Since the measurement of peptide hormones and circulating substrates will provide key experimental endpoints for each of the separate projects that make up this program project, funding is requested for an Assay Core laboratory. The primary purpose of this laboratory will be to establish and perform assays for the measurement of the key regulatory peptides necessary for the completion of the three projects. Routine assays for the core will include insulin, leptin, glucose, corticosterone, gastrin releasing peptide, and cholecystokinin. This core will also be responsible for adapting commercially available kits necessary to measure other hormones and peptides, labeling peptides for use as tracers, processing tissues for assay of peptides and development of new techniques and assays. This core will be utilized extensively by all 3 of the individual projects.