Summary of factors which affect PPARα.

<p>A. Summary of factors that activate PPARα. Although many chemicals and fatty acids (derived from hydrolysis of triglycerides) bind to and activate PPARα directly, some chemicals and diets likely activate PPARα indirectly by increasing the availability of endogenous PPARα activators. Downstream effects of PPARα activation include short-term responses of hepatocyte proliferation, activation of fatty acid transport and catabolism, and suppression of inflammatory responses. Under chronic exposure conditions, hepatocellular adenomas and carcinomas can develop. B. Summary of factors that suppress PPARα. A number of factors may suppress PPARα by increasing the activation of NF-kB and AP1 which physically interfere with the ability of PPARα to bind to DNA and regulate gene expression. Suppression of PPARα can lead to decreases in fatty acid catabolism and steatosis. Chronic suppression can lead to steatohepatitus.