Figure 4.

Effect of decreased AQP3 expression on permeability to warfarin/antipyrine. Caco-2 cells were plated in Transwell plates and incubated for 21 days. (A) Prostaglandin E₂ (PGE₂) was added to the apical side of the Transwell plate. At 1 h after treatment, the protein expression of AQP3 was analyzed by Western blotting and normalized to glyceraldehyde-3–phosphate dehydrogenase (GAPDH) expression. The mean levels of AQP3 protein expression in the control group were set as 100%. (B) Lucifer yellow alone or a combination of PGE₂ and lucifer yellow was added to the apical side of the Transwell plate. At 2 h after treatment, the concentration of lucifer yellow on the basal side was measured. (C) Warfarin alone or a combination of warfarin and PGE₂ was added to the apical side of the Transwell plate. The concentration of warfarin on the basal side was measured. (D) Antipyrine alone or a combination of antipyrine and PGE₂ 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.