To maintain acid–base balance, the renal tubules secrete hydrogen ions into the lumen at a rate equal to the sum of extrarenal acid generation and bicarbonate filtration. In this chapter we review the cellular mechanisms responsible for transepithelial hydrogen secretion…
Transmembrane transport of HCO − 3 and CO 2 is central to body pH and volume homeostasis. The Na + -independent, electroneutral CI − /HCO − 3 exchangers AE1/Band 3 and the related AE2 and AE3 polypeptides of the SLC4…
The SLC4 ( s o l ute c arrier 4) family is a group of a membrane proteins that share sequence homology and in general mediate the transport of bicarbonate. It should be noted that bicarbonate transport is not unique…
Because virtually every biological process is sensitive to changes in pH, acid–base homeostasis is of critical importance to cells and organisms, and has attracted considerable attention. Until relatively recently, acid–base homeostasis, for both clinicians and basic scientists, has been synonymous…
Hyperkalemia is a common electrolyte disorder that may cause life threatening cardiac arrhythmia. The trans-cellular distribution of K + limits the acute rise in P K . Regulation of K + excretion by the kidney maintains overall K + balance.…
Potassium (K + ) deficiency is a common and eventually life-treating condition. Hypokalemia is defined as serum K+ level less than 3.5 mM. This chapter, together with cornerstone mechanisms, reviews the newest molecular regulators of the K + homeostasis, including…
Overview of K + Distribution and Excretion–Internal and External Balance As the most abundant cation in intracellular fluid, K + plays an important role in a variety of cell functions. High K + concentration in cells and low K +…
Internal potassium homeostasis is defined as the regulation of potassium distribution between the intracellular and extracellular fluid compartments, as distinct from the net gain or loss of potassium from the body. While the kidney plays the predominant role in maintaining…
Renal epithelial transport depends on the coordinated function of potassium channels with ion transporters (co-transporters, channels, and exchangers) and ion pumps in apical and basolateral membranes of distinct cell types along the nephron of the mammalian kidney. Potassium (K +…
Diabetes insipidus is a disorder characterized by the excretion of abnormally large volumes (<30 ml/kg body weight/day for an adult patient) of dilute urine (<250 mmol/kg). Four basic defects can be involved. The most common, a deficient secretion of the…