ROLE OF PROGESTERONE RECEPTORS IN FSH SURGES

促性腺激素激增是非常重要的生物学事件， 卵巢和神经内分泌的适当细胞整合 信号.原发性LH和FSH激增依赖于 大脑中的神经和激素（雌激素，孕酮）刺激，以及 继发性FSH激增需要卵巢类固醇的协调作用， 垂体促性腺激素中的促性腺激素素和激活素。我们最近获得了 有证据表明，刺激排卵前和继发性 促性腺激素激增需要激活孕酮（P）受体 (PRs)，即使在没有循环P的情况下。因此，我们提出， 导致下丘脑释放GnRH激增的信号， 来自垂体的继发性FSH激增，必须收敛于PR水平， 神经元和促性腺激素。我们假设这些 整合过程依赖于E/2诱导PR表达的能力， 以及神经内分泌信号激活这些PR的能力， 配体独立的方式。具体地说，我们将检验这样一个观点， 神经递质信号可以激活神经元PR，导致刺激 促性腺激素释放激素和原发性促性腺激素激增，激活素和P可以 激活PR，促进继发性FSH激增的释放。 在目标1中，我们将使用微透析方法来确定 有助于释放次级FSH激增。在目标1中，我们将使用 微透析方法，以确定是否GnRH激增类固醇治疗 卵巢切除（OVX）大鼠，P 拮抗剂，或静脉内输注PR反义寡核苷酸， 破坏PR合成。在目标2和3中，我们将使用基因转移方法， 导入含有孕酮反应元件的融合基因， (PRE)连接到报告基因，在体外和体外下丘脑神经元中， vivo.我们将使用这种方法直接确定配体独立的 PR的激活发生在中枢神经元，并确定这是否 过程与排卵前峰产生过程有关。在 目标4，我们将直接评估公关在调解 激活素对FSH分泌的影响。激活素刺激将呈现给 来源于野生型和孕酮的垂体前叶细胞培养物 受体敲除（PRKO）小鼠，并且将测量FSH应答， 比较了如果在PRKO衍生培养物中观察到反应缺陷， 然后我们将进行基因转移实验， 将mPR导入PRKO衍生的细胞，并确定这些细胞的能力。 治疗以挽救FSH对激活素的反应性。在目标5和6中，我们 将PRE-reporter融合基因导入垂体前叶细胞， 以确定激活素是否可以激活PR，以及这是否 这一过程确实与FSH的发情释放有关。的 这些研究中获得的信息将对我们的 理解整合，细胞和分子事件， 包括排卵期峰产生过程。因此，它可以 对理解不孕症有重要意义 与类固醇反馈和中- 周期排卵激素激增。这些实验具有更广泛的意义， 也可能为细胞机制提供新的见解， 功能整合内分泌和神经信号，从而带来 关于各种各样的生物反应，比如那些涉及 动机行为，生殖发育，压力反应，或 学习和记忆。

Gonadotropin surges are critically important biological events that depend upon the appropriate cellular integration of ovarian and neuroendocrine signals. Primary LH and FSH surges are dependent upon integration of neural and hormonal (estrogen, progesterone) stimuli in the brain, and secondary FSH surges require coordinated actions of ovarian steroids, inhibin, and activin in pituitary gonadotropes. We recently obtained evidence that stimulation of both the preovulatory and secondary gonadotropin surges requires activation of progesterone (P) receptors (PRs), even in the absence of circulating P. We have thus proposed that signals leading to release of GnRH surges from hypothalamus, and to secondary FSH surges from pituitary, must converge at the level of PR in neurons and gonadotropes, respectively. We hypothesize that these integrative processes depend upon E/2,s capacity to induce PR expression, and the ability of neuroendocrine signals to activate these PRs in a ligand-independent manner. Specifically, we will test the idea that neurotransmitter signals can activate neuronal PRs, leading to stimulation of GnRH and primary gonadotropin surges, and that activin and P can activate PRs, contributing to release to release of secondary FSH surges. In Aim 1, we will use a microdialysis approach to determine if contributing to release of secondary FSH surges. In Aim 1, we will use a microdialysis approach to determine if GnRH surges in steroid-treated ovariectomized (OVX) rats are blocked by pretreatment with P antagonists,or i.c.v. infusions of PR antisense oligonucleotides to disrupt PR synthesis. In Aims 2 and 3, we will use a gene transfer method to introduce a fusion gene containing a progesterone response element (PRE) linked to a reporter gene, into hypothalamic neurons in vitro and in vivo. We will use this approach to directly determine ligand-independent activation of PRs occurs in central neurons, and ascertain whether this process is associated with the preovulatory surge-generating process. In Aim 4, we will directly assess the involvement of the PR in mediating the effects of activin on FSH secretion. Activin stimuli will be presented to anterior pituitary cell cultures derived from wild-type and progesterone receptor knock-out (PRKO) mice, and FSH responses will be measured and compared. If a response deficit is noted in the PRKO-derived cultures, then we will conduct gene transfer experiments in which we will introduce the mPR into PRKO-derived cells, and determine the ability of these treatments to rescue FSH responsiveness to activin. In Aims 5 & 6, we will transfer the PRE-reporter fusion gene into anterior pituitary cells both in vitro and in vivo to determine if activin can activate PRs, and if this process is indeed associated with the estrous release of FSH. The information gained in these studies will be of major significance in our understanding of the integrative, cellular, and molecular events that comprise the periovulatory surge-generating process. As such, it could have important implications for the understanding of infertilities associated with disruptions of steroid feedback and production of mid- cycle ovulatory hormone surges. Of broader significance, these experiments may also may also provide new insights into the cellular mechanisms which function to integrate endocrine and neural signals, and thereby bring about a variety of biological responses, such as those involved in motivated behaviors, reproductive development, stress responses, or learning and memory.