FIGURE 1.

HIF-1α and mitochondrial oxidants. Shown is the potential role of HIF-1α in regulating ROS levels under low oxygen conditions. Evidence suggests that low oxygen levels actually increase the levels of mitochondrial ROS. Once released, these oxidants appear to stabilize HIF-1α protein and thereby increase HIF-1α activity. In turn, through a variety of mechanisms, HIF-1α alters mitochondrial carbon metabolism by regulating such enzymes as lactate dehydrogenase A and PDK1 and potentially alters mitochondrial activity by augmenting cytochrome content. The end result of these HIF-1α-regulated activities is a potential reduction of the increased ROS levels induced by hypoxic stress.