川芎嗪在大鼠肝微粒体系统中的代谢研究

Study on metabolism of tetramethylpyrazine in system of rat liver microsomes

目的:通过离体和整体实验来研究川芎嗪(TMPz)代谢转化过程,探讨参与TMPz代谢的CYP450亚酶,为临床上合理用药提供科学依据。方法:建立TMPz的UV-HPLC检测方法,测定大鼠血浆和肝微粒体温孵液中TMPz及代谢产物,分析TMPz代谢消除率与各诱导和抑制剂之间的相关性;Nash法测定肝微粒体温孵液中ERY N-脱甲基酶活性,探索其与代谢物生成量之间的相关关系;测定DEX,Ket在体诱导或抑制后,大鼠血中的TMPz药物浓度,计算和比较药动学参数。结果:特异性CYP3A诱导剂DEX组中TMPz代谢物生成速率明显高于对照组,而主要诱导CYP2B的PB,β-NF组与对照组无明显区别;强效的CYP3A抑制剂Ket则显著抑制TMPz的代谢;TMPz的代谢速率与CYP3A的特征性ERY N-脱甲基反应呈现高度的相关性;在体诱导或抑制后TMPz的药动学参数中DEX组的CL(s)大于对照组,t1/2小于对照组;而Ket抑制的CL(s)小于对照组,t1/2大于对照组,差异均具有统计学意义。结论:CYP3A是介导TMPz生物转化的CYP450亚酶,川芎嗪与CYP3A酶抑制或诱导药合用可能存在药物间的相互作用。

Objective： The metabolic character of tetramethylpyrazine（TMPz） in rat liver microsomes was studied in vitro and in vivo to identify which isoforms of cytochrome P450 were responsible for TMPz metabolism in rats, offer the theoretical foundation for the fact that it is rational to use medicine in clinic. Method： Set up UV- HPLC method of TMPz, determine concentration of TMPz and its formation in rat plasma and liver microsomes incubation solution, analyze the correlation between TMPz＇s metabolic eliminate rate and each inducer. Erythromycin（ERY） N-demethylase activity of each sample in rat liver microsomes was measured using N-demethylation reaction of ERY as probe. The correlation between the rate of TMPz metabolite formation and the demethylase activity was analysed. After the SD rats who had been treated with inducer, inhibitor, or untreated, received administration of TMPz in vein, the plasma concentration of TMPz were determined by HPLC. Pharmacokinetic parameters of TMPz were computed and compared. Result： The disppearing rate of TMPz in the incubation solutions of the rats liver microsomes, which treated with DEX, were markedly quicker than that of control group （ P 〈 0.01 ）, while no obvious difference between β-NF group or PB and control group was observed （P 〉 0. 05 ）. The activity of ERY-N-demethylase in DEX-induced group was corespondingly enhanced, was much higer than that in control group. The correlation between the rate of TMPz metabolic product formation and the activity of N-demethylase was significant. After using Ket, the CYP3A inhibitor, the metabolism of TMPz could be significantly inhibited the metabolism of TMPz in rat liver microsomes. In vivo, CL（s） were larger than that of the control group, t1/2 were smaller than the control group in DEX group： By contrary, CL（s） was smaller than the control group,t1/2 was larger than the control group in Ket group. Conclusion： Results suggest that CYP3A plays a major role in TMPz metabolism in rats, TMPz lie in the possibility of Interaction among the medicines between TMPz and CYP3A inducers or inhibitors when they are used in clinic.