Relative levels of CYP2C8, CYP2C9, and CYP2C19 proteins and rates of tolbutamide and S-mephenytoin 4′-hydroxylation in human hepatocyte cultures
| Inducers3-a | CYP2C8 | CYP2C9 | CYP2C19 | Tolbutamide 4′(OH) | S-mephenytoin 4′(OH) |
|---|---|---|---|---|---|
| None | 36 ± 83-150 | 41 ± 213-150 | 42 ± 313-150 | 27 ± 203-150 | 12 ± 103-150 |
| Dexamethasone | 68 ± 293-160 | 61 ± 293-160 | 131 ± 863-160 | 61 ± 39 | N.D. |
| (1.9) | (1.5) | (3.1) | (2.2) | ||
| Rifampicin | 100 | 100 | 100 | 100 | 100 |
| (2.8)3-b | (2.4)3-b | (2.4) | (3.7) | (8.3) | |
| Phenobarbital | 102 ± 483-160 | 82 ± 43 | 121 ± 75 | 71 ± 19 | N.D. |
| (2.8) | (2) | (2.9) | (2.6) |
Data are from cultures FT126, FT127, FH128, FT131, FT135, FT137, FT138, FT142, FT143, FT150, FT151, FT155, FT156, and FT159. Relative levels with respect to the corresponding data in rifampicin-treated cells (arbitrarily taken as 100). Data are expressed as mean ± S.D.
N.D., not determined.
↵3-150 Significantly lower than in rifampicin-treated cells,P < 0.005, using the paired t test.
↵3-160 Significantly greater than in untreated cells,P < 0.05, using the paired t test.
↵3-a Inducer concentration: 10 μM for rifampicin and dexamethasone; 100 μM for phenobarbital.
↵3-b Induction ratio with respect to values in untreated cells.