AJP - Gastrointestinal and Liver Physiology, Vol 239, Issue 4 247-G254, Copyright © 1980 by American Physiological Society
Secretory response of the rabbit pancreas to cholecystokinin stimulation
D. Iacino, G. A. Scheele and C. Liebow
To test the capability of the pancreas to change the proportions of
proteins secreted in response to acute stimulation, we examined the effect
of cholecystokinin-pancreozymin stimulation on the relative discharge of 16
radiolabeled secretory proteins from the in vitro rabbit pancreatic gland.
[35S]-methionine was added to the bathing medium 4 h prior to the
experimental period. Secretion was then collected from the pancreatic duct
for two 1-h basal periods and for two 20-min periods following stimulation
with 5.1 mM cholecystokinin. Proteins were separated by two-dimensional
isoelectric focusing/sodium dodecyl sulfate gradient gel electrophoresis,
and the proportion of each radiolabeled protein in the secretion was
determined in each period. Statistical analysis of the relative
distribution of radioactive proteins in secretion showed an increased
variability in the distribution of secreted proteins following stimulation
(P < 0.005). Procarboxypeptidase A, a protein tentatively identified as
an acidic form of chymotrypsinogen, and a basic form of chymotrypsinogen
were significantly more stimulated than the average radiolabeled protein by
25, 31, and 17%, respectively, whereas the acidic form of trypsinogen was
significantly less stimulated by 18%.
