GLUTATHIONE PERMEABILITY OF CFTR

The cystic fibrosis transmembrane conductance regulator (CFTR) forms a n ion channel that is permeable both to Cl- and to larger organic anio ns. Here we show, using macroscopic current recording from excised mem brane patches, that the anionic antioxidant tripeptide glutathione is permeant in the CFTR channel. This permeability may account for the hi gh concentrations of glutathione that have been measured in the surfac e fluid that coats airway epithelial cells. Furthermore, loss of this pathway for glutathione transport may contribute to the reduced levels of glutathione observed in airway surface fluid of cystic fibrosis pa tients, which has been suggested to contribute to the oxidative stress observed in the lung in cystic fibrosis. We suggest that release of g lutathione into airway surface fluid may be a novel function of CFTR.