Effect of β-naphthoflavone on in situ formation of oxidative metabolites of valproic acid in sandwich-cultured rat hepatocytes treated with valproic acid
At 48 hours after plating, hepatocytes were pretreated with 20 µM β-naphthoflavone (BNF) or 0.1% dimethylsulfoxide (DMSO; vehicle) once every 24 hours for 72 hours and then treated with valproic acid (VPA; 10 or 15 mM) or culture medium (vehicle) for the next 24 hours. Culture supernatants were collected at the end of the 24-hour treatment period and subjected to gas chromatography–mass spectrometry assay for the quantification of the concentrations of oxidative metabolites of VPA. Data are expressed as mean ± S.E.M. for three rats.
| Metabolite | In Situ Concentration of VPA Metabolites (µM/0.7 × 106 cells) | |||
|---|---|---|---|---|
| 10 mM VPA | 15 mM VPA | |||
| 0.1% DMSO | 20 μM BNF | 0.1% DMSO | 20 μM BNF | |
| 4-ene-VPA | 0.06 ± 0.01 | 0.09 ± 0.01 | 0.05 ± 0.01 | 0.08 ± 0.01 |
| 4-keto-VPA | 0.15 ± 0.01 | 0.50 ± 0.06* | 0.22 ± 0.02 | 0.58 ± 0.08* |
| 4-OH-VPA | 2.5 ± 0.30 | 4.9 ± 0.54* | 2.1 ± 0.25 | 5.1 ± 0.46* |
| 5-OH-VPA | 1.4 ± 0.27 | 1.2 ± 0.17* | 1.3 ± 0.25 | 1.2 ± 0.24 |
| (E)-2,4-diene-VPA | None detected | None detected | None detected | None detected |
| (E,Z)-2,3′-diene-VPA | 0.16 ± 0.01 | 0.19 ± 0.01 | 0.15 ± 0.01 | 0.19 ± 0.02 |
| (E,E)-2,3′-diene-VPA | 1.7 ± 0.27 | 1.7 ± 0.21 | 1.7 ± 0.34 | 1.8 ± 0.34 |
| 3-ene-VPA | 1.2 ± 0.20 | 1.3 ± 0.14 | 1.0 ± 0.15 | 1.1 ± 0.13 |
| (E)-2-ene-VPA | 1.7 ± 0.13 | 1.5 ± 0.06 | 1.8 ± 0.21 | 1.8 ± 0.20 |
| 3-OH-VPA | 5.7 ± 1.2 | 11 ± 4.2 | 5.5 ± 1.5 | 18 ± 5.0* |
| 3-keto-VPA | 2.0 ± 0.63 | 1.7 ± 0.32 | 2.1 ± 0.99 | 2.2 ± 0.79 |
↵* Significantly different from the DMSO-pretreated vehicle control group, P < 0.05.