Coupling of fee bitter taste receptors to G-protein α-subunits in NCI-H716 cells, (a, b) DB increased the binding of [32P]GTP-azidoanilide to Gocgust (a) while decreasing binding to Gαi1,2 (b) in a concentration-dependent manner, (c, d) GNAT3, TAS2R4, TAS2R43 and TAS2R46 siRNAs reduced DB-induced GLP-1 secretion. Data are expressed as mean ± SEM. ***p<0.001