Becquemont L, Le Bot M A, Riche C, Funck-Brentano C, Jaillon P, Beaune P
Clinical Pharmacology Unit, Saint Antoine University Hospital, Paris, France.
Pharmacogenetics. 1998 Apr;8(2):101-8. doi: 10.1097/00008571-199804000-00002.
The aim of the present study was to evaluate the use of recombinant human cytochrome P-450 1A2 (rH-CYP1A2) in studies performed in vitro in order to predict metabolic drug-drug interactions occurring in man. In vitro metabolism of tacrine (a CYP1A2 probe) in the presence and absence of fluvoxamine, a CYP1A2 inhibitor, was investigated in human liver mircrosomes and with different rH-CYP. Vmax, Km and Ki determined with human liver microsomes were compared with those observed using rH-CYP1A2, assuming that 1 mg of liver microsomes contains, on average, 69 pmol of CYP1A2. The extent of tacrine metabolism inhibition procured by fluvoxamine with rH-CYP1A2, was compared with previous results observed in man. The Vax and Km for 1-hydroxytacrine formation rates obtained with rH-CYP1A2 were in good agreement with those observed in human liver microsomes (175+/-9 versus 140+/-60 pmol/min/mg for Vmax and 14+/-2 versus 16+/-2 microM for Km, respectively. The Ki of fluvoxamine on 1-hydroxytacrine formation rate observed with rH-CYP1A2 was similar to that observed with human liver microsome (0.35+/-0.05 versus 0.20+/-0.20 microM, respectively). Using the Km, Vmax and Ki determined with rH-CYP1A2, we calculated that fluvoxamine produced an inhibition of 1-, 2- and 4-hydroxytacrine formation rate of 91, 87 and 88%, respectively, in the range of tacrine and fluvoxamine concentrations observed in man. These percentages of inhibition calculated in vitro were in agreement with the percentage of fluvoxamine-dependent decrease in tacrine apparent oral clearance previously observed in man (83+/-13%). We conclude that human CYP1A2 expressed in yeast is a powerful tool to predict and to quantify drug-drug interactions in man.
本研究的目的是评估重组人细胞色素P-450 1A2（rH-CYP1A2）在体外研究中的应用，以便预测人体中发生的代谢性药物-药物相互作用。在人肝微粒体中以及使用不同的rH-CYP，研究了在存在和不存在CYP1A2抑制剂氟伏沙明的情况下他克林（一种CYP1A2探针）的体外代谢。假设1mg肝微粒体平均含有69pmol CYP1A2，将用人肝微粒体测定的Vmax、Km和Ki与使用rH-CYP1A2观察到的结果进行比较。将氟伏沙明对rH-CYP1A2诱导的他克林代谢抑制程度与先前在人体中观察到的结果进行比较。用rH-CYP1A2获得的1-羟基他克林形成速率的Vax和Km与在人肝微粒体中观察到的结果高度一致（Vmax分别为175±9和140±60pmol/min/mg，Km分别为14±2和16±2μM）。用rH-CYP1A2观察到的氟伏沙明对1-羟基他克林形成速率的Ki与用人肝微粒体观察到的相似（分别为0.35±0.05和0.20±0.20μM）。使用用rH-CYP1A2测定的Km、Vmax和Ki，我们计算出在人体中观察到的他克林和氟伏沙明浓度范围内，氟伏沙明分别对1-、2-和4-羟基他克林形成速率产生91%、87%和88%的抑制作用。体外计算的这些抑制百分比与先前在人体中观察到的氟伏沙明依赖性他克林表观口服清除率降低的百分比（83±13%）一致。我们得出结论，酵母中表达的人CYP1A2是预测和量化人体中药物-药物相互作用的有力工具。
