DC260126, a small organic antagonist for GPR40 (FFAR1), dose-dependently inhibits GPR40-mediated Ca2+ elevations stimulated by linoleic acid, oleic acid, palmitoleic acid and lauric acid (IC50=6.28, 5.96, 7.07, 4.58 μM, respectively), reduces GTP-loading and ERK1/2 phosphorylation stimulated by linoleic acid in GPR40-CHO cells, suppresses palmitic acid potentiated glucose-stimulated insulin secretion, and negatively regulates GPR40 mRNA expression induced by oleic acid in Min6 cells.