AJP - Gastrointestinal and Liver Physiology, Vol 242, Issue 3 215-G221, Copyright © 1982 by American Physiological Society
Effect of fasting and refeeding on pancreatic enzymes and secretagogue responsiveness in rats
P. C. Lee, S. Brooks and E. Lebenthal
Fasting reduced amylase and increased lipase concentrations but did not
affect trypsinogen concentrations in the adult rat pancreas. Fasting also
decreased the pancreatic contents of trypsinogen and amylase. A decrease in
the responsiveness of dispersed pancreatic acini to carbachol was evident
after 3 days of fasting but only at high concentrations of secretagogues.
Acini regained their responsiveness, and enzyme concentrations returned to
normal after refeeding. Serum insulin levels of fasted rats decreased to
one-fourth of control levels but rose to normal 24 h after refeeding.
Insulin or glucose given alone prevented the increase in lipase after
fasting. Both insulin and glucose were needed to maintain the acinar
response to secretagogues in fasted rats. Although cholecystokinin restored
the protein and trypsinogen content in fasted rats, it did not correct the
relative changes in the exocrine enzymes. There are therefore reversible
changes in the exocrine pancreas after fasting. Insulin, glucose, and
cholecystokinin seem to regulate these changes.
