caa a22 4500 477140556 CHVBK 20180405111731.0 cr unu---uuuuu 170330e19971101xx s 000 0 eng 10.1007/s002850050092 doi (NATIONALLICENCE)springer-10.1007/s002850050092 Modelling the control of ovulation and polycystic ovary syndrome [Elektronische Daten] [A. Chávez-Ross, S. Franks, H. D. Mason, K. Hardy, J. Stark] Abstract.:  The control of ovulation in mammalian species appears to be a highly robust process. The primary mechanism is believed to be competition amongst a group of developing follicles, mediated by a hormonal feedback loop involving in the first instance the pituitary. Successful follicles reach maturity and ovulate, the remainder atrophy and die. A model of this control process has been derived by Lacker and his group. Based on simple qualitative assumptions about the hormonal feedback loop, this is able to reflect many of the basic physiological features of ovulation in mammals. However, a fundamental hypothesis of Lacker's work is that all follicles are identical and respond to hormonal signals in precisely the same way. Not only is this improbable, but it also leads to several aspects of the model which are qualitatively unrealistic, most notable of these is its inability to accurately model the condition known as Polycystic Ovary Syndrome. This common malfunction of the ovulatory control mechanism accounts for up to three-quarters of cases of anovulatory infertility in humans and its understanding is therefore of considerable medical significance. In this paper we extend the analysis of Lacker's model to the case of non-identical follicles; this allows us to obtain behaviour much closer to that observed in PCOS patients and to draw some tentative conclusions about the mechanisms underlying this condition. Springer-Verlag Berlin Heidelberg, 1997 Key words: Ovulation nationallicence Lacker models nationallicence Polycystic ovary syndrome nationallicence PCOS nationallicence Chávez-Ross A. Centre for Nonlinear Dynamics and its Applications, University College London,Gower Street, London, WCIE 6BT, UK, GB aut Franks S. Department of Obstetrics and Gynaecology, St. Mary's Hospital Medical School, Imperial College of Science Technology and Medicine, London, W2 1PG, UK, GB aut Mason H. D. Department of Obstetrics and Gynaecology, St. Mary's Hospital Medical School, Imperial College of Science Technology and Medicine, London, W2 1PG, UK, GB aut Hardy K. Human Embryology Laboratory, Institute of Obstetrics and Gynaecology, Royal Postgraduate Medical School, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK, GB aut Stark J. Centre for Nonlinear Dynamics and its Applications, University College London,Gower Street, London, WCIE 6BT, UK, GB aut https://doi.org/10.1007/s002850050092 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s002850050092 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Chávez-Ross A. Centre for Nonlinear Dynamics and its Applications, University College London,Gower Street, London, WCIE 6BT, UK, GB aut NATIONALLICENCE 700 1- Franks S. Department of Obstetrics and Gynaecology, St. Mary's Hospital Medical School, Imperial College of Science Technology and Medicine, London, W2 1PG, UK, GB aut NATIONALLICENCE 700 1- Mason H. D. Department of Obstetrics and Gynaecology, St. Mary's Hospital Medical School, Imperial College of Science Technology and Medicine, London, W2 1PG, UK, GB aut NATIONALLICENCE 700 1- Hardy K. Human Embryology Laboratory, Institute of Obstetrics and Gynaecology, Royal Postgraduate Medical School, Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK, GB aut NATIONALLICENCE 700 1- Stark J. Centre for Nonlinear Dynamics and its Applications, University College London,Gower Street, London, WCIE 6BT, UK, GB aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer