Developmental toxicity of environmental chemicals

环境化学品的发育毒性

基本信息

批准号：
7066573
负责人：
FREDERICK S VOM SAAL
金额：
$ 35.4万
依托单位：
UNIVERSITY OF MISSOURI-COLUMBIA
依托单位国家：
美国
项目类别：
财政年份：
2002
资助国家：
美国
起止时间：
2002-08-04 至 2008-05-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): The goal of the proposed research is to investigate mechanisms mediating disruption by bisphenol A (BPA) of cellular signalling systems during prostate and seminal vesicle development. BPA leaches from plastic resulting in significant fetal exposure in humans. Exposure of fetal mice to low doses of BPA results in a permanent increase in prostate gland number, overall size and androgen receptors (AR), while a permanent decrease in seminal vesicle size occurs; preliminary evidence suggests this is due to a decrease in the enzyme 5a-reductase, required for dihydrotestosterone (DHT) formation. Our first hypothesis is that the effects of low, environmentally relevant doses of BPA (and low doses of diethylstilbestrol, DES, as a positive control) in the fetal mouse prostate occur via binding to estrogen receptor alpha (ERa), induction of EGF and, subsequently, also IGF-1 gene activity (and synthesis of these growth factors), leading to a permanent increase in AR gene expression and AR protein. Our second hypothesis is that much higher doses of DES, but not BPA, will result in the opposite outcome and interfere with prostate development via competing with DHT for binding to AR. In the seminal vesicles, we predict that there will be a dose-dependent inhibition of EGF and IGF-1, resulting in a permanent dose-related down-regulation of 5a-reductase activity. To test these hypotheses our first specific aim is to conduct in vivo studies in which pregnant CD-1 mice are administered environmentally relevant doses of BPA (and also DES). Our second specific aim is to conduct in vivo studies with high doses of BPA and DES, up to the maximum tolerated dose. Our third specific aim involves removing the fetal urogenital sinus and Wolffian ducts for studies in primary culture to answer specific mechanistic questions by administering very low through sub-lethal doses of DES and BPA. We will also determine whether EGF and IGF-l mimic effects of DES and BPA, and if administering antibodies to these proteins inhibits effects. The fourth specific aim is to determine whether high doses of DES, but not BPA, compete with DHT for binding to AR, thus producing an antiandrogenic effect. In these studies the prostate and seminal vesicles will be examined on gestation day 18, postnatal day 3 and in adult offspring. We will initially focus on AR, ERa, ERB, 5a-reductase, EGF and IGF-1, and measure both mRNA levels by RT-PCR and protein levels by western blot analysis. Organ morphology will be determined by 3-D computer reconstruction from histological sections, coupled with in situ hybridization and immunocytochemistry for the above mRNAs and corresponding proteins, including markers for cell types, proliferation and apoptosis. 5a-reductase activity will be determined by radiometric assay.

描述（由申请人提供）：拟议的研究的目的是研究前列腺和精确囊泡发育过程中细胞信号系统中介导双酚A（BPA）介导的机制。 BPA从塑料中浸出，导致人类大量暴露。胎儿小鼠暴露于低剂量的BPA导致前列腺数量，整体大小和雄激素受体（AR）永久增加，而精液囊泡大小的永久减少；初步证据表明，这是由于二氢睾丸激素（DHT）形成所需的酶5A还原酶的降低。我们的第一个假设是，低剂量的BPA（和低剂量的二乙基甲状腺乙醇，DES，作为一种阳性对照）是通过与雌激素受体α（ERPA）的结合，EGF的诱导以及随后的EGF诱导以及随后的，随后的，以及IGF-1 GENES的表现（以及这些生长量），并构成ARE AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR AR ARNISTINS提高。我们的第二个假设是，更高的DES剂量（而不是BPA）将导致相反的结果，并通过与DHT竞争与AR结合，从而影响前列腺的发展。在精液囊泡中，我们预测将依赖于EGF和IGF-1的剂量依赖性抑制，从而导致5A-还原酶活性的永久性下调。为了检验这些假设，我们的第一个具体目的是进行体内研究，其中对怀孕的CD-1小鼠进行环境相关的BPA（以及DES）。我们的第二个具体目的是用高剂量的BPA和DES进行体内研究，最大耐受剂量。我们的第三个具体目的是消除胎儿泌尿生殖器窦和沃尔夫语导管，以在原发性培养的研究中进行研究，以通过极低的下降剂量DES和BPA来解决特定的机械问题。我们还将确定DES和BPA的EGF和IGF-L模拟效应，以及对这些蛋白质的抗体是否抑制效应。第四个特定目的是确定高剂量的DES（而不是BPA）是否与DHT竞争与AR结合，从而产生抗雄激素作用。在这些研究中，将在妊娠第18天，产后第3天和成年后代检查前列腺和精液囊泡。我们最初将专注于AR，ERA，ERB，5A-还原酶，EGF和IGF-1，并通过RT-PCR和蛋白质水平通过Western Blot分析来测量MRNA水平。器官形态将由组织学切片的3-D计算机重建确定，再加上上述mRNA和相应蛋白质的原位杂交和免疫细胞化学，包括细胞类型，增殖和凋亡的标记。 5A还原酶活性将通过辐射测定法确定。