药物代谢中的肝细胞色素P450

肝细胞色素Ｐ４５０参与许多外源性物质（包括药物）的生物转化。本文从肝细胞色素Ｐ４５０在体内的分布及命名,被诱导和抑制的机制,对映体代谢的选择性与代谢差异遗传多态性以及国内外关于Ｐ４５０的研究方法等方面介绍了该领域研究的新进展。     

原代肝细胞培养在药物代谢研究中的应用

新鲜分离和单层培养的肝细胞已应用于药理,毒理学研究的各个方面,尤其是人原代肝细胞培养成为评价细胞色素Ｐ４５０诱导与抑制的理想体外模型。本文介绍了原代肝细胞的分离,培养方法及其在药物代谢研究中的应用。     

肝细胞色素P_(450)与药物代谢的研究进展

外源性化合物特别是药物进入体内后 ,很多都经过肝脏代谢 ,而肝药酶ＣＹＰ４５０ 是肝代谢药物的主要酶系。ＣＹＰ４５０ 同工酶能代谢药物使其失活 ,也能使某些无活性的物质转化成活性物质而产生药理作用或毒性。肝脏中ＣＹＰ４５０ 的不同类型及不同含量将直接影响药物的代谢转化、药物间相互作用等 ;同时 ,外源性化合物也能影响ＣＹＰ４５０ 在肝脏的表达 ,从而诱导或抑制其活性。了解ＣＹＰ４５０ 的特性 ,调控ＣＹＰ４５０ 的表达水平有助于临床合理用药及预防疾病 ,也一直是该领域的研究热点之一。１肝细胞色素Ｐ４５０ 同工酶迄今为…     

植物药及果蔬对药物代谢酶P450活性的影响

中草药及其他植物药在我国及东南亚国家应用广泛，在欧美也逐渐受到重视，一些中草药及植物药可能诱导或抑制肝脏细胞色素P450(CYP)药物代谢酶，从而引起自身及其他合用药物代谢的改变，因此可能导致药物不良反应和药物相互作用。     

对氯邻甲苯胺代谢中间体络合物作为一种新的可表征P450ⅡB…

正常大鼠肝微粒体与对氯邻甲苯胺温育不形成Ｐ４５０代谢中间体络合物，比苯巴比脂或多氯联苯１２５４预处理大鼠，显增高肝微粒体与ＰＣＴ形成ＭＩ络合物的能力，而用β－萘黄酮或地塞米松诱导大鼠却无类似影响。考虑到Ｐ４５０ⅡＢ亚族既可为ＰＢ亦可为ＡＲＯ所诱导增加，ＰＣＴ－ＭＩ事物生成或许可用来表征Ｐ４５０ⅡＢ。     

介导候选药代谢的肝细胞色素P450酶表型鉴定的定性和定量方法

新药研发需要对候选药物的代谢途径、每个代谢途径对总清除率的贡献以及参与代谢的酶进行详细研究。候选药物经过肝细胞色素P450(CYP)酶代谢的比例(f_m)可以用放射性同位素标记的方法在人体水平测定,而肝中某酶亚型的代谢占总的CYP参与代谢的比例(f_CYPi)可以用体外酶表型鉴定的方法来测定,这两个参数的乘积f_m×f_CYPi即为某个CYP酶亚型代谢参与某候选药物体内清除的百分比,对研究体内药物-药物相互作用具有重要意义。本文从定性和定量两方面综述体外酶表型鉴定的研究方法。     

