Peroxisome proliferators are non-genotoxic carcinogens which are purported to exert their effect on cells through their interaction with members of the nuclear hormone receptor family termed peroxisome proliferators activated receptors (PPARs). Nuclear hormone receptors are ligand-dependent intracellular proteins that stimulate transcription of specific genes by binding to specific DNA sequences following activation by the appropriate ligand. Studies indicate that PPARs are activated by peroxisome proliferators such as clofibric acid, nafenopin, and WY-14,643, as well as by some fatty acids. MW: 80 kDa.