1. Departments of Physiology (R.I., A.A., L.M.L., P.L.B.), University of Toronto, Toronto, Ontario M5S 1A8, Canada
2. Department of Medicine II, Klinikum rechts der Isar, Technische Universität München, Munich 81675, Germany (R.I.)
3. Department of Medicine, Campus Innenstadt, Ludwig-Maximilians-Universität München, Munich 80336, Germany (L.M.L.)
4. Nutritional Sciences (R.P.B.), University of Toronto, Toronto, Ontario M5S 1A8, Canada
5. Medicine (P.L.B.), University of Toronto, Toronto, Ontario M5S 1A8, Canada