AJP - Gastrointestinal and Liver Physiology, Vol 246, Issue 4 445-G450, Copyright © 1984 by American Physiological Society
Regulation of digestion. I. Effects of glucose and lysine on pancreatic secretion
J. H. Grendell, H. C. Tseng and S. S. Rothman
Previous cell-free studies have shown that glucose selectively elicits the
release of amylase from pancreatic zymogen granules, whereas lysine
promotes the selective release of trypsinogen. To investigate the
expression of these effects in situ, glucose or lysine was injected into
the celiac artery of anesthetized rats, either alone or together with the
pancreatic secretagogue cholecystokinin, to evaluate their effects on the
secretion of amylase and trypsinogen by the pancreas. When given alone
neither substance significantly changed the output of either enzyme.
However, when given with cholecystokinin, each altered the effect observed
with injection of cholecystokinin alone. The injection of glucose resulted
in a twofold increase in both peak and total amylase output without
significantly increasing trypsinogen secretion, whereas lysine increased
both peak and total trypsinogen output by about 50%, leaving amylase output
unchanged. These findings provide in situ confirmation for the selective
enzyme release produced by glucose and lysine in cell-free studies and
suggest that such end products of digestion can regulate the digestive
process by modifying the secretory response of the pancreas to
cholecystokinin.
