The pancreatic duct mucosal barrier.

The main pancreatic duct in cats possesses a relatively strong barrier to the diffusion of bicarbonate ions (HCO3-). We studied some of the characteristics of this barrier by perfusing the duct with a solution similar in composition to pancreatic juice before and after exposing the duct mucosa to various test agents. The difference in net flux of HCO3- across the duct before and after exposure to the test agent reflected damage to the barrier. The barrier was damaged by infected bile, aspirin (pH 2.3), hydrochloric acid (pH 2.3), ethanol (5 to 10 per cent), and secondary bile acids. It was not damged by sterile bile, aspirin (pH 6.5), and primary bile acids. These data indicate that the barrier to back diffusion in the pancreatic duct has unique properties, different in some respects from the properties of the gastric mucosal barrier. Furthermore, the barrier is vulnerable to some agents thought possibly to have a role in the pathogenesis of pancreatitis and pancreatic cancer.