Fig. 6.

Glucocorticoid receptor antagonist RU486 partially inhibited the dexamethasone (Dex)-induced stimulation of Bcrp, P-gp, and pregnane xenobiotic receptor (PXR) but had no effect on Mrp-2. Primary endothelial cells were untreated (CTL) or treated with dexamethasone (250 nM) alone or in combination with RU486 (250 nM) for 24 h. A: transcript levels of Bcrp and Mrp-2 were evaluated by RT-PCR, using total cellular RNA as described in materials and methods. B: protein levels of bcrp, p-gp, and mrp-2 from whole cells were evaluated by immunoblotting using 100 μg protein loaded per lane. Representative blots from an experiment performed 3 times are quantified by densitometry in the bar graph. **P < 0.01 vs. untreated (CTL) cells, *P < 0.05 vs. dexamethasone-treated cells, #P < 0.05 vs. untreated (CTL) cells. C: functional activity of BCRP and P-gp was determined by measuring the Ho342 dye accumulation in primary endothelial cells as described as materials and methods.