Fig. 5.

Unstimulated intake without food available after 4V injection of vehicle (0.9% saline), GLP-1 (10 μg), exendin-4 (0.1 μg), or liraglutide (2 μg). A: noncumulative 24-h water intake collapsed into 4-h bins. Hindbrain administration of exendin-4 or liraglutide also led to suppression of water intake, suggesting at least a partial contribution of the hindbrain in the observed hypodipsia. ^a,bBars with different letters, and within the same bin, are significantly different at P < 0.05. B: cumulative 24-h water intake. Cumulative 24-h water intake suggests that GLP-1 also had a suppressive effect on water intake and that the initial hypodipsia after GLP-1, exendin-4, or liraglutide administration was not compensated for during the testing period. *Significant differences from vehicle (P < 0.05). C: dark-phase water intake. GLP-1, exendin-4, or liraglutide administration suppressed water intake over the dark phase, with exendin-4 causing the greatest suppression. ^a,b,cBars with different letters are significantly different (P < 0.05). Data are shown as means ± SE. D: noncumulative water intake in 1-h bins. Examination of shorter bins did not reveal any significant effects of GLP-1R agonists. *Significant differences from controls within a given bin (P < 0.05; data from the whole 24-h test were analyzed, but for clarity only the first 4 bins are shown in the figure). Data are shown as means ± SE.