Figure 3 | Scientific Reports

Figure 3

From: Activation of intestinal olfactory receptor stimulates glucagon-like peptide-1 secretion in enteroendocrine cells and attenuates hyperglycemia in type 2 diabetic mice

Figure 3

Downstream signaling of geraniol-mediated GLP-1 secretion. (a) The active GLP-1-secreting effect of geraniol (100 μM) was blocked by transfections with siRNAs for the olfactory receptor genes, OR1A1 and OR1G1, CNGA2, and the olfactory G protein α-subunit gene, GNAL, but not for the taste G protein α-subunit gene, GNAT3, in differentiated NCI-H716 cells. (b) An AC inhibitor SQ22536 (SQ; 50 μM) blocked the GLP-1 secretion-inducing activity of geraniol. (c) Transfection of each siRNA successfully downregulated the corresponding target mRNA expression levels. (d) Olfactory siRNA transfection did not reduce the GLP-1-secreting effect of the bitter tastant denatonium benzoate (DB). Error bars show SEM. Statistics ANOVA followed by Dunnett’s post-hoc. *p < 0.05, **p < 0.01, ***p < 0.001. # NS, non-significant.

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