人细胞色素P450 3A活性测定

目的:建立测定人细胞色素P4503A酶活性的方法。方法:收集24h尿液,以HPLC法测定尿液中氢化可的松(HC)与6β-羟基氢化可的松(6β-OHC)的含量,以6β-OHC/HC来评估细胞色素P4503A酶的活性。结果:健康志愿者尿中6β-羟基氢化可的松和氢化可的松的比值为(8.5±3.0),肿瘤患者为(6.2±4.5)。结论:细胞色素P4503A酶的活性可以通过测定6β-OHC与HC的比值进行预测。     

上海学龄儿童细胞色素P450 3A酶活性分布

目的:调查上海地区1 169名6~15岁学龄儿童细胞色素P450 3A酶活性(cytochrome P450 3A activity,CA)的分布情况及正常值范围。方法:采用HPLC梯度洗脱法测定尿液中氢化可的松和6β-羟基氢化可的松的浓度,以地塞米松为内标,采用HP Hypersil ODS柱(250 mm×4 mm,5μm),流动相A相为CH3CN,B相为7.56 mmol/L(NH4)2SO4溶液,梯度设置:0~6.5 min,A:10%,B:90%;6.5~15 min,A:35%,B:65%,线性变化;15~24 min,A:35%,B:65%;24~28 min,A:10%,B:90%,线性变化;28~42 min,A:10%,B:90%。柱温30℃;流速1.0 mL/min;检测波长240 nm。数据分布形态检测采用Kolmogorov-Smirnov检验,男、女儿童酶活性之间的比较采用两个独立样本的t检验。结果:1 169名学龄儿童CA分布为左偏态分布,偏度系数为2.66,lgCA呈正态分布,偏度系数为0.027。CA正常值范围为1.00~25.47,男女性之间CA无显著性差异(P=0.919)。将未发育期、发育启动期和发育中期分别设为X=1、2、3,与CA平均值(Y)进行线性回归,得到回归方程为Y=0.685X+3.513(r=0.999 9)。结论:确定学龄儿童CA分布情况及其正常值范围,可为制定儿童个体化给药方案和给药剂量提供依据。     

上海市2671名儿童细胞色素P450 3A酶活性分布

目的 了解上海地区6～15岁学龄儿童细胞色素P450 3A酶活性(CA)的分布.方法 采用固相萃取-反相高效液相色谱测定尿液中氢化可的松和6β-羟基氢化可的松的浓度,以6β-羟基氢化可的松与氢化可的松的浓度比来表示CYP3A酶的活性.结果 2671名受检者CYP3A酶的活性为(2.75±2.75),各年龄间CYP3A活性(CA)的差异有统计学意义,年龄(X)与lgCA(Y)呈线性相关,线性回归方程为Y=0.052×X-0.096,r=0.963.结论 上海地区6～15岁学龄儿童CYP3A酶活性分布与年龄相关.     

细胞色素P450 3A研究进展

P4503A是细胞色素P450中含量最多的同工酶,临床中有60％以上的药物由其代谢。总结了CYP3A的分布、含量、亚型、表达与调控、与疾病的关系以及活性研究方法等研究进展。     

上海地区210名12周岁儿童CYP3A活性分布

目的:了解上海地区12岁儿童CYP3A酶活性的分布。方法:采用HPLC法测定尿液中氢化可的松和6β-羟基氢化可的松的浓度,以6β-羟基氢化可的松/氢化可的松的浓度比来表示CYP3A酶的活性。结果:210名受检者CYP3A酶的活性为(5.0±2.3),其中男性为(4.7±2.3),女性为(5.4±2.4)。结论:12岁儿童CYP3A酶活性无性别差异,正常值范围为0.96~26.55。     

