Cyclic adenosine monophosphate-stimulated anion transport in rabbit cortical collecting duct. Kinetics, stoichiometry, and conductive pathways

J Clin Invest. 1986 Dec;78(6):1621-30. doi: 10.1172/JCI112755.


Cyclic AMP stimulates HCO3 secretion and Cl self-exchange in rabbit cortical collecting tubule. We found that varying peritubular [Cl] changed the Cl self-exchange rate with saturation kinetics (Km, 3-4 mM). HCO3 secretion also showed saturation kinetics as a function of mean luminal [Cl] (Km, 4-11 mM). Both Cl self-exchange and Cl-HCO3 exchange thus appear to be carrier-mediated. Addition/removal of basolateral HCO3 qualitatively changed Cl and HCO3 transport as expected for Cl-HCO3 exchange, but quantitatively changed Cl absorption more than HCO3 secretion. The diffusive Cl permeability and the transepithelial conductance in the presence of HCO3/CO2 and cAMP were higher than in their absence suggesting that HCO3/CO2 and cAMP together increase a conductive Cl pathway parallel to a 1:1 Cl-HCO3 exchanger. Thus, cAMP not only stimulates the overall process of anion exchange (probably by increasing an electroneutral exchanger and/or a series Cl conductance), but also stimulates a Cl conductance parallel to the exchange process.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Absorption
  • Animals
  • Bicarbonates / metabolism*
  • Biological Transport / drug effects
  • Chlorides / metabolism*
  • Cyclic AMP / pharmacology*
  • Kidney Cortex / metabolism
  • Kidney Tubules / metabolism*
  • Kidney Tubules, Collecting / drug effects
  • Kidney Tubules, Collecting / metabolism*
  • Kinetics
  • Permeability
  • Rabbits


  • Bicarbonates
  • Chlorides
  • Cyclic AMP