Influence of polychlorinated biphenyls (PCBs) and phytoestrogens on prostaglandin F2α and E2secretion from bovine endometrial cells at a postovulatory stage of the estrous cycle

Abstract

Polychlorinated biphenyls (PCBs) and phytoestrogens were found to affect contractions of bovine uterus. Prostaglandins (PG) F₂_á and E₂ are also involved in the uterine contractility. Hence the aim of these studies was to investigate the effect of PCBs and some phytoestrogens on PG secretion from endometrial cells obtained on days 1–5 of the oestrous cycle. Cells were incubated in aerated atmosphere at 38°C for 24 h, separately with the mixture of PCBs – Aroclor 1248 (10 ng/ml), with individual congeners -77, -126 or -153 (each at the dose 100  g/ml), coumestrol, daidzein or genistein (each at the dose 10^–6M) or jointly each PCB with each of the phytoestrogens. Using the TOX1-kit neither Aroclor 1248 (Ar 1248) nor individual congeners were found to affect the viability of cells compared to the control (P > 0.05). All used PCBs markedly increased the metabolite of PGF₂_á(PGFM) concentrations (P < 0.05) but not PGE₂(P > 0.05). Hence the ratio of PGF₂_á to PGE₂ was also increased by PCBs. However, when these cells were incubated with each of the phytoestrogens, there was a decrease in both PGF₂_á and PGE₂ secretion compared to the control (P < 0.05) but without altering the PGF₂_á : PGE₂ ratio. Moreover, phytoestrogens could clearly reduce the concentrations of PGFM elicited by PCBs, and they reduced PGE₂ secretion compared to that evoked by PCB-126 and –153 only. Thus phytoestrogens can restore the proper ratio of PGF₂_á : PGE₂ secreted by the bovine endometrium.