Serotonin and the Dumping Syndrome

Recent evidence indicates that a humoral factor may be involved in the etiology of the dumping syndrome. The similarities between the symptoms of the dumping complex and those of hyperserotonemia have led to investigations designed to determine whether increased release or formation of serotonin may be involved in the pathophysiology of the dumping syndrome. Increased portal-vein serotonin levels have been demonstrated after hypertonic stimulation of proximal small bowel in dogs.¹ Although altered serotonin levels in human dumping syndrome have been reported,² the serotonin changes have not been found consistently.³ In the work reported here, repeated determinations in specially prepared platelet-rich plasma from peripheral venous blood showed consistent increases in serotonin levels after oral administration of glucose to patients with the dumping syndrome and after intraduodenal instillation of glucose to patients with normal gastrointestinal tracts. The levels in control patients given hypertonic glucose orally were unchanged. Thus the