Reproductive sequelae in female rats after in utero and neonatal exposure to the phytoestrogen genistein

Objective: To determine reproductive sequelae in female rats after in utero and lactational dietary exposure to genistein. Design: Experimental animal study. Setting: University laboratory. Animal(s): Sprague Dawley rats. Intervention(s): Pregnant rats were fed control rat chow or rat chow incorporated with genistein (approximately 50 mu g/d) beginning on day 17 of gestation and continuing until the end of lactation (postpartum day 21). Genistein-exposed female pups were divided into two groups on day 21. One group continued to receive a genistein-added diet (G70); the other group was changed to a control diet (Ex-G). At necropsy (days 21 and 70), blood and reproductive tissues were collected. Main Outcome Measure(s): Serum levels of gonadotropins and gonadal steroids and histopathologic examination of the ovaries. Result(s): The weight of the ovaries and uterus and serum levels of E-2 and progesterone in genistein-exposed rats on day 21 (G21) were significantly reduced compared with control rats. On day 70, serum levels of E-2, progesterone, LH, and FSH were similar in all groups. Atretic follicles and secondary interstitial glands were more common in G70 and Ex-G rats compared with control rats. Cystic rete ovarii was observed in some G70 and Ex-G rats. Conclusion(s): Our data indicate that in utero and lactational exposure to dietary genistein adversely affects reproductive processes in the adult female rat. (Fertil Steril(R) 1998;70:440-7. (C)1998 by American Society for Reproductive Medicine.).