DISTRIBUTION AND LOCALIZATION OF A NOVEL CHOLECYSTOKININ-RELEASING FACTOR IN THE RAT GASTROINTESTINAL-TRACT

The purpose of this study was to examine the distribution and localiza tion of an intestinal cholecystokinin (CCK)-releasing factor, called l uminal CCK-releasing factor (LCRF), in the gastrointestinal tract and pancreas of the rat. RIA analysis indicates that LCRF immunoreactivity is found throughout the gut including the pancreas, stomach, duodenum , jejunum, ileum, and colon with the highest levels in the small intes tine. Immunohistochemistry analysis shows LCRF immunoreactivity Staini ng in intestinal villi, Brunner's glands of the duodenum, the duodenal myenteric plexus, gastric pits, pancreatic ductules, and pancreatic i slets. These results indicate potential sources for secretagogue-stimu lated release of luminal LCRF and support the hypothesis that LCRF is secreted into the intestinal lumen to stimulate CCK release from mucos al CCK cells.