尿苷二磷酸葡萄糖醛酸转移酶的研究进展

目的:介绍尿苷二磷酸葡萄糖醛酸转移酶(UGT)的最近研究进展;方法:查阅了大量相关文献,总结了UGT的功能、诱导、底物及其基因研究等内容;结果:UGT是一种最重要的Ⅱ相代谢酶,对它的研究已经深入到基因水平,且可从分子水平上去解释它的作用机理;结论:人们对UGT有了更深更全面的了解。     

尿苷二磷酸葡萄糖醛酸转移酶的研究进展

目的：介绍尿苷二磷酸葡萄糖醛酸转移酶（UGT）的最近研究进展;方法：查阅了大量相关文献,总结了UGT的功能、诱导、底物及其基因研究等内容;结果：UGT是一种最重要的Ⅱ相代谢酶,对它的研究已经深入到基因水平,且可从分子水平上去解释它的作用机理;结论：人们对UGT有了更深更全面的了解。     

尿苷二磷酸葡萄糖醛酸转移酶基因多态性对药物代谢影响的研究进展

由尿苷二磷酸葡萄糖醛酸转移酶(UDP-glucuronosyltransferase,UGT)催化完成的葡萄糖醛酸结合反应是生物体内重要的Ⅱ相代谢途径,它与毒性或活性物质结合形成葡萄糖醛酸苷,将内源性、外源性化合物通过胆汁或肾脏排出体外。UGT是一个超家族酶,因主要利用UDP-尿苷二磷酸葡糖醛酸为糖基供体而得名。人类UCT广泛分布于体内的各种组织,包括肾、脑、皮肤、肠、脾、胸腺、心脏等,其中以     

尿苷二磷酸葡萄糖醛酸转移酶的调控及其介导的中药-药物相互作用研究进展

尿苷二磷酸葡萄糖醛酸转移酶(UGT)催化的葡萄糖醛酸化反应是的是Ⅱ相代谢中重要的代谢反应之一,对于维持内源性化合物如胆红素、胆汁酸的动态平衡和药物、致癌物等外源性化合物的处置过程起着至关重要的作用。尿苷二磷酸葡萄糖醛酸转移酶的表达和酶活性受多维机制的调控。深入研究其调控网络以及尿苷二磷酸葡萄糖醛酸转移酶介导的相关中药-药物相互作用,对于临床更安全、有效的使用中药提供了指导。因此,本文总结了尿苷二磷酸葡萄糖醛酸转移酶的转录前、转录水平、翻译后修饰等分子调节机制,以及由尿苷二磷酸葡萄糖醛酸转移酶介导的中药-药物相互作用相关的研究进展。     

人尿苷二磷酸葡萄糖醛酸转移酶基因多态性与相关疾病易感性

尿苷二磷酸葡萄糖醛酸转移酶(UGT)是体内重要的药物代谢Ⅱ相酶,具有明显的基因多态性。评价基因多态性对疾病易感性影响的重要性,建立基因多态性数据库并进行致病基因-疾病易感性的种群研究具有深远意义。本文拟就人UGT基因多态性及相关疾病易感性进行简述。     

尿苷二磷酸葡萄糖醛酸转移酶的转录调节与疾病相关性的研究进展

葡萄糖醛酸结合反应是体内重要的Ⅱ相代谢途径,主要由尿苷二磷酸葡萄糖醛酸转移酶（ UGT ）催化。尿苷二磷酸葡萄糖醛酸转移酶能参与多种内源性物质如胆红素、胆汁酸、甲状腺激素等的代谢,也能参与多种药物如阿片类镇痛药、非甾体抗炎药等药物的代谢,在代谢解毒方面起着重要作用。近年来对尿苷二磷酸葡萄糖醛酸转移酶的研究越来越深入,尿苷二磷酸葡萄糖醛酸转移酶与不同疾病的研究受到普遍关注。本文就转录因子介导的尿苷二磷酸葡萄糖醛酸转移酶的分子调节机制及其与不同疾病的相关性研究进行综述。     

