TABLE 1

The microsomal protein levels of P450 isoforms

Microsomes were prepared from livers perfused with 200 μM SNP for 0.5 or 1 h and subjected to various periods of washout. Values are expressed as mean ± S.E.M. (n = 4/group). The protein levels (pmol/mg microsomal protein) for control livers perfused for 0.5, 1.0, 2.0, and 3.0 h were 390, 440, 290, and 280 (2C11); 31, 29, 29, and 18 (3A2); 580, 560, 460, and 370 (2E1); and 260, 250, 230, and 180 (1A1/2), respectively.

SNP Perfusion Time
P450s 0.5-h Washout Period
1-h Washout Period
0 h
0.5 h
2.5 h
0 h
1 h
2 h
% control
CYP2C11 92 ± 15 88 ± 7 98 ± 10 91 ± 9 110 ± 13 68 ± 5a,b
CYP3A2 86 ± 8 84 ± 11 75 ± 15 90 ± 13 90 ± 4 88 ± 18
CYP2E1 92 ± 10 84 ± 6 98 ± 5 91 ± 8 110 ± 6 100 ± 10
CYP1A1/2
86 ± 10
94 ± 7
110 ± 7
89 ± 1
110 ± 8
110 ± 2

  • ↵ a Significantly different from its respective control: p < 0.01, ANOVA, followed by Fisher's test.

  • ↵ b Significant difference between 1- and 2-h washout groups: p < 0.01, ANOVA, followed by Fisher's test.