Testis İnişinin Moleküler Mekanizması

Erkeklerde spermatogenezin normal şekilde gerçekleşebilmesi için testislerin karın boşluğu dışında, vücuttan 2-3°C düşük sıcaklıkta skrotum adı verilen kese içerisine inmeleri gerekmektedir. Testis iniş mekanizması türler arasında farklılık gösterir. İnsanda testislerin intrabdominal seviyeden skrotuma inmeleri hormonal ve mekanik etkilere bağlı olarak transabdominal ve inguinoskrotal evreler sonunda gerçekleşmektedir. Kranial süspansör ligament dejenerasyonu ve gubernakular şişme reaksiyonu ile karakterize olan transabdominal evre Leydig hücrelerinden salınan INSL3 (İnsülin benzeri faktör-3) kontrolündedir. Testislerin inguinal kanaldan geçerek skrotuma indiği son evre olan inguinoskrotal evre ise androjen bağımlıdır. Testislerin iniş süreci INSL3 ve androjenler dışında, Sertoli hücrelerinden salınan MIS (Mülleryan inhibe edici madde), peritoneal bir divertikül olan vaginal prosses, meme hattı altındaki MFP (Meme yağ yastıkçığı) ile Hox genlerinin rol oynadığı kompleks bir süreçtir. Testis iniş mekanizmasında meydana gelen herhangi bir aksaklık durumunda, infertilite ve testiküler kanser nedenleri arasında sayılan anorşi, refraktil testis, kriptorşidizm ve ektopik testis görülebilmektedir.

Molecular Mechanism of Testis Descent

In order for spermatogenesis to occur normally in men, the testes must descend into the sac called scrotum at 2-3°Clower temperature than the abdominal cavity. Although the testes descent mechanism differs between the species.Testicular descent from the intrabdominal level to the scrotum occurs due to hormonal and mechanical effects. at theend of the transabdominal and inguin oscrotal stages in man. Transabdominal stage, which is characterized by cranialsuspensory ligament degeneration and gubernacular swelling reaction, is under the control of INSL3 (Insulin-likefactor-3) released from the Leydig cells. Inguinoscrotal stage, where the testes pass through the inguinal canal andreach the scrotum, is androgen dependent. Except for INSL3 and androgens, MIS (Mullerian inhibitory agent) releasedfrom Sertoli cells, vaginal process which is a peritoneal dirverticulum, MFP (Mammary fat pad) under the mammaryline and Hox genes take part in this complex testicular descent process. In case of any faulty that may occur in thetestes descending mechanism, anorchia, refractory testis, cryptorchidism and ectopic testis which are the causes ofinfertility and testicular cancer, may be observed.

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ISSN: 1300-3755
Yayın Aralığı: Yılda 4 Sayı
Başlangıç: 1992
Yayıncı: Çukurova Üniversitesi Tıp Fakültesi

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