The blood-testis barrier in men of diverse fertility status: an ultrastructural study.

The permeability of the blood-testis barrier was studied in 41 men of diverse fertility status by observing the distribution of lanthanum, and electron-opaque tracer administered during immersion fixation of testicular biopsies. Evidence for barrier mechanisms operating at the specialised tight junctions between Sertoli cells was seen in all specimens. In approximately one half of the seminiferous tubules examined this barrier appeared to be less effective as seen by the penetration of lanthanum past the Sertoli cell tight junctions. This phenomenon was found to be significantly related to both the tubular spermatogenetic activity as measured by a scoring method and the presence of subcellular changes in the Sertoli cells. A depression of spermatogenesis was associated with an increase in the incidence of tubules with apparently defective tight junctions. In men with obstructive azoospermia there was no increase in the incidence of this phenomenon.