Fig. 2. Effects of endosulfan on CYP1A1 transcriptional activity. (A) Effects of endosulfan on CYP1A1 mRNA expression in Hepa-1c1c7 cells. Cells were treated with endosulfan (Endo) or 3-MC for 6h. The cells were lysed, and total RNA was prepared to analyze CYP1A1 gene expression. PCR amplification of the housekeeping gene, β-actin, was performed for each sample. CYP1A1 mRNA expression was compared between treated and untreated cells at each time point by real-time PCR. Values represent the means from three independent experiments, each performed in triplicate. * p< 0.01, significantly different from the control, as determined by ANOVA by the Newman-Keuls test. (B) Effects of endosulfan on CYP1A1 promoter activity in Hepa-1c1c7 cells. Cells were transfected with pGL3-CYP1A1-Luc and subsequently treated with endosulfan or 3-MC for 18 h. Cells were then harvested and assayed for luciferase activity. Values represent the means from three independent experiments, each performed in triplicate. * p<0.01, significantly different from the control, as determined by ANOVA by the Newman-Keuls test. (C) Effects of endosulfan on CYP1A1 protein levels in Hepa-1c1c7 cells. Cells were treated with endosulfan or 3-MC for 24 h. The membrane was probed with a CYP1A1-specific antibody, and bands were visualized with ECL reagents. Each blot in this figure is representative of three independent experiments with similar results.