Effect of neurotensin on pancreatic and gastric secretion and growth in rats.

Plasma levels of neurotensin are increased by ingestion of fat, making this peptide a candidate for mediation of pancreatic adaptation to dietary fat. We examined the effects of doses of neurotensin on pancreatic secretion and growth to determine whether doses stimulating secretion also increased pancreatic growth and lipase content in rats. Because neurotensin inhibits gastric secretion in other species, we also measured its effects on gastric secretion and growth. In conscious rats, neurotensin (33, 100, and 300 micrograms kg-1 subcutaneously in gelatin) produced dose-related increases in pancreatic amylase output and decreases in basal gastric secretion. Duration of acid inhibition by neurotensin was longer than stimulation of amylase secretion. Chronic administration of the same doses of neurotensin to groups of rats every 8 h for 5 days produced small but statistically significant trophic effects on the pancreas. The highest dose of neurotensin significantly increased pancreatic weight (16%) and content of DNA (12%), protein (17%), and chymotrypsinogen (60%) but did not affect amylase or lipase content. There were no effects of neurotensin on any measurement of oxyntic or pyloric gland area growth. We conclude that although neurotensin stimulates both pancreatic secretion and growth, it is not the mediator of fat-induced pancreatic adaptation.