Fig. 4.
ATP-dependent K+ (KATP) channel closure is required for glucose-stimulated GLP-1 secretion in colon but not ileum. A and B: ELISA-based measurements of GLP-1 secretion from intestinal explants of ileum (A) and colon (B) of T1R3+/+ (black) and T1R3−/− (white) mice upon treatment with buffer (B), 250 mM glucose (G), or 50 μM glibenclamide (Gb). Each bar, n = 4 mice. Data are presented as means ± SE. *P < 0.01 vs. buffer for that genotype. C: ELISA-based measurements of GLP-1 secretion from colon explants from T1R3+/+ (black) and T1R3−/− (white) mice upon stimulation with buffer, 250 mM glucose, or 250 mM glucose in combination with 50 μM glibenclamide (G + Gb), 100 μM diazoxide (G + Dz), or 10 μM cromokalim (G + Cr). Each bar, n = 4 mice. Data are presented as means ± SE. *P < 0.01 vs. buffer for that genotype, except for comparison between buffer and glucose + cromokalim treatments in T1R3+/+ colon (P = 0.03, B). #P < 0.01 vs. glucose treatment for that genotype.