The goal of the Oxidative Damage and Mitochondrial Function Core is two-fold. First, we will continue to provide measurement of oxidative damage to lipid, DNA and protein in cells and tissues using the latest and most sensitive methods and technologic approaches. The second and new function of the Core is to provide several key assays of mitochondrial function including measures of reactive oxygen species generation, respiration and ATP production in isolated mitochondria and in cultured cells. Compromised mitochondrial function and accumulation of oxidative damage to cell components with age have been proposed as primary factors underlying age-associated alterations in physiologic function and pathology. A number of recent studies have suggested that the relation between mitochondrial dysfunction, oxidative damage and aging may not be as straightforward as originally proposed by Hamian more than 50 years ago. However, measures of oxidative damage and mitochondrial function continue to be important components of many studies on the underlying mechanisms of aging and age-related disease, and it is critical that these measures are done with the highest possible sensitivity and accuracy. The measurements offered by the Core require costly equipment and technologic expertise that prevent these types of analyses as routine measures in individual laboratories. The Specific Aims of the Oxidative Damage and Mitochondrial Function Core are as follows: 1. To provide sensitive and accurate measurements of oxidative damage to lipids, DNA and protein through analysis of F2-isoprostanes/isofurans (lipid oxidation), 8-oxo-2-deoxyguanosine (oxo8dG) (DNA oxidation), and oxidative modifications to proteins (carbonyls, disulfide content and alterations in protein hydrophobicity). 2. To provide high quality sensitive measurement of mitochondrial function in isolated mitochondria and cell culture using state-of-the-art techniques. 3. To provide education and consultation regarding methodology for assessing oxidative damage and mitochondrial function.