Inhibitory effect of neurotensin on pentagastrin-stimulated gastric acid secretion in pylorus-ligated rats.

Neurotensin is a known inhibitor of gastrin-stimulated acid secretion in dogs and humans. In order to study the dose-related effect of neurotensin, we prepared pentobarbital-anesthetized rats by pyloric ligation and collected gastric secretions one hour after injection of saline (Basal), pentagastrin, 6 micrograms/Kg subcutaneously (PG Alone), or pentagastrin plus neurotensin by tail vein injection (PG + NT). Acid output was calculated from the volume and pH of the samples, which correlated well with the output determined by titration with 0.02 N NaOH (r = 0.92). Basal output was 36 +/- 4 muEq/hr; stimulated output (PG Alone) was 64 +/- 5 muEq/hr, and output after PG + NT, 250 pmol/Kg, was 33 +/- 3 muEq/hr (p less than 0.001). The effect of neurotensin was dose-related over a range from 125 to 500 pmol/Kg. This technique may be useful in the biological evaluation of neurotensin-related peptides.