Mechanisms for postprandial release of motilin in humans

Abstract

Plasma concentrations of motilin rise in the first 30 min following the ingestion of a meal in man. To elucidate the mechanisms of this postprandial motilin release, we verified the effect of cerebral stimulation and of gastric distension, both events normally occurring in the early postprandial period, on plasma motilin concentrations. Cerebral stimulation was induced by modified sham feeding (MSF) and gastric distension was done by inflating (with 0, 60, 240, or 480 cc of air) a latex balloon positioned in the gastric fundus. The experiments were performed in healthy volunteers where antroduodenal contractile activity was continuously recorded and where plasma motilin was measured each 10 min. The stimuli were administered 30 min after a phase III of the migrating motor complex (MMC) was seen migrating from the antrum to the duodenum. The interval period between two successive spontaneous peak increases in plasma motilin was estimated at 113.7 +/- 8.5 min in 24 historical control subjects, and it lasted 97 +/- 13 min in the five control volunteers here distended with 0 cc of air (P = NS). This interval was significantly (P < 0.05) shortened with MSF (70 +/- 6.3 min) or following distension with 60 cc (60 +/- 11.4 min), 240 cc (54 +/- 1.9 min) or 480 cc of air (45 +/- 3.2 min). During the 60-min period following the administration of the stimuli, phase IIIs were not seen in the subjects distended with 0 cc of air or in those submitted to MSF.(ABSTRACT TRUNCATED AT 250 WORDS)

High interdigestive and postprandial motilin levels in patients with the irritable bowel syndrome

“…More specifically, it peaks before the onset of activity fronts that starts in the antrum, 11,13 and infusion of motilin can induce activity fronts 10 . It is also released after meal intake, but its role in the postprandial motility is less clear 26,27 . Another effect of motilin in the upper GI tract is to stimulate gallbladder emptying 28 .…”

Acute intraduodenal bile salt depletion leads to strong gallbladder contraction, altered antroduodenal motility and high plasma motilin levels in humans

“…It is theoretically possible that in the present study, early antral distension by the cholestyramine‐containing solution might have initiated motilin release and gallbladder contraction. Others have shown that balloon‐induced distension of the gastric fundus could release plasma motilin 32 . However, the fact that intraduodenal cholestyramine administration also greatly enhances gallbladder contraction and pancreatic secretion without significant CCK release, 2 argues against this possibility.…”

Motilin in human milk and its elevated plasma concentration in lactating women

“…It is well known that the circulating concentration of motilin in blood exhibits a cyclic variation that correlates with changes in duodenal motility. It has been demonstrated that the peak of plasma motilin corresponds to the onset of duodenal phase III activity in the fasting state in animals as well as in humans 16–17 . Because the cycle of motilin release is associated with the cycle of interdigestive motility, great variation in the cycle of motilin release is therefore expected among subjects, as well as within an individual subject.…”

“…We speculate that the lack of correlation between the motilin level in the blood and milk might be attributed to the following factors: (i) the time difference in reflecting postprandial peak levels of motilin in plasma and milk. The motilin level measured in the postprandial state was attributed to a baseline level plus a postprandial increase that peaks at 30 min after the meal 17 . It takes time for motilin to be secreted into milk and this postprandial increase in motilin was therefore not reflected in milk at the time of measurement; and (ii) the difference in half‐life time of motilin in milk and plasma.…”

“…It has been demonstrated that the peak of plasma motilin corresponds to the onset of duodenal phase III activity in the fasting state in animals as well as in humans. [16][17] Because the cycle of motilin release is associated with the cycle of interdigestive motility, great variation in the cycle of motilin release is therefore expected among subjects, as well as within an individual subject. To avoid such a variation in the motilin level in the fasting state, the specimens in the current study were taken 30 min after a standard meal.…”