Fig. 5.

Increased mitochondrial H₂O₂ production in response to high dietary fat impairs cardiac insulin signaling independent of endogenous changes in catalase. The ratio of phosphorylated (Thr308) to total Akt was determined in cardiac tissue from wild-type (A), mitochondrial targeted catalase overexpressing (mCAT; B), and catalase knockout (C and D) mice fed a low or high-fat diet for 1 wk or 3 days, as indicated. Values are presented as the mean ± SE. *P < 0.05, low vs. high-fat diet (n = 5).