Peroxisome proliferator-activated receptor alpha (PPAR-α) is a ligand-activated nuclear receptor transcription factor that regulates the fatty acid β-oxidation. An in vitro assay identified the p-methoxy phenyl ureido thiobutyric acid derivative KSM-01 (IC50= 0.28±0.09 nM) having a higher affinity to activate PPAR-α than the PPAR-α agonist GW7647 (IC50= 0.46±0.19 nM). In this study, we report the synthesis and initial in vivo evaluation of [11C] ...