Figure 2.

TCDD treatment degrades AhR expression in MG-63 cells and expresses functional AhR. MG-63 cells were treated with toluene (vehicle control) and 0.1, 1 and 10 nM TCDD for 24 and 72 h. (A) Western blot analysis revealed that AhR was degraded in a dose-dependent manner following TCDD treatment. The level of Cyp1a1 was quantitated by reverse transcription-polymerase chain reaction, which demonstrated an upregulation following TCDD treatment for (B) 6 and (C) 24 h. Results were representative of three different experiments. Data are presented as the mean ± standard error of the mean (n=3). *P<0.05, **P<0.01 vs. the toluene-treated cells. TCDD, 2,3,7,8-tetrachlorodibenzo-p-dioxin; AhR, aryl hydrocarbon receptor; Cyp1a1, cytochrome P450 1A1.