Environmental Estrogens Acting via a Membrane Receptor

性状（由申请方提供）：已知雌激素模拟物会污染 我们的环境，并可能导致有毒后果的内分泌 功能性破坏和启动或支持肿瘤生长。环境 雌激素先前已经测试了它们引起基因组改变的能力， 反应;然而，对这些化合物的非基因组反应还没有被发现。 探讨了我们已经鉴定了雌激素受体的α型 在GH 3/B6垂体瘤细胞的质膜中， 作为雌激素的膜启动作用的模型（快速雌激素诱导的 催乳素的释放）。富集膜雌激素受体（mER）的细胞 对雌二醇和DES的增殖作用更敏感; 这可能与催乳素的释放（催乳素作为生长因子， 因子）或调节细胞分裂的激酶的活化。异雌激素 最近与几种非基因组反应有关。因此很 重要的是要了解，如果异种雌激素可以通过膜启动 在我们的模型系统中与mER相关的机制。为了验证我们的假设， 我选择了7种化合物，代表了不同类型的 异种雌激素将测试它们在mER 4中产生效果的能力 vs. mER-细胞，以使反应对应于该受体的存在。 具体而言，我们的目标是：（1）测试选定的异种雌激素的 能够引起催乳素的快速分泌，增加细胞内 钙水平和MAP激酶的快速激活;和（2）检查 相同化合物结合ER α的膜形式的能力， 用于E2 -BSA-荧光素与mER的竞争结合的测定，以及用于 配体介导的mER α表位掩蔽。功能的引出与约束 然后将这些化合物的能力相互比较;它们可能是 通过这个途径比通过基因组途径更有效。阐明 雌激素模拟作用的另一种途径应该有助于开发未来的 环境处理指南，治疗干预后， 暴露，并确定环境和饮食雌激素作为 致病或预防剂。

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.