1. Institute of Diabetes Gerhardt Katsch Karlsburg e. V. (P.A., P.H., E.S., S.B., C.S.), 17495 Karlsburg, Germany
2. Department of Physiology, Ernst Moritz Arndt University (R.R.), 17489 Greifswald, Germany
3. Walter and Eliza Hall Institute of Medical Research (L.C.H.), Parkville 3050, Australia