Table 3.
Relative P450 protein levels in mouse hepatic microsomesa
| Treatment | Immunoreactive P450 protein levels | ||
|---|---|---|---|
| CYP1A2b | CYP2Bc | CYP3Ad | |
| NF | 9.5 ± 0.5 | 1.1 ± 0.1 | 1.0 ± 0.1 |
| PB | 2.1 ± 0.2 | 15.2 ± 1.1 | 5.3 ± 0.3 |
| DEX | 0.4 ± 0.1 | 14.9 ± 1.1 | 25.9 ± 1.0 |
| CO | 1.0 ± 0.1 | 1.0 ± 0.1 | 1.0 ± 0.2 |
P450 protein levels are expressed relative to those of CO-treated mice set at 1.00. The amount of immunoreactive P450 protein was calculated in terms of relative optical density units/mg of microsomal protein because purified or recombinant mouse P450 standards are not available. Values shown are the experimental mean ± SE of 3 or 4 determinations using pooled hepatic microsomes prepared from female mice that had been pretreated with NF, PB, DEX or CO. Purified or recombinant rat P450 enzymes were included on the gels as reference standards. Immunoreactive P450 protein bands were detected with antibodies directed against rat P450 enzymes as described in Experimental Procedures.
Only relative CYP1A2 levels are reported. CYP1A1 was not detected in hepatic microsomes from PB-, DEX- or CO-treated mice but was detected in hepatic microsomes from NF-treated mice. A relative CYP1A1 level was not determined for NF-treated mice due to the lack of a reference point.
The CYP2B level reported here corresponds to the immunoreactive band tentatively identified as CYP2B10 by reference to the electrophoretic mobility previously reported (52).
The CYP3A level reported here corresponds to the immunoreactive band tentatively identified as CYP3A11 by reference to the electrophoretic mobility previously reported (52).