心肌缺血再灌注损伤对大鼠肝细胞色素P450酶代谢的影响

目的探讨心肌缺血再灌注状态下,大鼠肝代谢功能和相关的氧化/抗氧化能力变化。方法雄性SD大鼠随机分为5组,除假手术组外,制备在体心肌缺血再灌注模型,并于缺血40min、再灌注15,60和180min分别处死大鼠,检测血浆丙氨酸转氨酶(ALT)和天冬氨酸转氨酶(AST)活性,肝匀浆丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性;以红霉素N-脱甲基酶、五氧基异噁唑O-脱乙基酶和苯胺羟化酶法为探针测定肝细胞色素P450(CYP)3A,CYP2B1和CYP2E1催化功能;RT-PCR法检测肝Ⅰ相药物代谢酶CYP3A1,CYP2B1/2,CYP2E1,以及Ⅱ相解毒酶NAD(P)H醌氧化还原酶(NQO1)及其上游因子NF-E2相关因子(Nrf2)mRNA水平。结果再灌注60 min,肝匀浆MDA含量升高(P<0.05),SOD活力下降(P<0.01);再灌注180 min时,血浆ALT和AST活性升高(P<0.05)。Nrf2基因于再灌注60 min时显著激活(P<0.05),下游因子NQO1 mRNA于再灌注180 min时明显上调(P<0.05)。CYP3A催化功能和mRNA水平分别于再灌注60和180 min开始明显降低(P<0.05);CYP2B1/2 mRNA和催化功能水平分别于再灌注15和180 min开始明显降低(P<0.05);CYP2E1催化功能无明显改变。结论大鼠心肌缺血再灌注可引起肝组织氧化应激及并导致功能损伤。在再灌注早期,具有抗氧化功能的NQO1在转录水平显著上调,其机制可能与上游因子Nrf2被激活相关;CYP3A和CYP2B催化功能在转录和(或)转录后水平明显下调。     

中药对药物代谢酶的影响

药物代谢酶在众多中西药物代谢中起着非常重要的作用.本文综述了近年来国内外学者就中药对药物代谢酶影响的研究思路、方法和进展.通过深入研究中药对药物代谢酶活性的影响,有利于中药基础理论的深入和发展;临床上应该重视中药与其他药物合用时所发生的代谢性相互作用,优化给药方案,从而提高临床用药的有效性和安全性.     

饮食与体内药物代谢

从食物成分，营养状态，饮食习惯及摄食方式等方面综述饮食对体内药物代谢的影响及其可能 机制。认识饮食对药物代谢的影响有助于临床上选择适当的饮食和调整用药方案。     

细胞色素P450与药物代谢的研究现状

细胞色素P450(CYP)在众多中西药物代谢中起着非常重要的作用。本文综述了与药物代谢相关的CYP亚型、CYP与药物相互作用的关系及中药对CYP的影响，旨在合理解释和预测临床上药物间相互作用和药物不良反应等。同时选择适当的药物作为探针来评价CYP的活性，为实现临床个体化给药提供科学依据。     

济泰片对人肝及Beagle犬肝中美沙酮代谢活性的影响

目的评价济泰片对人肝中美沙酮代谢活性潜在的抑制作用及对Beagle犬肝中美沙酮代谢活性潜在的诱导作用。方法在人肝微粒体中加入济泰片1.5～150 mg·L-1,CYP3A4抑制剂酮康唑及CYP2D6抑制剂奎尼丁,再加入美沙酮进行共孵育30 min。用美沙酮的代谢产物2-亚乙基-1,5-二甲基-3,3-二苯基吡咯烷(EDDP)的生成速率反映美沙酮的代谢活性,评价济泰片对美沙酮的抑制作用。Beagle犬ig给予济泰片0.1875,0.625和1.875 g·kg-1,每天1次,共36周后制备犬肝微粒体,在制备的犬肝微粒体中加入美沙酮进行共孵育30 min,检测济泰片组美沙酮的代谢产物EDDP的生成速率。结果阳性抑制剂酮康唑、奎尼丁能显著抑制人肝微粒体中的美沙酮代谢,而济泰片未见明显抑制作用。济泰片1.875 g·kg-1组Beagle犬肝微粒体中美沙酮去甲基化反应的反应速率、代谢能力及单位体质量代谢能力均显著高于正常对照组,分别为0.86±0.17 vs(0.49±0.10)cps.min-1.mg-1蛋白,228±62 vs(115±13)cps.min-1.mg-1蛋白,10.6±0.8 vs(24.4±5.6)cps.min-1.mg-1蛋白.g-1(P<0.05)。结论济泰片对人肝中美沙酮的代谢不会产生抑制作用。济泰片对Beagle犬肝中美沙酮代谢具有一定的诱导作用。     

