1. Department of Medicine, Division of Endocrinology (G.F.L., A.C., A.G.), University of Toronto, Toronto, Canada M5G 2C4
2. Department of Laboratory Medicine and Pathobiology (K.A.), University of Toronto, Toronto, Canada M5G 2C4
3. Department of Physiology (A.G.), University of Toronto, Toronto, Canada M5G 2C4