Mechanism of Pancreatic Secretion

Abstract

In a series of experiments performed on cats anesthetized by ure-thane, Mellanby 1 found that the introduction of bile of the proper reaction into the duodenum caused a copious secretion of pancreatic juice. The activity of the bile was found to be due to cholic acid and its compounds. The interpretation suggested was that the bile salts in the duodenum become associated with and make possible the absorption of secretin into the portal blood, and that this event rather than the passage of acid from the stomach is responsible for pancreatic secretion. It would seem to follow, if this theory were true, that the removal of bile from the intestine would check or greatly decrease the secretion of pancreatic juice. To determine this point, pancreatic and biliary fistulae were prepared in each of 2 dogs. The method has been previously described (Dragstedt, Montgomery, and Ellis 2 ), and permits the quantitative collection of each secretion during an entire 24 hour period or for several days. In the first test animal I secreted 4609 cc. of pancreatic juice and 692 cc. of bile in 6 days, when practically all of the bile and pancreatic juice was returned to the alimentary tract. During the succeeding 6 days no bile was returned and 5998 cc. of pancreatic juice and 416 cc. of bile were secreted. In the second test 3971 cc. of pancreatic juice and 752 cc. of bile were secreted in 6 days when both secretions were returned to the stomach whereas in the succeeding 6 days when only the pancreatic juice was returned, 4688 cc. of pancreatic juice and 426 cc. of bile were secreted. The results obtained with animal 2 were essentially similar. In each case the dog secreted a little more pancreatic juice when no bile was present in the intestine than when it was returned by mouth.

It seems quite definite, therefore, that, in the dog at least, bile salts cannot be considered essential either for the activation of pancreatic secretin or for its passage into the blood in effective form.