The potent, selective and orally active GPR119 agonist discovered at Arena Pharmaceuticals, Inc., AR231453 significantly increased insulin release in HIT-T15 cells (a hamster insulinoma-derived line with robust GPR119 expression) and in rodent islets. By contrast, no effect of this compound could be seen in islets isolated from GPR119-deficient mice, confirming that its effects were indeed mediated by GPR119.