ABSTRACT
The study and understanding of the renal regulation of acid-base balance has undergone remarkable progress over the last five decades. Starting from clearance studies at the level of the whole organism, the function of individual nephron segments has been defined with in vivo and in vitro microperfusion. The delineation of transport and regulatory mechanisms was further refined with the application of isolated membrane vesicles and model epithelial in cell culture. Recombinant DNA techniques allowed us to secure the identity for individual transporters and regulatory proteins. Two strategies have been used for the cloning of acid-base transporters. For proteins obtained in high abundance (e.g., the Cl=HCO3
exchanger and HþATPase), classical protein chemistry has been used to purify the proteins of interest. For others, approaches such as functional complementation in mammalian cells for the Naþ=Hþ exchanger or in Xenopus oocytes for the Naþ-HCO3
cotransporter. In this chapter, the current knowledge of the molecular definition of renal acid-base transporters is summarized, with emphasis on its implications for our understanding of the physiology of acid-base balance.
