1. The effects of glucagon on the secretion of pancreatic juice were investigated using blood-perfused canine pancreas preparations. 2. Intravenous administration of glucagon (3-30 mug/kg) to the donor dog elicited a dose-dependent increase in pancreatic secretion. Intra-arterial administration of glucagon (10-100 mug) into the perfused pancreas also elicited increased secretion. 3. There were slight increases in amylase concentration of the pancreatic juice with the largest doses of glucagon given by either route. 4. Glucagon-induced secretion was not modified by treatment with phentolamine, propranolol, atropine, guanethidine, tetradotoxin, haloperidol, prostaglandin F2alpha or calcitonin. 5. The results suggest that glucagon acts directly on the exocrine cells of the canine pancreas.

Amylases↗

PubMedDate not supplied

Effects of calcitonin on the secretion of pancreatic juice induced by dopamine, secretin and pancreozymin.

1. Effects of calcitonin on dopamine-, secretin- and pancreozymin-induced pancreatic secretion were investigated in the isolated blood-perfused canine pancreas. 2. The volume of pancreatic secretion induced by pancreozymin given intra-arterially (i.a.) was decreased by an i.a. infusion of 1 u/min of calcitonin, but that induced by dopamine or secretin given i.a. was not affected by calcitonin treatment. 3. Amylase concentration in pancreatic juice either in spontaneous secretion in the resting state or in that of stimulated secretion by pancreozymin was decreased approximately 30% by calcitonin treatment, but amylase concentration in pancreatic juice induced by dopamine or secretin was not affected by calcitonin treatment. 4. Calcitonin had no effect on bicarbonate concentration in pancreatic juice stimulated by these secretagogues. 5. Calcium concentration in pancreatic juice in the resting state was reduced about 36% by calcitonin treatment. Calcitonin caused a decrease in a calcium concentration in the pancreozymin-induced secretion, but did not cause any change in the dopamine- or secretin-induced one. 6. These results suggest that calcitonin may affect the secretory mechanism of the acinar cells but not that of the ductular cells, and that the acinar cells are active even in the resting state.

Amylases↗

PubMedDate not supplied

Effects of 2-nicotinamidoethyl nitrate (SG-75) on pancreatic secretion in the isolated, blood-perfused pancreas of the dog.

1. The effects of 2-nicotinamidoethyl nitrate (SG-75) on the secretion of pancreatic juice were compared with those of acetylcholine, secretin and pancreozymin in the isolated, blood-perfused dog pancreas. 2. Intra-arterial administration of SG-75 (0.3-3 mg) elicited a dose-dependent increase in pancreatic secretion. Acetylcholine (10-100 micrograms), secretin (0.03-0.3 units) and in pancreozymin (0.1-1.0 units) also elicited increased secretion. 3. Secretory responses to acetylcholine were inhibited by treatment with atropine, while SG-75-, secretin-, and pancreozymin-induced secretions were not modified. 4. Bicarbonate concentrations in pancreatic juice induced by SG-75 and secretin were increased in a dose-dependent manner. However, there were slight changes with acetylcholine or pancreozymin. 5. Amylase activity in pancreatic juice was increased by SG-75, acetylcholine and pancreozymin, but was decreased by secretin. 6. These results suggest that SG-75 stimulates pancreatic secretion by acting both on the acinar and ductular cells of the dog pancreas.

Acetylcholine↗

PubMedDate not supplied

Effects of verapamil on pancreatic exocrine secretion induced by dopamine, secretin and pancreozymin in the dog.

1. The effects of verapamil on dopamine-, secretin- and pancreozymin-induced pancreatic secretion were investigated in the isolated, blood-perfused canine pancreas in vivo. 2. The volume of pancreatic secretion either in the resting state or induced by pancreozymin given intra-arterially (i.a.) was decreased by an infusion of 5 micrograms/min of verapamil; that induced by dopamine or secretin i.a. was also decreased but the changes were not statistically significant. 3. Protein concentration in pancreatic juice either in the resting state or in that of stimulated secretion by pancreozymin was decreased significantly, but protein concentration induced by dopamine or secretin was not affected, by verapamil treatment. 4. Verapamil had no effect on bicarbonate concentration in pancreatic juice secreted either in the resting state or when stimulated by these secretagogues.5. These results suggest that verapamil, at least in part, may affect the secretory mechanisms of acinar cells but not that of the ductular cells.

Animals↗

PubMedDate not supplied

Effects of prostacyclin and prostaglandin E2 on the secretion of pancreatic juice in the dog.

1. Effects of prostacyclin (PGI2) and prostaglandin E2 (PGE2) on the secretion of pancreatic juice were investigated in preparations of the blood-perfused canine pancreas. 2. PGI2 did not affect the basal or secretin-induced pancreatic secretion. However, PGE2 caused a dose-related inhibition of the secretin-induced secretion not only in preparations of the constant pressure perfusion but also of the constant flow perfusion. 3. These results suggest that PGE2, but not PGI2, may control the secretory mechanism of the pancreatic secretion in dogs.

Animals↗