Article Figures & Data
Figures
- FIG. 1.
Concentration dependence of Papp in the secretory direction (BL-AP) of MXF-HCl across Calu-3 monolayers. The graph shows the total Papp, reflecting active transport and passive diffusion. Data are expressed as means ± SEM (n = 3). A sigmoidal dose-response equation was used to fit the data (R2 = 0.92).
- FIG. 2.
Amounts of MXF transported across Calu-3 monolayers over time in the absence (control) and presence of verapamil (100 μM), PSC-833 (3 μM), or probenecid (100 μM). The concentration of MXF in the donor compartment was 50 μM (21.9 μg/ml MXF). Data are expressed as means ± SEM (n = 4 to 6). Two-way ANOVA and Bonferroni's post hoc test were used to compare BL-to-AP transport against AP-to-BL transport. *, P < 0.001.
- FIG. 3.
Rifampin upregulates expression of P-gp in Calu-3 cells. Cells were exposed to rifampin for 15 days at 10 and 25 μM concentrations. P-gp expression was analyzed by immunoblotting with specific antibodies to MDR1 and actin. (A) Representative immunoblot. (B) Intensity of C219 band relative to actin band intensity and normalized to control (0 μM). Data are expressed as means ± SEM (n = 4 or 5). One-way ANOVA and Bonferroni's post hoc test were used to compare the data against the control. *, P < 0.05; **, P < 0.01.
Tables
- TABLE 1.
P app of MXF (50 μM) in the presence of different inhibitors or inducers of transport proteins in the AP-to-BL and BL-to-AP directions, together with the ER across Calu-3 monolayers
Inhibitor or inducer Affected transporter Papp (10−6 cm·s−1)a ER AP-to-BL direction BL-to-AP direction Control 5.25 ± 0.18 10.53 ± 0.10 2.0 Verapamil P-gp, MRP 8.05 ± 0.27*** 8.07 ± 0.05** 1.0 PSC-833 P-gp, not MRP 8.87 ± 0.06*** 7.74 ± 0.02** 0.9 Probenecid MRP, not P-gp 4.42 ± 0.03 (NS) 9.58 ± 0.37 (NS) 2.2 Rifampinb 10 μM P-gp, MRP 4.35 ± 0.33* 11.86 ± 0.13** 2.7 25 μM P-gp, MRP 4.08 ± 0.30** 12.48 ± 0.18** 3.1
