The Effect of Subtotal Gastrectomy Upon External Pancreatic Secretion in Dogs

Abstract

The influence of gastric juice upon external secretion of the pancreas was first suggested by the classic work of Bayliss and Starling2, in which it was shown that dilute hydrochloric acid, introduced into the duodenum, is capable of provoking a pancreatic response. The mechanism of this ' reaction was shown to involve the release of a hormone, secretin, from the duodenal mucosa into the blood stream, which conveys it to the pancreas. The same observers reported that the more proximal portions of the small intestine (i.e., duodenum and upper jejunum) contain larger quantities of secretin than its more distal segments, and extracts of mucosa from the terminal ileum evoked no pancreatic response at all. Purified secretin, on injection, stimulates the secretion of water and bicarbonate, but the output of enzymes is relatively low. Secretion of the pancreatic enzymes depends either upon stimulation by way of the vagus nerves3, or upon another hormone, pancreozymin, which is elaborated in the intestinal mucosa • Clinical interest in the secretin mechanism of pancreatic secretion has recently been enhanced by the observation that acute inflammatory disease of the pancreas may be produced by voluminous pancreatic secretion in the presence of obstructed pancreatic ducts5• 6. As a result, attempts have been made to lessen the daily output of pancreatic juice in patients with acute pancreatitis by gastric aspiration7 and administration of anti-cholinergic drugs such as Banthine8, the rationale being to reduce the amount of gastric acid entering the duodenum, and thus minimize stimulation by secretin. With similar reasoning, chronic pancreatitis has been treated by subtotal gastrectomy9. However, a recent report of ThistlethwaitelO on the effect of subtotal gastrectomy upon pancreatic secretion in dogs indicates that the influence of this operation is variable. In spite of this report it seems reasonable to suppose that some change in pancreatic response must be expected as a result of the decrease in acidity and the diversion of gastric chyme which accompanies the operation. In fact, Annis and Hallenbeckll have shown a decisive reduction in the pancreatic response to food following subtotal gastrectomy. Accordingly, to clarify this point effectively, a project * Submitted for publication Nov. 11, 1953. A preliminary report of this work was presented before the Clinical Research Forum of the N. Y. Academy of Medicine, April 23, 1952, (1). This work was supported in part by grants from the Altman Foundation and Wyeth, Inc.