Table 5.

Comparison of the responses to peroxisome proliferators (e.g., Wy-14,643) in wild-type, Pparα-knockout, PPARα-humanized mice and humans.

Response to peroxisome proliferators	Wild-type mice	Ppara-null mice	PPARa-humanized mice	Humans
PPARa expression	Murine Pparα	None	Human PPARα	Human PPARα
Increase in peroxisomes	Yes	No	No	No
Induction of enzymes in fatty acid oxidation, synthesis, transport	Yes	No	Yes	No
Induction of cell cycle genes	Yes	No	No	No
Cell proliferation	Yes	No	No	No
Hypolipidemia	Yes	No	Yes	Yes
Increased risk of cancer	Yes	No	No	No