Project Abstract The requested instrument is a DELTA Q™ Isotope Ratio Mass Spectrometer. This state-of-the-art instrument allows for the precise and sensitive measurement of the isotopes of carbon, nitrogen, sulfur, oxygen and hydrogen from the plasma of a variety of different biospecimens, including whole blood, urine and breath. Our collaborative team of perinatal, pediatric, and adult scientists share the common goal of understanding how alternations in metabolism affect an individual’s risk for developing cardiovascular disease, diabetes, and obesity. Major and Minor users in this group include NIH-funded individuals who are actively studying the fetal antecedents of heart disease and diabetes (Major users: Brown, Rozance, Stremming, Wesolowski, Limesand; Minor users; Anthony, White) and the impact of activity and diet on metabolism and diabetes and obesity risk (Major user: Bergouignan). The instrument will enhance the goals of our NIH-funded research projects by providing measurements of enrichment of carbon, hydrogen, and oxygen after infusion of stable isotope tracers, which enable us to estimate substrate oxidation rates and total daily energy expenditure in response to disease states (placental insufficiency and IUGR in early stages of life, obesity and diabetes in later stages of life) as well as therapeutic interventions such as dietary intervention, growth factor supplementation, and exercise. We have outstanding technical expertise to process samples and optimally maintain the instrument, a cost-effective financial plan to support the instrument, and significant institutional support to maximize utilization of the instrument for all users. In summary, the DELTA QTM IRMS instrument will further our understanding of substrate metabolism, with the long-term goal of minimizing risk of obesity and diabetes.