Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California.
Brain Research Institute, David Geffen School of Medicine, University of California, Los Angeles, California.
J Am Soc Nephrol. 2023 Jan 1;34(1):8-13. doi: 10.1681/ASN.0000000000000008.
H+ or base transporters and channels in the mammalian genome play important roles in the maintenance of numerous cellular biochemical and physiologic processes throughout the body. Among the known base transporters, those within the SLC4 and SLC26 gene families are involved in cell, transepithelial, and whole organ function. Whether the functional properties of these transporters involve HCO3-, CO32-, or HCO3-/CO32- stimulated H+ (or OH-) transport has not received widespread attention in the literature. Accordingly, "bicarbonate" is the term typically used in most textbooks without greater specificity. Moreover, clinicians and physiologists have historically focused on the blood HCO3- concentration as the base term in the Henderson-Hasselbalch equation in the analysis of clinical acid-base abnormalities, thus, bicarbonate has been assumed to be the species reabsorbed along the nephron as required to maintain the blood [HCO3-] at approximately 25 mM. However, accumulating data in the literature suggest that carbonate, rather than bicarbonate, is the species absorbed across the proximal tubule basolateral membrane, whereas in the collecting duct, bicarbonate is indeed transported. Various experimental approaches leading to this new concept are herein reviewed.
哺乳动物基因组中的 H+ 或碱基转运体和通道在维持全身众多细胞生化和生理过程中发挥着重要作用。在已知的碱基转运体中，SLC4 和 SLC26 基因家族中的那些参与细胞、跨上皮和整个器官功能。这些转运体的功能特性是否涉及 HCO3-、CO32- 或 HCO3-/CO32- 刺激的 H+（或 OH-）转运，在文献中并没有得到广泛关注。因此，在大多数教科书中，通常使用“碳酸氢盐”一词，而没有更具体的说明。此外，临床医生和生理学家在分析临床酸碱失衡时，历史上一直将血液 HCO3-浓度作为 Henderson-Hasselbalch 方程中的碱基术语，因此，假设碳酸氢盐是沿着肾单位被重吸收的物质，以维持血液[HCO3-]约为 25 mM。然而，文献中的累积数据表明，碳酸盐而不是碳酸氢盐是跨近端小管基底外侧膜吸收的物质，而在集合管中，确实存在碳酸氢盐的转运。本文综述了导致这一新概念的各种实验方法。
