Stimulation of the Small Intestine by Nutrients in Relation to Phase of the Migrating Motor Complex

BACKGROUND: The relationship between the preceding phase of the migrating motor complex (MMC) and postprandial motility in the small intestine was studied. METHODS: In eight healthy subjects small-bowel manometry was performed, and a 55-ml caloric liquid bolus (280 kJ) containing paracetamol and 14C-D-xylose was instilled into the duodenum during phase I and late phase II of the intestinal MMC, respectively, in randomized order. Blood samples were drawn at regular intervals and analysed for insulin, gastrin, glucose, paracetamol, and 14C-D-xylose. RESULTS: After bolus administration during late phase II a phase-III-like activity succeeded by quiescence occurred in the duodenum in seven of eight subjects, whereas administration during phase I initiated irregular contractions in seven of eight subjects (P < 0.05). The caloric bolus induced a significant increase in serum insulin and gastrin. Areas under the curves for serum insulin, gastrin, glucose, paracetamol, and 14C-D-xylose were not modulated by the preceding phase of the MMC. CONCLUSIONS: The present study shows that a nutrient bolus instilled into the intestinal lumen induces MMC-like activity when administered during late phase II. These findings provide further evidence of interference between MMC and postprandial motility.