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[Bicarbonate reabsorption in proximal renal tubule: molecular mechanisms and metabolic acidosis.] [Article in Chinese]

GUO Yi-Min, LIU Ying, CHEN Li-Ming^*

Department of Biophysics and Molecular Physiology, Key Laboratory of Molecular Biophysics of Ministry of Education, Huazhong University of Science &； Technology School of Life Science &； Technology, Wuhan 430074, China

Abstract

HCO3^- reabsorption in the renal tubules plays a critically important role in maintaining the global acid-base balance. Loss of HCO3^- causes metabolic acidosis. Proximal renal tubule is the major site for HCO3^- reabsorption, accounting for more than 80% of total HCO3^- reabsorption along the nephron. Over the past more than half centuries, tremendous progresses have been made on understanding the molecular mechanisms underlying the HCO3^- reabsorption in proximal tubules. The transepithelial movement of HCO3^- involves the coordinated operation of machineries on both the apical and the basolateral membranes of the epithelial cells. On the apical domain, Na⁺-H⁺ exchanger NHE3 and the vacuolar H⁺-ATPase are two major pathways mediating the apical uptake of HCO3^--related species. Taken together, NHE3 and H⁺-ATPase are responsible for about 80% of HCO3^- reabsorption in the proximal tubule. The remaining 20% is likely mediated by pathways yet to be characterized. On the basolateral membrane, NBCe1 represents the only major known pathway mediating the extrusion of HCO3^- coupled with Na⁺ into the interstitial space. In the present article, we provide a historical view about the studies on the mechanisms of HCO3^- reabsorption since 1940s. Moreover, we summarize the latest progresses emerging over the past decade in the physiological as well as pathological roles of acid-base transporters underlying the HCO3^- reabsorption in proximal tubules.

Key words: bicarbonate transporter; acid-base balance; metabolic acidosis;

Received: 2014-04-01　　Accepted: 2014-05-07

Corresponding author: 陈历明　　E-mail: liming.chen@mail.hust.edu.cn

Citing This Article：

GUO Yi-Min, LIU Ying, CHEN Li-Ming. [Bicarbonate reabsorption in proximal renal tubule: molecular mechanisms and metabolic acidosis.] [Article in Chinese]. Acta Physiol Sin 2014; 66 (4): 398-414 (in Chinese with English abstract).