Activation of peroxisome proliferator-activated receptor-α (PPAR-α) has been recently reported to inhibit vascular inflammatory response and prevent cardiac hypertrophy. However, it is unclear how the activation of PPAR-α regulates hypertrophic response. In the present study, we found that application of fenofibrate and overexpression of PPAR-α inhibited endothelin-1 (ET-1)-induced phosphorylation of protein kinase B (Akt) at Ser473 and glycogen synthase kinase3β (GSK3β) at Ser9, and prevented ET-1-induced nuclear translocation of NFATc4 in cardiomyocytes. Moreover, co-immunoprecipitation studies showed that fenofibrate strongly induced the association of nuclear factor of activated T cells (NFATc4) with PPAR-α. These results suggest that activation of PPAR-α inhibits ET-1-induced cardiac hypertrophy through regulating PI3K/Akt/GSK3β and NFAT signaling pathways. © 2007 Federation of European Biochemical Societies.