Kinetic parameters for the production of major testosterone metabolites by human liver microsomes and CYP3A4
| Human Liver Microsomes | CYP3A4 | |||||||
|---|---|---|---|---|---|---|---|---|
| Km | Vmax | CLint | R2 | Km | Vmax | CLint | R2 | |
| μM | nmol/mg protein/min | μl/mg protein/min | μM | nmolnmol 3A4/min | μl/nmole 3A4/min | |||
| 6β-OHTST | 120.4 ± 19.4a | 36.3 ± 2.3a | 300.0a | 0.94 | 107.7 ± 12.5a | 284.8 ± 12.5a | 2600.0a | 0.97 |
| 2β-OHTST | 119.2 ± 18.0a | 2.0 ± 0.1b | 20.0b | 0.95 | 122.8 ± 14.1a | 15.7 ± 0.7b | 130.0b | 0.98 |
| 15β-OHTST | 138.9 ± 28.2a | 0.8 ± 0.1c | 6.0c | 0.91 | 108.7 ± 16.4a | 7.1 ± 0.4c | 70.0c | 0.96 |
Means in the same column followed by the same letter are not significantly different (P < 0.01). Values are the mean ± S.E.M. (n = 3).