炎症过程中细胞色素P450酶活性降低及其机制的研究进展

机体在感染或炎症状态下,肝脏细胞色素P450药物代谢酶mRNA表达和蛋白含量显著降低,酶的催化活性降低。这种变化对人体内药物代谢过程乃至相关药物临床治疗安全性具有显著影响。细胞色素P450异构酶活性降低具有不同的变化过程与模式,反映细胞色素P450酶系具有多种活性调节机制。现有研究表明,细胞色素P450酶活性降低主要发生在基因表达环节,由多种炎症细胞因子介导。阐明炎症对细胞色素P450活性的影响有助于明确细胞色素P450酶活性的调控机制,对指导临床安全合理用药具有重要意义。     

抗组胺药敏感性的细胞色素P-450在不同年龄组大鼠肝脏微粒体中的测定

抗组胺药敏感性细胞色素P-450(简称HP-450)主要存在于肝脏微粒体,是一个有组胺H₁受体和细胞色素P-450(CytP-450)两种物质特性的蛋白质,我们利用[³H]mepyramine为同位素标记进行受体配体结合实验,检测HP-450随着大鼠增龄而致的动力学特征,同时又从酶学比较Cytp-450在不同年龄组大鼠肝脏微粒体内的变化规律和趋势,发现HP-450和CytP-450都明显地随着大鼠年龄而变化,其中HP-450的Bmax值和Kd值在大鼠出生后2至8周内增加最快,8至10周达到最高水平并趋向稳定状态,CytP-450也有同样的趋势,并且HP-450的增长与CytP-450的增长幅度具有良好的相关性(相关系数r=0.625)。实验中未曾发现性别间的差异。     

酮康唑对大鼠肝脏CYP450酶系的影响*

目的:观察酮康唑对大鼠肝细胞色素P450及其主要亚型的影响。方法:Sprague-Dawley大鼠用140,280,420μmol.kg-1.d-1酮康唑连续灌胃7 d,测定肝脏微粒体中总CYP450含量和CYP1A1,1A2,1B1,2B1/2,2E1和3A亚型活性。结果:不同剂量酮康唑给药后大鼠肝脏脏器系数、CYP1A1和1B1亚型活性明显增高(P<0.05,P<0.01);总CYP450含量和CYP3A活性显著降低(P<0.01);低剂量的酮康唑抑制CYP1A2和CYP2B1/2亚型的活性,高剂量却出现了诱导作用(P<0.05,P<0.01)。各剂量组对CYP2E1均无明显影响。结论:酮康唑对大鼠肝脏CYP450及主要药物代谢亚型CYP1A1,1A2,1B1,2B1/2和3A有影响,临床长期用药或与经肝脏CYP450代谢的药物联合应用时要注意监测血药浓度和肝脏功能,防止药物代谢减缓出现蓄积中毒或药物代谢加快而降低药效。     

CYP450在SAP组织中的表达及对临床治疗的指导意义

目的:研究急性重症胰腺炎(SAP)模型中CYP450(细胞色素P450)在组织中的表达及对临床治疗的指导意义.方法:以3%牛磺胆酸钠逆行胰胆管注射制备鼠SAP模型,检测血清淀粉酶,采用免疫组织化学方法分别对雄性SD大鼠SAP制备模型术后4 h、12 h及正常对照组标本中CYP450的表达进行检测.结果:CYP450主要表达于胞浆,SAP模型组空肠、肝脏组织中的CYP450表达均明显高于正常对照组(P＜0.001).结论:CYP450在大鼠SAP中表达显著增强,提示其在SAP的疾病发展及临床治疗中都具有重要意义.     

细胞色素P450药物代谢研究方法分析与评价

细胞色素P450（cytochromeP450,CYP450）是一组结构和功能相关的超家族基因编码的同工酶,主要存在于人的肝脏中,参与许多内源性以及外源性物质的生物转化,外源性物质特别是药物进入体内以后,很多都是经过肝脏代谢,     

肝脏中的细胞色素P-450与组胺受体

<正> 1 肝脏中细胞色素P-450、组织胶和组织胺受体1.1 肝脏中细胞色素P-450的理化特性及其在机体中的生理功能细胞色素P-450(Cytochrome P-450,简称Cyt P-450)酶系位于肝细胞内质网系膜。主要由Cyt P-450、Cyt-b_5、NADPH-Cyt P-450还原酶、NADH-b_5-还原酶和环氧化物水化酶等组成。此酶作用时需NADPH和分子氧,且催化反应的底物特异性差,因而被称为混合功能氧化酶     

