Micropuncture analysis of the cellular mechanisms of electrolyte secretion by the in vitro rabbit pancreas

• Published in: The Journal of general physiology Vol. 65; no. 1; pp. 22 - 45
• Main Authors: Swanson, C H, Solomon, A K
• Format: Journal Article
• Language: English
• Published: United States The Rockefeller University Press 01.01.1975
• Subjects: Acetates - metabolism; Acetates - pharmacology; Animals; Bicarbonates - metabolism; Bicarbonates - pharmacology; Biological Transport, Active; Carbon Dioxide; Hydrogen-Ion Concentration; In Vitro Techniques; Ouabain - pharmacology; Pancreas - metabolism; Partial Pressure; Punctures; Rabbits; Sodium - metabolism
• ISSN: 0022-1295; 1540-7748
• DOI: 10.1085/jgp.65.1.22

Micropuncture techniques have been used to study electrolyte secretion by the spontaneously secreting in vitro rabbit pancreas over a wide range of environmental conditions. Pancreatic secretion does not have a strong requirement for HCO3 and secretion continues at nearly normal rates when exogenous HCO3 is replaced by acetate. Acetate concentration in the juice averages 70 meq/liter, nearly three times the environmental concentration. The similar characteristics exhibited by HCO3 and acetate secretion indicate that they are secreted by a common mechanism involving active H transport. In vitro acid-base alterations demonstrate that the secretion rate is controlled by the environmental HCO3 concentration and to a much lesser extent by the pCO2. Secretion also requires active Na transport across the mucosal membrane. The effects of ouabain and a low Na environment strongly suggest coupling between the transport of Na and H and a cellular mechanism for electrolyte secretion is proposed involving Na-H exchange mechanisms at both the mucosal and serosal membranes.