Ki values for inhibition of 1,3-dimethyluric acid formation from theophylline and inhibition of 1′- and 4-hydroxylation of midazolam in rat hepatocytes and hepatic microsomes
Mean data of three preparations ± S.D. are shown. Each preparation was studied with three substrate concentrations over a range of inhibitor concentrations.
| Inhibitor | Substrate | Pathway | Hepatocyte Ki | Microsomal Ki* |
|---|---|---|---|---|
| μM | ||||
| Enoxacin | Theophylline | 1,3-Dimethyluric acid | 120 ± 65 | 2800 ± 1200 |
| Clarithromycin | Midazolam | 1′-Hydroxylation | 75 ± 24 | 1000 ± 100 |
| 4-Hydroxylation | 60 ± 30 | 650 ± 80 | ||
| Saquinavir | Midazolam | 1′-Hydroxylation | 0.50 ± 0.035 | 0.22 ± 0.07 |
| 4-Hydroxylation | 0.47 ± 0.099 | 0.11 ± 0.01 | ||
| Nelfinavir | Midazolam | 1′-Hydroxylation | 2.94 ± 1.02 | 0.46 ± 0.1 |
| 4-Hydroxylation | 1.16 ± 0.49 | 0.33 ± 0.02 | ||
↵* Statistical difference between hepatocytes and microsomes (P < 0.01).