Figure 1. Summary of species differences in response to non-genotoxic carcinogen peroxisome proliferators. Murine peroxisome proliferator–activated receptor (mPPARα)–expressing and human PPARα (hPPARα)–expressing mice were fed a diet containing Wy-14,643 for 2 weeks, and fasting serum triglyceride levels (A), hepatomegaly (B), and hepatocyte proliferation (C) were measured. (D) A model for the difference between species in fatty-acid (FA) transport in response to PPARα ligand. Ac-CoA, Acetyl CoA; BrdU, 5´-bromodeoxyuridine; Con, control; NADH, oxidized nicotinamide adenine dinucleotide; ROS, reactive oxygen species; Wy, Wy-14,643–treated.