Estrogenic and antiestrogenic effect of in vitro treatment of follicular cells with 2,3,7,8-tetrachlorodibenzo-p-dioxin

Objective. Two types of follicular cells from preovulatory ovary were cultu red in vitro separately and in co-culture to test difference in 2,3,7,8-tet rachlorodibenzo-p-dioxin (TCDD) action on particular cell types. Methods. The accumulation of TCDD in follicular wall was analysed using cou pled capillary gas chromatography-mass spectrometry. Whole preovulatory fol licles were isolated from ovary and incubated with prolonged exposure to 0. 1 nM TCDD or single exposure to 10 nM TCDD for four days. In the second par t of experiments direct effects of TCDD on steroidogenesis were investigate d in porcine theca cells (Tc) and granulosa cells (Gc) cultured alone and i n co-culture (GT). The media were collected after four days for steroid ana lysis. Results. 59.3% and 81.2% of TCDD added to the culture medium was accumulate d after 0.1 and 10 nM, respectively. TCDD in a dose-dependent manner increa sed estradiol secretion with concomitant progesterone secretion by theca in terna cells. On the other hand decrease of both progesterone and estradiol secretion by granulosa cells cultured alone and in co-culture with theca ce lls was noted. Conclusion. Different cell-specific estrogenic or antiestrogenic effect of TCDD were found in ovarian follicles. (C) 2001 Elsevier Science Ltd. All ri ghts reserved.