EN
Dichlorodiphenyltrichloroethane (DDT) is a persistent insecticide, recognized as an environmental pollutant. Due to its lipophilic properties, DDT and its metabolite (DDE) are accumulated in tissues of farm animals. The aim of the study was to examine the influence of DDT and DDE on estradiol, progesterone and oxytocin secretion from the ovary and on prostaglandin (F2α and E2) secretion from the uterus, was investigated. Granulosa, luteal and endometrial cells from cows at 8-12 days of the estrous cycle were treated for 24-72 h with 0.1-10 ng/ml of DDT, p,p’-DDE, o,p’-DDE or with a technical mixture of DDE isomers. Neither DDT nor DDE were found to affect the viability of cells compared to the control. They also did not affect the secretion of estradiol from granulosa cells. The utilized pollutants increased (P < 0.05-0.001) the progesterone and oxytocin secretion from luteal and granulosa cells. They also stimulated (P < 0.05) PGF2á secretion but simultaneously reduced (P < 0.001) PGE2 secretion from endometrial cells. Hence the ratio of PGF2α to PGE2 was markedly changed, from 1:1 in the control, up to 1:4-10 in treated cells. It has been concluded that DDT and its metabolites may impair regulation of the estrous cycle in cows by stimulation of oxytocin secretion from luteal and granulosa cells and by stimulation of PGF2α and the simultaneous inhibition of PGE2 secretion from endometrial cells.