Inhibition of OCT1 by CsA and other drugs with and without 30-minute preincubation in stably transfected human embryonic kidney cells
Data represent the mean ± S.D. The IC50 values were estimated by Phoenix as indicated in Materials and Methods. [14C]Metformin (2 µM) was used as a probe substrate. Therefore, the IC50 values are considered as Ki (assuming competitive inhibition) because the ratio of metformin concentration to Km is small (<0.2).
| Drug | IC50 | IC50 Fold Shift | |
|---|---|---|---|
| Without 30-Minute Preincubation | With 30-Minute Preincubation | ||
| µM | µM | ||
| Cyclosporine A | 21.6 ± 4.5 | 0.43 ± 0.12 | 50.2 |
| Quinidine | 7.7 ± 0.9 | 4.5 ± 0.7 | 1.7 |
| Pyrimethamine | 1.8 ± 0.2 | 1.3 ± 0.1 | 1.4 |
| Ritonavir | 2.2 ± 0.3 | 1.1 ± 0.1 | 2.0 |
| Trimethoprim | 9.6 ± 1.2 | 9.2 ± 0.7 | 1.1 |