腺苷蛋氨酸对L02细胞尿苷二磷酸葡萄糖醛酸转移酶表达的影响

目的探讨腺苷蛋氨酸(S-adenosyl-L-methionine,SAMe)对尿苷二磷酸葡萄糖醛酸转移酶(Uridine Diphosphate Glucuronsyltrans-ferase,UGT)表达的调节作用。方法体外培养L02细胞加入药物分别处理0～72 h后应用RT-PCR法观察SAMe对UGT mRNA的作用。结果 0.5 mmol/L的SAMe在24～72 h可上调UGTmRNA的表达,0.1～1 mmol/L的SAMe都能上调UGTmRNA的表达,但0.5mmol/L的作用最强,强于苯巴比妥。结论 SAMe可以上调UGTmRNA的表达,从而促进胆红素代谢。     

孤儿核受体对尿苷二磷酸葡萄糖醛酸转移酶基因转录调节的研究进展

尿苷二磷酸葡萄糖醛酸转移酶（UDP-glucuro-nosyltransferase,UGT）属于Ⅱ相药物代谢酶。它能催化葡醛酸与其相应底物结合,是化学物质在生物体内进行Ⅱ相生物转化时最重要的一类酶。越来越多的研究发现,孕烷X受体（pregnaneXreceptor,PXR）、组成型雄甾烷受体（constitutiveandrostanere-ceptor,CAR）等孤儿核受体（orphannuclearreceptors）及其他转录因子能调节UGT基因的转录,这些受体及因子分布和活性的差异可导致UGT酶表达和分布的差异。此外,研究表明化合物通过核受体（NR）介导的UGT酶表达量的变化可能是影响化合物体内代谢的一条重要途径。由于UGT酶表达量与激素平衡、药物疗效、药物毒副作用及肿瘤等多种疾病发病预后密切相关,所以研究核受体对Ⅱ相代谢酶的调节作用在预测药物相互作用、指导临床合理用药及人类疾病的预防等方面都具有重要意义。     

尿苷二磷酸葡醛酸转移酶介导的酪氨酸激酶抑制剂药物相互作用研究进展

近年来由代谢酶和转运体介导的酪氨酸激酶抑制剂(TKIs)的药物相互作用(DDI)已成为临床治疗的一个重要问题。除CYP450酶,尿苷二磷酸葡醛酸转移酶(UGTs)是参与TKIs代谢的另一类代谢酶,而且在体外多数TKI对UGTs呈抑制作用。TKIs与UGTs底物或抑制剂联合用药可能发生潜在的有临床意义的DDI。本文将重点研究UGTs介导的TKIs的药物-药物相互作用以及UGT1A基因型对TKIs的药物相互作用的影响,并探讨解决策略,以期为临床医师和药师对TKIs的安全合理应用提供参考。     

尿苷二磷酸葡醛酸转移酶的代谢类型及影响因素

尿苷二磷酸葡醛酸转移酶 (UGT)是一类Ⅱ相代谢酶 ,能催化葡醛酸与其相应底物结合。该过程是机体的重要排泄途径之一。目前 ,有 15种人类UGT被确证有活性 ,而且对它们的底物选择性方面有了进一步认识 ,但UGT的酶学研究相对于细胞色素P4 5 0还比较落后 ,有待于进一步提高。     

