The Terminal Segment of the Seminiferous Tubules and the Blood-Testis Barrier Before and After Efferent Ductule Ligation in the Rat

The ultrastructure of modified Sertoli cells in the terminal segment of the seminiferous tubules in the rat was studied in material fixed by perfusion through the thoracic or the abdominal aorta. The central lumen of the terminal segment was not distinct under normal conditions, but became quite evident with an increased intratesticular pressure caused by efferent ductule ligation. The modified Sertoli cells were characterized by a marked increase in number of microtubules and microfilaments, extensive inter-Sertoli cell junctions, vacuolated cytoplasm, and considerably dilated intercellular spaces. Three types of specialized cell contacts were found between modified Sertoli cells: typical inter-Sertoli cell junctions, desmosome-like devices, and septate-like tight junctions. These specialized cell contacts were efficient in preventing lanthanum to penetrate into the lumen of the terminal segment both before and after efferent ductule ligation. Moreover, it was found that typical inter-Sertoli cell junctions prevented lanthanum penetration into the adluminal compartment of the seminiferous tubules even after efferent ductule ligation.