TABLE 3.
In vitro metabolism of testosterone
Liver, lung, OM, and brain microsomes were prepared from 2-month-old male WT and Cyp2a(4/5)bgs-null mice. Reaction mixtures contained 50 mM phosphate buffer, pH 7.4, 10 µM testosterone, 1 mM ascorbic acid, 1 mM NADPH, and 0.1 mg/ml (for OM and liver) or 0.5 mg/ml (for lung and brain) microsomal protein. The values presented are means ± S.D. (n = 3).
| Tissue | Genotype | Rates of Product Formation |
|||||||
|---|---|---|---|---|---|---|---|---|---|
| 15α-OH-T | 15β-OH-T | 2β-OH-T | 16α-OH-T | 16β-OH-T | 6α-OH-T | 6β-OH-T | 11α-OH-T | ||
| pmol/min/mg protein | |||||||||
| Lung | WT | 80 ± 5 | 3 ± 1 | 4 ± 1 | 30 ± 6 | 7 ± 2 | <0.02a | <0.02 | <0.02 |
| Null | 3 ± 0b | <0.01 | <0.01 | 30 ± 7 | 2 ± 1b | <0.02 | <0.02 | <0.02 | |
| OM | WT | 4100 ± 200 | 320 ± 60 | 380 ± 50 | <0.5 | <0.1 | <0.2 | <0.2 | <0.2 |
| Null | <0.1 | <0.1 | <0.1 | <0.5 | <0.1 | <0.2 | <0.2 | <0.2 | |
| Brain | WT | 0.16 ± 0.03 | <0.01 | <0.01 | 0.14 ± 0.03 | 0.03 ± 0.01 | 0.04 ± 0.01 | <0.01 | 0.02 ± 0.00 |
| Null | 0.14 ± 0.03 | <0.01 | <0.01 | 0.08 ± 0.03b | 0.03 ± 0.01 | 0.04 ± 0.01 | <0.01 | 0.02 ± 0.00 | |
| 15β-OH-T | 16α-OH-T | 6β-OH-T | |||||||
| Liverc | WT | 5.6 ± 1.2 | 260 ± 20 | 120 ± 30 | |||||
| Null | 2.3 ± 0.1b | 250 ± 30 | 120 ± 20 | ||||||
OM, nasal olfactory mucosa; WT, wild type.
Estimated on the basis of detection limits, which were respectively 0.02 (15α-OH-T), 0.01 (15β-OH-T), 0.07 (2β-OH-T), 0.02 (16α-OH-T), 0.01 (16β-OH-T), and 0.03 (6α-OH-T, 6β-OH-T, and 11α-OH-T) pmol on column.
Significantly lower than the corresponding WT value, P < 0.01 (Student’s t test).
Only previously reported major metabolites were determined (Zhou et al., 2010).