The Regulation of Gastric Acid Secretion

by / Friday, 17 September 2010 / Published in Physiology


The key player in regulating gastric acid secretion is the H+/K+ ATPase, which is a magnesium-dependent pump.  The following are the basic steps of gastric acid production and secretion:

  1. H+ is generated within the parietal cell from the dissociation of water.  Hydroxyl ions rapidly combine with CO2 via carbonic anhydrase.
  2. HCO3- is transported outside the cell in exchange of chloride (maintains intracellular pH of the parietal cell).
  3. Cl- and K+ are transported into the lumen, which is necessary for secretion of acid.
  4. H+ pumped out of the cell and into the lumen in exchange for K+ through a proton pump.
  5. H+ accumulation generates an osmotic gradient that causes outward diffusion of water, leading to gastric acid production (HCl, KCl), and a small amount of NaCl

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