重组人尿苷二磷酸葡糖醛酸转移酶2B7三个功能性突变体的构建、表达及活性比较

目的构建人尿苷二磷酸葡糖醛酸转移酶(UGT)2B7重组酶的3个功能性突变体UGT2B7*71S(A71S,211G>T),UGT2B7*2(H268Y,802C>T)和UGT2B7*5(D398N,1192G>A),以进一步研究该酶野生型和其突变体在对底物作用过程中的功能差异。方法应用细菌/杆状病毒系统,将构建的pFastBac-UGT2B7*71S,pFastBac-UGT2B7*2和pFastBac-UGT2B7*5重组质粒转化E.coli DH10Bac大肠杆菌,通过转座作用获得各自的重组粘粒(bac-mid),然后将其转染草地夜蛾(Sf)9细胞后,产生重组杆状病毒。这些病毒再感染Sf9细胞,即可获得野生型UGT2B7*1及其突变体的重组酶。野生型及突变体酶的活性以7-羟基-4-三氟甲基香豆素(7-HFC)为底物,用荧光法测定并分析比较。结果利用杆状病毒/昆虫细胞系统,成功地构建人UGT2B7重组酶的3个功能性突变体。UGT2B7*1对7-HFC的Km值为(0.331±0.018)mmol·L-1,Vmax值为(2.14±0.04)μmol·min-1·g-1蛋白;UGT2B7*71S对7-HFC的Km值为(0.260±0.026)mmol·L-1,Vmax值为(1.36±0.05)μmol·min-1·g-1蛋白;UGT2B7*2对7-HFC的Km值为(0.53±0.06)mmol·L-1,Vmax值为(9.5±0.5)μmol·min-1·g-1蛋白;UGT2B7*5对7-HFC的Km值为(0.59±0.05)mmol·L-1,Vmax值为(7.52±0.28)μmol·min-1·g-1蛋白。结论应用细菌/杆状病毒系统,成功构建了UGT2B7的3个功能性突变体,这些突变体可进一步用于对其他底物的代谢活性比较。     

尿苷二磷酸葡醛酸转移酶介导的胆汁酸代谢过程及其内源和外源影响因素研究进展

尿苷二磷酸葡萄糖醛酸转移酶(UDP-glucuronosyltransferases, UGTs)作为人体中一种非常重要的II相代谢酶,不仅参与外源性化合物代谢清除,也在胆汁酸等内源性物质的代谢调控中扮演重要角色。解析尿苷二磷酸葡萄糖醛酸转移酶介导的胆汁酸代谢过程及其内源和外源影响因素有助于增强对相关疾病的治疗和预防。尿苷二磷酸葡萄糖醛酸转移酶对胆汁酸代谢调控作用受到多种内源性和外源性因素影响。本文将重点探讨核受体、遗传因素、外源化合物及肝脏相关疾病等因素对UGT酶作用的影响,讨论体内潜在的胆汁酸动态平衡干预机制。     

重组人尿苷二磷酸葡糖醛酸转移酶287三个功能性突变体的构建、表达及活性比较

目的 构建人尿苷二磷酸葡糖醛酸转移酶(UGT)287重组酶的3个功能性突变体UGT2B7 *71S(A71S,211G>T),UGT2B7 *2(H268Y,802C>T)和UGT2B7 *5(D398N,1192G>A),以进一步研究该酶野生型和其突变体在对底物作用过程中的功能差异. 方法 应用细菌/杆状病毒系统,将构建的pFastBac-UGT2B7 *71S,pFastBac-UGT2B7 *2和pFastBac-UGT2B7 *5重组质粒转化E.coli DH10Bac大肠杆菌,通过转座作用获得各自的重组粘粒(bac-mid),然后将其转染草地夜蛾(Sf)9细胞后,产生重组杆状病毒.这些病毒再感染Sf9细胞,即可获得野生型UGT2B7 *1及其突变体的重组酶.野生型及突变体酶的活性以7-羟基4-三氟甲基香豆素(7-HFC)为底物,用荧光法测定并分析比较. 结果 利用杆状病毒/昆虫细胞系统,成功地构建人UGT2B7重组酶的3个功能性突变体.UGT2B7 *1对7-HFC的Km值为(0.331±0.018)mmol·L-1,Vmax值为(2.14±0.04)μmol·min-1·g-1蛋白;UGT2B7 *71S对7-HFC的Km值为(0.260±0.026)mmol·L-1,Vmax值为(1.36±0.05)μmol·min-1·g-1蛋白;UGT2B7 *2对7-HFC的Km值为(0.53±0.06)mmol·L-1,Vmax值为(9.5±0.5)μmol·min-1·g-1蛋白;UGT2B7 *5对7-HFC的Km值为(0.59±0.05)mmol·L-1,Vmax值为(7.52±0.28)μmol·min-1·g-1蛋白. 结论 应用细菌/杆状病毒系统,成功构建了UGT2B7的3个功能性突变体,这些突变体可进一步用于对其他底物的代谢活性比较.     

