Activation of the human PXR by metyrapone, rifampicin, and dexamethasone
| Treatment | Fold (ER6)3-tk-CAT versus Control |
|---|---|
| Rifampicin (20 μM) | 3.0 ± 0.552-a |
| Rifampicin (20 μM), no PXR plasmid | 1.1 ± 0.60 |
| Metyrapone (10 μM) | 1.5 ± 1.41 |
| Metyrapone (100 μM) | 3.3 ± 0.292-a |
| Metyrapone (500 μM) | 9.7 ± 3.052-a |
| Dexamethasone (100 μM) | 5.1 ± 1.832-a |
CV-1 cells transiently cotransfected with an expression vector pSG5-hPXRΔATG and a CAT reporter construct (ER6)3-tk-CAT were treated with inducers from stocks prepared in dimethyl sulfoxide at a concentration 1000-fold of that required in the medium. Controls were treated with 0.1% (v/v) dimethyl sulfoxide. After 24 h, cells were harvested, extracts were prepared by freeze-thaw, and normalized CAT activities were determined. No PXR plasmid: transfection control, cells transfected with reporter plasmid but not with the PXR expression plasmid.
↵2-a Significantly different-fold induction versus control using Student's t test (two-tailed), P > 95%.