MORPHOLOGICAL AND ENZYMATIC STUDY OF MEMBRANE-BOUND VESICLES FROM THELUMEN OF THE RAT EPIDIDYMIS

The epithelium of caput and cauda epididymidis of the rat was studied with transmission electron microscopy (TEM) and freeze-fracture techni ques. In thin sections of both zones, the tissue consisted mainly of t all columnar cells (principal cells) with long stereocilia. Clusters o f small membrane-bound vesicles were located in the lumen between or i mmediately over the stereocilia. Freeze-fracture replicas also display ed groups of smooth-surface vesicles in the same location. Membrane-bo und vesicles isolated from the lumen of the rat epididymis were studie d by TEM. In thin sections, some of them contained an electron dense m aterial and others looked empty. In addition, the hydrolases: beta-gal actosidase, N-acetyl-glycosaminidase, alpha-mannosidase, aryl-sulfatas e and beta-glucuronidase were detectable in pellets of vesicles treate d with Triton X-100. The results presented here indicate the presence of membrane-bound vesicles observed by two different methodologies in the rat epididymal fluid and demonstrate five glycosidases in their co ntent.