Fig. 6.

Unidirectional transport of doxorubicin. Radioactive doxorubicin (A, 1.0 µM for OATP1A2; B, 0.2 µM for OATP1Bs) was administered to the apical or basal compartments of monolayers of transporter-expressing MDCKII cells in transwells. The opposite compartments were added with media without radioactive doxorubicin. Cells were then incubated and equal amount (50 µl) of media were taken out from both compartments at given time points, followed by measurement for doxorubicin radioactivity. There were no significant differences in doxorubicin transport among control, single-, or double-transfected cell lines for OATP1A2 (A to B, B to A) or OATP1B1/1B3 (A to B). Data are expressed as mean ± S.E. (n = 4). A to A, apical to apical; A to B, apical to basal; B to A, basal to apical.