Regulation of the preovulatory gonadotropin surge by endogenous steroids

摘要: Abstract Estradiol secreted by growing ovarian follicle(s) has been considered classically to be the neural trigger for preovulatory surge of gonadotropins. The observation that estradiol-induced gonadotropin in ovariectomized rats is lesser magnitude and duration than found cycling rat at proestrus resulted a search other steroid regulators. Progesterone major regulator surge. It can only act presence an estrogen background, which necessary synthesis progesterone receptors. In estrogen-primed rat, able initiate enhance observed on day limit it 1 day. physiological role induction demonstrated attenuation progesterone-induced endogenous receptor antagonist RU486 inhibitor trilostane. promoter region follicle-stimulating hormone (FSH)-β gene contains multiple response elements brings about FSH release as well. reduction 5α-position appears important regulation secretion. Corticosteroids appear play significant secondary late early estrus.