Table 2

 Isoglycaemic clamp studies mimicking glycaemia. Blood glucose and β cell response during intravenous glucose infusion.

Saline ivEx(9-39) iv
Duodenal glucose (kcal/min)12.52.5 (recovery)12.52.5 (recovery)
Ex(9-39), exendin(9-39)amide; iv, intravenous.
Mean (SEM) of AUC over basal during each 60 minute infusion period (n = 9). The incretin effect reflects the difference in incremental β cell secretory response between duodenal glucose, as shown in table 1, and isoglycaemic intravenous glucose shown here. Differences were compared using two way repeated measures ANOVA employing individual incremental or decremental values over basal during the respective periods.
*p<0.05 versus experiments mimicking glycaemia during duodenal glucose and saline iv.
Blood glucose (mmol/l/60 min)7.0 (0.6)13 (1.3)7.6 (0.8)8.7 (0.8)*17 (1.4)*8.6 (1.2)
Intravenous glucose load (kcal)54 (2.9)98 (10)75 (10)59 (5.8)106 (16)95 (17)
Insulin (mU/l/60 min)31 (7.3)84 (18)43 (8.8)40 (8.6)118 (30)*77 (24)*
C peptide (ng/ml/60 min)5.2 (0.7)15 (2.8)13 (1.8)5.8 (1.0)20 (4.9)*21 (7.4)*
Incretin effect based on insulin (%)48 (8.2)70 (5.6)76 (4.4)23 (6.0)*36 (5.2)*58 (3.9)*
Incretin effect based on C peptide (%)41 (8.5)51 (9.1)54 (8.8)19 (11)*22 (11)*36 (11)*