甘草酸二铵对大鼠肝微粒体细胞色素P450酶含量及活性的影响

目的研究甘草酸二铵对大鼠肝微粒体的蛋白含量、CYP450酶总量和CYP2C6、CYP2C11、CYP2D2活性的影响。方法 Wistar大鼠灌胃给予甘草酸二铵[50 mg/(kg·d)],连续7 d,测定其肝微粒体蛋白含量、CYP450蛋白含量以及CYP2C6、CYP2C11和CYP2D2活性。结果与对照组比较,甘草酸二铵给药组大鼠肝微粒体蛋白含量及肝微粒体CYP450含量差异无统计学意义(P>0.05),CYP2C6、CYP2C11酶的活性差异有统计学意义(P<0.05),CYP2D2酶活性差异无统计学意义(P>0.05)。结论甘草酸二铵可以抑制CYP2C6、CYP2C11酶的活性。     

淫羊藿苷对不同月龄大鼠肝微粒体细胞色素P450的影响

目的 揭示淫羊藿苷(Ica)对大鼠肝微粒体细胞色素P450的含量及部分亚型的影响,并比较月龄的差异.方法 ig给予6月龄和18月龄的♂SD大鼠Ica( 60 mg· kg -1),4周后取肝脏,用钙沉淀法提取肝微粒体,BCA法测定微粒体蛋白浓度;用一氧化碳还原差示光谱法测定CYP450的含量;用ELISA法测定CYP1 A1、CYPb5的含量;用比色法测定苯胺羟化酶(反映CYP2E1活性)和红霉素-N-脱甲基酶(反映CYP3A活性)的活性;用real - time RT - PCR检测CYP1 A1、CYP2A3、CYP2E1、CYP3A1、CYP3A2和CYP4B1 mRNA的表达.结果 60 mg· kg-1 Ica明显增加了CYP450的总酶和CYP1 A1的含量、CYP3A的活性及CYP1 A1、CYP3A1、CYP3A2 mRNA的表达,降低了CYP2E1的活性及其mRNA的表达;但Ica对上述各指标的诱导或抑制作用在大鼠月龄方面差异不明显;Ica对CYPb5的含量及CYP2A3、CYP4B1 mRNA的表达未见明显影响.结论 Ica对大鼠肝微粒体CYP450总酶、CYPI A1和CYP3A具有诱导作用,对CYP2E1具有抑制作用,该作用未见明显月龄差异.     

细胞色素P450(CYP450)遗传多态性研究进展

近年来对CYP450基因型和表型相关性的研究越来越受到重视,从临床合理用药方面来说,人们希望利用基因型分析来了解个体中药物代谢酶的活性,期望既能提高药物治疗水平同时又降低不良反应的发生;从新药研发角度来说,研究药物的代谢酶CYP450的功能能够指导新药的设计、筛选及优化。该文通过查阅国内外相关文献综述了近年来关于CYP450遗传多态性研究的进展,分别介绍了CYP2C19、CYP2C9、CYP3A4、CYP2D6、CYP1A2和CYP2E1这6种主要的药物代谢酶。研究CYP450对新药设计、筛选、评价及优化有重要意义。     

银杏叶提取物对细胞色素P450影响的研究进展

银杏叶提取物(Ginkgo biloba extract,GBE)是目前使用最为广泛的中草药之一。GBE与其他药物合用是否产生药物相互作用得到关注。GBE与其他药物合用,可能通过影响肝药酶的活性发生药物相互作用,其中GBE对肝药酶的诱导或抑制作用的研究较为深入。本综述回顾了近年来报道的关于GBE对细胞色素P450 CYP3A4、CYP2C9、CYP1A2、CYP2C19的影响。     

中国人肝微粒体中细胞色素P450酶含量和活性的个体间差异(英文)

目的:比较不同中国人肝微粒体中几种重要细胞色素P450(CYP)的酶含量和活性。方法:运用West-ern斑点分析和光密度扫描,对17个汉族、17个壮族和8个苗族受试者肝微粒体中的细胞色素P4501A2(CYP1A2)、2C9及3A4进行定量;非那西丁、甲磺丁脲、异喹胍和奥美拉唑分别用于体外测量CYP1A2、2C9、2D6及3A4的活性。结果:CYP1A2、2C9及3A4的含量和活性具有很大的个体间变异,另外CYP2D6的活性在各样本间也有很大差异;CYP3A4(32％)是中国人肝微粒体中含量最丰富的CYP,CYP2C9(19％)和CYP1A2(16％)的含量也很可观;除了CYP1A2的含量和活性具有一定的种族和性别差异外,未发现其它CYP具有种族和性别差异;CYP1A2、2C9和3A4的酶蛋白含量分别和它们的活性具有很好的相关性。结论:我们的结果为在中国人中进行药物代谢研究提供了非常有价值的信息。     

