Regulation of intracellular pH in the rabbit cortical collecting tubule

J Clin Invest. 1990 Jan;85(1):274-81. doi: 10.1172/JCI114423.


The cortical collecting tubule (CCT) is an important nephron segment for Na+, K+, water and acid-base transport. Differential loading characteristics of the pH sensitive dye 2',7'-bis-(2-carboxyethyl)-5(and-6)carboxyfluorescein (BCECF) and basolateral Cl- removal were used to identify and study intracellular pH (pHi) regulation in each of three cell types involved in this transport. Both principal cells and beta-intercalated cells were found to have a basolateral Na+/H+ exchanger based on the Na+ and amiloride sensitivity of pHi recovery from acid loads. Intercalated cells demonstrated abrupt pHi changes with basolateral Cl- removal. alpha-intercalated cells alkalinized; beta-intercalated cells acidified. In the beta-intercalated cells, luminal Cl- removal blocked changes in pHi in response to changes in luminal HCO3- or peritubular Cl-, providing direct evidence for a luminal Cl-/HCO3- exchanger. In principal cells, brief removal of either peritubular or luminal Cl- resulted in no change in pHi; however, return of peritubular Cl- after prolonged removal resulted in a rapid fall in pHi consistent with a basolateral Cl-/HCO3- exchanger, which may be relatively inactive under baseline conditions. Therefore, Cl-/HCO3- exchange is present in all three cell types but varies in location and activity.

Publication types

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

MeSH terms

  • Amiloride / pharmacology
  • Animals
  • Carrier Proteins / metabolism
  • Chlorides / metabolism
  • Chlorides / pharmacology
  • Fluoresceins
  • Fluorescent Dyes
  • Homeostasis
  • Hydrogen-Ion Concentration
  • In Vitro Techniques
  • Kidney Cortex / drug effects
  • Kidney Cortex / physiology*
  • Kidney Tubules / physiology*
  • Kidney Tubules, Collecting / drug effects
  • Kidney Tubules, Collecting / physiology*
  • Kinetics
  • Nephrons / physiology
  • Perfusion
  • Rabbits
  • Sodium / pharmacology
  • Sodium-Hydrogen Exchangers


  • Carrier Proteins
  • Chlorides
  • Fluoresceins
  • Fluorescent Dyes
  • Sodium-Hydrogen Exchangers
  • Amiloride
  • 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein
  • Sodium