Ligands for peroxisome proliferator-activated receptors alpha (PPARalpha) are clinically used for the treatment of patients with hyperlipidemia. As we have previously shown, a synthetic ligand of PPARalpha, fenofibrate, has a stimulatory effect on insulin secretion in clonal hamster insulinoma beta-cell line HIT-T15 cells. We have also demonstrated that fenofibrate directly inhibits ATP-sensitive potassium (K(ATP)) channels, an effect independent of PPARalpha. In this study, fenofibrate was shown to be able to reduce voltage-dependent K(+) (K(v)) channel currents in voltage-independent manner. Therefore, fenofibrate may modulate insulin secretion not only via inhibition of K(ATP) channels but also via reduction of the K(v) channel current.