Dose-response characteristics of neonatal exposure to genistein on pituitary responsiveness to gonadotropin releasing hormone and volume of the sexually dimorphic nucleus of the preoptic area (SDN-POA) in postpubertal castrated female rats

摘要: Estrogen exposure during critical periods of development promotes androgenization the brain, which is reflected in altered morphology, behavior, and cyclic hormone secretion females. Previous work our laboratory demonstrated that neonatal female rats injected with pharmaceutical or naturally occurring estrogens had decreased GnRH-induced LH increased volume SDN-POA as 42 day castrates. The current experiment defines dose-response characteristics to isoflavonoid phytoestrogen genistein (G) on pituitary sensitivity GnRH volume. Litters rat pups received subcutaneous injections either corn oil, 1, 10, 100, 200, 400, 500, 1000 micrograms G days 1 10 life. litters were ovariectomized weaned 21. On blood was drawn from right atrial catheters immediately prior to, 5, 15, 30 min following a single injection 50 ng/kg GnRH. Only dose associated response GnRH, while progressive increases levels decreasing secretion. only 500 groups compared controls. results confirm low doses have nonandrogenizing, pituitary-sensitizing effects, higher mimic more typical effects estrogens. use both morphologic physiologic end points completely reproductive consequences environmental estrogen CNS development.