Human placental glucuronidation and transport of 3'azido-3'-deoxythymidine and uridine diphosphate glucuronic acid.

These studies were performed to characterize the contribution of the uridine diphosphate glucuronosyltransferase (UGT) enzymes to the clearance of 3'-azido-3'-deoxythymidine (AZT) in vivo and to assess the regulation of UGT activity [including the disposition of the cofactor uridine diphosphate glucuronic acid (UDPGA)] in the placenta. Transport of AZT and the cofactor UDPGA across the human placenta and the glucuronidation capacity of the placenta for AZT were assessed using a human placental cell line (JEG-3), primary cultures of villous term placenta, placental subcellular fractions, and a recirculating perfusion model. Glucuronidation of AZT was consistently observed at approximately 2% of the dose administered. High levels of AZT in cultured primary placental cells and lines caused autoinhibition of AZT metabolism. AZT crossed the perfused placenta in a bidirectional fashion and was at equilibrium after 3 h, whereas the AZT-glucuronide metabolite was excreted preferentially into the maternal compartment. In contrast, UDPGA (10 microM) was rapidly transferred from the maternal to the fetal circulation, being complete after 4 h of perfusion. AZT is transported and glucuronidated by the human placenta, but that placental metabolism of the drug is not significant for whole-body clearance. Likewise therapeutic failure of AZT (5-15%) is not due to placental obstruction of drug passage. Finally, the activity of the UGT enzymes in the placenta is not rate-limited by the supply of UDPGA cofactor, whereas the preferential transport of UDPGA toward the fetus observed here may indicate a role in fetal development.     

Effects of adenosine on glucuronidation and uridine diphosphate glucuronic acid (UDPGA) synthesis in isolated rat hepatocytes

Dibutyryl cyclic adenosine 3':5'-monophosphate (DBcAMP) has been shown to inhibit glucuronidation of p-nitrophenol in a concentration-dependent manner in isolated rat hepatocytes. Adenosine (ADO) also decreased glucuronidation in a similar fashion. The effects of adenosine were examined on the variables controlling glucuronidation in intact cells. The addition of adenosine was without effect on either glucuronyltransferase or beta-glucuronidase. Adenosine decreased uridine diphosphate glucuronic acid (UDPGA) levels by 62% and, subsequently, inhibited glucuronidation by 41% in isolated rat hepatocytes. Since the synthesis of UDPGA requires NAD+ for the dehydrogenation of UDP-glucose, alterations in the redox state could account for the decrease in intracellular UDPGA levels. The effects of ADO (500 microM) on lactate and pyruvate content and redox state were examined in rat hepatocytes. ADO caused a 2.1-fold increase in lactate levels and a 2.65-fold increase in the [lactate]/[pyruvate] ratio. The NAD+/NADP ratio, therefore, was decreased by 63% in the presence of ADO. Carbohydrate reserve also affects UDPGA levels; thus, graded concentrations of glucose (5.5, 25, and 50 mM) were added to cells incubated with ADO. At 5.5 mM glucose, ADO caused a 61% decrease in glucuronide formation, while at concentrations of 25 and 50 mM glucose, the inhibition was diminished by 53 and 47% respectively. ADO appears to have decreased the synthesis of UDPGA by decreasing the NAD+/NADH ratio, thus inhibiting UDP-glucose dehydrogenase. Carbohydrate reserve also appears to be involved in the inhibition of glucuronidation mediated by ADO.     

