Environmental Estrogens Acting via a Membrane Receptor

描述(申请人提供)：已知的雌激素模拟物会污染 我们的环境，并可能导致内分泌的毒性后果 功能障碍，以及肿瘤生长的启动或支持。环境 雌激素此前已被测试其诱导基因组的能力 反应；然而，对这些化合物的非基因组反应尚未 探索过了。我们已经确定了雌激素受体的阿尔法型 (ERpha)在GH3/B6垂体瘤细胞的质膜上，其服务于 作为雌激素膜启动作用的模型(快速雌激素诱导 催乳素的释放)。富含膜雌激素受体(MER)的细胞 对雌二醇和DES的增殖作用反应更灵敏； 这可能与催乳素的释放(催乳素作为生长 因子)或激活调节细胞分裂的激酶。异种雌激素 最近与几个非基因组反应有关。因此，它是非常 了解外来雌激素是否可以通过膜启动起作用很重要 在我们的模型系统中，与MER相关联的机制。为了检验我们的假设，我们 我挑选了代表不同类别的7种化合物的曲目 异种雌激素。他们将接受在mer4中产生效果的能力测试。 Vs.Mer-细胞，以便对该受体的存在产生反应。 具体地说，我们的目标是：(1)测试选定的外来雌激素 导致催乳素快速分泌的能力，细胞内增加 钙水平和MAP激酶的快速激活；以及(2)检查 相同化合物与ERpha膜形式结合的能力 2-牛血清白蛋白-荧光素与聚合体结合的竞争分析 配基介导的MERA表位掩蔽。功能引出与捆绑 然后将这些化合物的能力相互比较；它们可能是 通过这一途径比通过基因组途径更有效。澄清 雌激素模拟作用的另一种途径应该有助于开发未来 环境处理指南，事后的治疗干预 暴露，以及确定环境和饮食中的雌激素为 致病或防病药剂。

DESCRIPTION (provided by applicant): Estrogen mimetics are known to contaminate our environment, and may contribute to toxic consequences of endocrine functional disruption, and initiation or support of tumor growth. Environmental estrogens have previously been tested for their abilities to elicit genomic responses; however, nongenomic responses to these compounds have not been explored. We have characterized the alpha form of the estrogen receptor (ERalpha) in the plasma membrane of GH3/B6 pituitary tumor cells, which serve as a model for membrane-initiated actions of estrogens (rapid estrogen-induced release of prolactin). Cells enriched for the membrane estrogen receptor (mER) are much more responsive to the proliferative effects of estradiol and DES; this could be related to either prolactin release (prolactin acting as a growth factor) or activation of kinases which regulate cell division. Xenoestrogens were recently implicated in several nongenomic responses. Therefore, it is very important to learn if xenoestrogens can act through membrane-initiated mechanisms linked to the mER in our model system. To test our hypothesis we have selected a repertoire of 7 compounds representing different classes of xenoestrogens. They will be tested for their ability to produce effects in mER4 vs. mER- cells in order to corrate responses to the presence of this receptor. Specifically, our aims are to: (1) Test the selected xenoestrogens for their ability to cause rapid secretion of prolactin, increases in intracellular calcium levels, and rapid activation of MAP kinases; and (2) examine the ability of the same compounds to bind to the membrane form of ERalpha using assays for competition for binding of E2 -BSA-fluorescein to the mER, and for ligand-mediated masking of an mERa epitope. The function-eliciting and binding abilities of these compounds will then be compared to each other; they may be more potent through this pathway than through the genomic pathway. Elucidating another pathway for estrogen mimetic actions should help to develop future guidelines for environmental handling, therapeutic interventions after exposures, and the identification of environmental and dietary estrogens as disease-causing or -preventing agents.