Mammary Gland Morphology and Gene Expression Signature of Prepubertal Male and Female Rats Following Exposure to Exogenous Estradiol

In order to properly understand whether xenoestrogens act as estrogens, it is essential to possess a solid portrait of the physiological effects of exogenous estradiol. Because the estrogen-dependent gene expression is one of the primary biomarkers of estrogenic action, we have assessed effects of three doses of exogenous estradiol (0.1, 1.0 and 10 µg/kg of body weight/day) on the mammary gland morphology and gene expression profiles by microarray analysis of prepubertal male and female rats of both sexes compared to untreated controls. Estradiol was administered subcutaneously with minipumps from weaning at PND21 to the end of the experiment at PND33. The data suggest that the male mammary is a sensitive tissue for estrogenicity assessment.为明确环境雌激素（xenoestrogens）是否具备雌激素活性，需充分掌握外源性雌二醇（exogenous estradiol）的生理效应。鉴于雌激素依赖型基因表达是雌激素作用的核心生物标志物之一，本研究通过微阵列分析（microarray analysis），以未处理对照组为参照，评估了三种剂量（0.1、1.0和10 μg/kg体重/天）的外源性雌二醇对青春期前雌雄大鼠的乳腺形态及基因表达谱的影响。本研究采用微型渗透泵皮下给药，给药周期为出生后第21天（PND21，断奶日）至出生后第33天（PND33，实验结束日）。实验数据表明，雄性乳腺是用于雌激素活性评估的敏感组织。