OBJECTIVE To observe the effect of cAMP-PKA signal pathway on the activity of cytochrome P4503A (CYP3A) in L02 cells, and to explore the mechanism. METHODS L02 cells were treated with agonist 8-Br-cAMP 10 μmol· L-1 and inhibitor H-89 10 μmol· L-1. The expression of pregnane X receptor (PXR) and protein kinase A (PKA) protein were detected by Western blotting and immunohistochemistry. The activity of CYP3A was detected by ultraviolet spectrophotometry. RESULTS Compared with the activity of CYP3A [ (0.28 ±0.02)μmol·min-1 ·g-1 protein], the expression of PXR (0.45 ±0.14) and PKA (211 ±20) in normal control group, the activity of CYP3A[ (0.43 ±0.01 ) μmol·min -1 ·g-1 protein], and the expression of PXR (0.69 ±0.21 ) and PKA (296 ± 18) increased in 8-Br-cAMP group while the expression of PKA (176 ± 14)decreased. The activity of CYP3 A [ ( 0.39 ± 0.05 ) μmol· min - 1· g - 1 protein ] and the expression of PXR (0.47 ±0.13) were no statistical significance in H-89 group. CONCLUSION The cAMP-PKA singal pathway can regulate the CYP3A in L02 cells.%目的 探讨cAMP-PKA信号通路对细胞色素P4503A(CYP3A)在正常肝细胞L02表达中的作用.方法 102细胞中分别加入8-溴-环腺苷酸(8-Br-cAMP)10μmol·L及抑制剂H-8910μmol·L,培养48 h,分别采用完整细胞免疫组化法、Western印迹法和红霉素-N-脱甲基法检测细胞中PKA、孕烷X受体(PXR)及CYP3A的表达.结果 与正常对照组PKA蛋白表达(211±20)、PXR蛋白表达(0.45±0.14)及CYP3A的活性[(0.38±0..2)μmol·min·g蛋白]相比,8-Br-cAMP 10μmol·L处理后,细胞PKA蛋白表达(296±18)升高、PxR蛋白表达(0.69±0.21)升高、CYP3A的活性[(0.43±0.01)μmol·min·g蛋白]增强;H-89 10μmol·L处理后细胞中PKA蛋白表达(176±14)降低,PxR蛋白表达(0.47±0.13)及CYP3A的活性[(0.39±0.05)μmol·min'-1>·g]减弱,无统计学差异.结论 cAMP-PKA信号通路可能是药物代谢酶CYP3A的调控途径之一.
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