Naciff Jorge M, Torontali Suzanne M, Overmann Gary I, Carr Gregory J, Tiesman Jay P, Daston George P
Miami Valley Innovation Center, The Procter and Gamble Company, Cincinnati, Ohio 45253-8707, USA.
Birth Defects Res B Dev Reprod Toxicol. 2005 Apr;74(2):164-84. doi: 10.1002/bdrb.20032.
In a previous study, we determined the effects of 17-alpha-ethynyl estradiol (EE) on gene expression using microarrays that represented approximately 9,000 genes, which was the state of-the-art. Higher content arrays with almost double the number of genes have since become available. In order to better determine whether common sets of gene expression changes can be predictive of estrogenic activity, we have replicated the previous experiment using the more comprehensive microarray.
Immature 20-day-old Sprague-Dawley rats were exposed to 0.1, 1, and 10 microg EE/kg/day ( subcutaneously [s.c.]), for four days, dosing from postnatal day (PND) 20-23). Changes in a more comprehensive expression level of 15,923 rat annotated genes and expressed sequence tags were evaluated on PND 24.
By comparing the response of the treatment groups versus controls using various statistical parameters, we determined that the expression of 1,394 genes showed a significant change with respect to control (p< or =0.0001), to at least one of the EE dosages. The tissues from animals exposed to 0.1 microg EE/kg/day showed changes in the expression of only 33 genes, whereas when they were exposed to 1 or 10 microg EE/kg/day, the expression of 409 and 548 genes was modified, respectively. A dose-dependent analysis indicated that 592 genes showed a robust and significant response to EE exposure (increased or decreased). Our analysis confirmed the regulation of previously identified estrogen-sensitive genes, and clearly identified novel mediators of estrogen actions, both in the uterus as well as in the ovary.
This compendium of genes represents the largest compilation of estrogen-responsive genes that has ever been identified for the immature uterus and ovary of any species, and can be used to generate testable hypothesis to improve the understanding of the molecular pathways associated with physiological and pathophysiological responses to exposure to chemicals with estrogenic properties.
在之前的一项研究中，我们使用代表约9000个基因的微阵列（这在当时是最先进的技术）确定了17-α-乙炔基雌二醇（EE）对基因表达的影响。此后，基因数量几乎翻倍的更高通量阵列已经问世。为了更好地确定常见的基因表达变化集是否能够预测雌激素活性，我们使用更全面的微阵列重复了之前的实验。
将20日龄未成熟的斯普拉格-道利大鼠皮下注射0.1、1和10微克EE/千克/天，持续四天（从出生后第20天至第23天给药）。在出生后第24天评估15923个大鼠注释基因和表达序列标签的更全面表达水平的变化。
通过使用各种统计参数比较治疗组与对照组的反应，我们确定，相对于对照组，至少在一种EE剂量下，1394个基因的表达有显著变化（p≤0.0001）。暴露于0.1微克EE/千克/天的动物组织中，只有33个基因的表达发生了变化，而当它们暴露于1或10微克EE/千克/天 时，分别有409和548个基因的表达发生了改变。剂量依赖性分析表明，592个基因对EE暴露表现出强烈且显著的反应（增加或减少）。我们的分析证实了先前确定的雌激素敏感基因的调控，并明确鉴定出了子宫和卵巢中雌激素作用的新介质。
这个基因汇编代表了针对任何物种未成熟子宫和卵巢所鉴定出的最大的雌激素反应基因集，可用于生成可检验的假设，以增进对与暴露于具有雌激素特性的化学物质后的生理和病理生理反应相关的分子途径的理解。
