Regulation of intracellular pH in the colonic epithelial cell line HT29 clone 19A

Intracellular pH (pHi) of the colonic tumor cell line HT29 cl. 19A was studied by microspectrofluorometry using the pH-sensitive dye BCECF. Single cells within a confluent monolayer grown in a polarized manner on permeable supports were examined. An amiloride-sensitive Na(+)-H+ exchange and a stilbene-insensitive Cl(-)-HCO3- exchange mechanism have been identified in the basolateral membrane. This Na(+)-H+ exchange mechanism in the basolateral membrane is an acid extruder, whereas the Cl(-)-HCO3- exchanger is an acid loader. Both of these in the basolateral membrane located mechanisms are important for the maintenance of intracellular pH in HT29 cl. 19A cells.