Effects of the pesticides prochloraz and methiocarb on human estrogen receptor α and β mRNA levels analyzed by on-line RT-PCR

Abstract

Exposure to endocrine disrupters such as dioxins, PCBs and certain pesticides are suspected to affect human reproductive health. We have analyzed the effect of the currently used pesticides prochloraz and methiocarb on the estrogen receptor (ER)α and β mRNA levels in parallel with the natural ligand, 17β-estradiol (E2). Using the highly sensitive on-line RT-PCR technique we were able to quantify the ERα and ERβ mRNA levels in the human breast cancer cell line, MCF7-BUS. Upon exposure with E2 or prochloraz a down regulation of ERα and ERβ mRNAs was observed after 48 h of treatment. Co-treatment with the ER antagonist ICI 182,780 abolished these mRNA down regulations. Western blot analyses elicited a decreased ER protein level after 3 h of exposure with prochloraz but after 24 h the ERα protein level had recovered to basal level. Methiocarb exposure had no effect on the ERα mRNA level, whereas an increase in the ERβ mRNA level was observed after 3 h of exposure. Our study demonstrates that like E2, prochloraz had the potential to down regulate the expression of ERα and ERβ mRNAs as well as the ERα protein level in MCF7-BUS cells.