Expression and Function of Na+HCO3− Cotransporters in the Gastrointestinal Tract

• Published in: Annals of the New York Academy of Sciences Vol. 915; no. 1; pp. 1 - 14
• Main Authors: SEIDLER, URSULA, ROSSMANN, HEIDI, JACOB, PETRA, BACHMANN, OLIVER, CHRISTIANI, STEPHANIE, LAMPRECHT, GEORG, GREGOR, MICHAEL
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.12.2000
• Subjects: Animals; Biological Transport - physiology; Carrier Proteins - genetics; Carrier Proteins - metabolism; Gastric Mucosa - metabolism; Gene Expression - physiology; Humans; Intestinal Mucosa - metabolism; Sodium-Bicarbonate Symporters
• ISSN: 0077-8923; 1749-6632
• DOI: 10.1111/j.1749-6632.2000.tb05219.x

: The stomach, duodenum, colon, and pancreas secrete HCO3− ions into the lumen. Although the importance of HCO3− secretion for the maintenance of mucosal integrity, a normal digestion, and the reabsorption of Cl− has been well established, the molecular nature of the apical and basolateral HCO3− transporting proteins has remained largely unknown. Functional studies have suggested that a Na+HCO3− cotransport system, similar but not identical to the well‐characterized Na+HCO3− cotransporter in the basolateral membrane of the kidney proximal tubule, is present in duodenal and colonic enterocytes, pancreatic ducts cells, and gastric cells and involved in HCO3− uptake from the interstitium. This report describes our work towards understanding the molecular nature, cellular origin, and functional relevance of the Na+HCO3− cotransporter(s) in the stomach and intestine and reviews work by others on the function and localization of Na+HCO3− cotransport processes in the gastrointestinal tract.