In the absence of nutrients, pancreatic-biliary secretions in the jejunum do not exert feedback control of human pancreatic or gastric function

Feedback inhibition of basal pancreatic enzyme secretion by luminal pancreatic enzymes appears to be an important regulator of pancreatic secretion in some laboratory animals. To determine whether pancreatic enzymes in the jejunum influence pancreatic or gastric functions in healthy man, we intubated six subjects with a gastric sump tube and a four-lumen duodenal tube which provided (1) a duodenal perfusion site, (2) a duodenal aspiration site, (3) an inflatable balloon immediately distal to the aspiration site, and (4) a jejunal perfusion site immediately beyond the balloon. In this way, the gastroduodenal segment could be functionally separated from the remainder of the intestine. The jejunum was exposed to normal saline, active pancreatic-biliary secretions, or pancreatic-biliary secretions in which the enzymes had been inactivated by heat. Ten minutes after initiation of each jejunal perfusion, normal saline was instilled into the stomach. No differences in trypsin secretion, gastric acid secretion, or gastric emptying occurred with the different jejunal perfusates. We therefore conclude that normal man, in the absence of intraluminal nutrients, does not exhibit a jejunal pancreatic enzyme-dependent feedback control mechanism for pancreatic enzyme or gastric secretion. However, our study does not exclude the possibility of a duodenal feedback regulatory mechanism.