Effect of an infusion of Gn-RH upon levels of sex hormones in prepubertal and pubertal girls: evidence for relative ovarian insensitivity.

Changes in levels of sex steroids and gonadotropins were measured in 16 normal prepubertal and 15 pubertal girls prior to and after a 3 hour infusion of 100 microgrm synthetic gonadotropin releasing hormone (Gn-RH). Plasa estradiol (E2) concentrations rose significantly (p less than 0.02) from 29.7 +/- 4.6 (SE) pg/ml in the basal period to to 46.8 +/- 7.1 at the end of the infusion in the pubertal girls but were unchanged in the prepubertal girls. Estrone (E1), progesterone (P), 17-HYDROXYPROGESTERONE (17OHP), TESTOSTERONE (T), DIHYDROTESTOSTERONE (DHT), and androstenedione (A), dehydroepiandrosterone (DHA) and dehydroepiandrosterone sulfate (DHAS) levels were not altered in either maturity group. Basal plasma E2, E1, T, DHT, DHA and DHAS concentrations significantly correlated with the releasable pool of LH evoked by Gn-RH from the pituitary gonadotropes. We conclude: 1) The ovary is not highly and rapidly responsive to transient elevations of endogenous gonadotropin, and 2) Adrenal androgens may to some extent modulate the maturation of the hypothalamic-pituitary-gonadal system, at least as reflected by the pituitary response to exogenous Gn-RH.