1. Department of Physiological Sciences, Physiology Unit, Faculty of Medicine and Health Sciences, Bellvitge Campus, Universitat de Barcelona, IDIBELL, L'Hospitalet del Llobregat, 08907 Barcelona, Spain
2. Department of Gynecology, Gynecological Endocrinology and Reproduction Unit, Hospital Universitari Sant Joan de D�u, Esplugues de Llobregat, 08950 Barcelona, Spain
3. Department of Basic Nursing, Faculty of Medicine and Health Sciences, Universitat de Barcelona, IDIBELL, L' Hospital et del Llobregat, 08907 Barcelona, Spain
4. Sanford Burnham Prebys Medical Discovery Institute (SBP), La Jolla, CA 92037, USA