Investigation of the role of CYP1A2 in irosustat metabolism
Formation of irosustat metabolites in incubations with native and CYP1A2-fortified HLM. Results are expressed as percentage of inhibition for each separate metabolite and are the mean values from duplicate incubations. Inhibitors: FU, 1 μM furafylline; MIX, 10 μM quercetin + 2 μM sulfaphenazole + 20 μM tranylcypromine + 0.5 μM ketoconazole. Microsomal protein concentration: 1 mg/ml ± 20 pmol/ml recombinant human CYP1A2. Incubation time: 15-min preincubation ± furafylline followed by 40-min incubation, Irosustat concentration: 50 μM. Bold numbers represent percentage of inhibition >20%. Italic values represent high variability for M11 because peak areas were close to the limit of detection.
| Matrix | Chemical Inhibitors | Inhibition | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| M7 | M8 | M9 | M11 | M13 | M14 | M16 | M18 | P-36 | ||
| % | ||||||||||
| Native HLM | FU | 1.4 | 2.0 | 4.3 | −59.5 | 1.7 | 2.7 | 1.2 | 2.4 | 1.9 |
| MIX | 66.2 | 100 | 74.6 | 100 | 65.0 | 49.5 | 70.3 | 64.4 | 47.7 | |
| MIX + FU | 65.6 | 100 | 81.3 | 100 | 66.5 | 54.6 | 81.3 | 68.0 | 54.6 | |
| CYP1A2-fortified HLM | FU | −2.6 | −8.2 | −0.3 | −15.0 | 7.0 | 24.9 | 12.1 | 0.8 | −17.1 |
| MIX | 44.7 | 44.7 | 58.2 | 100 | 44.3 | 23.7 | 29.6 | 46.1 | 22.6 | |
| MIX + FU | 56.3 | 61.5 | 72.9 | 100 | 61.1 | 54.2 | 53.8 | 60.7 | 32.8 | |