Comparative uterine gene expression analysis after dioxin and estradiol administration

The environmental pollutant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) adversely affects many organisms. TCDD exposure is known to be associated with abnormal development, hepatotoxicity and endocrine effects. It has also been reported to have antiestrogenic activity in addition to estrogenic activity. In order to clarify the effects of TCDD in the uterus, we evaluated the patterns of gene expression after TCDD and estradiol administration. Of the 10 000 arrayed genes, only a few were affected by both estradiol and TCDD. Although the subset of genes that responded to estrogen was also activated by TCDD, the response to TCDD was more limited than that observed in response to estradiol. Therefore, according to our analysis of gene expression patterns, TCDD had partial and weak estrogenic activity in the uterus.