Ductal Bicarbonate Secretion in Human Cholestatic Liver Diseases
Primary bile is formed by the secretion to the canalicular lumen of biliary lipids, organic anions, glutathione, ions and water. In humans secretin is the main physiological stimulant of ductular secretion. In the late forties Grossman et al demonstrated that the hormone increases ductular bile flow with formation of low viscosity bile. One decade later Waitman and coworkers showed that secretin induced choleresis in association with reciprocal changes in biliary concentration of chloride and bicarbonate resulting in the generation of a bicarbonate-rich bile. During the last years important progress in the field of biliary physiology lead to the identification of a number of cholangiocyte receptors, transporters and channels participating in the generation of hydroionic fluxes to bile. Cholestatic syndromes such as primary biliary cirrhosis, primary sclerosing cholangitis, retention of bile constituents and immuno-inflammatory injury of bile ducts.