Interference of Xenoestrogen o , p ′-DDT on the Action of Endogenous Estrogens at Environmentally Realistic Concentrations

Estrogenic effects of individual chemicals and mixtures of 17β-estradiol (E 2 ) and o , p ′-DDT were examined using pS2 and PR gene expressions in MCF-7 cells. Interactions between E 2 and o , p ′-DDT were evaluated by a statistical method based on factorial design. At levels close to environmentally realistic concentrations, no significant interactions between E 2 and o , p ′-DDT were observed, suggesting that the xenoestrogen ( o , p ′-DDT) could act in an additive way with the endogenous estrogen (E 2 ). These results demonstrated the utility of this statistical method in a mixture study, and highlight the potential interference and health risk of low-level xenoestrogens, such as o , p ′-DDT.