The intestinal phase of gastric secretion refers to the fact that gastric secretion is stimulated under certain circumstances by the introduction of food into the upper portions of the small intestine. This stimulation seems to be mediated by a humoral agent, since it is exhibited by the vagus-denervated total stomach pouch or the Heidenhain pouch. The most satisfactory demonstration of the intestinal phase of secretion is made using a vagus-denervated total stomach pouch. During fasting such a pouch secretes little or no acid but secretes moderate amounts of gastric juice in response to food taking. Under these conditions, food that has not been acidified by mixture with the gastric content is the stimulating agent. This fact is of great significance, since it is now well established that the introduction of acid solutions into the duodenum inhibits gastric secretion, probably by means of an inhibitory hormone released from the duodenal mucosa.
Dragstedt LR. The Intestinal Phase of Gastric Secretion. AMA Arch Surg. 1959;78(3):498-499. doi:10.1001/archsurg.1959.04320030142024