Differentiation and Polarized Function of Sertoli Cells In Vitro

The seminiferous epithelium is composed of two populations of cell types, supportive epithelial elements, the highly polarized Sertoli cells and differentiating elements, the germ cells. The Sertoli cell is a tall, narrow, columnar cell that extends from the basal lamina of the seminiferous epithelium to the tubule lumen. It possesses numerous lateral branches which surround the developing germ cells and it appears to provide support for their differentiation. The basal aspects of the Sertoli cells are linked by specialized tight junctional complexes and these junctions subdivide the seminiferous epithelium into two compartments, basal and apical (Dym and Fawcett, 1970). The tight junctions form the morphological basis of the blood-testis barrier. The basal domain of the cell, in contact with extracellular matrix molecules, possesses receptors for circulating plasma constituents (e.g., FSH receptors — Orth and Christensen, 1977). The apical surface of the cell, in contact with the tubule lumen, is undoubtedly involved in sperm release (Fawcett, 1975). An examination of the ultrastructure of the Sertoli cell reveals a highly polar organization of the organelles (Fawcett, 1975).