恩诺沙星对小鼠肝微粒体细胞色素P450影响的研究

恩诺沙星(errofloxacin,EF)是动物专用药,有抗菌谱广、杀菌力强、速效等特点,广泛应用于兽医临床[1].细胞色素 P450(P450)是最重要的肝微粒体混合功能氧化酶,对阐明药物代谢及相互作用和指导临床用药有重要意义.已有大量研究报道,EF 可抑制鸡、猪、鱼等 P450 [2-3],而对小鼠 P450 研究较少,且 EF 对其 CYP2B6、2C9 的影响尚未见报道.本文以小鼠为研究对象,观察 EF 对小鼠 CYP2B6、2C9 等 P450 酶系的影响,从而揭示药物与机体的相互作用,同时也为临床合理用药提供理论参考.     

毛冬青胶囊对大鼠体内细胞色素P450 代谢活性的影响*

目的：采用Cocktail探针药物法研究毛冬青胶囊对大鼠CYP1A2、CYP3A2、CYP2C6、CYP2D1、CYP2D2和CYP2E1体内代谢活性的影响。方法：分别以茶碱、咪达唑仑、甲苯磺丁脲、奥美拉唑、右美沙芬和氯唑沙宗作为探针底物,将大鼠随机分为3组：空白对照组、毛冬青的低剂量组和高剂量组。低、高剂量组每日分别灌胃给予毛冬青胶囊1.8、3.6 g·kg-1,空白对照组每日给予与低剂量组等体积的生理盐水,各组均为1次/天,连续14 d。各组分别于第15天给予Cocktail探针药物,于给药前、后不同时间点取血,用LC-MS/MS检测各探针药物的血药浓度,计算药代动力学参数。结果：茶碱低剂量组cmax、AUC0-t有极显著差异（P≤0.01）;甲苯磺丁脲高剂量组和氯唑沙宗低剂量组AUC0-t有显著差异（P≤0.05）;其他无统计学差异。结论：毛冬青胶囊对大鼠体内CYP2C6和CYP1A2有强诱导作用,对CYP2E1有中强诱导作用,其他亚型基本无影响。     

细胞色素P450的工具药选择及种属差异的研究进展

药物对代谢酶的影响以及代谢产生的药物相互作用与药物安全性密切相关。细胞色素P450(CYP)是参与内、外源性化合物I相代谢反应的重要超家族酶系。特异性探针、诱导剂、抑制剂以及实验动物模型广泛应用于CYP介导的代谢途径以及药物相互作用研究。已知CYP底物存在明显重叠性,且表达调控机制种属差异显著,故研究中选择适当的实验动物以及特异性的探针、诱导剂和抑制剂,成为影响数据外推的关键问题。本文简要综述了CYP1A2,CYP2C9,CYP2C19,CYP2D6,CYP3A4/5的常用体内外探针、诱导剂、抑制剂以及动物种属表达调控的差异。     

细胞色素氧化酶P450及其遗传多态性

细胞色素氧化酶P45 0是药物代谢中的一个重要的酶系。近年来 ,对细胞色素P45 0氧化酶与药物氧化代谢多态性的关系进行了研究。CYP2C19与CYP2D6等在表型和基因型水平上均发现存在氧化代谢多态性 ,并对其分子机制有了深入的了解 ,而CYP2C9,CYP1A1等其他酶可能存在多态性 ,但其分子机制尚不清楚。本文综述了这些P45 0酶的底物 ,种族差异 ,遗传多态性 ,以及其对药物代谢和疾病易感性的影响     

三氯乙烯对3种细胞色素P450酶基因表达的影响

目的 探讨三氯乙烯（Trichloroethylene,TCE)对人体淋巴细胞瘤细胞株（MCL-5）中3种细胞色素P450酶基因（CYP1A1、CYP2E1、CYP3A4）表达的影响,并研究剂量反应关系和时间反应关系,方法 用常规的细胞培养方法,0.5、1.0、1.5、2.0mmol/L TCE处理细胞12、24、48、72h。利用提纯RNA和cDNA的药盒,合成cDNA,然后逆转录聚合酶反应（RT-PCR）表达3种CYP450基因,以β-Actin作为内对照,分析不同处理剂量和时间时基因表达的强度。结果 在MCL-5细胞株中都有基本的表达,CYP1A1表达在用1.0、1.5、2.0mmol/LTCE处理48h后有被上调的趋势,而且上调趋势随处理时间延长耐加强;CYP2E1、CYP3A4表达不受TCE处理时间长短的影响。3种CYP450酶基因的表达受TCE剂量的影响。3随0.5mol/L,1.0、1.5、2.0mmol/L剂量的增加有上调的趋势,结论 TCE对CYP450酶系统中的CYP2E1、CYP1A1、CYP3A4基因有明显的诱导作用。这些基因被诱导后的结果。可能会导致相对应酶活性的增加,同时加强对TCE的代谢,使TCE的代谢产物增加。     

