The goal of the Geroscience Redox Biology Core is to provide investigators with a coordinated and comprehensive evaluation of the molecules, pathways, and systems that contribute to oxidative metabolism and oxidative stress. These analyses include state of the art accurate and sensitive measures of redox and energy balance as well as oxidative damage, reactive oxygen species production and mitochondrial function. Redox status and oxidant homeostasis have a major impact on physiologic processes. As a consequence, they contribute significantly to basic mechanisms of aging as well as a number of age-related diseases, and are key pathways in geroscience. The Specific Aims for this Core are the following: Specific Aim 1. To perform accurate and comprehensive analyses of redox status (GSH/GSSG, NADPH/NADP+, NADH/NAD+,), and oxidative stress and damage markers (lipid peroxidation, e.g., F2-isoprostanes; protein oxidation, e.g., carbonyls; and DNA oxidation, e.g. 8-oxo-deoxyguanosine). Redox and oxidative damage endpoints are present in limited amounts and may be unstable. The expertise in the Geroscience Redox Biology Core allows for these analyses to be performed with the highest possible sensitivity and accuracy. In addition, the analyses the Geroscience Redox Biology Core provides are especially appropriate for a Research Core because they require costly equipment and significant technologic expertise that prevents these types of analyses to routine measures in individual laboratories. Finally, because we are analyzing levels of highly specific biological compounds, our redox and oxidative damage assays can be applied to tissues or cells from any living organism. Specific Aim 2. To provide assays of mitochondrial function, energetic status, and reactive oxygen species generation using permeabilized tissue, isolated mitochondria, and cell culture models. Although these assays require fresh tissue/cells, we have successfully performed these services for investigators at external sites who can send us small numbers of mice. Specific Aim 3. To provide in vivo analyses of free radical production, we have expanded the capabilities of the Geroscience Redox Biology Core in this renewal to include in vivo analyses of redox and energy status, vascular dysfunction, and tissue structural changes. The Geroscience Redox Biology Core will now provide in vivo redox analyses of free radical levels and oxygen status using magnetic resonance imaging (MRI) and immuno-spin trapping (IST). In addition functional MRI (fMRI), will be used for oxygen status and energy status obtained from tissue-localized phosphorous (31P)- and hydrogen (1H)-MR spectroscopy. Overall, the Geroscience Redox Biology Core will provide a comprehensive panel of endpoint markers of redox balance and oxidative stress as well as measures of contributing factors such as mitochondrial function and free radical generation in vitro and in vivo that can impact many aspects of anging and Geroscience.