Peroxisome proliferator-activator receptor delta(PPARD),a ligand-activated transcription factor,belongs to the PPARs family,which get its name for their chemicals that induce proliferation of peroxisomes,organelles that contributes to the oxidation of fatty acids. PPARD is a receptor for peroxisome proliferator and once activated by a ligand,it binds to and activates the promoter elements of target genes,such as acylCoA oxidase gene. But it act as a repressor for the NPC1L1 gene.