Gastric bypass increases postprandial insulin and GLP-1 in nonobese minipigs

Abstract

Background: Gastric bypass in obese patients induces a dramatic increase of postprandial insulin and glucagon-like peptide-1 (GLP-1) secretion, independently of weight loss. We explored postprandial insulin and GLP-1 secretion in nonobese minipigs before and after RYGB.

Methods: Lean adult Göttingen minipigs (n = 7) were submitted to an open gastric bypass surgery mimicking the clinical procedure in humans (30-cm(3) gastric pouch/150-cm alimentary limb/70-cm biliary limb). All animals were evaluated at baseline and then 10 and 30 days after surgery. At each time point, serum glucose, insulin, GLP-1 and D-xylose levels were measured 3 h after a standardized mixed meal.

Results: Weight remained stable during follow-up. Insulin and GLP-1 responses to the test meal were dramatically and similarly increased at 10 days and 1 month after RYGB. Maximal postprandial insulin and GLP-1 levels were 16.3 ± 1.7 mIU/l and 71.7 ± 16.5 pmol/l at baseline, 111.5 ± 38.9 mIU/l and 320.8 ± 84.0 pmol/l at 10 days and 96.6 ± 10.4 mIU/l and 297.3 ± 79.1 pmol/l at 1 month, respectively. D-Xylose absorption remained unchanged before and after surgery.

Conclusions: RYGB induced a dramatic increase of postprandial insulin and GLP-1 secretion in nonobese minipigs. This preclinical model could help to understand the underlying metabolic effects of RYGB, focusing on the role of postsurgical anatomical rearrangement, especially duodenojejunal exclusion and ileal brake. This study supports the use of RYGB in diabetic nonobese patients in absence of obesity.