Proacrosin and the Differentiation of the Spermatozoa

Using the indirect immunofluorescence staining technique, the occurrence and localization of proacrosin, the zymogen form of acrosin, was studied during sperinatogenesis in the bull, rain, boar and rabbit. Proacrosin staining was demonstrable for the first time in the early hapboid spermatid and increased with the differentiation of the spermatid to spermatozoon. The spermatozoon is covered by a cap.bike structure of uniform fluorescence corresponding to the acrosomal compart-ment of the male gamete. No fluorescence could be found in dipboid spermatogenic cells, i.e., in spermatogonia and spermatocytes. An identical developmental pattern of proacrosin was ob-served with the indirect immunoperoxidase staining technique. However, with this staining tech-nique a distinct distribution of proacrosin staining was observed in the acrosome of epididymal and ejaculated spermatozoa of the bull, ram, boar, rabbit and man. Proacrosin seems to be distributed in the acrosome in granules rather than in the homogeneous form, as was indicated by the results of indirect immunofluorescence staining