酒精性肝损伤大鼠细胞色素P450 CYP2E1和细胞色素P450 CYP3A的代谢活性

目的观察酒精性肝损伤对大鼠细胞色素P450CYP3A(CYP3A)和细胞色素P450CYP2E1(CYP2E1)代谢活性的影响。方法采用ig给予白酒制备大鼠酒精性肝损伤模型,检测血清中谷丙转氨酶(GPT)和谷草转氨酶(GOT)活性,采用HE染色法光镜下观测酒精对肝脏损伤程度。大鼠ip给予CYP3A探针药物咪达唑仑10mg·kg-1或ig给予CYP2E1探针药物氯唑沙宗50mg·kg-1后,采用高效液相色谱法测定不同时间点大鼠血浆中咪达唑仑和氯唑沙宗的血药浓度,并应用3P87软件计算其药代动力学参数,以考察CYP2E1和CYP3A的代谢活性的变化。大鼠ig给予氯唑沙宗80mg·kg-1后,热板方法测定大鼠添足次数和添足反射潜伏期。结果酒精性肝损伤可致大鼠肝小叶结构不清,肝索排列紊乱,肝细胞体积增大,呈弥漫性中度水变性,肝窦受压,大部分肝细胞胞浆内见大小不等的脂肪空泡;与正常对照组相比,酒精性肝损伤组大鼠GPT和GOT活性分别增加了16.0%和20.0%(P<0.05,P<0.01)。酒精性肝损伤致大鼠CYP2E1对探针药物氯唑沙宗的代谢活性增强,AUC,t1/2和cmax分别降低了38.0%,30.5%和35.0%(P<0.05);酒精肝损伤组大鼠氯唑沙宗镇痛效果明显降低;酒精性肝损伤致大鼠CYP3A对探针药物咪达唑仑的代谢活性增强,AUC,t1/2和cmax分别降低了122.6%,54.9%和56.9%(P<0.01,P<0.05)。结论酒精性肝损伤可使大鼠CYP2E1和CYP3A代谢活性增强。     

细胞色素P450—3A4相关的药物相互作用

目的：综述与细胞色素P4503A4相关的药物相互作用。方法：检索Medline和中国药学文摘。结果：发现多种由CYP3A4催化代谢的药物之间可以竞争药物代谢酶,引起药物相互作用,CYP3A4的抑制剂和诱导剂均可以抑制或诱导CYP3A4催化代谢的药物代谢。导致有益或不良的药物相互作用。结论：CYP3A4催化代谢的药物联合使用,特别是CYP3A4抑制剂与底物联合使用时,可能因为抑制了药物的代谢而导致严重的药物不良反应。     

上海市中小学女生CYP3A酶活性分析

目的:分析女中小学生CYP3A酶活性及其变化趋势。方法:用HPLC梯度洗脱法测定573名女中小学生尿液中6β-羟基氢化可的松和氢化可的松的含量,并通过计算其比值分析CYP3A的活性。结果:在青春期开始发育时CYP3A酶的活性降低,且发育后酶活性个体差异变大。结论:中小学女生年龄跨越大,临床使用经CYP3A酶代谢的药物时应根据身体发育情况适当调整。     

体外研究人细胞色素P450在雌二醇代谢中的作用(英文)

目的:研究雌二醇在cDNA表达的P450和人肝微粒体中的代谢机制,为在体内研究细胞色素P450活性与肿瘤发生的关系提供依据。方法:用HPLC-ECD法测定雌二醇的代谢产物。通过雌二醇在不同cDNA表达的P450中代谢,13例人肝微粒体中相关性研究,抑制剂对代谢的影响以及微粒体中17β-羟基脱氢化和2-羟基化代谢的催化动力学的研究来推断雌二醇的代谢机理。结果:在cDNA表达的P450中,催化2-羟基化代谢的P450按活性排列依次为CYP1A2、CYP3A4、CYP2C9。CYP2C9、CYP2C19和CYP2C8均具有较高的催化17β-羟基脱氢化活性。抑制CYP1A2与抑制CYP3A4对2-羟基化代谢产物生成的影响相似,可认为CYP1A2和CYP3A4在人肝微粒体中催化2-羟基化代谢的作用相近。雌二醇代谢的途径与底物浓度有关,低浓度时(1,10μmol/L)17β-羟基脱氢化为主要代谢途径;高浓度时(100μmol/L),2-羟基化成为主要代谢途径。结论:高底物浓度时,雌二醇主要由CYP1A2和CYP3A4催化代谢为2-羟基化产物。低底物浓度时,主要由CYP2C9、CYP2C19和CYP2C8催化生成17β-羟基去氢化产物。     

