1. From the Department of Cellular and Molecular Medicine (E.M.F., P.L.S.M.G., J.C.G., R.L., N.S., J.D.E.) and Biomedical Sciences Graduate Program (E.M.F., J.C.G., N.S., J.D.E.), University of California San Diego, La Jolla, CA; and Section on Integrative Physiology and Metabolism, Joslin Diabetes Research Center, Harvard University, Cambridge, MA (K.I.S.).