Brief Communication

Nonlinear dynamics of endocrine feedback in hypothalamico-pituitary-ovarian (HPO) axis and its prospective role in screening and understanding etiology of ovarian cancer

  • Chinmoy K. Bose

Received Date: 17.11.2006 Accepted Date: 21.02.2007 J Turk Ger Gynecol Assoc 2007;8(1):76-79

The idea of feedback mechanisms in endocrine medicine has remained ill conceived especially in the light of modern control theory where energy transfer is understood in a system wise fashion. The idea is based on reductionism i.e. describing function on a discrete molecular level whilst at the macro level the desired accuracy is not achieved. Endocrinology text books have even gone with this wind of discreteness, some even drastically cut the subject to a bare minimum probably agreeing to the sanctity of its omnipotence. End product inhibition, regulatory enzymes, allosteric configuration changes and other physiological phenomena are examples of biological feedback mechanisms. It is not astonishing that modern control theory with all its mathematical facets has already gained a perceptible entry into the endocrinology literature. Applications of chaos theory in gynaecology and obstetrics were proposed in the early 1980ties. Applications of biomathematics including nonlinear control theory is fast gaining ground and, like molecular biology in last decade can not be ignored anymore. For our understanding of hormone function to progress, endocrinological feedback mechanisms as part of gynaecological and obstetric assessment needs to be understood within complex systems science. Turkish Hipotalamik-pituiter-over (HPO) aksinda endokrin geri-beslemein non-lineer dinamigi ve bunun over kanserini tarama ve etiyolojisini anlamadaki prospektif rolü Özellikle enerji transferinin sisteme dayali bir sekilde görüldügü modern kontrol teknolojisinin isiginda bakildiginda, endokrin tipta geri-besleme mekanizmasi fikrine hala süpheyle bakilmaktadir. Bu fikir redüksiyonizme, yani makro seviyede arzulanan titiz ölçüm degerlerine ulasilamazken, fonksiyonu belirsiz moleküler seviyede tanimlamaya dayanmaktadir. Endokrinoloji kitaplari bu belirsizlik akimina kapilmakla kalmayip, bazilari belki de bu akimin her seye kadir kutsalligini onayladiklarindan, geri-besleme mekanizmasi fikrine gerekli önemi vermemislerdir. Son ürün inhibisyonu, düzenleyici enzimler, allosterik dizilim degisiklikleri ve diger fizyolojik fenomenler biyolojik geri-besleme mekanizma örnekleridir. Tüm matematiksel boyutlariyla ele alindiginda, modern kontrol teorilerinin endokrinoloji literatürüne kayda deger bir sekilde girmesi sasirtici degildir. Kaos teorisinin jinekoloji ve obstetrikte uygulanmasi 80’lerin basinda önerilmistir. Non-lineer kontrol teorisini içeren biyomatematik uygulamalari hizla yayginlasmaktadir ve son 10 yilda moleküler biyolojide oldugu gibi, artik göz ardi edilemez. Hormon fonksiyonlarini daha iyi anlayabilmemiz için jinekolojik ve obstetrik degerlendirmenin bir bölümü olarak endokrinolojik geri-besleme mekanizmalarinin kompleks sistem bilimi kapsaminda anlasilmasi gerekir.

Keywords: endocrine feedback, dynamical system, Lyapunav exponent, nonlinearity, ovarian cancer