Some Properties Shared by Amino Acids and Entero-oxyntin

Abstract
The intestinal phase of gastric secretion is thought to be due to the release of a hormone from the gut mucosa, and several properties have been attributed to this as-yet unidentified hormone. An amino acid solution, known to stimulate gastric secretion, was tested to see if it possesses several of these properties, i.e., inactivation by the liver, and the ability to augment the maximum responses to pentagastrin and histamine. In 6 dogs with Heidenhain pouches the gastric secretory responses to peripheral and portal i.v. administration of a solution of mixed L-amino acids were measured. The mean peak response of 3 such separate peripheral infusions in each dog was 370 .mu.eq/30 min while the peak response to intraportal infusion was only 45 .mu.eq/30 min (P < .05). In 3 dogs with Heidenhain pouches the i.v. administration of amino acids together with pentagastrin resulted in significant augmentation of the peak response to pentagastrin alone (P < .025). Similarly, administration of amino acids with histamine resulted in augmentation of the peak response to histamine alone (P < .05). Because amino acids mimic the actions of the "intestinal phase hormone" in these respects it is suggested that they may account, at least in part, for the intestinal phase of gastric secretion. In addition, amino acids absorbed during protein digestion may contribute to the gastric hypersecretion which is regularly seen with portosystemic shunts.