Factors regulating amylase secretion from chicken pancreatic acini in vitro

In mammals, cholecystokinin regulates pancreatic exocrine secretion under physiological conditions. We have shown, however, that cholecystokinin at physiological concentrations does not induce pancreatic amylase secretion in birds. Therefore, we investigated the effects of various neurotransmitters and gut hormones on the pancreatic amylase secretory response in isolated chicken pancreatic acini. Acetylcholine (half-maximal stimulation at 800 nM) and vasoactive intestinal polypeptide (half-maximal stimulation at 40 pM) produced a concentration-dependent increase in amylase secretion at physiological concentrations. The combination of acetylcholine and vasoactive intestinal polypeptide produced an additive response in amylase secretion. Sodium nitroprusside, a spontaneous nitric oxide releaser, and bombesin, induced amylase secretion at concentrations greater than 10 nM and 100 nM, respectively. Gastrin and secretin increased amylase secretion at pharmacological concentrations (10 to 100 nM). Our findings suggest that neural regulation is important for pancreatic enzyme secretion in birds and the contribution of gut hormones seems to be physiologically unimportant.