Trophic effect of truncal vagotomy on the rat pancreas

The trophic effect of truncal vagotomy was studied in rats. Three months after vagotomy and pyloroplasty pancreatic weight was significantly increased by 40% (p less than 0.001). Gastric stasis and consecutive distension of the stomach was observed in the majority of vagotomized animals despite pyloroplasty; the trophic effect of vagotomy on the pancreas was most pronounced in animals with severe stomach distension. Basal gastrin levels were increased after truncal vagotomy but did not correlate to gastric stasis and to the hypertrophy and hyperplasia of the exocrine pancreas. Basal pancreatic polypeptide hexapeptide levels were not altered after vagotomy. Morphometric studies on the endocrine pancreatic tissue showed that the relative volume density decreased due to the increase in exocrine tissue. However, the total islet cell mass remained constant. It is concluded that chronic truncal vagotomy has a trophic effect on the exocrine but not on the endocrine pancreas; additional factors besides gastrin seem to be responsible for this.