Cryopreservation of rat,dog and human hepatocytes: influence of preculture and cryoprotectants on recovery,cytochrome P450 activities and induction upon thawing

Several cryopreservation protocols for hepatocytes have been proposed over the past few years, but their effectiveness varies greatly as a function of the characteristics of the method used. One factor in the success of cryopreservation is the quality of cells before freezing. The results suggest that the cryopreservation of hepatocytes in a medium containing polyvinylpyrrolidone (PVP), in addition to DMSO, constitutes a convenient means of long-term storage of hepatocytes for preparing primary cultures to be used in drug metabolism studies. The combined use of the two cryoprotectants is particularly critical for low-viability cell suspensions. An interesting alternative to increase cell viability is the preculture of hepatocytes before cryopreservation. By the use of this procedure, high-quality cells, estimated in terms of post-thaw recovery, viability, adaptation of hepatocytes to culture, drug-metabolizing capability and cytochrome P450 induction, are obtained. Therefore, cryopreserved hepatocytes can provide a regular source of metabolically competent cells for in vitro investigations of the metabolic profile of new drugs and drug–drug interactions in pharmaco-toxicological research.     

The utility of cold-preserved human hepatocytes in studies on cytochrome P450 induction and hepatic drug transport

Abstract

1. Human hepatocytes that had been cold-preserved in SureTran^TM matrix (Abcellute Ltd, Cardiff, UK) were used for studies on cell viability, cytochrome P450 (CYP) 3A4, 2B6 and 1A2 induction and hepatic drug transporters. It has recently been shown that basal CYP activities are maintained in cold-preserved hepatocytes (Palmgren et al., 2012).

2. After 5?d of cold preservation, the viability was still more than 70%, and after 8?d it was around 60%. In hepatocytes that had been cold-preserved for 3?d, the activity of CYP3A4 was induced around 15-fold upon treatment with 8?µM rifampicin for 72?h. For CYP2B6, the activity was induced 4- to 16-fold in hepatocytes that had been cold-preserved for 3?d and thereafter treated with 1?mM phenobarbital for 72?h. The activity of CYP1A2 was low and close to the limit of detection in non-treated cells that had been cold-preserved for up to 3?d, while the activity increased in cells treated with 0.3–25?µM β-naphthoflavone for 72?h. CYP3A4, 2B6 and 1A2 mRNA levels were only determined with hepatocytes from one donor and increased upon treatment with the inducers.

3. Hepatic uptakes of estrone-3-sulfate, taurocholate, ipratropium and rosuvastatin were stable in human hepatocytes that had been cold-preserved for up to 2?d.

4. In summary, cold-preserved human hepatocytes demonstrate retained viability and can advantageously be used for in vitro induction studies and for studies of hepatic uptake transporters.     

CYP450酶特性及其应用研究进展

细胞色素P450（CYP450）是药物和其他内、外源物的主要代谢酶,本文综述了人体内参与药物代谢的几种主要代谢酶CYP3A4、CYP2D6、CYP2C9、CYP2C19、CYP2E1、CYP1A2和CYP2A6的分子生物学特征,中药对药物代谢酶的影响及药物代谢酶在临床药物治疗和新药研究过程中的应用。     

