Biochemical mechanisms and regulation of hydrogen transport in renal tubules.

In normal humans, blood pH and bicarbonate concentration are maintained within a very narrow range despite wide variations in dietary intake. The mechanisms involved in the chronic regulation of acid-base homeostasis relate to the kidney in general, and specifically to changes in membrane-bound ATPases and exchangers. This review summarizes some of the data regarding the Na/H exchanger, the H-ATPase and its interaction with Na,K-ATPase and the Ca-ATPase and Ca/H exchanger in renal tissue. While there remain gaps in our knowledge, the significant advances in molecular biology along with the development of selective ligands and dyes for localization have allowed an important picture to emerge regarding transport in the kidney. These data, when integrated with biochemical information and clinical observation, provide a clearer understanding of physiology and the pathophysiology of disease. Some information, particularly involving the Ca-ATPase and Ca/H exchanger, comes primarily from other tissues; however, these important observations provide a framework which adds to our body of work in the kidney.