Effect of secretagogues on pancreatic exocrine secretion in the monkey and the dog

The effects of secretin, cholecystokinin, dopamine, histamine and acetylcholine on the secretion of pancreatic juice were investigated in the monkey and the dog. In the resting state, bicarbonate concentration and the volume of pancreatic juice in the monkey were greater than those in the dog. However, the protein concentration of pancreatic juice in the monkey was less than that in the dog. Intravenous administration of secretin, cholecystokinin, histamine and acetylcholine caused a dose dependent increase in pancreatic secretion in both species. The responses in the monkey were greater than those in the dog. Dopamine caused pancreatic secretion only in the dog. The increase in bicarbonate concentrations of pancreatic juice induced by secretin and histamine in the monkey were greater than that in the dog. Increase in protein concentrations of the juice induced by cholecystokinin and acetylcholine in the monkey were less than that in the dog. However, pancreatic juice pH in both species was the same and was not affected by the secretagogues in the resting state or during the stimulation by secretogogues. From these results, it is concluded that there is a species difference in the secretory actions of the secretagogues in the monkey and the dog.