Role of vagus nerve in secretion of gastric inhibitory polypeptide in dogs.

In order to clarify the role of the vagus nerve in the secretion of gastric inhibitory polypeptide (GIP), experiments were performed on dogs. Response of plasma GIP to intraduodenal instillation of glucose was slightly lower in a group which received atropine, than in a group of normal dogs. The response of plasma GIP to intraduodenal glucose load was not different between vagotomized dogs and normal dogs. Electric stimulation of the vagus nerve did not produce any significant changes in plasma GIP in anesthetized dogs. In conclusion, the present study indicates that the role of the vagus nerve on GIP secretion is tiny, if any, and that the nervous influence does not overcome the effect of intraluminal administration of glucose.