Physiological property of estrogen-HEADreceptor positive hypothalamic neurons visualized in transgenic rats

雌激素参与大脑发育过程中的内分泌和行为性别分化，以及成年后生殖神经内分泌和行为的性别特异性调节。细胞雌激素信号是通过核雌激素受体(ER)来传递的，包括经典的ERα和新近克隆的ERβ。这两种雌激素受体在视前区、下丘脑、边缘结构均有表达，参与了生殖调控。然而，ERβ是否像ERα一样以性别特异的方式表达仍存在争议。两个ER在相同神经元中的共定位也尚未建立，这将通过形成异二聚体改变转录的特异性，并在不同的细胞中根据ERα和ERβ的比例产生不同的对雌激素的反应。通过基因靶向干扰ERα或ERβ影响生殖的各个方面。雌性和雄性ERα基因敲除小鼠是可育的，ERβ基因敲除…更多的雌性会降低生育能力。在ERα或ERβ基因敲除的女性中，存在无排卵和出血性或多囊卵巢。该综合征至少部分是由于促性腺激素释放激素(GnRH)分泌的中心机制，因为几种减少促性腺激素分泌的方案改善了缺陷。雌激素对促性腺激素分泌的负反馈作用在ERα干扰的雌性和雄性小鼠中受到影响，但雌激素可以在雄性去势小鼠的POA中诱导孕激素受体，可能是通过ERβ。然而，与使用ER基因敲除小鼠相关的主要警告是，这两个ER可能相互作用来调节某些细胞的转录活性，使得分开识别ERα和ERβ的作用变得困难。雌激素诱导的孕激素受体作为神经转录因子，通过改变参与GnRH神经元调节的神经递质的合成或活性来触发雌性大鼠的GnRH激增。POA前腹侧脑室周围核(AVPV)中的孕激素受体可能特别重要。雌性大鼠的AVPV是性二态的，其多巴胺能神经元的数量是雄性的3倍多。AVPV还含有性二型性群肽能神经元或谷氨酸受体亚单位，并与女性特异性排卵释放GnRH有关，它直接投射到GnRH神经元。事实上，局限于这一区域的小病变会阻止雌性大鼠促性腺激素的循环释放，并最终达到无排卵、持续发情的状态。将孕激素受体反义寡核苷酸注入邻近动静脉曲张的第三脑室，阻断受体蛋白的诱导，防止黄体生成素手术。我们发现动静脉动静脉曲张中ERβ的表达存在显著的性别差异。新生儿激素状况改变了性别表型。ERβ基因共定位于84%的雌激素ERα免疫反应细胞中，可能是多巴胺能的。将ERβ反义寡核苷酸注入邻近动静脉曲张的第三脑室可减少ERβ蛋白的表达，并产生恒定的阴道间情期。较少

Estrogens are involved in both endocrine and behavioral sex differentiation during brain development and sex-specific regulation of reproductive neuroendocrinology and behavior in adulthood. Cellular estrogen signaling is conveyed by nuclear estrogen receptors (ER) which include the classical ERα as well as the recently cloned ERβ. Both ERs are expressed in the preoptic area (POA), hypothalamus, limbic structures, which have been implicated in the regulation of reproduction. It is controversial, however, whether ERβ is expressed in sex-specific manner like ERα. Co-localization of the two ERs in identical neurons, which would alter the specificity of the transcription by forming heterodimers and produce variable responses to estrogen in different cells depending on the ratios of ERα and ERβ they contain, is also yet to be established.Disruption of either ERα or ERβ by gene targeting affects various aspects of reproduction. Female and male ERα knockout mice are inflertile and ERβ knockou … More t females have a reduced fecundity. Anovulation and hemorrhagic or polycystic ovary are present in either the ERα or ERβ knockout females. The syndrome is due, at least partially, to the central mechanism for the secretion of gonadotropin-releasing hormone (GnRH), because several regimens that decrease gonadotropin secretion ameliorate the defects. Negative feedback action of estrogen on gonadotropin secretion is compromised in ERα-disrupted female and male mice, but progesterone receptor can be induced by estrogen in the POA of male castrates, presumably through ERβ. The major caveat associated with the use of ER knockout mice, however, is that the two ERs may interact to modulate transcriptional activity in certain cells, making separate identification of the action of ERα and ERβ difficult.Estrogen-induced progesterone receptors act as a neuronal transcription factor which triggers GnRH surge in the female rat by altering synthesis or activity of neurotransmitters involved in the regulation of GnRH neurons. Progesterone receptors in the anteroventral periventricular nucleus (AVPV) of the POA may be particularly important. The AVPV is sexually dimorphic with over 3 times as many dopaminergic neurons in the female rat compared with males. The AVPV also contains sexually dimorphic populations of peptidergic neurons or glutamate receptor subunits, and has been implicated in the female-specific ovulatory release of GnRH with its direct projections to GnRH neurons. Indeed, small lesions confined to this region block the cyclic release of gonadotropins in the female rat and culminates in an anovulatory, persistent estrous state. Injections of progesterone receptor antisense oligonucleotides into the third ventricle adjacent to the AVPV blocks the induction of the receptor protein and prevents luteinizing-hormone surge.We found a striking sex difference in the ERβ expression in the AVPV.Neonatal steroid status altered the sexual phenotype. ERβ mRNA co-localized in 84% of estrogen ERα immunoreactive cells, and may be dopaminergic in nature. Infusion of ERβ antisense oligonucleotides into the third ventricle adjacent to the AVPV diminished ERβ protein and produced constant vaginal diestrus. Less