Inhibition of rat pancreatic secretion by neurotensin: mechanism of action.

The effect of neurotensin on rat pancreatic secretion was studied in the conscious animal as well as on pancreatic lobules. In vivo neurotensin induced a dose-related inhibition of both water and protein basal secretion. Protein secretion was much more depressed than fluid secretion. Neurotensin did not modify the pancreatic response to exogenous secretin or cholecystokinin-pancreozymin, or to intraduodenal infusion of HCl. On the other hand neurotensin totally inhibited the increase in volume as well as in protein output to an intraduodenal infusion of oleic acid, but did not change the delayed inhibitory effect on protein output. In vitro, neurotensin did not affect basal and cholecystokinin stimulated pancreatic secretion. These results indicate that: 1) neurotensin could interfere with the release of hormones from the gut (cholecystokinin, and possibly VIP), 2) neurotensin did not mimic the delayed protein inhibitory effect observed after administration of oleic acid.