Oocyte Maturation Process and Affecting Factors

Yıl 2009, Cilt: 18 Sayı: 4, 227 - 240, 01.12.2009

Yurdun Kuyucu Özgül Tap

Öz

Normal female fertility depends on normally occuring oogenesis and maturation progress. Oogenesis and folliculogenesis are different progresses but occure in a harmony and at the same time. Oogenesis includes the events that take place matur ovum produced from primordial germ cells. Although folliculogenesis includes the stages primordial, primary, secondary, matur (Graaf) follicules in the influece of gonadotropines and local growth factors. During oocyte maturation meiosis is distrupted till the puberty. Under LH influence it starts again and first meiosis completes before ovulation. Oocyte maturation can be regarded as the process of coming metaphase II from prophase I of oocyte at the puberty and can be studied as nuclear and cytoplasmic maturation. Meiosis is completed when fertilization occures and zygot is formed. In this article oogenesis, folliculogenesis and oocyte maturation process are summerized with related studies and reiews are revised.

Anahtar Kelimeler

Oogenesis, folliculogenesis, oocyte maturation, MPF

Oosit Olgunlaşma Süreci ve Düzenleyici Faktörler

Öz

Normal dişi fertilitesi, oosit gelişim ve olgunlaşmasının doğru şekilde gerçekleşmesine bağlıdır. Oogenezis ve follikülogenezis farklı olaylardır ancak uyumlu ve eşzamanlı oluşurlar. Oogenezis, primordiyal germ hücrelerinden olgun ovum meydana gelinceye kadar süren olayları kapsar. Follikülogenezis ise gonadotropin ve lokal büyüme faktörleri etkisi altında oluşan primordiyal, primer, sekonder, olgun (Graaf) follikül evrelerini içerir. Oosit maturasyonu sırasında mayoz bölünme, puberteye kadar kesintiye uğramaktadır . LH etkisi ile tekrar ilerlemeye başlayarak ovulasyon öncesinde I. mayoz bölünme tamamlanır. Oosit maturasyonu pübertede profaz I aşamasındaki oositin metafaz II aşamasına gelmesi olarak kabul edilebilir ve nüklear ve sitoplazmik maturasyon olarak incelenmektedir. İkinci mayoz bölünme fertilizasyonun gerçekleşmesi ile birlikte tamamlanır ve zigot oluşur. Bu makalede oogenezis, follikülogenezis ve oosit maturasyon süreci, ilgili çalışma ve derlemeler gözden geçirilerek, özetlenmiştir.

Anahtar Kelimeler

Oogenezis, follikülogenezis, oosit maturasyonu, MPF

Kaynakça

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