Table 1.
CYP1A activity of HaCaT cells exposed to inhibitors of CYP1A in commercial DMEM (Com) or in DMEM prepared with purified tryptophan (Pure)
| % inhibition† |
Induction‡ |
||
| Compound (concentration) | Com | Com | Pure |
| TCDD (1 nM) | 24.1 ± 1.48ns | 24.5 ± 2.03 | |
| Trioxalen (1 μM) | 33.0 ± 9.1* | 1.48 ± 0.18** | 0.05 ± 0.03 |
| Ketoconazole (10 μM) | 69.7 ± 1.7*** | 1.31 ± 0.22*** | 0.27 ± 0.05 |
| Ellipticine (0.05 μM) | 43.3 ± 3.4*** | 9.01 ± 1.03*** | 3.88 ± 0.32 |
| Genistein (10 μM) | 14.2 ± 5.3ns | 1.10 ± 0.07*** | 0.02 ± 0.04 |
| Diosmin (10 μM) | 40.8 ± 3.3** | 0.79 ± 0.06*** | 0.18 ± 0.04 |
| α-Naphtoflavone (0.25 μM) | 62.2 ± 2.9*** | 1.46 ± 0.14*** | 0.08 ± 0.03 |
| Cycloheximide (18 μM) | 65.8 ± 1.9*** | 3.45 ± 0.33*** | 0.27 ± 0.04 |
| α-Tocopherol (50 μM) | 14.9 ± 6.2ns | 0.54 ± 0.03*** | 0.13 ± 0.02 |
| DMSO (0.1%, vol/vol) | 0.25 ± 0.04*** | 0.05 ± 0.02 | |
| EtOH (0.1%, vol/vol) | 0.33 ± 0.04** | 0.16 ± 0.03 | |
†Percent inhibition of TCDD-induced EROD activity following 6 h of exposure in the absence of any other addition; means ± SE of triplicate measurements. Significance of inhibition compared with TCDD is depicted with asterisks (ns, non significant; *P < 0.05; **P < 0.01; ***P < 0.001).
‡Mean EROD activity (pmol resorufin/mg protein) ± SE following 12 h of exposure. Differences in EROD induction for respective treatment in the commercial compared with the pure media were tested. ns, non significant; *P < 0.05; **P < 0.01; ***P < 0.001. EROD induction at several time points is shown in Fig. S6.