1. Veterans Administration Hospital, University of Texas Southwestern Medical School, Dallas 75216
2. Department of Physiology, University of Texas Southwestern Medical School, Dallas 75216
3. Department of Internal Medicine, University of Texas Southwestern Medical School, Dallas 75216
4. Department of Biochemistry, University of Texas Southwestern Medical School, Dallas 75216
5. Hormone Laboratory, Fundacion Jimenez Diaz, Ciudad Universitaria, Madrid. Spain
6. Institut d'Histologie et Embryologie, Ecole de Medecine, Université de Genève, Geneva, Switzerland