2430名中小学生健康志愿者晨尿中6β-OHFC/FC分布

目的 观察2430名中小学生健康志愿者晨尿中6β-氢化可的松(6β-OHFC)与氢化可的松(FC)比值(6β-OHFC/FC)的分布.方法 采用HPLC法测定尿液中6β-OHFC和FC的含量,用6β-OHFC/FC计算健康儿童个体内CYP3A酶的活性.结果 儿童健康志愿者CYP3A酶活性分布经自然对数转换,呈正态分布,其值为(-0.663±1.573),其中男性为(-0.641±1.563),女(-0.683±1.583).结论 CYP3A酶活性随着年龄进入生理发育期而有所增加,但不同性别间差别无统计学意义.     

上海地区208名儿童CYP3A活性分布

目的:了解上海地区3岁儿童CYP3A酶活性的分布。方法:采用高效液相色谱法(HPLC)测定尿液中氢化可的松和6β-羟基氢化可的松的浓度,以6β-羟基氢化可的松/氢化可的松的浓度比来表示CYP3A酶的活性。结果:208名受检者CYP3A酶的活性为4.0±1.9,其中男性为4.2±1.9,女性为3.7±1.8。结论:3岁儿童CYP3A酶活性无性别差异,正常值范围为1.13~13.77。     

The distribution and gender difference of CYP3A activity in Chinese subjects

AIMS: To investigate the distribution of CYP3A activity in the Chinese population, and to test for gender-related differences in CYP3A activity. METHODS: Using midazolam as a probe drug, CYP3A activity in 202 Chinese healthy subjects (104 men) was measured by plasma 1'-hydroxymidazolam:midazolam (1'-OH-MDZ:MDZ) ratio at 1 h after oral administration of 7.5 mg midazolam. The different phases of the menstrual cycle including preovulatory, ovulatory and luteal phases of 66 women phenotyped with midazolam were recorded. The concentrations of 1'-OH-MDZ and MDZ in plasma were measured by HPLC RESULTS: A 13-fold variation of CYP3A activity (log1'-OH-MDZ:MDZ: range -0.949-0.203) was shown. The CYP3A activity was normally distributed as indicated by the frequency distribution histogram, the probit plot and the Kolmogorov-Smirnov test (P > 0.05). The CYP3A activity of women was higher than that of men (median: -0.36 vs -0.43, P < 0.05; 95% CI for difference: -0.127, -0.012). There was a significant difference in CYP3A activity between the three phases of the menstrual cycle. The activity was highest in the preovulatory phase and decreased sequentially in the ovulatory and luteal phases (P < 0.05). CONCLUSIONS: A normal distribution of CYP3A activity was observed in the Chinese population. The CYP3A activity is higher in female subjects than in males. CYP3A activity differed across the phases of the menstrual cycle.     

The effects of modifying in vivo cytochrome P450 3A (CYP3A) activity on etoricoxib pharmacokinetics and of etoricoxib administration on CYP3A activity

To investigate the influence of modifying in vivo cytochrome P450 3A (CYP3A) activity on the pharmacokinetics of etoricoxib, a selective inhibitor of cyclooxygenase-2, and of etoricoxib administration on CYP3A activity, a 3-part, randomized, crossover study was conducted in 3 panels of healthy volunteers. In part I, 8 subjects were administered a single dose of 60 mg etoricoxib alone and following daily doses of 400 mg ketoconazole, a known strong inhibitor of CYP3A. In part II, 8 different subjects were administered a single dose of 60 mg etoricoxib alone and following daily doses of 600 mg rifampin, a known strong inducer of CYP3A. In parts I and II, plasma samples were collected following each etoricoxib dose and analyzed for etoricoxib. In part III, 8 different subjects were administered 120 mg etoricoxib or placebo once daily for 11 days, and the erythromycin breath test was administered on day 11 of each period. Coadministration of etoricoxib with daily doses of ketoconazole resulted in an average 43% increase in etoricoxib AUC; based on previous studies, this increase would not be expected to have any clinically meaningful effect. In contrast, coadministration of etoricoxib with daily doses of rifampin had a potentially clinically important effect on etoricoxib pharmacokinetics (average 65% decrease in etoricoxib AUC). Etoricoxib had no effect on hepatic CYP3A activity, as assessed by the erythromycin breath test.     

