Comparison of inhibin B and estradiol responses to intravenous FSH in women with polycystic ovary syndrome and normal women.
BACKGROUND
Inhibin B (Inh B) is produced by pre-antral and early antral follicles whereas estradiol (E(2)) is a product of follicles undergoing antrum formation. This temporal distinction is evident in the patterns of Inh B and E(2) release earlier and later during the follicular phase of the menstrual cycle, respectively. However, in previous studies of women with polycystic ovary syndrome (PCOS) and normal controls, release of these granulosa cell (GC) products appears to be simultaneous in response to FSH stimulation. In order to reconcile these disparate findings, we conducted dose-response studies in both PCOS women and normal controls to determine whether GC product responses were due to the amount of FSH administered. In addition, we compared FSH-stimulated responses in PCOS women at various stages of recovery following ovarian suppression with a long-acting GnRH agonist to examine whether Inh B and E(2) responses reflected the level of ovarian follicle activity (i.e. circulating E(2) levels).


METHODS
Women with PCOS, 18-35 years (n = 23), and normal ovulatory controls, 18-35 years (n = 10) were recruited for study. Dose-responses were assessed over 24 h following intravenous administration of 0 (saline), 37.5, 75 and 150 IU of recombinant human FSH (r-hFSH) in PCOS and normal women. In addition, E(2) and Inh B responses to 150 IU of r-hFSH were assessed at baseline and 4, 6 and 8 weeks following suppression of ovarian steroidogenesis by a long-acting GnRH agonist in PCOS women.


RESULTS
In PCOS women and normal controls, serum Inh B and E(2) exhibit similar and simultaneous dose-responsiveness to FSH stimulation. During recovery from ovarian suppression, basal and stimulated Inh B release appear to be restored earlier than that of E(2) in PCOS women.


CONCLUSIONS
These findings are consistent with the notion that, in PCOS women, the level of ovarian follicle activity largely determines the earlier release of Inh B compared with E(2).
Departments of Reproductive Medicine, University of California, San Diego, School of Medicine, 9500 Gilman Drive, La Jolla, CA 92093-0633, USA.
Marcus A
MA
Rosencrantz
Deborah S
DS
Wachs
Mickey S
MS
Coffler
Pamela J
PJ
Malcom
Michael
M
Donohue
R Jeffrey
RJ
Chang
D000293:Adolescent; D000328:Adult; D004958:Estradiol / Q000097:blood*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000008:administration & dosage / Q000494:pharmacology*; D006728:Hormones / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D007265:Inhibins / Q000097:blood*; D007275:Injections, Intravenous; D011085:Polycystic Ovary Syndrome / Q000097:blood*
D006728:Hormones; C422364:inhibin B; D004958:Estradiol; D007265:Inhibins; D005640:Follicle Stimulating Hormone