心血管药物速效救心丸和通心络胶囊对大鼠细胞色素P450酶的影响

目的:观察速效救心丸和通心络胶囊对大鼠药物代谢酶细胞色素P450(CYP450)的影响。方法:给予大鼠试验药物后制备肝及小肠微粒体,CO还原差示光谱法测定肝微粒体CYP450含量,蛋白免疫印迹法检测肝微粒体中CYP1A2、CYP2C11、CYP2E1、CYP3A和肠微粒体中CYP3A蛋白的表达量。结果:速效救心丸组和通心络胶囊组与空白对照组比较,大鼠肝脏CYP450含量无显著变化(P>0.05);但是West-ern blotting实验对肝脏和肠道中多种CYP450酶表达量测定的结果显示,速效救心丸可诱导肝脏CYP1A2表达,但抑制肝脏CYP2C11和肠道CYP3A表达(P<0.05);通心络胶囊可诱导大鼠肝脏CYP1A2、CYP2E1蛋白表达(P<0.05)。结论:速效救心丸和通心络胶囊对大鼠肝脏CYP450酶总量无影响,但是,在蛋白质水平对特定亚型蛋白的表达量有影响,由此可能引发的药物相互作用不容忽视。     

RNA干扰在氧化代谢酶功能研究中的应用进展

RNA干扰(RNAi)是真核细胞内某些双链RNA能高效、特异地结合并降解互补mRNA,阻断其基因的表达,介导序列特异的基因沉默,导致细胞出现特定基因表达缺失的表型。RNAi技术作为抑制策略具有特异性、选择性和高效性等优点,被用于特异性的沉默细胞色素P450酶、脂氧合酶、环氧化酶和单胺氧化酶等氧化代谢酶的基因,探讨这些酶对内、外源化学物的生物转化作用及其与某些疾病发生、发展和治疗的关系,发现了一些代谢酶的新功能,获得了对动脉粥样硬化、多囊卵巢综合征、肾病综合征以及多种癌症等疾病发生机制新的认识以及防治的新方法和新线索。     

中药对细胞色素P450酶活性影响及研究方法进展

细胞色素P450酶是机体肝脏中最重要的代谢系统,参与临床上所用大部分药物的生物转化过程;中药成分复杂,在临床上常与西药联用。该文通过查阅国内外相关文献,总结中药对CYP450酶的影响作用的研究进展,重点介绍了CYP450酶的几种主要亚型以及目前主要的研究方法,对新药筛选、临床合理用药提供重要依据。     

炎性细胞因子调节药物代谢酶的研究进展

摘 要炎症状态下许多重要的药物代谢酶表达及活性发生下调,药物代谢酶表达及活性的改变直接影响机体对药物的处置过程,导致药物不良反应的发生。大量研究表明,炎症反应中机体会释放大量的细胞因子,而其中某些炎性细胞因子参与下调药物代谢酶的表达及活性,其中细胞色素P450酶首当其冲。由于细胞因子对细胞色素P450酶的调节作用与炎症的发展程度以及疾病的治疗进程有关,临床上很难预测这种调节作用的结果。因此,弄清炎症情况下细胞因子对药物代谢酶的调节作用对分析和解释临床上发生的药物不良反应具有重要意义。本文综述了炎症状态下细胞因子对细胞色素P450酶的调控研究进展,探讨了其可能的作用机制以及临床意义。     

HP450和CytP450在大鼠急性肝炎中的变化

目的研究四氯化碳、醋氨酚、半乳糖胺诱发大鼠急性肝炎时肝脏微粒体中ＨＰ４５０及ＣｙｔＰ４５０的变化。方法采用［３Ｈ］ｍｅｐｙｒａｍｉｎｅ为放射性配体，利用受体－配体结合技术检测ＨＰ４５０，用差示光谱法检测ＣｙｔＰ４５０，同时采用荧光法检测外周血液中组织胺水平。结果在３种肝毒剂诱发大鼠发生急性肝炎时，大量肝脏微粒体中ＨＰ４５０的水平显著降低，大鼠肝脏微粒体中的ＣｙｔＰ４５０含量也明显下降，ＨＰ４５０和ＣｙｔＰ４５０的降低具有一致性，此外还发现急性肝炎动物血清中的组织胺水平明显高于正常组（Ｐ＜０．０１）。结论大鼠肝脏微粒体中ＨＰ４５０的水平在急性肝炎中显著降低，可能与受体的“下行调节”及肝毒物质降低ＣｙｔＰ４５０有关，检测人体肝脏组织中ＨＰ４５０水平、外周血中ＨＰ４５０的酶促反应中间代谢物、代谢终产物，是否可作为判断人体急性肝炎时肝脏损害程度的一个特异性指标，值得进一步研究与探讨。     

