Glucose stimulates GLP-1 secretion from the perfused rat intestine by a dose- and absorption-dependent manner. Glucose stimulates GLP-1 secretion from the perfused rat intestine by a dose- and absorption-dependent manner. Data are shown as means ± 1 SEM. GLP-1 total concentrations (pmol/L) (black line) and venous glucose concentrations (mmol/L) (blue line) are shown in response to 5% (w/v) luminal glucose (A) or 20% (w/v) luminal glucose (E). Averaged GLP-1 total concentrations (pmol/L) are shown at baseline and in response to 5% (w/v) glucose (B) or 20% (w/v) glucose (F). Averaged venous glucose concentrations (pmol/L) are shown at baseline and in response to 5% (w/v) glucose (C) or 20% (w/v) glucose (G). D and H: Correlation analysis of venous GLP-1 (total) concentration (pmol/L) and venous glucose concentrations (mmol/L). BBS was included at the end of the experiments as a positive control. Statistical significance between stimulant and baseline levels was tested by paired t test. ****P < 0.0001 (n = 6). Rune E. Kuhre et al. Diabetes 2015;64:370-382 ©2015 by American Diabetes Association