GASTRIN AND THE GROWTH OF THE GASTROINTESTINAL-TRACT

While the proliferative effects of gastrin in the gastric fundus are w ell established, there is a considerable degree of confusion regarding the role of gastrin on the growth of the small intestine and colon. T he hypothesis that gastrin is trophic throughout the gut was tested by giving three doses of pentagastrin and one of gastrin 17 to rats main tained by total parenteral nutrition (TPN). The rats were fed intraven ously for one week, with the various peptides added to the TPN diet. T he number of vincristine arrested metaphases per gland or crypt was th en scored to determine the proliferative state. Both gastrin 17 and pe ntagastrin were found to be trophic in the gastric fundus, but not to the gastric antrum. A proliferative response was also seen in the duod enum, but with Little evidence of a dose response element. No effect o n small bowel weight was seen, and no proliferative effect was noted i n the mid small bowel, thus the duodenal effect could be attributed to a local action of increased acid output on the duodenum, not a genera l role throughout the small intestine. No proliferative effects of pen tagastrin or gastrin were seen in the colon. It is therefore concluded that the trophic role of gastrin is restricted to the gastric fundus and the proximal duodenum.