中国汉族人群中CYP3AP1基因型与CYP3A活性的相关性研究

目的:研究中国汉族人群中CYP3AP1基因型的分布特征及其与CYP3A活性的相关性.方法:以口服7.5mg咪哒唑仑后1小时血浆中1′-羟化咪哒唑仑与咪哒唑仑的比值作为CYP3A活性的衡量指标,测定191名中国汉族健康受试者的CYP3A活性,并利用多聚酶链式反应-限制性片段长度多态性(PCR-RFLP)方法对已知CYR3A活性受试者的DNA进行CYP3AP1基因分型.结果:CYP3AP1不同基因型个体的CYR3A活性存在显著差异(P<0.05).A_(-44)等位基因纯合子个体的CYP3A活性低于A_(-44)G杂合子,而G_(44)等位基因纯合子个体的CYP3A活性最高.结论:CYP3AP1基因型与体内CYP3A活性的增加存在相关性.     

人细胞色素P450 3A4突变体CYP3A4.3,CYP3A4.4,CYP3A4.5和CYP3A4.18重组酶的异源表达与活性

目的重组表达人细胞色素P450(CYP)3A4突变体CYP3A4.3,CYP3A4.4,CYP3A4.5和CYP3A4.18蛋白,为CYP3A4代谢活性的体外研究提供单一酶源。方法应用杆状病毒表达系统构建含有上述各CYP3A4突变体基因序列的重组病毒,将其连同含人源还原型烟酰胺腺嘌呤二核苷磷酸-P450氧化还原酶(POR)和细胞色素b5基因的重组病毒共同感染昆虫草地夜蛾细胞Sf9得到CYP3A4突变体与POR和细胞色素b5共表达的重组蛋白,分别以高效液相色谱法和荧光分析法测定各重组酶对睾酮和7-甲氧基-4-三氟甲基香豆素的代谢活性。结果在mRNA分子水平上验证了CYP3A4突变体CYP3A4*3,CYP3A4*4,CYP3A4*5和CYP3A4*18基因在Sf9细胞中的转录。感染了各重组病毒的Sf9细胞裂解液对睾酮和7-苄氧基-4-三氟甲基香豆素有明显代谢。结论应用杆状病毒-昆虫细胞表达系统在体外成功表达了具有催化活性的人CYP3A4突变体CYP3A4.3,CYP3A4.4,CYP3A4.5和CYP3A4.18蛋白,其中CYP3A4.5活性显著低于野生型蛋白,CYP3A4.18活性显著高于野生型蛋白,而CYP3A4.3和CYP3A4.4与野生型蛋白活性近似。     

The utility of CYP3A activity endogenous markers for evaluating drug-drug interaction between sildenafil and CYP3A inhibitors in healthy subjects

Cytochrome P450 (CYP) 3A-related drug-drug interaction (DDI) studies are needed during drug development to determine clinical interaction effects. We aimed to evaluate DDI between sildenafil and two CYP3A inhibitors, clarithromycin and itraconazole, regarding the changes in pharmacokinetics and endogenous markers. An open-label, one-sequence, one-period, two-treatment parallel study was conducted in 32 healthy Korean subjects. Each of 16 subjects were randomly assigned to the clarithromycin and itraconazole groups. Both groups received a single dose of sildenafil 25 mg as a control, and either clarithromycin 250 mg or itraconazole 100 mg was administered four times to inhibit CYP3A activity. Pharmacokinetics of sildenafil showed the similar magnitude of inhibitory effects of the two inhibitors on total CYP3A activity; both inhibitors similarly increased systemic exposure of sildenafil by 2-fold. Urinary 6β–OH–cortisone/cortisone and plasma 4β–OH–cholesterol were significantly decreased after clarithromycin administration but not after itraconazole. A significant correlation between sildenafil CL/F and metabolic markers of CYP3A activity was observed after clarithromycin administration. We confirmed that sildenafil has moderate pharmacokinetic interaction with clarithromycin and itraconazole. Endogenous markers well reflected the CYP3A inhibition of clarithromycin, suggesting possible utility in DDI study with moderate to strong CYP3A inhibition; however, there are limitations in predicting intestinal CYP3A mediated DDI.