Characterization of intrafollicular steroid hormones, inhibin, and follistatin in women with and without polycystic ovarian syndrome following gonadotropin hyperstimulation.

The etiology of polycystic ovary syndrome (PCOS) is unexplained. Since no major deficiencies are reported in serum FSH or inhibin, we hypothesized that abnormal levels of a paracrine modulator of FSH action within the ovary may be associated with the arrest of follicular growth seen in the PCOS ovary. Follicular fluid aspirates were collected from women with (n = 7) or without (n = 17) PCOS during oocyte retrieval for in vitro fertilization. Aspirates were assayed for total inhibin, inhibin A (InhA), inhibin B (InhB), and follistatin (FS), as well as for estradiol, progesterone (P4), androstenedione, and total protein. Hormone levels were compared between women with and without PCOS using all aspirates (some of which were collected from multiple follicles at once) and also between aspirates containing fluid from a single follicle only (PCOS, n = 30; non-PCOS, n = 107). P4 levels were significantly (p < 0.01) reduced in PCOS versus non-PCOS women as evidenced by analysis of all follicles as well as in single-follicle aspirates only. In addition, InhA, P4, and FS increased with follicle volume, and InhB decreased significantly in non-PCOS, but not in PCOS, follicles. Therefore, although follicular development can be induced in PCOS patients with gonadotropins, hormonal responses within the ovary appear inappropriate in terms of concentrations or patterns of secretion. These data support the concept that PCOS is associated with a deficit in the paracrine control of folliculogenesis.