AJP - Gastrointestinal and Liver Physiology, Vol 251, Issue 4 475-G480, Copyright © 1986 by American Physiological Society
Fate of pancreatic enzymes during small intestinal aboral transit in humans
P. Layer, V. L. Go and E. P. DiMagno
To determine survival of pancreatic enzymes during small intestinal aboral
transit in humans, seven healthy volunteers were intubated with an oroileal
tube. By using nonabsorbable markers we measured the cumulative amount of
lipase, trypsin, and amylase activities and lipase and trypsin
immunoreactivities delivered postprandially to the duodenum, midjejunum,
and terminal ileum. We found that as the enzymes moved from duodenum to
ileum, 74% of amylase activity, 22% of trypsin activity, and 1% of lipase
activity survived transit. Enzymatic activity and immunoreactivity of
trypsin and lipase disappeared at different rates, suggesting that for
these enzymes the sites of enzymatic activity and immunorecognition are not
identical. Since tryptic activity is present even in the absence of
immunorecognizable trypsin, complete structural integrity of the trypsin
molecule may not be essential for its enzymatic activity. The short
intraluminal survival of lipolytic activity may partially explain why
patients with progressive exocrine pancreatic insufficiency malabsorb fat
earlier than other nutrients.
