FIGURE 6.

Effects of IO and CP on (A) P-gp activity and (B) intracellular concentrations of the P-gp substrate digoxin. Cells were pretreated with cyclosporine A (10 μM) for 15 min to inhibit P-gp activity before addition of DG. Results represent the mean ± SD of three separate measurements and are expressed relative to the control without cyclosporine A. ^∗P < 0.01, ^∗∗P < 0.01 vs. control. CsA, cyclosporine A; DG, digoxin; IO, Kijitsu, P-gp, p-glycoprotein; CP, Chinpi; VD₃, 1α,25-dihydroxyvitamin D₃.