and sex steroid concentrations in serum.

Consecutive daily serum samples were obtained over 25-30 days from 2 pre-pubertal girls (Stage I), 2 girls with breast development alone (Stage II); one girl with both breast development and pubic hair (Stage III), and 2 girls who were six months and three years post-menarche, respectively (Stage IV). All serum samples were assayed for LH, FSH, progesterone and 17-hydroxyprogesterone. Sera from 6 girls were assayed for testosterone, and sera from 3 were assayed for oestradiol. The patterns of gonadotrophins and sex steroid concentrations in both Stage I and Stage II girls were characterized by day to day stability. LH and FSH concentration was increased in Stage II subjects, while steroid concentration were similar to those in Stage I. The Stage III subject showed marked, apparently random, fluctuations in the concentrations of LH, FSH, oestradiol and 17-hydroxyrogesterone. In Stage IV, as early as six months post-menarche, there was a definte peak in the serum concentration of gonadotrophins, 17-hydroxyprogesterone and oestradiol. However, luteal phase length and maximal progesterone levels of these post-menarchial girls were less than those observed for normal adult females. These data are consistent with evolution of the adult menstrual pattern of hormone secretion through a series of developmental stages.