title: Micropuncture analysis of the cellular mechanisms of electrolyte secretion by the in vitro rabbit pancreas.
abstract: 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.
mesh_terms: D000085:Acetates / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D001639:Bicarbonates / Q000378:metabolism* / Q000494:pharmacology; D001693:Biological Transport, Active; D002245:Carbon Dioxide; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D010042:Ouabain / Q000494:pharmacology; D010179:Pancreas / Q000378:metabolism*; D010313:Partial Pressure; D011677:Punctures; D011817:Rabbits; D012964:Sodium / Q000378:metabolism*
chemical_list: D000085:Acetates; D001639:Bicarbonates; D002245:Carbon Dioxide; D010042:Ouabain; D012964:Sodium