Gastrin receptors in the human gastrointestinal tract and pancreas.

The specific binding of 125I-labeled gastrin-17 was studied in samples of human gastric mucosa, duodenal mucosa, colonic mucosa or pancreatic tissue obtained surgically. With regard to gastric fundic mucosa, the criteria for receptor binding were studied, and saturability, high affinity, tissue specificity and hormone specificity were demonstrated. The dissociation constant for gastric fundic mucosa was 1.6 X 10(-9)M, and the binding capacity was 15 fmol/mg protein. Tissue specificity studies revealed a high degree of gastrin receptor binding in human gastric fundic mucosa, duodenal mucosa and pancreas, whereas antral mucosa and colonic mucosa demonstrated a low degree of binding.