RÉSUMÉ
Objective To determine the estrogenic activity of dibutyl phthalate DBP. Methods The tested compound was dibutyl phthalate. Human estrogen-dependent MCF-7 breast cancer cells were cultured in RPMI 1640 medium containing 10% fetal bovine serum FBS. Five days before the addition of the tested compounds the cells were rinsed by phosphate balanced solution PBS and the medium was substituted with a phenol red-free RPMI 1640 medium containing 5% dextral charcoal-stripped FBS. The respective tested compound was added in fresh medium and the control cells received only the vehicle ethanol. The proliferation of MCF-7 cells was analyzed by the MTT assay growth curves mitotic index and coloning efficiency. Results Compared with the control the proliferation of tested cells treated with DBP like estradiol was markedly enhanced and the activity of the cell proliferation reached the maximum at 10-5 mol/L DBP. During log phase the mitotic index of the test cells treated with DBP and estradiol was significantly increased. The cell coloning efficiency was enhanced which was treated by 10-5 mol/L DBP only for 48 hours. The results showed the time-dependent and dose-dependent model. Conclusion Dibutyl phthalate may enhance the proliferation of human breast cancer MCF-7 cells in vitro that demonstrates an estrogenic activity of dibutyl phthalate.