1. Endocrine Research Unit and Department of Biochemistry (F.G., L.C.H., S.K., B.L.R.) Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905;
2. Molecular Biology (T.C.S.), Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905;
3. Amgen, Inc. (C.R.D.), Thousand Oaks, California