|
| Author and year | Study size (n) | Stimulus | Total or active/intact GLP-1 and assay/detection method | GLP-1 levels: i-IFG/IFG | GLP-1 levels: i-IGT/IGT | GLP-1 levels: IFG/IGT | BMI | Age | Ethnicity | Diagnostic criteria (year) | Ref. |
|
| Wang et al. 2016 | 80 | 3 h OGTT (75 g) | Total plasma GLP-1
ELISA, Westand Biological Technology | Not determined (ND) | No change in time point GLP-1levels, ΔGLP-1, or 3 h AUC GLP-1 versus NGT | ND | Matched | Matched | Han Chinese | WHO (‘98) | [7] |
|
| Faerch et al. 2015 | 1462 | 2 h OGTT (75 g) | Total GLP-1: (7–36)NH2 & (9–36)NH2
Antiserum 89390. RIA | Women:
rAUC0–30: reduced versus NGT
rAUC0–120: reduced versus NGT
iAUC120: reduced versus NGT | Women:
rAUC0–30: reduced versus NGT
rAUC0–120: reduced versus NGT | Women:
rAUC0–120: reduced versus NGT
iAUC30: reduced versus NGT
iAUC120: reduced versus NGT
Both sexes: reduced 120 min versus NGT | Not matched | Not matched | Danish | WHO (‘06) | [9] |
|
| Yabe et al. 2015 | 102 | 2 h OGTT (75 g)
MTT (480 kcal) | Intact: two-site sandwich ELISA GLP-1: (7–36)NH2 & (7–37)
DPP-4 inhibitor: √
Total: GLP-1 (7–36)NH2 & (9–36)NH2
Antiserum 89390—Lab. of Holst JJ. | ND (fasting plasma glucose ≥110 mg/dl/6,1 mmol/l excluded) | No change in intact or total GLP-1 in fasting or post-prandial(GLP-1 levels and 2 h AUC) versus NGT in both challenges | ND | IGT and NGT matched | IGT and NGT not matched | Japanese | Japanese Diabetes Society | [19] |
|
| Zheng et al. 2014 | 474 | OGTT (75 g) | Active GLP-1: (7–36)NH2 & (7–37)
Active ELISA, Millipore | Fasting GLP-1 reduced in NGT subjects who developed prediabetes 4 year later
Prediabetes = i-IFG, i-IGT, IFG/IGT—not distinguished between subtypes | Not matched. Higher in subjects developing prediabetes | Not matched. Higher in subjects developing prediabetes | Chinese | WHO (‘98) | [25] |
|
| Hussein et al. 2014 | 80 | 30 min OGTT (75 g) | Total GLP-1
ELISA (4141), DRG® (Springfield, NJ) | No difference in 30 min GLP-1 in obese IFG versus obese NGT | ND | No difference in 30 min GLP-1 in obese IFG/IGT versus obese NGT | Normal weight versus obese (obese groups: matched) | Not matched | Egyptian | ADA (‘06) | [27] |
|
| Fernandez-Garcia et al. 2014 | 40 | 3 h high-fat meal (60 g) | Active GLP-1: (7–36)NH2
EIA, Phoenix Pharmaceuticals
DPP-4-inhibitor: ? | No diff between 0 and 180 min GLP-1. Lower 180 min GLP-1 in IFG versus Low-Ins-Res-NGT | ND | ND | Morbidly obese. Matched | Matched | Spanish | ADA (‘11) | [17] |
|
| Shen et al. 2013 | 43 | 2 h OGTT (75 g) | Total GLP-1
RIA, Millipore | ND | No change in fasting GLP-1 versus NGT. GLP-1 levels at 30, 60, and 90 min and 120 min-AUCreduced versus NGT | ND | Matched | Matched | Chinese | WHO (‘99) | [28] |
|
| Zhang et al. 2012 | 531 | 2 h OGTT (75 g) | Total GLP-1
ELISA, USCNLIFE™ kits
(Uscnlife Science & Technology Company) | No change: fasting GLP-1, 2 h GLP-1, and ΔGLP-1 | No change: fasting GLP-1 and 2 h GLP-1.
