title: Plasma level of glucagon-like peptide 1 in obese Egyptians with normal and impaired glucose tolerance.
abstract: OBJECTIVE
  Low GLP-1 has been implicated in obesity and type 2 diabetes. Some studies reported reduced post-prandial GLP-1 levels in type 2 diabetics, whereas others reported GLP-1 levels not reduced in patients with impaired glucose tolerance (IGT) or type 2 diabetes. We undertook this study to evaluate the effect of obesity and pre-diabetes on GLP-1 levels in response to 75 g oral glucose.
  
  
  METHODS
  Eighty subjects comprised four groups: 20 control subjects (normal weight and normal glucose tolerance (NGT)), 20 obese with NGT, 20 obese with impaired fasting glucose (IFG) and 20 obese with both IFG and impaired glucose tolerance (IGT). Laboratory tests included fasting blood glucose (FBG), 75 g glucose OGTT, fasting insulin and glucose-stimulated GLP-1 (30 min after 75 g glucose). Insulin resistance was quantified using HOMA-IR.
  
  
  RESULTS
  GLP-1 levels were significantly decreased in obese subjects compared to controls (571.17 ± 170.37 vs. 908.50 ± 169.90 pg/mL, p <0.001) and it was negatively correlated with body mass index (BMI) and waist circumference in all studied groups. Levels of GLP-1 were negatively correlated with HOMA-IR in all obese groups (r = -0.75, p <0.001). No significant difference was found in GLP-1 levels between all obese subjects (611.50 ± 187.96, 577.50 ± 150.85, 524.50 ± 167.35 pg/mL respectively, p >0.05). Morbidly obese cases (n = 15) had a significantly higher fasting insulin (25.20 ± 2.49 vs. 14 ± 3.81 μIU/ml), higher HOMA-IR (6.69 ± 1.2 vs. 3.48 ± 1.20), and lower GLP- 1 (212.0 ± 35.64 vs. 603.82 ± 136.35 pg/mL) (p <0.001) compared to non-morbid obese cases (n = 45).
  
  
  CONCLUSIONS
  Obesity reduces the GLP-1 levels. In insulin resistance, GLP-1 levels were reduced and it was related to the degree of insulin resistance.
authors: Endocrinology Unit, Faculty of Medicine, Ain Shams University, Cairo, Egypt.
authors: Magda S
authors: MS
authors: Hussein
authors: Endocrinology Unit, Faculty of Medicine, Ain Shams University, Cairo, Egypt. Electronic address: manalabushady@hotmail.com.
authors: Manal M
authors: MM
authors: Abushady
authors: Research Institute of Ophthalmology, Cairo, Egypt.
authors: Safa
authors: S
authors: Refaat
authors: Research Institute of Ophthalmology, Cairo, Egypt.
authors: Rasha
authors: R
authors: Ibrahim
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood; D005215:Fasting; D005260:Female; D052216:Glucagon-Like Peptide 1 / Q000097:blood*; D018149:Glucose Intolerance / Q000097:blood*; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood*; D009767:Obesity, Morbid / Q000097:blood; D011236:Prediabetic State / Q000097:blood
chemical_list: D001786:Blood Glucose; D007328:Insulin; D052216:Glucagon-Like Peptide 1
keywords: Glucose tolerance; Impaired fasting glucose; Obesity; Type 2 diabetes