Effect of motilin on the rate of gastric emptying and gut hormone release during breakfast.

The effect of an infusion of natural motilin on the rate of gastric emptying of a standard breakfast was studied in 5 subjects using Caesium 129-tagged resin particles. Emptying rates were measured on 4 separate days. On 2 days, the subjects receive only saline (controls), while on the other 2 days a motilin infusion of 0.34 pmol/kg/min for 60 min, followed by 0.68 pmol/kg/min for 60 min, was given. All infusions were blind and given in random order. At the end of the low-dose motilin infusion 31 +/- 4% of the meal had emptied, compared with 17 +/- 2% with saline infusion (P less than 0.01). A similar effect was also seen with the high-dose infusion. Plasma motilin concentrations rose from a basal of 68 +/- 13 pmol/liter to 126 +/- 10 pmol/liter during low-dose motilin infusion and to 170 +/- 11 pmol/liter during the high dose. No significant change in basal or postprandial levels of glucose, gastrin, pancreatic glucagon, pancreatic polypeptide, gastric inhibitory peptide, enteroglucagon, or vasoactive intestinal peptide was noted, but postprandial insulin release was greater during motilin infusion.