Reduced ΔGLP-1versus NGT | Reduced fasting GLP-1 versus i-IGT; reduced 2 h GLP-1 versus NGT, i-IFG, i-IGT; reduced ΔGLP-1 versus NGT, i-IFG, i-IGT | Matched | Matched | Han Chinese | ADA (‘06) | [29] |
|
| Smushkin et al. 2012 | 165 | 2 h OGTT (75 g) | Active GLP-1: N-terminusepitope + epitope in middle of peptide
Inactive GLP-1: N-terminus epitope + epitope in middle of peptide
Total: active + inactive
DPP-4 inhibitor: √
Theranos System: fully automated, Chemiluminescence ELISA | No change in either active or total GLP-1 in fasting or postprandial response (max, 2 h AUC, 2 h AAB) versus NFG/NGT | No change in fasting active or total GLP-1. Increased integrated incremental concentrations (AAB) of total (2 h) GLP-1 versus NFG/NGT. Otherwise, no change in active or total postprandial GLP-1 response versus NFG/NGT | No change in either active or total GLP-1 in fasting or postprandial response (max, 2 h AUC, 2 h AAB) versus NFG/NGT | Not matched | Not matched | American | ADA (‘03≤) | [14] |
|
| Pala et al. 2010 | 56 | 2 h OGTT (75 g) | Active GLP-1: (7–36)NH2 & (7–37)
ELISA, Linco—N-terminal specific
DPP-4 inhibitor: √ | ND | Decreased 30 min GLP-1 and 2 h AUC GLP-1 in IGT versus NGT | ND | Matched | Matched | Not reported | WHO (‘98) | [26] |
|
| Nathanson et al. 2010 | 509 men | 60 min OGTT (75 g) | Total GLP-1: (7–36)NH2 & (9–36)
RIA, C-terminal specific (7–36)NH2 | ND | No change in fasting and 60 min GLP-1 versus NGT. Reduced ΔGLP-1 versus NGT | ND | Not reported | Matched | Swedish | WHO (‘99) | [30] |
|
| Lee et al. 2010 | 40 | 2 h OGTT (75 g)
MTT(480 kcal) | Active GLP-1
ELISA, Linco
DPP-4 inhibitor: √ | ND | No change in peak GLP-1 or 2 h–iAUC in IGT versus NGT in both challenges | ND | Not matched | Matched | Japanese | WHO | [20] |
|
| Faerch et al. 2008 | 66 | 3 h OGTT (75 g)
(IVGTT)
(Clamp) | Total GLP-1: (7–36)NH2 & (9–36)NH2
Antiserum number 89390
Department of Biomedical Sciences—University of Copenhagen | Fasting GLP-1: no change versus NGT.
Significantly higher 3 h AUC versus NGT | Fasting and 3 h AUC GLP-1: no change versus NGT | ND | Significant higher in i-IFG, i-IGT versus NGT | Matched | Europid | WHO (‘99) | [21] |
|
| Muscelli et al. 2008 | 51 | 3 h OGTT (75 g)
(Isoglycaemic IV test) | Total GLP-1: 7-36NH2 & 9-36NH2
Antiserum number 89390. RIA | ND | No change in either GLP-1 levels or 3 h AUC GLP-1 versus NGT | ND | Matched | Matched | Not reported | ADA (‘97) | [22] |
|
| Laakso et al. 2008 | 278: GLP-1 (874) | 2 h OGTT (75 g)
(IVGTT)
(Clamp) | Total GLP-1: (7–36)NH2 & (9–36)NH2
Antiserum number 89390 | Reduced 15, 90, and 120 min GLP-1 versus NGT.
Reduced AUC0–240 versus NGT | Reduced 15, 90, and 120 min GLP-1 versus NGT.
Reduced AUC0–240 versus NGT | Reduced 15, 90, and 120 min GLP-1 versus NGT.
Reduced AUC0–240 versus NGT | — | — | Danish | ADA (‘03) | [23] |
|
| Vollmer et al. 2008 | 48 | 4 h OGTT (75 g)
Mixed meal (820 kcal) | Total GLP-1: (7–36)NH2 & (9–36)NH2
Antiserum number 89390. RIA | ND | No change in GLP-1levels in both challenges versus NGT | ND | Matched | Matched | Not reported | WHO | [24] |
|
| Rask et al. 2004 | 30 women | 3 h OGTT (75 g) | Total GLP-1: (7–36)NH2 & (9–36)NH2 RIA | ND | No change in fasting GLP-1, GLP-1 levels, 30-minAUC, 60 min AUC GLP-1 versus NGT. Reduced first 30 min [GLP-1] increase versus NGT | ND | Matched | Matched | Caucasian | Not reported (Fulfil WHO & ADA) | [31] |
|
| Toft-Nielsen et al. 2001 | 102 | 4 h mixed meal (2250 kJ) | Total GLP-1: (7–36)NH2 & (9–36)NH2
Antiserum number 89390. RIA | ND | No change in fasting GLP-1 or 4 h AUC GLP-1 versus NGT | ND | Not matched | Matched | Danish | WHO (‘85) | [18] |
|
| Ahrén et al. 1997 | 13 women | 2 h OGTT (75 g) | Total GLP-1: (7–36)NH2 & (9–36)NH2
Antiserum number 89390. RIA | ND | No change in fasting GLP-1, GLP-1 increase (AUC0–60) or GLP-1 decrease versus NGT | ND | Matched | Matched | Not reported | WHO (‘85) | [32] |
|
