REGULATION OF OVARIAN FOLLICULAR ESTRADIOL PRODUCTION

本提案的目的是确定各种因素和条件 调节卵泡中雌二醇的合成。 雌二醇 排卵前卵泡发育的主要类固醇产物 持续的雌二醇分泌对于卵泡达到 排卵状态 有证据表明一些物种 卵泡膜细胞和颗粒细胞都需要雌二醇的产生 因为卵泡膜细胞产生雄激素， 雌激素通过颗粒细胞。 据信FSH和 LH是卵泡发育和雌二醇的必需物质 分泌物 虽然LH刺激雄激素的产生，在许多 种，FSH和LH在调节转换的作用， 除了大鼠外，对雄激素与雌二醇的关系知之甚少。 这 该提案旨在研究FSH和LH在以下方面的作用： 牛类固醇生成和卵泡发育， 滤泡内类固醇作为潜在调节剂的作用 卵泡类固醇产生。 具体地说，促性腺激素的内源性水平将改变， 在牛发情周期的特定时间，通过注射 促黄体生成素或抗黄体生成素血清。 对卵泡的影响 将通过以下方法在体内评估发育和消退： 卵巢和某些实验中的卵泡的超声检查 将被分离并培养卵泡细胞以确定 内源性促性腺激素水平的改变对 类固醇生成能力。 在其他实验中， 雄激素和雌二醇作为卵泡内调节因子 将通过培养卵泡膜和/或 从牛的排卵前卵泡获得的颗粒细胞， 不同浓度和组合的大鼠 类固醇，在促性腺激素存在和不存在的情况下。 最后， 卵泡分泌雌二醇与 将使用黄体酮和催产素探索黄体化 分泌和颗粒细胞形态作为 黄体化 拟议的实验将提供一个更好的理解 促性腺激素和类固醇在调节 卵泡分泌雌二醇，因此，可能最终导致 开发更好的诱导排卵方法， 调节生育率。

The objective of this proposal is to identify factors and conditions that regulate estradiol synthesis in ovarian follicles. Estradiol is the dominant steroid product of developing preovulatory follicles and continued estradiol secretion is essential for follicles to reach ovulatory status. There is evidence for a number of species that both theca and granulosa cells are needed for estradiol production because the theca cells make androgen which is aromatized to estradiol by the grandulosa cells. It is believed that both FSH and LH are essential for follicular development and estradiol secretion. Although LH stimulates androgen production in many species, the roles of FSH and LH in regulating the conversion of androgen to estradiol are poorly understood, except in rats. This proposal is designed to investigate the roles of FSH and LH in steroidogenesis and follicle development in cattle and to examine the actions of intrafollicular steroids as potential regulators of follicular steroid production. Specifically, endogenous levels of gonadotropins will be altered at specific times during the bovine estrous cycle by injections of inhibin or an antiserum to LH. The effects on follicular development and regression will be assessed in vivo by ultrasonography of the ovaries and in some experiments follicles will be isolated and follicle cells cultured to determine the effects of altered endogenous gonadotropin levels on their steroidogenic capabilities. In other experiments the roles of androgen and estradiol as intrafollicular regulators of steroidogenesis will be explored by culturing theca and/or granulosa cells obtained from preovulatory follicles of cattle and rats with various concentrations and combinations of these steroids, in the presence and absence of gonadotropins. Finally, the relationship between follicular estradiol production and luteinization will be explored, using progesterone and oxytocin secretion and granulosa cell morphology as markers for luteinization. The proposed experiments will provide a better understanding of the actions of gonadotropins and steroids in the regulation of follicular estradiol secretion and thus, may eventually lead to the development of better methods of inducing ovulation and regulating fertility.