Increasing concentrations (100 nM to 10 µM) of TUG-424 enhances glucose-stimulated insulin secretion significantly already at 100 nM and with a maximal effect at 3 µM. The approximately 2-fold stimulation of secretion by TUG-424 in the presence of 12 mM glucose is comparable to that induced by palmitate in the presence of the same glucose concentration. Basal insulin secretion at 2.8 mM glucose is slightly but significantly reduces by TUG-424.