Effect of intravenous and intrajejunal fat infusion on gastric acid secretion and plasma neurotensin-like immunoreactivity in man.

The effects of intrajejunal and intravenous infusion of fat (100 ml Intralipid 20%) on pentagastrin-stimulated gastric acid secretion and on the concentrations of plasma neurotensin-like immunoreactivity (p-NTLI) were studied in eight healthy subjects. Gastric acid secretion was studied for a 1.5-h period at 15-min intervals after fat administration. Acid secretion was reduced by 58% and 36%, respectively, after intrajejunal and intravenous administration. The concentration of p-NTLI rose significantly from 29 to 177 pmol/l at 45 min after intrajejunal administration but did not change after intravenous infusion. The results indicate that large volumes of fat inhibit gastric acid secretion by a neurotensin-independent postabsorptive mechanism and by an intestinal mechanism that may in part be mediated by neurotensin.