Influence of liver disease and environmental factors on hepatic monooxygenase activity in vitro

Summary The effects of liver disease and environmental factors on hepatic microsomal cytochrome P-450 content, NADPH-cytochrome c reductase (reductase) activity and aryl hydrocarbon hydroxylase (AHH) activity have been simultaneously investigated in 70 patients undergoing diagnostic liver biopsy. The activity of reductase was not significantly affected by the presence of liver disease or any of the environmental factors studied. Cytochrome P-450 content decreased with increasing severity of liver disease whereas AHH activity was only significantly reduced in biopsies showing hepatocellular destruction. None of the parameters of monooxygenase activity varied significantly with the age or sex of the patients. Alcohol excess was associated with decreased cytochrome P-450 content and AHH activity and this effect was independent of the histological status of the biopsy. Both high caffeine intake and cigarette smoking increased AHH activity in the absence of any change in cytochrome P-450 content. There was a positive correlation between the number of meat meals eaten per week and cytochrome P-450 content. Chronic treatment with enzyme-inducing anticonvulsants appeared to increase both cytochrome P-450 content and AHH activity. Despite differential effects of liver disease and environmental influences on cytochrome P-450 content and AHH activity there was a highly significant correlation between the two parameters. The results of the present study correlate well with the known effects of disease and environment on drug metabolism in vivo.     

Stimulatory effects of benzene on rabbit liver and kidney microsomal cytochrome P-450 dependent drug metabolizing enzymes

Treatment of rabbits with benzene (880 mg/kg/day), s.c. for 3 consecutive days, caused 3.8- and 5.7-fold increases in aniline 4-hydroxylation rates of liver and kidney microsomes, respectively. Benzene treatment markedly enhanced hydroxylation rates ofp-nitrophenol by liver and kidney by 7.2- and 4.2-fold, respectively. Both of these enzymes are associated with cytochrome P-450 LM3a. In contrast, the activity of benzphetamine N-demethylase, associated with P-450 LM2, was not altered significantly in either liver or kidney microsomes. Although the total cytochrome P-450 contents of liver and kidney microsomes were not altered significantly by the benzene treatment, in the case of liver microsomes, formation of a new cytochrome P-450 with an apparent M_r of 51,400 was observed on SDS-PAGE. On the other hand, in the kidney microsomes, the intensity of the bands corresponding to approximate M_r of 50000 and 51400 was markedly increased. The results of the present work, in combination with those of the previous work (Arinç et al. 1988), indicate the existence of tissue specificity in the induction of rabbit P-450 isozyme by benzene.A preliminary account of this work has been presented at the Nato Advanced Study Institute on Molecular Aspects of Monooxygenases and Bioactivation of Toxic Compounds, August 27–September 7, 1989, Izmir, Turkey.     

细胞色素P450和医学

细胞色素P450(CYP,P450)是一个血红蛋白家族的通用名称.这是一个非常巨大、种类丰富的酶家族,广泛存在于进化谱系所有生物体中(从细菌到人).已经发现和命名的不同CYP蛋白超过11500个(截止至2009年2月),但只有少数进行了详细研究.该家族参与到生命进程中众多的新陈代谢反应,包括羟基化、N-,O-,和S-脱烷基化、磺化氧化、环氧化、脱氨、脱硫、脱卤、过氧化和N-氧化还原作用.本文介绍了细胞色素P450的研究历史、结构、命名法、分类及功能.人类和动物细胞色素P450酶类与诸多疾病相关,尤其是肝病和癌症.三个细胞色素P450基因家族(CYP 1,CYP2和CYP3)似乎参与大量抗生素代谢反应.人们正在深入研究CYP450的功能,为不久的将来能战胜肝病、癌症和其他疾病提供可能性.     

