The Metabolic Regulation Core (MRC) provides services that are distinct in that they permit complex study of mouse models without handling or stress. The MRC has continually refined its methodology to accurately assess metabolism in healthy, conscious mice. The Core has improved the accuracy of methods to measure metabolic flux using isotopes and developed blood replacement methods to prevent anemia due to blood withdrawal. Besides the unique skills of the MRC in chronically implanting catheters into the carotid artery and jugular vein for sampling and infusions, it has developed techniques to catheterize the portal vein and stomach to deliver hormones and nutrients by their physiologic routes. The MRC has developed experimental designs to apply stable isotopes to measure hepatic metabolic flux in vivo and in vitro. The ability of the MRC to gain vascular access in the absence of stress permits flexibility as well as sophistication. For example the intracerebroventricular delivery of a compound on whole body metabolic flux or hormone secretion has been assessed. Additional services include in vitro perfusion techniques (liver, pancreas, skeletal muscle). It partners with the DRTC Islet Procurement and Analysis Core to provide high quality islets to investigators as well as tools to characterize islet function. MRC has developed novel imaging technology to study metabolic processes in real time at the physiological and molecular levels. Imaging Resources include: a multi-photon excitation confocal microscope to visualize real time kinetics of calcium, NAD(P)H, pH the movement of biomolecules (e.g. insulin) across the vascular endothelium and tissue blood flow using fluorescent probes in whole organ preparations and in vivo; The MRC provides state-of-the-art technology to comprehensively characterize metabolic regulation in mouse models of metabolic disease.