Table 1

Information on human liver microsomal preparations used in the study

Parameter MeasuredMale DonorsFemale DonorsP1-a
 Number of the donors2112
 Age of the donors (yr)47 ± 356 ± 16
 Adjusted protein content (mg/ml)2020
 Total P450 content1-b 0.45 ± 0.290.43 ± 0.200.851
 Cytochrome b 5content1-c 0.46 ± 0.120.38 ± 0.130.085
 NADPH-cytochrome creductase1-c 205.3 ± 63.2195.9 ± 53.30.667
 Caffeine N3-demethylation (1A2)1-d 47.0 ± 24.233.1 ± 50.50.291
 Coumarin 7-hydroxylation (2A6)1-d 1769.8 ± 1878.91470.6 ± 1283.30.630
S-Mephenytoin N-demethylation (2B6)1-d 136.6 ± 210.9107.6 ± 111.60.662
 Tolbutamide methyl-hydroxylation (2C9)1-d 291.7 ± 216.1213.4 ± 86.00.241
S-Mephenytoin 4′-hydroxylation (2C19)1-d 73.7 ± 130.393.4 ± 133.20.681
 Dextromethorphan O-demethylation (2D6)1-d 255.0 ± 171.8125.3 ± 97.00.023
 Chlorzoxazone 6-hydroxylation (2E1)1-d 2202.1 ± 601.31648.0 ± 846.90.036
 Dextromethorphan N-demethylation (3A4)1-d 115.1 ± 194.9109.2 ± 101.90.923
 Testosterone 6β-hydroxylation (3A4/5)1-d 3963.5 ± 4951.64981.2 ± 3944.70.547
 Lauric acid 12-hydroxylation (4A11)1-d 1145.2 ± 524.1927.4 ± 477.10.245

Note: The contents of total P450, b5, and cytochrome c reductase and the activities for various P450 isoforms were determined according the methods described (Pearce et al. (1996).

  • 1-a P values were calculated by using the two-tailed, unpaired t test.

  • 1-b Total P450 content is expressed as nanomoles per milligram of protein.

  • 1-c Cytochrome b5 content is expressed as nanomoles per milligram of protein per minute.

  • 1-d P450 dependent activities are expressed as picomoles per milligram of protein per minute.