Endocrine Abstracts

Gastrectomy is associated with profound metabolic changes, yet the endocrine adaptations underlying post-surgical weight loss remain poorly understood. This prospective observational study aimed to characterise postprandial GLP-1 responses and their relationship to satiety, weight loss, and nutritional status following gastrectomy. Patients undergoing elective gastrectomy for gastric cancer were assessed preoperatively and at 10 days, 6 weeks, and 3 months postoperatively using serial mixed-meal tolerance testing and symptom questionnaires. Significant weight loss was observed at 3 months (mean %BWL 14.4 ± 2.1, p < 0.0001). Postprandial GLP-1 secretion increased markedly from day 10, with a near tripling of GLP-1 AUC (p = 0.007) and a four-fold rise in peak GLP-1 concentrations (p = 0.02). The GLP-1 response curve maintained its shape across timepoints (p = 0.14), indicating increased magnitude but unchanged secretion dynamics. Fasting GLP-1 levels did not change significantly. Satiety scores increased significantly at 6 weeks (mean 50.0 vs 4.8 pre-op, p = 0.008), but this effect was not sustained at 3 months. Lack of appetite scores rose transiently postoperatively but did not reach statistical significance (p = 0.06). Eating symptoms increased at 6 weeks and 3 months (p = 0.04). Biochemical changes included reductions in vitamin E (p = 0.04), albumin (p = 0.02), total protein (p = 0.007). No significant relationships were identified between GLP-1 indices or satiety scores and percentage weight loss. These findings highlight early, sustained exaggerated postprandial GLP-1 secretion following gastrectomy, with a transient rise in satiety. The results provide insight into incretin-mediated endocrine adaptations post-gastrectomy, relevant to metabolic changes observed after upper gastrointestinal surgery.