Figure 7.

Expression of MDR1 (a) and CYP3A4 (b) in Caco-2 cells transfected with the empty vector (−pPXR) and PXR vector (+pPXR) after treatment with budesonide, rifampicin or vehicle only. In two independent experiments, cells were transfected during 48 h, followed by 48 h drug treatment. mRNA expression was determined by quantitative real-time PCR. Results are normalized to the respective control cells and expressed as mean±s.e.m. (n=5–6). ^*P<0.05, ^**P<0.01, ^***P<0.001 vs control cells.