Ultrastructure of human Sertoli cells at early gonad embryogenesis Ultrastructure des cellules de Sertoli humaines aux stades embryonnaires precoces de la differenciation gonadique

Abstract

The morphofunctional development of Sertoli cells defines the testicular differentiation. These somatic cells are mostly of mesonephric origin and can be first recognized in 7 week-old embryos altogether with the formation of testicular cords. The latter organize as primordial germ cells surrounded by pre-Sertoli cells. Due to the great synthetic activity of pre-Sertoli cells the rough endoplasmic reticulum develops. The basal lamina of the cords becomes distinguishable at 7 to 8 weeks of development. Either prespermatogonia and pre-Sertoli cells actively proliferate but the latter greatly outnumber prespermatogonia. Many interdigitations and cytoplasmic processes are observed between neighboring pre-Sertoli cells. Due to the proliferative activity a sort of compartmentalization is established inside the cords in which pre-Sertoli cells tend to localize closer to the basal membrane embracing the prespermatogonia with long and thin cytoplasmic processes. One of the main features typical