Kw. Simpson et al., CELLULAR-LOCALIZATION AND HORMONAL-REGULATION OF PANCREATIC INTRINSIC-FACTOR SECRETION IN DOGS, The American journal of physiology, 265(1), 1993, pp. 70000178-70000188
Gastric mucosal cells are considered to be the principal site of intri
nsic factor (IF) production in most mammals. Recent observations in do
gs suggest that the pancreas is the major site of IF production in thi
s species. The present study was undertaken to determine the cellular
origins of canine pancreatic IF by combining in situ hybridization wit
h immunocytochemistry and to examine the potential role of physiologic
al pancreatic secretagogues, cholecystokinin octapeptide (CCK-8) and s
ecretin, as mediators of canine pancreatic IF secretion. A human IF cD
NA probe (J. Hewitt et al., Genomics 10: 432-440, 1991), validated for
use in the dog, identified IF mRNA in parietal cells in the gastric f
undus, gastric gland cells in the pyloric antrum, and in secretory duc
t cells of the pancreas. Immunocytochemistry using antibody against ra
t IF confirmed that these cells, as well as secretory ducts of salivar
y glands, synthesized an immunoreactive protein. In stimulated secreti
ons of anesthetized dogs, mean 45-min outputs of IF, haptocorrin, and
trypsinogen were 13-, 8-, and 16-fold greater during stimulation with
CCK-8 than with secretin. No synergistic effects of combined stimulati
on were observed for IF or haptocorrin, although a synergistic effect
was observed for trypsinogen. These findings demonstrate that IF is sy
nthesized in the canine stomach, pancreas, and probably salivary gland
s and that CCK-8 mediates IF secretion from pancreatic duct cells.