1. Leibniz Institute for Age Research/Fritz Lipmann Institute (M.T.-A., J.M., C.G., S.L., D.W., K.B., H.H.), D-07745 Jena, Germany
2. Laboratory of Comparative Endocrinology (V.M.D.), Katholieke Universiteit, B-3001 Leuven, Belgium
3. Max Planck Institute for Experimental Endocrinology (K.B.), 30625 Hannover, Germany
4. Erasmus Medical Center (T.J.V.), 3000-DR Rotterdam, The Netherlands