Terada Y, Tomita K, Nonoguchi H, Marumo F
Second Department of Internal Medicine, Tokyo Medical and Dental University, Japan.
Kidney Int. 1993 Jun;43(6):1251-9. doi: 10.1038/ki.1993.177.
Recent studies revealed that angiotensin II (Ang II) interacts with two pharmacologically different subtypes of cell surface receptors. Type I Ang II (AT1) receptor is characterized by signal transduction mediated through G protein and phospholipase C. In this study, the micro-localization of mRNAs coding for AT1 receptor and angiotensinogen was carried out in the rat kidney, using an assay of reverse transcription and polymerase chain reaction (RT-PCR) in individual microdissected renal tubule segments along the nephron, glomeruli, vasa recta bundle, and arcuate arteries. Large signals for AT1 receptor were detected in the glomerulus, proximal convoluted tubule (PCT), proximal straight tubule (PST), cortical collecting duct, and vascular system. Small signals were also seen in medullary thick ascending limb, outer medullary collecting duct, and inner medullary collecting duct (IMCD). Angiotensinogen mRNA is expressed largely in PCT, PST, and a small amount in glomerulus and vasa recta. Our data demonstrate that Ang II could be produced locally in proximal tubule and vasa recta bundle, and that the AT1 receptor was widely distributed not only in the glomerulus and vessels but also in tubules from PCT to IMCD.
最近的研究表明，血管紧张素II（Ang II）与两种药理学特性不同的细胞表面受体亚型相互作用。I型血管紧张素II（AT1）受体的特征是通过G蛋白和磷脂酶C介导信号转导。在本研究中，采用逆转录聚合酶链反应（RT-PCR）检测法，对大鼠肾脏中编码AT1受体和血管紧张素原的mRNA进行了微定位，该检测针对肾单位、肾小球、直小血管束和弓状动脉中各个显微解剖的肾小管节段进行。在肾小球、近端曲管（PCT）、近端直管（PST）、皮质集合管和血管系统中检测到AT1受体的强信号。在髓质厚升支、外髓集合管和内髓集合管（IMCD）中也可见弱信号。血管紧张素原mRNA主要在PCT、PST中表达，在肾小球和直小血管中有少量表达。我们的数据表明，Ang II可能在近端小管和直小血管束中局部产生，并且AT1受体不仅广泛分布于肾小球和血管，还分布于从PCT到IMCD的肾小管中。
