The peroxisome proliferator-activated receptor mediates the induction of CYP4A6, a cytochrome P450 fatty acid omega-hydroxylase, by clofibric acid.

Gene transfer experiments indicate that induction by the peroxisome proliferators, clofibric acid and WY-14,643, of luciferase expression driven by the promoter and 5'-flanking sequences of the rabbit cytochrome P450 4A6 gene (CYP4A6) is dependent on cotransfection of expression plasmids for the peroxisome proliferator-activated receptor, PPAR. Activation by PPAR is observed in the absence of the inducers. However, a mutant, PPAR-G (Glu282----Gly) activated luciferase expression only in the presence of peroxisome proliferators. Deletion analysis has localized a response element to a 34-base pair segment located 677 base pairs upstream of the CYP4A6 transcription start site that is similar to an element that regulates the response of the rat fatty acyl-CoA oxidase gene to peroxisome proliferators and that binds PPAR.