Neurotensin, Vasoactive Intestinal Peptide, and Roux-en-Y Gastrojejunostomy: Their Role in the Dumping Syndrome

This study evaluated the effect of gastric bypass on the glucose, insulin, vasoactive intestinal peptide (VIP), neurotensin, and motilin response to orally administered glucose in eight morbidly obese patients before and after operation. Preoperatively, all eight patients remained asymptomatic during an oral glucose tolerance test, which showed glucose intolerance and hyperinsulinism. Plasma VIP, neurotensin, and motilin remained below detectable levels for the entire test. At three months following gastric bypass (21% weight loss), all eight patients became acutely ill during a repeated oral glucose tolerance test and had the following symptoms: facial flushing (eight patients), palpitations (eight patients), nausea (seven patients), abdominal fullness (seven patients), pallor (four patients), diaphoresis (two patients), vomiting (two patients), and diarrhea (two patients). Significant release of neurotensin occurred in seven patients while three patients had release of VIP, further implicating these two peptides as part of the pathophysiologic spectrum of the “dumping syndrome.”