The Polysialic Acid (PSA), glycosydic moiety of the Neural Cell Adhesion Molecule (N-CAM), and alpha- and beta-Catenins, which mediate interaction between Cadherins and cytoskeletal proteins, participate in cell adhesion phenomena in numerous organs and tissues. We have performed an immunohistochemical analysis, in hibernating toad testis and in GnRH-reactivated hibernating animals. In hibernating toads we could demonstrate PSA-immunoreactivity (PSA-IR) within the seminiferous tubules, in clusters of primary spermatocytes, spermatids and spermatozoa, in follicular and Sertoli cells. PSA-IR was seen in peritubular, Leydig and efferent duct cells. In GnRH-treated toads PSA-IR persists in primary spermatocyte groups. alpha-Catenin is localized in the basal laminae of seminiferous tubules and in Leydig cells of hibernating toads. This did not change after hormonal treatment. In hibernating toads, beta-Catenin was detected only in Leydig cells and within seminiferous tubules on basal spermatocystes and limiting spermatozoa clusters. In GnRH-treated toads, the beta-Catenin-IR was less intense in Leydig cells and vanished within seminiferous tubules.