[1] Univ Wisconsin Madison, Dept Biochem, Madison, WI 53706 USA
[2] Univ Washington, Dept Pathol, Med Ctr, Seattle, WA 98195 USA
[3] Univ Alabama Birmingham, Dept Med, Div Endocrinol Diabet & Metab, Birmingham, AL 35294 USA
[4] Univ Wisconsin, Dept Med, Div Endocrinol Diabet & Metab, Sch Med & Publ Hlth, Madison, WI 53705 USA
[5] William S Middleton Mem Vet Adm Med Ctr, Madison, WI 53705 USA
[6] Univ Sydney, Fac Med & Hlth, Charles Perkins Ctr, Sch Med Sci, Sydney 2006, Australia
[7] Univ Wisconsin Madison, Dept Chem, Madison, WI 53706 USA