Identification of cytochrome P450 isoforms involved in the metabolism of loperamide in human liver microsomes

Objective: The purpose of the present study was to elucidate the cytochrome P450 (P450) isoform(s) involved in the metabolism of loperamide (LOP) to N-demethylated LOP (DLOP) in human liver microsomes. Methods: Three established approaches were used to identify the P450 isoforms responsible for LOP N-demethylation using human liver microsomes and cDNA-expressed P450 isoforms: (1) correlation of LOP N-demethylation activity with marker P450 activities in a panel of human liver microsomes, (2) inhibition of enzyme activity by P450-selective inhibitors, and (3) measurement of DLOP formation by cDNA-expressed P450 isoforms. The relative contribution of P450 isoforms involved in LOP N-demethylation in human liver microsomes were estimated by applying relative activity factor (RAF) values. Results: The formation rate of DLOP showed biphasic kinetics, suggesting the involvement of multiple P450 isoforms. Apparent K_m and V_max values were 21.1 M and 122.3 pmol/min per milligram of protein for the high-affinity component and 83.9 M and 412.0 pmol/min per milligram of protein for the low-affinity component, respectively. Of the cDNA-expressed P450 s tested, CYP2B6, CYP2C8, CYP2D6, and CYP3A4 catalyzed LOP N-demethylation. LOP N-demethylation was significantly inhibited when coincubated with quercetin (a CYP2C8 inhibitor) and ketoconazole (a CYP3A4 inhibitor) by 40 and 90%, respectively, but other chemical inhibitors tested showed weak or no significant inhibition. DLOP formation was highly correlated with CYP3A4-catalyzed midazolam 1-hydroxylation (r_s=0.829; P<0.01), CYP2B6-catalzyed 7-ethoxy-4-trifluoromethylcoumarin O-deethylation (r_s=0.691; P<0.05), and CYP2C8-catalyzed paclitaxel 6-hydroxylation (r_s=0.797; P<0.05). Conclusion: CYP2B6, CYP2C8, CYP2D6, and CYP3A4 catalyze LOP N-demethylation in human liver microsomes, and among them, CYP2C8 and CYP3A4 may play a crucial role in LOP metabolism at the therapeutic concentrations of LOP. Coadministration of these P450 inhibitors may cause drug interactions with LOP. However, the clinical significance of potential interaction of LOP metabolism by CYP2C8 and CYP3A4 inhibitors should be studied further.     

三七总皂苷对CYP450的影响及药物相互作用预测

目的：研究三七总皂苷（血塞通）对肝微粒体CYP450酶不同亚型的影响，进一步了解其在肝脏的代谢特点并据此对该药与其他药物相互作用的安全性进行预测，为临床合理应用提供依据。方法：检测肝药酶CYP1A2和CYP3A4的专属探针药物咖啡因、氨苯砜的原型浓度，采用原型药物减少初始速率测定法考察其体外代谢变化情况，从而评价三七总皂苷对CYPIA2、CYP3A4的诱导或抑制作用。结果：三七总皂苷对肝药酶CYPIA2有诱导作用，而对CYP3A4无影响。结论：三七总皂苷对CYP450。不同亚型酶的影响不同。在临床应用时，尤其是与CYPIA2代谢有关的药物合用时，应充分考虑到这种影响，以避免潜在的毒性或不良反应。     

细胞色素P450 2C19单碱基突变位点CYP2C19m1的分析

目的:CYP2C19ml是引起CYP2C19酶活性缺陷的主要等位基因,有83％左右的慢代谢者含有CYP2C19ml等位基因,本文试图建立一步PCR测定CYP2C19ml等位基因的方法。方法:根据等位基因特异扩增(ASA)原理设计两对分别特异扩增野生型等位基因和突变型等位基因的引物,建立了一步PCR测定CYP2C19ml等位基因的方法。结果:对39位随机受试者进行了基因分型研究,发现3位CYP2C19ml纯合子、18位CYP2C19ml杂合子,其余18位为野生型纯合子。结论:说明效法能够用于测定CYP2C19ml等住基因,并且证明该法具有简便、快速和污染少的优点。     

Cytochrome P450 2C8 and CYP3A4/5 are involved in chloroquine metabolism in human liver microsomes

