Neonatal Endocrine Disruption and Ovarian Senescence

描述（由申请人提供）：发育中的哺乳动物雌性生殖道对被称为内分泌干扰物的环境毒物的作用特别敏感。胎儿/新生儿暴露于内分泌干扰物如己烯雌酚（DES）可永久性地改变生殖器官的结构和功能，包括子宫、输卵管和卵巢。新生儿暴露于DES的一个关键形态学表现是在新生儿卵巢中诱导大量多卵泡（POF），这表明在原始卵泡形成过程中生殖细胞：体细胞关联异常。假设DES诱导POF可减少卵巢原始卵泡的补体，加速卵巢衰老。这一假设将通过比较暴露于新生儿DES的仓鼠卵巢的原始卵泡含量与未处理对照组的时间来验证。将测定成年仓鼠正常生殖期和衰老期卵巢的原始卵泡含量，并测试大剂量低剂量DES的影响。为了解决DES作用的潜在基因靶点，将监测卵母细胞特异性因子生长分化9 （GDF-9）的表达。GDF-9在新生仓鼠卵巢原始卵泡中表达，并在原始卵泡发生期间表达。因此，GDF-9可能是内分泌干扰物的靶点。据推测，新生儿暴露于DES会改变GDF-9的表达，从而改变原始卵泡形成的正常过程。新生儿DES暴露对新生儿卵巢GDF-9 mRNA含量和定位的时间影响将分别通过半定量RT/PCR和原位杂交进行评估。通过免疫组织化学检测GDF-9蛋白表达。在成年和衰老的卵巢中，将测定GDF-9 mRNA的表达，并将其与上述测定的原始卵泡含量相关联，以评估GDF-9是否反映了现有的卵母细胞池，从而可以作为一种方便的标记物。这些研究将提供关于内分泌干扰物原型对卵巢功能关键参数影响的新的重要信息，并将建立一种有用的方法来评估其他对环境重要的内分泌干扰物的影响。

DESCRIPTION (provided by applicant): The developing mammalian female reproductive tract is particularly sensitive to actions of environmental toxicants referred to as endocrine disruptors. Fetal/neonatal exposure to endocrine disruptors such as diethylstilbestrol (DES) can permanently alter structure and function of reproductive organs including the uterus, oviduct, and ovary. A key morphological manifestation of neonatal DES exposure is the induction of numerous polyovular follicles (POF) in the neonatal ovary, indicative of abnormal germ cell: somatic cell association during primordial follicle genesis. It is hypothesized that the induction of POF by DES reduces the ovarian complement of primordial follicles, which accelerates ovarian senescence. This hypothesis will be tested by comparing primordial follicle content temporally in the ovaries of hamsters exposed to neonatally to DES relative to non-treated controls. Primordial follicle content of ovaries during the normal reproductive period in the adult hamster and in the aging ovary will be determined and the impact of a broad low-dose range of DES will be tested. To address potential gene targets of DES action, the expression of the oocyte-specific factor growth differentiation 9 (GDF-9) will be monitored. GDF-9 is expressed in the neonatal hamster ovary in primordial follicles and is expressed during the period of primordial follicle genesis. Hence, GDF-9 may be an endocrine disruptor target. It is hypothesized that neonatal DES exposure modifies GDF-9 expression, which alters the normal course of primordial follicle formation. The temporal impact of neonatal DES exposure upon GDF-9 mRNA content and localization in the neonatal ovary will be assessed by semi-quantitative RT/PCR and in situ hybridization, respectively. GDF-9 protein expression will be assessed via immunohistochemistry. In the adult and aging ovary, GDF-9 mRNA expression will be determined and correlated to the primordial follicle content determined above to assess whether GDF-9 reflects the existing oocyte pool and thus, can be used as a convenient marker. These studies will provide new and important information regarding the impact of a prototypic endocrine disruptor upon a key parameter of ovarian function and will establish a useful method to assess the impact of other environmentally important endocrine disruptors.