Endocrine Traits of Polycystic Ovary Syndrome in Prenatally Androgenized Female Sprague-Dawley Rats

Abstract

Although hyperandrogenism is an important condition and is considered the possible pathogenesis behind polycystic ovary syndrome (PCOS), data supporting this is still scarce. We sought to determine whether or not prenatal androgen exposure leads to PCOS and the possible cellular mechanisms involved. To induce prenatal androgen exposure, pregnant rats were treated with daily subcutaneous injections of free testosterone (T) or dihydrotestosterone (DHT) from embryonic days 16 to 19, and their female offspring were studied as adults. The mRNA expression of the progesterone receptor (PR) in the preoptic area (POA) hypothalamus was higher in the experimental groups than in the control group after ovariectomy and stimulation with estradiol benzoate. The levels of T, P, leutinizing hormone (LH), and estradiol were higher in the experimental groups than in the control groups. The frequency and magnitude of LH secretion was increased in experimental rats as compared with the control group. The anogenital distance of the experimental groups was prolonged and the nipple number was lower than that of the control group. Almost all experimental rats had prolonged or irregular estrous cycles. The experimental groups had fewer corpus luteum and preovulatory follicles and more preantral follicles and antral follicles than the controls. Our findings are consistent with the hypothesis that excess androgen during the prenatal period may cause PCOS. Additionally, we show that hyperandrogenic interference in the release of preovulatory LH surges is mediated by the suppressive effects of androgens on PR expression in POA-hypothalamic tissue.