内源性物质药物生物等效性评价的探讨

内源性物质是体内已有的物质,内源性物质药物生物等效性的评价因为体内自身物质的存在变得复杂化。文中以内源性物质和生物等效性为关键词,检索Pubmed和万方数据库,对常用的内源性物质药物的生物等效性评价方法进行了综述。     

浅谈药品注册中HPLC法测定原料药有关物质的问题

本文分析了在原料药申报中采用 HPLC 方法测定有关物质存在的问题;简述了药品注册中有关物质测定方法的建立及质量控制的几点建议。     

Protein expression of various hepatic uridine 5′‐diphosphate glucuronosyltransferase (UGT) enzymes and their inter‐correlations: a meta‐analysis

Avoiding cytochrome P450 (CYP) related drug interactions in the development of new drug candidates means that glucuronidation by uridine 5′‐diphosphate glucuronosyltransferase (UGT) enzymes is expected to become a more prominent pathway in the metabolism of new drug candidates designed by pharmaceutical companies. Therefore, determining the abundance and activity of these enzymes is of value in the process of scaling in vitro data to in vivo metabolic parameters. Many of the studies involving the measurement of UGTs were conducted with too few samples, which did not provide a good indication of population values and the level of variability. Meta‐analysis is used in the current study to combine all reported values (eight studies that used LC‐MS isotope‐labelled standard targeted quantitative methods), detect inconsistencies between the various datasets and describe correlations of expression between the quantified UGT enzymes. Some heterogeneity was observed between studies, especially in the UGT1A4, 2B7 and 2B10 datasets. However, in the absence of information on the inter‐laboratory consistency of assays, it is difficult to assign these differences to the heterogeneity of the samples. Large inter‐individual variability was observed in the collated data across this family of enzymes. Positive correlations between the expression levels of certain UGT enzymes were found in the collated data. These included the pairs: UGT1A4/2B4 (r_s = 0.71, p < 0.0001, n = 82), UGT2B4/2B15 (r_s = 0.63, p < 0.0001, n = 83), UGT2B7/2B15 (r_s = 0.81, p < 0.0001, n = 99). These correlations can be explained by common regulatory mechanisms involved in the expression of these proteins. Copyright © 2014 John Wiley & Sons, Ltd.     

尿苷二磷酸葡醛酸转移酶的研究进展

尿苷二磷酸葡醛酸转移酶(UGT)是体内最重要的Ⅱ相代谢酶,它可以参与许多内源性物质如胆红素、甾体激素、甲状腺激素、胆汁酸和脂溶性维生素等的代谢,在许多药物如阿片类药物、镇痛药、非甾体抗炎药和抗惊厥药等的代谢中也发挥着重要的作用。UGT在药物的吸收、分布、代谢和排泄中发挥重要作用。研究UGT特别是其基因多态性及其介导的药物-药物相互作用不仅可以指导临床用药,也可以揭示内源性物质代谢紊乱的机制。本文就UGT的分类、组织分布、对药物吸收的影响、基因多态性及其所介导的药物-药物相互作用进行综述。     

Bioequivalence of endogenous substances facing homeostatic equilibria: an example with potassium

Oral administration of endogenous substances in most cases results in negligible net increases in baseline plasma concentrations, associated with high variability. This poses the problem of their bioequivalence. Using the data obtained from a bioequivalence investigation of potassium aspartate (test vs reference formulation), the authors demonstrate the inconsistency of bioequivalence based on plasma concentrations and standard methods. Potassium aspartate was given orally at a dose of 15.8 mmoles to 12 healthy volunteers as test and reference values according to a two-period, two-formulation, two-sequence design. The individual net values of the area under the curve of plasma concentration (AUC) and cumulative urinary excretion (CUE), both obtained with the test formulation as post-dose minus baseline, were multiplied by 2, 3, 4, 5 and 6 and added to the baseline in order to simulate the administration of increasing single doses of the test, assuming dose-linear kinetics. Data generated with the test formulation were compared with original data of the reference according to 90% confidence intervals. With AUC, bioequivalence of test and reference formulations was demonstrated with 1 : 1, 2 : 1 and 3 : 1 test to reference dose ratios. With CUE only the 1 : 1 dose ratio comparison produced bioequivalence. The authors conclude that bioequivalence of endogenous substances conducted with standard procedures in most cases is a useless exercise. With potassium and more generally with drugs cleared via urine, urinary excretion would reflect the extent of absorption more faithfully than AUC.