Furthermore, GPs still stimulate bicarbonate secretion in CFTR-deficient mice, and recently Slc26a4 (pendrin) was suggested as target for UGN-dependent chloride transport in intercalated cells of kidney cortical collecting duct suggesting the existence of CFTR-independent signaling pathway for GPs in cystic fibrosis patients [64]. This evidence concerns the gene SLC26A4 and cystic fibrosis.