Regulation of cholangiocyte bicarbonate secretion

The objective of this review article is to discuss the role of secretin and its receptor in the regulation of the secretory activity of intrahepatic b ile duct epithelial cells (i.e., cholangiocytes). After a brief overview of cholangiocyte functions, we provide an historical background for the role of secretin and its receptor in the regulation of ductal secretion. We revi ew the newly developed experimental in vivo and in vitro tools, which lead to understanding of the mechanisms of secretin regulation of cholangiocyte functions. After a description of the intracellular mechanisms by which sec retin stimulates ductal secretion, we discuss the heterogeneous responses o f different-sized intrahepatic bile ducts to gastrointestinal hormones. Fur thermore, we outline the role of a number of cooperative factors (e.g., ner ves, alkaline phosphatase, gastrointestinal hormones, neuropeptides, and bi le acids) in the regulation of secretin-stimulated ductal secretion. Finall y, we discuss other factors that may also play an important role in the reg ulation of secretin-stimulated ductal secretion.