Effect of polychlorinated biphenyls (PCBs) on basal and OT-stimulated calcium concentrations in myometrial cells in cows.

We investigated the effect of PCB-77, -126 or -153 (10 or 100 ng/ml) on free intracellular calcium concentrations([Ca2+]i) in bovine myometrial cells from days 1-5 of the estrous cycle. Cells were incubated with or without PCBs for 48 h (38 degrees C, aerated atmosphere) and thereafter [Ca2+]i was measured by means of fluorescent calcium indicator Fura-2. PCBs increased basal concentrations of [Ca2+]i measured before oxytocin (OT) challenge. The increase in [Ca2+]i in cells incubated with PCBs and challenged with OT was inhibited or delayed when compared to control OT-stimulated cells (p<0.05). The applied doses of PCBs did not affect viability of myometrial cells. In conclusion, the influence of PCBs upon intracellular calcium mobilization in myometrial cells impaired the bovine uterus contractility.