Molucular analysis of tissue distribution and structure-function relationship of transporters responsible for the regulation of drug transport

负责药物转运调节的转运蛋白的组织分布和结构功能关系的分子分析

基本信息

批准号：
08457620
负责人：
INUI Ken-ichi
金额：
$ 5.57万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

项目摘要

Tissue distribution and structure-function relationship of membrane transporters responsible for absorption and excretion of drugs have been studied, and then following results were obtained.1.Structure-function relationship of H^+-coupled peptide transportersWhen stable transfectans expressing rat peptide transporters PEPT1 and PEPT2 were treated with DEPC, a histidine-modifying agent, glycylsarcosine uptake by both transfectants were decreased. Interactions of dipeptides and beta-lactam antibiotics were analyzed, and then it became clear that alpha-amino moiety of beta-lactam antibiotics should interact with histidine residues, and may participate in substrate recognition.2.Tissue distribution and functional characteristics of renal organic ion transporters.(1)Organic anion transporter, OAT-K1 : Expression of mRNA along nephron segments was analyzed by RT-PCR.OAT-K1 mRNAs were mainly expressed in proximal straight tubules of superficial and juxtamedullary nephrons. Western blot analysis revealed that OAT-K1 is expressed only in brush-border membranes of renal tubules. Methotrexate transport by the transfectants stably expressing OAT-K1 was significantly inhibited in the presence of nonsteroidal anti-inflammatory drugs (NSAID).(2)Organic cation transporter, OCT2 : Because tetraethylammonium transport by OCT2 was H^+-gradient independent and was affected by membrane potential, OCT2 is deduced to be basolateral-type organic cation transporter. By constructing stable transfectants expressing OCT1 or OCT2, transport characteristics were further analyzed, and then it became clear that both OCT1 and OCT2 are basolateral-type organic cation transporters with broad substrate specificity and have similar substate recognition in each other.

Tissue distribution and structure-function relationship of membrane transporters responsible for absorption and excretion of drugs have been studied, and then following results were obtained.1.Structure-function relationship of H^+-coupled peptide transportersWhen stable transfectans expressing rat peptide transporters PEPT1 and PEPT2 were treated with DEPC, a histidine-modifying agent, glycylsarcosine两种转染剂的吸收均减少。 Interactions of dipeptides and beta-lactam antibiotics were analyzed, and then it became clear that alpha-amino moiety of beta-lactam antibiotics should interact with histidine residues, and may participate in substrate recognition.2.Tissue distribution and functional characteristics of renal organic ion transporters.(1)Organic anion transporter, OAT-K1 : Expression of mRNA along nephron segments was通过RT-PCR.AIT-K1 mRNA分析主要在浅表和近叶肾肾上腺的近端直立小管中表达。蛋白质印迹分析表明，燕麦k1仅在肾小管的刷膜膜中表达。在非甾体类抗炎药（NSAID）存在下，通过稳定表达OAT-K1的转染剂甲氨蝶呤的转运受到显着抑制。（2）有机阳离子转运蛋白，OCT2：由于eT2的四乙基铵转运oct2被H^+梯度独立，并受到了质量的影响。通过构造表达Oct1或Oct2的稳定转染物，进一步分析了运输特性，然后很明显OCT1和OCT2都是具有广泛底物特异性的基底外侧有机阳离子转运蛋白，并且相互识别相似。