Sertoli Cells

Sertoli cells are located in the germinal epithelium and play a supportive role in the development of spermatozoa. These cells have abundant cytoplasm, extending from the basement membrane to the lumen. Sertoli cells have a characteristic oval nucleus with hyperchromatic nucleolus. The cytoplasmic contents and blood-testis barrier are clearly visualized under the electron microscope.

Like all epithelial cells, the Sertoli cells are avascular. Sertoli cells support the germ cell progenitors and help to transfer nutrients from the nearby capillaries. The developing spermatogonia depend on the Sertoli cells for all of their nourishment. The blood-testis barrier formed by Sertoli cells effectively isolates the developing spermatogonia, spermatocytes, spermatids and mature spermatozoa from blood. Differentiating spermatozoa nestle in pockets in the peripheral cytoplasm of these cells.

Sertoli cells also produce testicular fluid, including a protein that binds to and concentrates testosterone, which is essential for the development of the spermatozoa. They also aid in the translocation of differentiated cells into the lumen, and phagocytosing degenerated germ cells and surplus cytoplasm remaining from spermiogenesis.