1. The Wenner-Gren Institute, Biologihus F3, University of Stockholm, S-106 91 Stockholm, Sweden
2. Departamento Endocrinología Experimental, Instituto de Investigaciones Biomédicas, Facultad Autónoma de Medicina (U.A.M.). Arzobispo Morcillo 4. E-28029 Madrid, Spain
3. Research Veterans Administration, Wadsworth Medical Center, Los Angeles, CA 90073, U.S.A.