Effects of erythromycin on plasma gastrin, somatostatin, and motilin levels in healthy volunteers and postoperative cancer patients

Erythromycin, an antibiotic agent, is known to be a motilin receptor agonist. Motilin is a peptide hormone that regulates gastric motility. One of the gastrointestinal motility regulatory factors has been assumed to be the induction of changes in the levels of peptides (gastrin, somatostatin and motilin) in plasma. We have elucidated the effects of erythromycin by examining changes in the plasma levels of gastroinitestinal peptides. In this study, we investigated the effects of erythromycin on the plasma levels of gastrointestinal peptides (somatostatin, motilin, and gastrin) in healthy volunteers and patients with delayed gastric emptying (DGE). After a single oral administration, erythromycin caused a significant increase in plasma gastrin-like immunoreactive substance (IS) levels at 60 min. But the agent did not alter the levels of somatostatin- and motilin-IS. DGE is the most frequent postoperative complication after pylorus-preserving pancreatoduodenectomy. Molitin is assumed to be one important factor that influences DGE. We also examined the effects of erythromycin on the plasma motilin-IS levels of postoperative patients. The plasma motilin-IS levels were increased after 1 week of oral administration of erythromycin compared with preadministration. These results suggest that the pharmacologic effects of erythromycin in promoting gastric emptying are closely related to changes in plasma motilin-IS levels.