GLP-1 and changes in glucose tolerance following gastric bypass surgery in morbidly obese subjects

Obes Surg. 2006 Dec;16(12):1594-601. doi: 10.1381/096089206779319338.


Background: It has been proposed, that the dramatic amelioration of type 2 diabetes following Roux-en-Y gastric bypass (RYGBP) could by accounted for, at least in part, by changes in glucagon-like peptide-1 (GLP-1) secretion. However, human data supporting this hypothesis is scarce.

Methods: A 12-month prospective study on the changes in glucose homeostasis, and active GLP-1 in response to a standard test meal (STM) was conducted in 34 obese subjects (BMI 49.1+/-1.0 kg/m(2)) who had different degrees of glucose tolerance: normal glucose tolerance (NGT, n=12), impaired glucose tolerance (IGT, n=12), and type 2 diabetes (n=10).

Results: At 6 weeks after RYGBP, despite the subjects still being markedly obese (BMI 43.5+/-0.9 kg/m(2)), fasting plasma glucose and HbA1c decreased in the 3 study groups (P<0.05). Insulin sensitivity improved, but was still abnormal in a comparable proportion of subjects among groups (P=0.717). When insulin secretion was accounted for the prevailing insulin sensitivity, an increase was found in subjects with diabetes (P<0.05) although it remained lower compared to NGT- and IGT-subjects (P<0.01). At 12 months follow-up, no differences among groups were found in the evaluated glucose homeostasis parameters. Compared to baseline, at 6 weeks the incremental AUC(0-120') of active GLP-1 in response to the STM increased in NGT and IGT (P<0.05) but not in subjects with diabetes (P=0.285). However, the GLP-1 response to a STM was comparable among groups at 12 months follow-up (P=0.887).

Conclusions: 1) RYGBP was associated with an improvement but not complete restoration of glucose homeostasis at 6 weeks after surgery. 2) GLP-1 is not a critical factor for the early changes in glucose tolerance.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Area Under Curve
  • Blood Glucose / metabolism*
  • Diabetes Mellitus, Type 2 / metabolism
  • Female
  • Follow-Up Studies
  • Gastric Bypass* / methods
  • Glucagon-Like Peptide 1 / metabolism*
  • Glucose Tolerance Test
  • Glycated Hemoglobin A / analysis
  • Humans
  • Insulin / metabolism*
  • Insulin Resistance
  • Male
  • Middle Aged
  • Obesity, Morbid / metabolism*
  • Obesity, Morbid / physiopathology
  • Obesity, Morbid / surgery
  • Prospective Studies
  • Time Factors
  • Treatment Outcome
  • Weight Loss*


  • Blood Glucose
  • Glycated Hemoglobin A
  • Insulin
  • Glucagon-Like Peptide 1