Fig. 5.

Integrity of the BTB in EI testes. The seminiferous epithelium of EI-240 testes after the administration of lanthanum; thin sections were examined without staining. The tracer was not detected in the intercellular cleft around the germ cells (A). In contrast, the electron tracer penetrated into the spaces between adjacent Sertoli cells in the adluminal compartment up to the lumen (B, arrows). The asterisk indicates the same mature spermatid (A and B). L, lumen of seminiferous tubule; G, germ cell; BL, basal lamina.