Table 2.
Changes in plasma concentrations of glucose, immunoreactive insulin (IRI), glucagon, and incretins throughout meal tolerance tests, and area under the concentration–time curves, before and after sitagliptin treatment
| Laboratory value | Timing | Time after meal (min) | AUC0–2h | AUC0–4h | |||||
|---|---|---|---|---|---|---|---|---|---|
| 0 | 15 | 30 | 60 | 120 | 240 | ||||
| Glucose [mg/dL (mmol/L)] | Before | 154 ± 39 (8.5 ± 2.2) | 166 ± 42 (9.2 ± 2.3) | 203 ± 45 (11.3 ± 2.5)*** | 255 ± 66 (14.2 ± 3.7)*** | 259 ± 82 (14.4 ± 4.6)*** | 180 ± 69 (10.0 ± 3.8)** | 457 ± 115 (25.4 ± 6.4) | 896 ± 248 (49.7 ± 13.8) |
| After | 133 ± 34 (7.4 ± 1.9)# | 153 ± 37 (8.5 ± 2.1)* | 148 ± 40 (8.2 ± 2.2)## | 201 ± 55 (11.2 ± 3.1)***,## | 168 ± 59 (9.3 ± 3.3)***,## | 123 ± 43 (6.8 ± 2.4)## | 369 ± 108 (20.5 ± 6.0)††† | 701 ± 246 (38.9 ± 13.7)††† | |
| IRI (μU/mL) | Before | 5.04 ± 2.40 | 11.37 ± 7.57* | 14.22 ± 9.05*** | 19.10 ± 7.29*** | 26.79 ± 19.08*** | 10.52 ± 6.57* | 34.0 ± 14.9 | 68.3 ± 35.5 |
| After | 6.07 ± 3.42 | 8.80 ± 4.67 | 15.56 ± 6.64*** | 20.70 ± 8.99*** | 32.28 ± 18.42*** | 10.44 ± 7.33* | 36.3 ± 16.7 | 75.0 ± 37.1 | |
| Glucagon (pg/mL) | Before | 80.6 ± 32.4 | 94.9 ± 31.1*** | 104.1 ± 33.1*** | 98.8 ± 31.6*** | 94.5 ± 27.7*** | 86.5 ± 26.1* | 195 ± 57 | 376 ± 105 |
| After | 81.3 ± 33.1 | 88.7 ± 33.1* | 92.5 ± 32.4*** | 91.3 ± 32.7*** | 84.4 ± 29.1 | 81.0 ± 23.9 | 180 ± 57† | 349 ± 105†† | |
| Active GLP-1 (pmol/L) | Before | 3.13 ± 1.02 | 4.28 ± 2.93 | 7.16 ± 4.14 | 7.35 ± 5.16 | 7.84 ± 7.42 | – | 10.5 (8.5, 15.2) | – |
| After | 5.28 ± 3.55 | 9.69 ± 6.79**,## | 14.58 ± 7.01***,## | 12.95 ± 8.79***,## | 19.03 ± 12.85***,## | – | 26.4 (16.7, 32.4)‡ | – | |
| Total GIP (pmol/L) | Before | 11.2 ± 6.3 | 41.5 ± 26.8** | 117.0 ± 67.2*** | 122.3 ± 87.4*** | 76.5 ± 40.7*** | – | 186 ± 106 | – |
| After | 7.2 ± 4.4 | 40.2 ± 23.3** | 109.9 ± 52.7*** | 97.3 ± 54.5*** | 57.0 ± 27.6*** | – | 154 ± 73 | – | |
Data expressed as mean ± standard deviation or median with quartile values (25 %, 75 %)
AUC 0—2h area under the concentration–time curve from time zero to 2 h, AUC 0–4h area under the concentration–time curve from time zero to 4 h, GLP-1 glucagon-like peptide-1, GIP glucose-dependent insulinotropic polypeptide, IRI immunoreactive insulin
* p < 0.05, ** p < 0.01, and *** p < 0.001 vs. 0 min, # p < 0.05 and ## p < 0.001 vs. before sitagliptin treatment (determined by ad hoc Fisher’s least significant differences procedure after two-way repeated measures ANOVA). † p < 0.05, and †† p < 0.01, and ††† p < 0.001, and ‡ p = 0.003 vs. before sitagliptin treatment (determined by paired t test and Wilcoxon signed rank test, respectively)