Effect of TCDD Exposure on

Endometriosis is a debilitating disease estimated to affect 10% of reproductive-age women and characterized by the growth of endometrial tissue outside of the uterus. The present study char-acterizes a human endometrial explant culture model for studying the direct effects of TCDD exposure by assessing the expression of CYP1A1 and CYP1B1 mRNA (Northern blotting), protein (West-ern blotting), and activity (7-ethoxyresorufin-O-deethylase; EROD) in explants cultured with and without TCDD. Explants were obtained at laparoscopy or laparotomy from women under-going surgery for tubal ligation, endometriosis, or pelvic pain unrelated to endometriosis. The explants were cultured with 10 nM estradiol (E2) or 1 nM E2 plus 500 nM progesterone (P4) with or without TCDD (first 24 h). The expression of CYP1A1 and CYP1B1 mRNA was greatest with 10 nM TCDD and increased up to 72 h after initial exposure. EROD activity increased up to 120 h.