1. Endocrinology Department, Hospital de Especialidades, Centro Médico Nacional Siglo XXI, IMSS, Cuauhtémoc 330, Colonia Doctores, 06720 Mexico City, DF, Mexico
2. Experimental Endocrinology Investigation Unit, Hospital de Especialidades, Centro Médico Nacional Siglo XXI, IMSS, Cuauhtémoc 330, Colonia Doctores, 06720 Mexico City, DF, Mexico