Comparison of scup and rat liver microsomal enzyme activities and CYP1A inactivation
| Assay | Scup Liver Microsomes (n = 7) | Rat Liver Microsomes (n = 3) |
|---|---|---|
| Spectral P-450 (nmol/mg) | 0.75 ± 0.234-a | 2.38 ± 0.60 |
| CYP1A4-b (nmol/mg) | 0.38 ± 0.15 | 0.26 ± 0.28 |
| NADPH oxidation4-c (nmol/min/mg) | 20 ± 4 | 5 ± 1 |
| Cytochrome c reductase activity (nmol/min/mg) | 125 ± 39 | 263 ± 55 |
| TCB metabolism (pmol/min/mg) | 0.3 ± 0.1 | 38.5 ± 7.8 |
| EROD activity (nmol/min/mg) | 4.8 ± 0.9 | 2.5 ± 0.3 |
| MROD activity (nmol/min/mg) | 2.2 ± 0.8 | 0.1 ± 0.0 |
↵4-a Data are means ± S.D. for individual pools of microsomes.
↵4-b The immunoreactive bands were visualized with nitroblue tetrazolium and 5-bromo-4-chloro-3-indoyl-phosphate, and quantified by video image analysis by comparison to scup standards of known CYP1A1 concentration. Where appropriate, the CYP1A1 values for rat are relative, reported as scup CYP1A equivalents.
↵4-c Calculated by subtracting the rate of NADPH oxidation with the carrier present from the rate of oxidation with TCB present.