motilin

Motilin is the gut’s “housekeeping” hormone, active mostly between meals. During fasting it triggers strong, sweeping waves of intestinal contraction that act like a janitor, clearing out leftover food, debris, and bacteria to keep the gut clean and ready for the next meal.

Motilin is a peptide hormone released by cells in the upper small intestine during the fasting state, when the gut is empty. It drives the migrating motor complex — recurring waves of muscular contraction that sweep from the stomach down the small intestine roughly every 90 to 120 minutes between meals. Eating interrupts this pattern, replacing it with the slower mixing movements of digestion.

Motilin has a notable clinical twist: the antibiotic erythromycin happens to activate the motilin receptor strongly. Because of this, low-dose erythromycin is sometimes used not as an antibiotic but as a prokinetic drug to stimulate stomach emptying in people with gastroparesis (a sluggish, poorly emptying stomach).