AJP - Gastrointestinal and Liver Physiology, Vol 247, Issue 1 1-12, Copyright © 1984 by American Physiological Society

ARTICLES

Systemic acid-base disorders and intestinal electrolyte transport

A. N. Charney and G. M. Feldman

Disorders of systemic acid-base balance have recently been shown to markedly alter intestinal electrolyte transport. These studies were based on earlier acid balance studies in humans and animals, data suggesting the presence of intestinal mucosal Na+-H+ and Cl-HCO-3 exchange processes and the reported effects of acid-base variables on other epithelia. In vivo studies have shown that intestinal net sodium and chloride absorption is markedly affected by systemic pH and carbon dioxide tension (Pco2). Specifically, systemic acidemia (in the rat ileum) and hypercapnia (in the rat colon) increase sodium and chloride absorption, while alkalemia and hypocapnia decrease absorption. In addition, net bicarbonate secretion (in both segments) varies directly with the plasma HCO3 concentration. The rabbit ileum has been studied both in vivo and in vitro and is affected in a similar way. The rat jejunum and rabbit distal colon and gallbladder do not respond to changes in blood pH and Pco2, consistent with the apparent absence of a mucosal Na+-H+ exchange process in these segments. Evidence suggests important roles for cellular carbonic anhydrase activity and the intracellular concentrations of hydrogen, bicarbonate, and calcium ions and calcium-calmodulin in mediating or modulating the effects of the systemic acid-base disorders. In addition, systemic pH may alter the effects of the neural and humoral mediators of intestinal transport.

This article has been cited by other articles:

				D. S. Goldfarb, W. S. Sly, A. Waheed, and A. N. Charney Acid-base effects on electrolyte transport in CA II-deficient mouse colon Am J Physiol Gastrointest Liver Physiol, March 1, 2000; 278(3): G409 - G415. [Abstract] [Full Text] [PDF]