Chloroquine has been used for many decades in the prophylaxis and treatment of malaria. It is metabolized in humans through the N-dealkylation pathway, to desethylchloroquine (DCQ) and bisdesethylchloroquine (BDCQ), by cytochrome P450 (CYP). However, until recently, no data are available on the metabolic pathway of chloroquine. Therefore, the metabolic pathway of chloroquine was evaluated using human liver microsomes and cDNA-expressed CYPs. Chloroquine is mainly metabolized to DCQ, and its Eadie-Hofstee plots were biphasic, indicating the involvement of multiple enzymes, with apparent Km and Vmax values of 0.21 mM and 1.02 nmol/min/mg protein 3.43 mM and 10.47 nmol/min/mg protein for high and low affinity components, respectively. Of the cDNA-expressing CYPs examined, CYP1A2, 2C8, 2C19, 2D6 and 3A4/5 exhibited significant DCQ formation. A study using chemical inhibitors showed only quercetin (a CYP2C8 inhibitor) and ketoconazole (a CYP3A4/5 inhibitor) inhibited the DCQ formation. In addition, the DCQ formation significantly correlated with the CYP3A4/5-catalyzed midazolam 1-hydroxylation (r = 0.868) and CYP2C8-catalyzed paclitaxel 6alpha-hydroxylation (r = 0.900). In conclusion, the results of the present study demonstrated that CYP2C8 and CYP3A4/5 are the major enzymes responsible for the chloroquine N-deethylation to DCQ in human liver microsomes.     

Thiomers: Inhibition of cytochrome P450 activity

The aim of the present study was to investigate the potential of different thiolated polymers (thiomers) on the catalytic activity of CYP450s on one hand and to explore new inhibitors for CYP activity on the other hand. Several thiolated polymers including poly(acrylic acid)-cysteine (PAA-cysteine), chitosan-thioglycolic acid (chitosan-TGA), and thiolated PEG-g-PEI copolymer along with brij® 35, myrj® 52 and the well-established CYPP450 inhibitor verapamil were screened for their CYP3A4 and CYP2A6 inhibitory activity, and their IC₅₀ values were determined. Both enzyme inhibition assays were performed in 96-well microtiter plates. 7-Benzyloxy-4-(trifluoromethyl)-coumarin (BFC) and 7-hydroxycoumarin (7-HC) were used as fluorescent substrates in order to determine CYP3A4 and CYP2A6 catalytic activity, respectively. All investigated compounds inhibited CYP3A4 as well as CYP2A6 activity. All tested (thiolated) polymers were found to be more potent inhibitors of CYP3A4 than of CYP2A6 catalytic activity. Apart from verapamil that is a known CYP3A4 inhibitor, brij® 35 and myrj® 52 were explored as potent inhibitors of CYP3A4 and CYP2A6 catalytic activity. Among the tested polymers, the rank order for CYP3A4 inhibition was PAA-cysteine (100 kDa) > brij® 35 > thiolated PEG-g-PEI copolymer (16 kDa) > myrj® 52 > PAA (100 kDa) > PAA-cysteine (450 kDa) > verapamil > PAA (450 kDa) > chitosan-TGA (150 kDa) > chitosan (150 kDa). On the other hand, the rank order of CYP2A6 inhibition was brij® 35 > PAA-cysteine (100 kDa) > chitosan-TGA (150 kDa) > PAA (100 kDa) > thiolated PEG-g-PEI copolymer (16 kDa) > PAA-cysteine (450 kDa) > chitosan (150 kDa) > verapamil > PAA (450 kDa) > myrj® 52. Thus, this study suggests that (thiolated) polymers display a promising potential to inhibit cytochrome P450s activity and might turn out to be potentially valuable tools for improving the oral bioavailability of actively secreted compounds by avoiding intestinal metabolism.     

伊曲康唑对健康成人肝细胞微粒体细胞色素P450同工酶1A2、3A4活性的作用

目的观察伊曲康唑对健康成人肝细胞微粒体细胞色素P450同工酶1A23、A4活性的作用,为临床上安全有效地联合用药提供实验依据。方法采用健康成人肝细胞微粒体,分为对照组和伊曲康唑处理组。处理组分别加入0.1、0.2、1.0、2.0、10.0、20.0 mg.L-1的伊曲康唑1mL,对照组仅加入培养液,孵育15 min后再加入CYP450同工酶1A2和3A4的相应底物(分别为非那西丁和睾酮)再孵育20min。反应终止后用高效液相色谱仪测量代谢产物(分别为对乙酰氨基酚与6β-羟基睾酮)的生成量代表1A2和3A4的活性。结果细胞色素P450同工酶1A2的相对活性百分比各处理组与对照组比较差异无显著性意义(P>0.05),而同工酶3A4的相对活性百分比随伊曲康唑质量浓度增加逐渐减小,各处理组与对照组比较差异均有显著性意义(P<0.05)。细胞色素P450同工酶3A4的相对活性百分比减小到对照组50%时(IC50)伊曲康唑的质量浓度为0.16 mg.L-1。结论伊曲康唑在临床应用血药质量浓度范围内,对健康成人肝细胞微粒体细胞色素P450同工酶1A2的活性无显著影响,然而对细胞色素P450同工酶3A4的活性有抑制作用。