Fig. 3.

Arterial plasma insulin concentrations during the hyperglycemic clamp after portal (left) or jugular (right) infusion of glucagon-like peptide-1 (GLP-1)(7–36). For both infusion sites, arterial plasma insulin concentrations were significantly higher when GLP-1 was infused after dipeptidylpeptidase 4 (DPP4) inhibition by vildagliptin (empty) than without vildagliptin (filled) (repeated measures 2-way ANOVA P < 0.0001 for dose and DPP4 inhibition). Bonferroni post tests showed significantly higher arterial plasma insulin concentrations with vildagliptin (vilda) compared with native GLP-1 infusions for all concentrations except for infusion of the highest dose into the jugular vein. ***P < 0.001; **P < 0.01; *P < 0.05. All values are mean ± SE.