The effect of vasoactive intestinal polypeptide on meal-stimulated gastric acid secretion in man

The effect of vasoactive intestinal polypeptide (VIP) on meal-stimulated gastric acid secretion was studied in six healthy volunteers. Acid secretion was stimulated by instillation of a 10% solution of peptone, which was adjusted to pH 5.5, circulated through the stomach via a double-lumen gastric tube by a peristaltic pump. The acid secretion was estimated by continuous titration by a pH-stat. The subjects were studied twice on separate days, receiving an intravenous infusion of either VIP (1 microgram/kg/h) or saline. No effect on acid secretion was found. Mean serum gastrin concentration rose from 42 pmol/l to 150 pmol/l during meal stimulation and was unaffected by infusion of VIP. Plasma VIP concentration during infusion of saline was 6.8 pmol/l and during VIP infusion, 82.8 pmol/l. Plasma VIP concentration was unaffected by the peptone meal.