The Effect of Intraduodenal Instillation of Oleic Acid on Plasma Neurotensin-like Immunoreactivity and on Gastric Acid Secretion Stimulated by Betazole and Sham Feeding in Man

Abstract

Intraduodenal administration of oleic acid has previously been shown to inhibit gastric acid secretion induced by pentagastrin in man. This inhibition was dose-dependent and significantly correlated to a rise in plasma concentration of neurotensin-like immunoreactivity (NTLI). Maximal inhibition occurred with a volume of oleic acid of 20 ml. In the present study intraduodenal instillation of 20 ml of oleic acid inhibited acid secretion evoked by sham feeding in healthy subjects but did not significantly inhibit the near-maximal acid secretion stimulated by the histamine analogue betazole. The inhibition of acid secretion induced by sham feeding was the same (about 45%) as the inhibition of pentagastrin-stimulated secretion. Plasma NTLI rose significantly in both the sham feeding and betazole experiments and peaked at about 145 pM. The results are in agreement with the inhibitory characteristics of neurotensin and support the hypothesis that the inhibition of gastric acid secretion by small amounts of intestinal fat is at least partly mediated by neurotensin.

Key-words:

• Betazole
• gastric acidity determination
• neurotensin
• oleic acid
• sham feeding