Hoshi T
Laboratory of Physiology, School of Food and Nutritional Sciences, University of Shizuoka.
Nihon Rinsho. 1992 Jul;50(7):1467-74.
In the kidney, more than 99% of filtered free amino acids are reabsorbed by the proximal tubule. The brush border membrane of this segment is known to possess at least 5 independent amino acid carriers; neutral alpha-amino, basic, acidic, neutral beta-amino and imino acid carriers. Ionic interactions have been shown to be markedly different among these carriers. Characteristics of the interaction were outlined for each carrier. Basolateral membrane carriers have not been investigated extensively, but existence of neutral amino acid carrier (s) devoid of ionic interaction has been established. In addition, a Na+ plus K+ gradient-dependent transport has been identified for acidic amino acids and a Na+ exchange carrier has been suggested for basic amino acids. Also, asymmetric ionic interactions are suggested for luminal and basolateral membrane carriers for beta-amino acids. Proton-dependent carrier (s) for di- and tri-peptides has also been identified in the proximal tubule.
在肾脏中，超过99%的滤过游离氨基酸被近端小管重吸收。已知该节段的刷状缘膜至少拥有5种独立的氨基酸载体：中性α-氨基、碱性、酸性、中性β-氨基和亚氨基酸载体。已表明这些载体之间的离子相互作用明显不同。概述了每种载体相互作用的特征。基底外侧膜载体尚未得到广泛研究，但已证实存在无离子相互作用的中性氨基酸载体。此外，已确定酸性氨基酸存在Na⁺加K⁺梯度依赖性转运，并有人提出碱性氨基酸存在Na⁺交换载体。还提示β-氨基酸的管腔膜和基底外侧膜载体存在不对称离子相互作用。在近端小管中也已鉴定出二肽和三肽的质子依赖性载体。
