Development and characterization of secretin-stimulated secretion of cultured rat cholangiocytes

We sought to develop a cholangiocyte cell culture system that has preservation of receptors, transporters, and channels involved in secretin-induced secretion. Isolated bile duct fragments, obtained by enzyme perfusion of normal rat liver, were seeded on collagen and maintained in culture up to 18 wk. Cholangiocyte purity was assessed by staining for gamma-glutamyl transpeptidase (gamma-GT) and cytokeratin-19 (CK-19). We determined gene expression for secretin receptor (SR), cystic fibrosis transmembrane conductance regulator, Cl-/HCO3- exchanger, secretin-stimulated cAMP synthesis, Cl-/HCO3 exchanger activity, secretin-stimulated Cl- efflux, and apical membrane-directed secretion in polarized cells grown on tissue culture inserts. Cultured cholangiocytes were all gamma-GT and CK-19 positive. The cells expressed SR and Cl-/ HCO3- exchanger, and secretin-stimulated cAMP synthesis, Cl-/ HCO3- exchanger activity, and Cl- efflux were similar to freshly isolated cholangiocytes. Forskolin (10(-4) M) induced fluid accumulation in the apical chamber of tissue culture inserts. In conclusion, we have developed a novel cholangiocyte line that has persistent HCO3-, Cl-, and fluid transport functions. This cell system should be useful to investigators who study cholangiocyte secretion.