NEUROTENSIN AND OXYNTOMODULIN-(30-37) POTENTIATE PYY REGULATION OF GASTRIC-ACID AND SOMATOSTATIN SECRETIONS

The present study was designed to investigate, in cats provided with both a gastric fistula and a denervated fundic Heidenhain pouch, the effect of peptide YY (PYY) on pentagastrin-stimulated gastric acid and somatostatin secretions and to determine whether neurotensin (NT) and the COOH-terminal octapeptide of oxyntomodulin [Oxm-(30-37)] would modify these secretions. Intravenous infusion of PYY (0.1 nmol.kg-1.h-1), NT (15 nmol.kg-1.h-1), or Oxm-(30-37) (60 nmol.kg-1.h-1) did not affect basal acid secretion. However, they significantly inhibited pentagastrin-stimulated gastric acid output up to 50% (P < 0.01) in the main stomach. Furthermore, they significantly increased gastric somatostatin release by +750, +1,700, and +600% over basal level (P < 0.01) for (in nmol.kg-1.h-1) 0.1 PYY, 15 NT, and 60 Oxm-(30-37), respectively. On the other hand, the effects of 0.1 nmol.kg-I -h-1 PYY were potentiated by subthreshold doses of NT (5 nmol.kg-1.h-1) or Oxm-(30-37) (15 nmol.kg-1.h-1). These findings suggest that there could be a cooperation between the three peptides in the intestinal regulation of gastric secretions.