2,3,7,8-tetrachlorodibenzo-p-dioxin alters follicular steroidogenesis in time- and cell-specific manner

To show the direct effect of TCDD on ovarian steroidogenesis theca (Tc) and granulosa (Gc) cells were cultured separately or as a co-culture (GT). Cel ls were cultured in M199 medium supplemented every day with 0.1 nM TCDD or only at the beginning of the culture with 10 nM of TCDD. After 48, 96 and 1 44 h culture media were collected for steroids content analysis. In Tc cult ured alone TCDD caused an increase in E2 production after 48 and 96 h of cu lture: while exposure of Tc on TCDD for 144 h caused the decrease in both T and E2 secretion. In Cc cultured alone and in GT cultures the increase in E2 secretion was observed only after 48 h. while a long term exposure to TC DD (96 and 144 h) caused a decrease of both P4 and E2 secretion. The result s of the present study suggest various, time-dependent mechanisms of TCDD a ction on ovarian cells.