Figure 5.

Effect of decreased P-glycoprotein (P-gp) expression on permeability to warfarin/antipyrine. Caco-2 cells were plated in Transwell plates and incubated for 21 days. (A) Indomethacin was added to the apical side of the Transwell plate. After 2 days, the protein expression of P-gp was analyzed by western blotting and normalized to GAPDH expression. The mean levels of P-gp protein expression in the control group were set as 100%. (B) Warfarin alone or a combination of warfarin and indomethacin was added to the apical side of the Transwell plate. The concentration of warfarin on the basal side was measured. (C) Antipyrine alone or a combination of antipyrine and indomethacin was added to the apical side of the Transwell plate. The concentration of antipyrine on the basal side was measured. The data are presented as the mean ± SD for six experiments. Student’s t-test: ** p < 0.01 vs. the control value.