Peroxisome proliferators and signal transduction

Hypolipidemic peroxisome proliferators (HPPs), as plasticizers, agrochemicals, hypolipidemic drugs, and other structurally unrelated xenobiotics are known to induce a pleiotropy of similar short- and long-term effects in treated animals.(1-3) Increased synthesis of specific mRNAs for peroxisomal and microsomal enzymes, which is followed by an increased number and size of hepatic peroxisomes and induction of specific cytochrome P450, increased amounts of liver fatty acid and fatty acyl-CoA binding proteins (FABP and ACBP), and acyl-CoA hydrolases are well known examples of short-term HPP effects.(1-3) On the other hand, long-term treatment of susceptible laboratory animals results in the development of hepatic tumor by non-genotoxic mechanisms.(3,4)