GLP-1 and changes in glucose tolerance following gastric bypass surgery in morbidly obese subjects.
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.
Morínigo
Rosa
R
Obesity Unit, Hospital Clínic Universitari, Barcelona, Spain.
Lacy
Antonio M
AM
Casamitjana
Roser
R
Delgado
Salvadora
S
Gomis
Ramon
R
Vidal
Josep
J
D000328:Adult; D019540:Area Under Curve; D001786:Blood Glucose / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism; D005260:Female; D005500:Follow-Up Studies; D015390:Gastric Bypass / Q000379:methods; D052216:Glucagon-Like Peptide 1 / Q000378:metabolism*; D005951:Glucose Tolerance Test; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000378:metabolism* / Q000503:physiopathology / Q000601:surgery; D011446:Prospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D015431:Weight Loss
D001786:Blood Glucose; D052216:Glucagon-Like Peptide 1; D006442:Glycated Hemoglobin; D007328:Insulin