Concentrations of Gastrin and Secretin in the Alimentary Tract of the Cat

The distribution of gastrin and secretin in the alimentary tract of the cat was determined from the esophagogastric junction to the ileocecum. The total content and concentration of each of these hormones in mucosal extracts taken from the gastric fundus, gastric antrum, proximal and distal duodenum, proximal and distal jejunum, and ileum were measured with specific radioimmunoassays. The gastric antrum contained the highest concentration of gastrin, but appreciable amounts also were found in the duodenum. The highest concentrations of secretin were found in the duodenum, but impressive quantities were measured in the jejunum. The role of extra-antral gastrin and of those stores of secretin beyond the proximal duodenum (where the pH probably never falls to levels associated with release of secretin) currently are unknown.