细胞色素P450介导的氯沙坦钾对瑞格列奈在大鼠肝微粒体中代谢的影响

Effect of Losartan on the Metabolism of Repaglinide in Liver Microsomes of Rats by CYP450

关键词:  瑞格列奈  氯沙坦钾  肝微粒体  UPLC  酶促反应动力学  IC₅₀值

Key words:  repaglinide  losartan  liver microsome  UPLC  enzyme kinetic  IC₅₀ value

摘要:

目的 研究瑞格列奈在大鼠肝微粒体中的酶促反应动力学，并考察氯沙坦钾对其在大鼠肝微粒体中代谢的影响。方法 建立大鼠肝微粒体体外孵育体系对瑞格列奈的代谢进行研究；以洛伐他汀为内标，应用UPLC测定大鼠肝微粒体中瑞格列奈的浓度。采用底物减少法，通过GraphPad Prism 5.0软件计算瑞格列奈的酶促反应动力学常数V_max和K_m；分别以系列浓度氯沙坦钾（2.5~50μmol·L^-1）与瑞格列奈（44 μmol·L^-1）于37℃水浴中共同孵育，并测定肝微粒体中瑞格列奈的减少量，考察氯沙坦钾对瑞格列奈的抑制作用。结果 瑞格列奈在大鼠肝微粒体的最佳孵育时间为40 min，最佳蛋白质量浓度为1 mg·mL^-1；瑞格列奈酶促反应动力学参数V_max=47.29μmol·min^-1·（mg·protein）^-1，K_m=51.41 μmol·L^-1；氯沙坦钾对瑞格列奈在体外肝微粒体抑制作用的IC₅₀值为17.89 μmol·L^-1。结论 氯沙坦钾对瑞格列奈在大鼠肝微粒体中的代谢具有较强的抑制作用，两药联合应用可能发生相互作用，具有诱发低血糖的风险。

Abstract:

OBJECTIVE To characterize the enzymatic kinetics of repaglinide in rat liver microsome and study the effect of losartan on the metabolism of rat liver microsome. METHODS The metabolism of raglenay by establishing the in vitro incubation system of liver microsome in rats. UPLC method was used to detect the concentration of repaglinide in rat liver microsome with lovastatin as internal standard. The enzyme kinetic parameters of V_max and K_mwas calculated by determining the reduction of repaglinide with GraphPad Prism 5.0 software. Repaglinide(44 μmol·L^-1) was jointly incubated with a series of concentrations of losartan(2.5-50 μmol·L^-1) in a 37℃ water bath, respectively. The reduction of repaglinide in liver microsomes was also measured, and the inhibitory effect of losartan potassium on repaglinide was investigated. RESULTS The optimal incubation time in rat liver microsomes was 40 min, and the optimal protein concentration was 1 mg·mL^-1. The enzyme kinetics parameters of repaglinide were as follows:V_max=47.29 μmol·min^-1·(mg·protein)^-1, K_m=51.41 μmol·L^-1. The IC₅₀ value of the inhibitory effect of losartan potassium on repaglinide liver microsomes in vitro was 17.89 μmol·L^-1. CONCLUSION Losartan has a significant effect on the metabolism of repaglinide in liver microsomes. Drug interaction may occur when the two drugs are combined, and there is a risk of hypoglycemia.