Project Summary This application is in response to Funding Opportunity Announcement PAR-15-139 a five day course entitled” Isotope Tracers in Metabolic Research: Principles and Practice in Kinetic Analysis”. The course faculty will present state of the art methods for using both radioactive and stable isotopes to investigate whole body and organ metabolism in vivo and intracellular flux rates and pathway regulation in vivo and in vitro. The basic aspects of modeling will be considered, as well as specific applications to the study of carbohydrate, fat, protein metabolism and energy balance. Theoretical and practical matters related to sample analysis by mass spectrometry and NMR will be discussed, including detailed numerical examples of calculations involved in determining isotopic enrichment and basic kinetic parameters. Advanced lectures will discuss in more detail the use of positional and mass isotopomer analysis for intracellular flux rates and various aspects of protein and amino acid metabolism. Specific applications (hyperinsulinemic euglycemic clamp) for use in humans and animals will be presented. The course uses a lecture format combined with problem discussions. In addition a popular aspect of the course is that trainees meet one on one with course faculty to discuss their specific research project and can present their project in an evening session. A new addition is detailed theory and experimental protocols to monitor specific pathways in a webinar style format that will be available on the course website to the entire research community. Typically, 75-85 trainees attended the course each year. Feedback from attendees has been very laudatory. A number of trainees have developed new research projects using isotope technologies. Thus this popular course builds on and reinforces fundamental skills needed to study metabolic processes that are relevant to the mission of NIDDK.