title: Coupling between chloride absorption and base excretion in isolated skin of Rana esculenta.
abstract: The net excretory fluxes of base (HCO3- or OH-) and the unidirectional fluxes of chloride were measured and their relationship examined in isolated frog skin maintained in open- or short-circuit (OC and SC) conditions. When the mucosal solution was a 2 mM choline chloride solution and the serosal solution a Ringer solution buffered with a HCO3-/CO2 mixture, the rate of base excretion was -105 +/- 10 in OC and -60 +/- 7 neq h-1 cm-2 in SC. A highly significant correlation was observed between the influx of chloride and the excretion of base. As a function of external chloride both these parameters followed saturation kinetics, Vmax being obtained for a chloride concentration below 2 mM. The removal of chloride in the external solution was followed by a 70 or 100% inhibition of base excretion in OC and SC conditions, respectively. Chloride transport is dependent on the presence of a HCO3-/CO2 mixture in the internal or the external medium. This transport, as well as base excretion, is inhibited to a considerable extent by removal of HCO3-/CO2 or by acetazolamide (10(-3) M). This investigation characterizes a saturable transport system in which chloride absorption and base excretion are coupled.
mesh_terms: D000086:Acetazolamide / Q000494:pharmacology; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D001001:Anura; D001693:Biological Transport, Active / Q000187:drug effects; D002712:Chlorides / Q000378:metabolism*; D005665:Furosemide / Q000494:pharmacology; D066298:In Vitro Techniques; D011893:Rana esculenta; D012867:Skin / Q000378:metabolism*; D012869:Skin Absorption; D012964:Sodium / Q000378:metabolism; D013267:Stilbenes / Q000494:pharmacology; D013431:Sulfates / Q000378:metabolism
chemical_list: D002712:Chlorides; D013267:Stilbenes; D013431:Sulfates; D000584:Amiloride; D005665:Furosemide; D012964:Sodium; D000086:Acetazolamide