Spermatogenetic arrest with inhibition of acrosome and sperm tail development.

Testicular biopsies from two brothers with pathologic spermatograms revealed a spermatogenetic arrest at early spermatid maturation. No sign of acrosome or sperm tail formation was found in spermatids. Using a polyclonal antibody against vimentin, Sertoli cells appeared in the normal shape and distribution pattern. At the ultrastructural level no significant pathologic alterations of Sertoli cells were visible. A monoclonal antibody against tubulin gave a diffuse perinuclear reaction in spermatogonia, spermatocytes and spermatids. Some tubulin-immunoreactive material was also present in the apical portions of the Sertoli cells. Ultrastructural studies of spermatids revealed a complete absence of the centrioles and axonemal structures in early spermatids. Acrosome formation was inhibited at the early Golgi stage. The numerous spermatids present within germinal epithelium contained an abundance of elongate mitochondria and membrane profiles surrounding the nucleus. The ultrastructural findings indicate a maturation stop of spermatids at a very early stage with complete inhibition of acrosome and sperm tail formation. The underlying mechanism could be a lack of specific structural proteins.