人肝微粒体和重组人尿苷二磷酸葡萄糖醛酸基转移酶（UGT）对S-萘普生和去甲基萘普生的葡萄糖醛酸化作用：UGT2B7在萘普生消除中的作用
S-Naproxen and desmethylnaproxen glucuronidation by human liver microsomes and recombinant human UDP-glucuronosyltransferases (UGT): role of UGT2B7 in the elimination of naproxen.
作者信息
Bowalgaha Kushari, Elliot David J, Mackenzie Peter I, Knights Kathleen M, Swedmark Stellan, Miners John O
机构信息
Department of Clinical Pharmacology, Flinders University and Flinders Medical Centre, Bedford Park, Adelaide, Australia.
出版信息
Br J Clin Pharmacol. 2005 Oct;60(4):423-33. doi: 10.1111/j.1365-2125.2005.02446.x.
AIMS
To characterize the kinetics of S-naproxen ('naproxen') acyl glucuronidation and desmethylnaproxen acyl and phenolic glucuronidation by human liver microsomes and identify the human UGT isoform(s) catalysing these reactions.
METHODS
Naproxen and desmethylnaproxen glucuronidation were investigated using microsomes from six and five livers, respectively. Human recombinant UGTs were screened for activity towards naproxen and desmethylnaproxen. Where significant activity was observed, kinetic parameters were determined. Naproxen and desmethylnaproxen glucuronides were measured by separate high-performance liquid chromatography methods.
RESULTS
Naproxen acyl glucuronidation by human liver microsomes followed biphasic kinetics. Mean apparent K(m) values (+/-SD, with 95% confidence interval in parentheses) for the high- and low-affinity components were 29 +/- 13 microm (16, 43) and 473 +/- 108 microm (359, 587), respectively. UGT 1A1, 1A3, 1A6, 1A7, 1A8, 1A9, 1A10 and 2B7 glucuronidated naproxen. UGT2B7 exhibited an apparent K(m) (72 microm) of the same order as the high-affinity human liver microsomal activity, which was inhibited by the UGT2B7 selective 'probe' fluconazole. Although data for desmethylnaproxen phenolic glucuronidation by human liver microsomes were generally adequately fitted to either the single- or two-enzyme Michaelis-Menten equation, model fitting was inconclusive for desmethylnaproxen acyl glucuronidation. UGT 1A1, 1A7, 1A9 and 1A10 catalysed both the phenolic and acyl glucuronidation of desmethylnaproxen, while UGT 1A3, 1A6 and 2B7 formed only the acyl glucuronide. Atypical glucuronidation kinetics were variably observed for naproxen and desmethylnaproxen glucuronidation by the recombinant UGTs.
CONCLUSION
UGT2B7 is responsible for human hepatic naproxen acyl glucuronidation, which is the primary elimination pathway for this drug.
目的
研究人肝微粒体对S-萘普生（“萘普生”）酰基葡萄糖醛酸化以及去甲基萘普生酰基和酚羟基葡萄糖醛酸化的动力学特征，并鉴定催化这些反应的人尿苷二磷酸葡萄糖醛酸基转移酶（UGT）同工型。
方法
分别使用来自6例和5例肝脏的微粒体研究萘普生和去甲基萘普生的葡萄糖醛酸化。筛选人重组UGT对萘普生和去甲基萘普生的活性。观察到显著活性时，测定动力学参数。通过单独的高效液相色谱法测量萘普生和去甲基萘普生葡萄糖醛酸苷。
结果
人肝微粒体对萘普生的酰基葡萄糖醛酸化呈现双相动力学。高亲和力和低亲和力组分的平均表观米氏常数（±标准差，括号内为95%置信区间）分别为29±13 μmol/L（16，43）和473±108 μmol/L（359，587）。UGT 1A1、1A3、1A6、1A7、1A8、1A9、1A10和2B7可使萘普生葡萄糖醛酸化。UGT2B7的表观米氏常数（72 μmol/L）与高亲和力人肝微粒体活性处于同一水平，且被UGT2B7选择性“探针”氟康唑抑制。虽然人肝微粒体对去甲基萘普生酚羟基葡萄糖醛酸化的数据通常能很好地拟合单酶或双酶米氏方程，但去甲基萘普生酰基葡萄糖醛酸化的模型拟合结果尚无定论。UGT 1A1、1A7、1A9和1A10催化去甲基萘普生的酚羟基和酰基葡萄糖醛酸化，而UGT 1A3、1A6和2B7仅形成酰基葡萄糖醛酸苷。重组UGT对萘普生和去甲基萘普生葡萄糖醛酸化的过程中，可不同程度地观察到非典型葡萄糖醛酸化动力学。
结论
UGT2B7负责人类肝脏中萘普生的酰基葡萄糖醛酸化，这是该药物的主要消除途径。
Zotero 插件