Fig. 9.

Time-dependent induction of CYP3A4 mRNA in ETR-treated primary human hepatocytes is PXR-dependent. Primary human hepatocytes were treated with 10 μM ETR or DMSO (control) for 6, 12, 24, or 72 h, and changes in P450 mRNA expression were quantified by qPCR normalizing to GAPDH. Data are presented as ratios over DMSO controls and represent treatments performed in four separate hepatocytes preparations (A). Primary human hepatocytes were treated with DMSO, ETR (10 μM), or RIF (10 μM) in the presence and absence of the PXR antagonist SFN (25 μM). RIF, an established PXR-dependent CYP3A4 inducer, was used as a positive control. Data were obtained using qPCR and are presented as ratios over control, representing the means ± S.D. of treatments performed in three separate hepatocytes preparations (B).