Drug Metabolism Activities of Isolated Rat Hepatocytes in Monolayer Culture

Abstract: The levels of cytochrome P-450 in hepatocytes cultured as monolayers for 22 hrs in Dulbecco's modified Eagle medium supplemented with serum and insulin was reduced to approximately 40% of initial values of freshly isolated hepatocytes. In correspondance with this the activities of the cytochrome P-450 monooxygenases aryl hydrocarbon (benzo(a)pyrene) hydroxylase (AHH) and ethylmorphine (EM) N-demethylase were reduced to 40 and 22% of their initial activities, respectively. Modifying the culture medium through omission of cysteine and cystine, and adding dexamethazone and delta-amino levulinic acid, increased the content of cytochrome P-450 to 59 % and EM N-demethylase to 46 % of initial values, but was without effect on AHH activity. However, further modifications by adding high concentrations of asparagine and leucine increased AHH activity to 62% of initial values, but did not further enhance the total content of cytochrome P-450 or the EM N-demethylase activity. The activities of cytochrome P-450 reductase, flavin containing monooxygenase, epoxide hydrolase and glutathione S-transferase decreased less (to about 70–80% of initial values) than cytochrome P-450 associated monooxygenase activities, whereas UDP-glucuronyl transferase decreased to about 50% of initial values. In contrast to what was observed regarding cytochrome P-450 and associated monooxygenase activities, modification of the incubation conditions did not affect the non-cytochrome P-450 enzymatic activities.     

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。     

Characterization of cytochrome P450 isoenzymes in primary cultures of pig hepatocytes

Despite the fact that pigs are increasingly used in pharmacological and toxicological studies, knowledge on the enzymes which metabolize xenobiotics, in particular cytochrome P450 (CYP) enzymes, in pigs is still very limited. Primary cultures of pig hepatocytes were used to characterize CYP enzymes. The characterization was performed at the level of enzymatic activities, apoprotein and mRNA analyses. Enzyme inducers investigated were β-naphthoflavone (BNF), phenobarbital (PB), dexamethasone (DEX) and rifampicin (RIF). After 48 hr of BNF treatment, CYP1A protein and mRNA levels were increased, and ethoxyresorufin O-deethylation and caffeine 3-demethylation were strongly induced. PB and RIF increased the levels of CYP3A apoprotein and mRNA, whereas BNF down-regulated CYP3A and related activities. PB and RIF treatment resulted in increased ethylmorphine N-demethylation and testosterone hydroxylation, which appears to be the result of CYP3A induction. Hybridization of pig RNA with a human CYP2C9 cDNA probe showed a PB and RIF inducible CYP, which was down-regulated by BNF. Similar inducing effects were observed for tolbutamide, a marker substrate for CYP2C. DEX was not a potent inducer, although some induction of CYP3A mRNA was observed. The present results indicate the absence of CYP2B and probably CYP2D enzymes and activities in pig liver. Despite some dissimilarities, the results indicate that pigs, apart from their very human-like physiology, might represent a more appropriate model species for oxidative drug metabolism in humans than rats.     

底物加料方式对氢化可的松发酵的影响

考察了甾体11β-羟基化过程中,底物17α,21-二羟基孕甾-4-烯-3,20-二酮-21-醋酸酯(2)投料时间、投料量及pH对细胞色素P-450(3)诱导和氢化可的松(1)产量的影响.在此基础上提出了生产1的诱导发酵改进方法:菌体生长至16h投入2 0.3g/L,培养至24h补加2 0.7g/L,培养至32h调至pH6.5,以后每12h调节一次.结果表明,在发酵周期不变(68h)的情况下,3蛋白量和1产量分别比一次投料法提高了11.2%和12.7%.     

己烯雌酚对人肝微粒体内CYP3A4和CYP2C9酶的抑制作用

目的:体外实验考察己烯雌酚(DES)对细胞色素P450 3A4(CYP3A4)和细胞色素P450 2C9(CYP2C9)活性的抑制作用,以评佑DES通过抑制这两个重要的细胞色素P450(CYP)亚型而引发药物-药物相互作用的可能性.方法:混合人肝微粒体与不同浓度的DES(或阳性抑制剂),CYP3A4或CYP2C9的探针...     

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。