Central role of peroxisome proliferator-activated receptors in the actionsof peroxisome proliferators

Peroxisome proliferators (PPs) are a large class of structurally dissimilar chemicals that have diverse effects in rodents and humans. Most, if not al l, of the diverse effects of PPs are mediated by three members of the nucle ar receptor superfamily called peroxisome proliferator-activated receptors (PPARs). In this review, we define the molecular mechanisms of PPs, includi ng PPAR binding specificity, alteration of gene expression through binding to DNA response elements, and cross talk with other signaling pathways. We discuss the roles of PPARs in growth promotion in rodent hepatocarcinogenes is and potential therapeutic effects, including suppression of cancer growt h and inflammation.