急性实验性肝损伤对大鼠酮洛芬Ⅱ相代谢和胆排泄的影响

目的探讨通过酮洛芬(KP)代谢参数的变化分析肝脏功能的可能性。方法以KP为工具药,用四氯化碳(CCl_4)和α-萘异硫氰酸酯(ANIT)建立急性肝损伤大鼠模型。体内实验,KP 20 mg·kg~(-1)iv后,测定大鼠血浆、胆汁中KP及其Ⅱ相代谢物酮洛芬葡萄糖醛酸结合物(S-KPG和R-KPG)。体外微粒体孵育实验,测定KP葡萄糖醛酸化反应v_(max)和K_m。结果体内实验结果显示,与对照组相比,CCl_4肝损伤模型大鼠KPG累计胆排泄率降低[(54±18)% vs (90±7)%],ANIT肝损伤模型大鼠的KPG胆排泄几乎完全被抑制[(4.9±2.0)%]。与对照组比,CCl_4和ANIT肝损伤模型组KP药动学参数lgAUC_(0～∞)增加[(5.26±0.19),(5.05±0.10) vs (4.67±0.07)]、~t1/2β延长[(284.2±150.0),(129.0±37.0)min vs (67.8±21.7)min]、清除率降低[(0.046±0.019),(0.080±0.011)mL·min~(-1) vs (0.169±0.026)mL·min~(-1)],血浆KPG浓度明显升高。与对照组比较,ANIT肝损伤模型组血浆S-KPG的AUC_(0～∞)增高了约10倍。微粒体孵育试验表明,与对照组比,CCl_4和ANIT肝损伤模型组大鼠肝脏葡萄糖醛酸转移酶活性有轻至中度降低,v_(max):(0.9±0.5),(1.1±0.6)mmol·g~(-1)·min~(-1) vs (2.9±0.9)mmol·g~(-1)·min~(-1);K_m:(6.8±1.6),(5.4±1.5)mmol·L~(-1) vs (13.6±1.2)mmol·L~(-1)。结论急性肝损伤时KP药代动力学参数发生改变,说明可以通过考察KP的动力学参数的变化,尤其是lgAUC_(0～∞),t_(1/2β),清除率和KPGs累计胆排泄率,来反映肝功能情况。

Ketoprofen glucuronidation and bile excretion in experimental hepatic injury rats

AIM To investigate the effects of experimental hepatic injury on the liver glucuronidation and bile excretion of ketoprofen（KP） and its glucuronides (KPGs). And to provide new experimental tool to evaluate the intrinsic liver capacity of metabolism and elimination. METHODS KP（20 mg·kg^-1） was intravenously administered to carbon tetrachloride （CCl₄） or alpha-naphthylisothiocyanate （ANIT） induced hepatic injury male rats. Concentrations of KP and its glucuronides （S-KPG and R-KPG） in plasma and bile were determined by RP-HPLC. The enzymatic parameters of KP glucuronidation were determined by the microsomal incubation experiment. RESULTS There was significant difference in the accumulative bile excretion of KPGs between the CCl₄ intoxicated rats and the normal rats〔(54±18)% vs (90±7)%〕, while it was extremely inhibited in ANIT intoxicated rats〔(4.9±2.0)% vs (90±7)%〕. As the result of reduction of KPGs excreted in bile, the lgAUC_{（0～∞）} of KP was higher in blood of CCl4 and ANIT hepatic injury rats than those of the normal rats〔(5.26±0.19), (5.05±0.10) vs (4.67±0.07)〕. Meanwhile, t_1/2β of KP was longer 〔(284.2±150.0), (129.0±37.0) min vs (67.8±21.7) min 〕and the clearance of KP was lower 〔(0.046±0.019), ( 0.080±0.011) mL·min^-1 vs (0.169±0.026) mL·min^-1〕in CCl₄ and ANIT hepatic injury rats. Specifically, ANIT caused approximately 10-fold elevation of AUC_{（0～∞）} of plasma S-KPG. In microsomal incubation experiment, the lucuronyltransferase activity was impaired in CCl₄ and ANIT intoxicated rats. CONCLUSION It can be inferred that KP is therefore a reasonable model drug to evaluate the intrinsic liver capacity of glucuronidation and elimination of the phaseⅡ metabolites in hepatic injury. And the changes in pharmacokinetic parameters (lgAUC_{（0～∞）}, t_1/2β, clearance and the accumulative bile excretion of KPGs) of KP can be used to evaluate the liver function.