*4.9. Western Blot Analysis*

Equal amounts of proteins from membranes of each group were separated by SDS-PAGE and transferred to nitrocellulose membranes. The *p*-glycoprotein was purchased from Calbiochem (Darmstadt, Germany). Mrp2/3 antibodies were purchased from Abcam (Cambridge, UK). The western blot analysis was performed as described previously [24].