Inhibitors of steroidogenesis as agents for the treatment of hormone-dependent cancers

Oestrogens and androgens stimulate growth in hormone-dependent breast and prostate cancers respectively. Modern strategies seek to remove the influence of hormones on tumour growth using anti-oestrogens (breast) or anti-androgens (prostate) which block the action of the hormone on its receptor. For prostate cancer patients LHRH (luteinising hormone releasing hormone) agonists, which decrease testes synthesis of testosterone are also used. Newer alternative (or sequential) strategies aim to deplete circulating and tissue levels of the respective mitogenic hormone by inhibition of a specific target enzyme involved in its steroidogenic pathway: for breast cancer - aromatase (P450_AROM) or 17β-hydroxysteroid dehydrogenase (17β-HSD) Type 1 isoenzyme or the metabolic enzyme oestrogen sulfatase; for prostate cancer - 17α-hydroxylase: 17, 20-lyase (P450 17) or 5α-steroid reductase (5α-SR) or 17β-HSD Type 3 isoenzyme. The use of P450_AROM inhibitors as sequential agents in breast cancer patients is well established; inhibitors of the other target enzymes are under development and could be sequential or combinational agents. Certain P450 17 inhibitors for prostatic cancer treatment protect the metabolism of retinoic acid (RAMBAs) and 1α,25-dihydroxy vitamin D-3, thereby being cellular differentiation and antiproliferative mimics. These new cytochrome P450 targets and the built-in action of the P450 17 inhibitors may be shown at a later date to alter or delay the progression of the disease from hormone-dependent to hormone-independent. This review discusses the progress made in developing of clinically useful steroidogenesis inhibitors for the relevant disease and some of the difficulties encountered in maintaining/achieving remission due to the changing nature of the disease.     

黄芩苷对小鼠肝细胞色素P450的选择性诱导

目的　观察黄芩苷对小鼠肝细胞色素P450及其亚家族的影响。方法　用紫外分光光度法分别测定小鼠肝微粒体细胞色素P450与b5含量及氨基比林N-脱甲基酶(ADM)、7-乙氧基香豆素O-脱乙基酶(ECD)、苯并芘羟化酶(AHH)活性。用蛋白印迹杂交技术鉴定细胞色素P450同功酶。结果　黄芩苷可使小鼠肝微粒体细胞色素P450含量显著增加,并使ADM,ECD及AHH 3种酶活力显著增强。对6种P450同功酶的鉴定结果显示,黄芩苷可选择性诱导1A1,2B1及2C11 3种同功酶,对细胞色素b5含量及3A2,2D1和2E1 3种同功酶无诱导作用。结论　黄芩苷对小鼠肝细胞色素P450有选择性诱导作用。     

Inhibition of Cytochromes P450: Existing and New Promising Therapeutic Targets

Mammalian cytochromes P450 have been shown to play highly important roles in the metabolism of drugs and xenobiotics as well as in the biosynthesis of a variety of endogenous compounds, many of them displaying hormonal function. The role of P450s as therapeutic targets is still inadequately recognized although several P450 inhibitors became efficient drugs that even reached blockbuster status. Here, we try to give a comprehensive overview on cytochromes P450s, which are already well-established targets – particularly focussing on the treatment of infectious diseases, metabolic disorders and cancer – and on those, which have a high potential to become successful targets. In addition, the design of inhibitors of cytochromes P450 will be discussed.     

Cytochrome P-450 and Drug-induced Spectral Interactions in the Hepatic Microsomes of Trout,Salmo trutta lacustris*

Abstract The properties of various components of a drug-oxidizing mono-oxygenase system in the liver of trout (Salmo trutta lacustris) were studied. The concentration of the cytochrome P-450 was about 7 nmol/g liver wet weight when measured in the 12,000 × g supernatant and 0.2 nmol/mg protein when measured in the “microsomal” fraction. The activity of NADPH-cytochrome c reductase was about 2000 nmol cyt. c reduced/g liver/min. measured in the homogenate and 20 nmol/mg protein/min. when measured in the “microsomal” fraction. The distribution of the cytochrome P-450 into different centrifugal fractions indicates that it is localized in the endoplasmic reticulum. The cytochrome P-450 present in the fish liver microsomal fraction was capable of interacting with different substances resulting in type II (aniline, n-octylamine, cyanide) and a reversed type I (n-butanol) spectra. Substances producing type I spectra in the rat liver microsomes, did not give any spectra (hexobarbital, SKF 525A) or gave unclassified spectral changes with the fish liver cytochrome P-450 (bromobenzene, DDT, piperonyl butoxide). Spectral dissociation constants were calculated for aniline and n-octylamine. Further experiments indicated that the mono-oxygenase system in the trout liver microsomes can metabolize aminopyrine, aldrin and 3,4-benzpyrene.