Changes in plasma pancreatic polypeptide and gastrin in sows after eating and atropine

Changes in plasma gastrin, pancreatic polypeptide and pulse rate were examined in three adult female pigs in which venous cannulae had been placed and in two of which arterial cannulae allowed sampling of arterial blood or recording of pulse rate. Gastrin, pancreatic polypeptide and pulse rate increased when the pigs ate after fasting overnight. Pancreatic polypeptide was reduced to or below resting levels following administration of atropine (25, 50 or 100 micrograms/kg intravenously) after which gastrin remained at about its previous levels or rose and pulse rates rose. It is concluded that in the pig, as in other species, there is a cholinergic muscarinic (atropine sensitive) mechanism contributing both to postprandial increases of pancreatic polypeptide and of gastrin.