Three-dimensional structure of the Sertoli cell in the shiba goat.

The three-dimensional structure of the Sertoli cell in the miniature "shiba" goat was examined using scanning electron microscopy. In the basal portion of the seminiferous epithelium, spermatogonia and/or spermatocytes were located in compartments enclosed by adjacent Sertoli cells. From the basal aspect, they were situated in successive recesses. In the middle portion, early round spermatids halfway embedded in the Sertoli cell were recognized. The exposed surfaces of these spermatids were wrapped with ramifying processes which were derived from the Sertoli cell. In the apical portion, only the heads of the maturing spermatids invaded the Sertoli cell. As the spermatid matured, the apical Sertoli process varied in range to finally release the spermatid head. It is probably that the maturing spermatids gradually leave the apical Sertoli process and ultimately segregate themselves from the seminiferous epithelium.