Fig. 4.

Effects of CAR-phenytoin- or PXR-rifampicin-mediated induction on pVNTR-S modulation of CYP2C9 promoter activity. HepG2 cells were cotransfected with reporter gene constructs containing the pVNTR-M, pVNTR-L, or pVNTR-S allele, in the presence or absence of other SNPs/haplotypes, together with transcription factors CAR or PXR. Cells were then treated with either 50 μM phenytoin (PHT) or 10 μM rifampicin (Rif), respectively, at 24 h after transfection, and luciferase activities were measured another 24 h after treatment. Data are mean ± S.D., n = 3. Compared with reference construct M1, *, P < 0.05 (analysis of variance with Dunnett's post hoc test).