title: Impaired secretion of total glucagon-like peptide-1 in people with impaired fasting glucose combined impaired glucose tolerance.
abstract: OBJECTIVE
  We assessed the serum glucagon-like peptide-1 (GLP-1) levels for Chinese adults with pre-diabetes (PD) and newly-diagnosed diabetes mellitus (NDDM) during oral glucose tolerance test (OGTT). The relationships between total GLP-1 level and islet β cell function, insulin resistance (IR) and insulin sensitivity (IS) were also investigated.
  
  
  METHODS
  A 75g glucose OGTT was given to 531 subjects. Based on the results, they were divided into groups of normal glucose tolerance (NGT), isolated impaired fasting glucose (IFG), isolated impaired glucose tolerance (IGT), IFG combined IGT (IFG+IGT) and NDDM. Total GLP-1 levels were measured at 0- and 2-hour during OGTT. Homeostasis model assessment of β cell function (HOMA-β), HOMA of insulin resistance (HOMA-IR), Gutt and Matsuda indexes were calculated. The relationships between GLP-1 level and β cell function, IR and IS were analyzed.
  
  
  RESULTS
  The levels of total fasting GLP-1 (FGLP-1), 2h GLP-1 (2hGLP-1) and 2hGLP-1 increments (∆GLP-1) following OGTT reduced significantly in IFG+IGT and NDDM groups (P<0.005). HOMA-β , HOMA-IR, Gutt and Matsuda indexes demonstrated various patterns among NGT, isolated IFG, isolated IGT, IFG+IGT and NDDM groups (P<0.05). Spearman rank correlation analysis and multivariable linear regression model suggested that some levels of correlation between GLP-1 levels, ∆GLP-1 and β cell function, IR (P<0.05).
  
  
  CONCLUSIONS
  The total GLP-1 levels and its response to glucose load decreased significantly in IFG+IGT group, compared to isolated IFG or IGT group. They were even similar to that of NDDM group. Moreover, there were observable correlations between impaired GLP-1 secretion and β cell function, IR and IS.
authors.affiliation: Division of Endocrinology, West China Hospital of Sichuan University, 37 Guoxuexiang, Chengdu, Sichuan 610041, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Zhang
authors.forename: Xialian
authors.initials: X
authors.lastname: Tang
authors.forename: Hongyi
authors.initials: H
authors.lastname: Cao
authors.forename: Qingguo
authors.initials: Q
authors.lastname: Lü
authors.forename: Nali
authors.initials: N
authors.lastname: Li
authors.forename: Yupu
authors.initials: Y
authors.lastname: Liu
authors.forename: Xiangxun
authors.initials: X
authors.lastname: Zhang
authors.forename: Yuwei
authors.initials: Y
authors.lastname: Zhang
authors.forename: Mingming
authors.initials: M
authors.lastname: Cao
authors.forename: Jun
authors.initials: J
authors.lastname: Wan
authors.forename: Zhenmei
authors.initials: Z
authors.lastname: An
authors.forename: Nanwei
authors.initials: N
authors.lastname: Tong
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D005215:Fasting; D005260:Female; D052216:Glucagon-Like Peptide 1 / Q000097:blood / Q000378:metabolism*; D005951:Glucose Tolerance Test; D006801:Humans; D006943:Hyperglycemia / Q000097:blood; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D011236:Prediabetic State / Q000097:blood
chemical_list: D001786:Blood Glucose; D007328:Insulin; D052216:Glucagon-Like Peptide 1