Comparison of IC50 values for the inhibition of OCT2-mediated NBD-MTMA transport (column A) or of OCT2-mediated transport of metformin (Met) determined in the present study (column B) or in the study by Zolk et al. (2009) (column C)
| Inhibitor | AaNBD- MTMA IC50 | BaMet IC50 | CbMet IC50 | cIC50Met/IC50NBD |
|---|---|---|---|---|
| μM | ||||
| Imipramine | 1.4 ± 0.3 (5) | 0.77 ± 0.29 (3) | 0.4 | 0.55 (0.3) |
| Clonidine | 4.5 ± 0.9 (5) | 0.68 ± 0.22 (4) | 1.5 | 0.15 (0.3) |
| Carvedilol | 13.1 ± 0.7 (3) | — | 15 | (1) |
| Verapamil | 21.0 ± 1.7 (3) | 20.0 ± 7.6 (2) | 5 | 0.95 (0.2) |
| Quinidine | 29.6 ± 5.6 (4) | 6.4 ± 0.9 (3) | 8 | 0.22 (0.3) |
| Cimetidine | 70.4 ± 8 (5) | 25.4 ± 11.3 (4) | — | 0.36 |
| Chloroquine | 117 ± 9.0 (3) | 9.6 ± 1.2 (2) | — | 0.08 |
| Flecainide | 234 ± 3.0 (2) | — | 61 | (0.3) |
—, values not obtained.
↵a Numbers represent the mean (± S.E.) of the number (indicated in parentheses) of separate experiments performed OCT2-expressing CHO cells.
↵b Values were obtained from Fig. 6C in Zolk et al. (2009).
↵c Values in italics represent the ratio of IC50 for inhibition of metformin transport measured by Zolk et al. (2009) versus the IC50 for inhibition of NBD-MTMA transport measured in the present report, whereas nonitalicized values stem from the present report.