Figure 9. Effect of diuretics on glycine-triggered GLP-1 release.

GLUTag cells were cultured overnight with bendrofluazide (50 μm), bumetanide (10 μm) or no diuretic added to the standard culture medium. GLP-1 secretion was measured the following day in response to a 2 h incubation period in standard bath solution containing the same diuretic (or no diuretic) and either glucose (Gluc, 10 mm), glycine (Gly, 1 mm), glycine plus strychnine (Gly + St, 1 mm and 10 μm), or no additions (Con) (n = 4 for each). Secretion was normalized to the baseline release in the absence of nutrients and diuretics measured in parallel on the same day. Statistical significance was tested firstly by ANOVA, and subsequently by Student's unpaired t test, if appropriate; **P < 0.01; n.s., not significant.