HISTOLOGICAL STUDY OF THE SEMINIFEROUS EPITHELIUM IN THE JAPANESE RATSNAKE, ELAPHE CLIMACOPHORA - IDENTIFICATION OF SPERMATOGONIUM

To clarify the features of the seminiferous epithelium of the Japanese rat snake, Elaphe climacophora, the identification of spermatogonium and the examination of features of cell to cell junctions were perform ed in the present study. As for the identification, 5-bromo-2-deoxyuri dine (BrdU) incorporation was examined immunohistochemically to mark s permatogonia. The seminiferous epithelium was observed throughout a ye ar at the electron microscopic level. BrdU immunoreactivity was detect ed not only in the cells of the first layer of the seminiferous epithe lium but also in the second and/or third layers. The cells immunoreact ive in the first layer did not seem to attach to the basement membrane and were recognized throughout a year. To investigate cell to cell ju nctions, we performed actin filament detection by phalloidin staining. Distribution of actin filaments was different from that in mammalian species. At the ultrastructural level, Sertoli-Sertoli cell junctions were observed. Sertoli cells formed junctional complexes. Tight juncti ons were clearly found, but lacked the backing by actin filaments. The se results indicate that the blood-testis barrier of the Japanese rat snakes was structurally different from that of mammalian species. In c onclusion, the seminiferous epithelium of the Japanese rat snake is in termediate in morphology between amphibians and mammals.