Entactin ultrastructural immunolocalization in the basal laminae of mouse seminiferous tubules and with only subtle changes following hypophysectomy.

While entactin has been recently reported in the mouse seminiferous tubule lamina propria at the light microscope level, the purpose of this paper was twofold: 1) to determine the ultrastructural localization of entactin with the two basal laminae that form the lamina propria of the mouse, and 2) to determine if immunoreactive entactin changes following hypophysectomy. The localization of entactin was demonstrated by three different means: 1) immunofluorescent localization in semi-thin cryosections of the testis, 2) immunoperoxidase staining in a preparation of isolated lamina propria, and 3) immuno-gold staining in ultra-thin sections of testis. These techniques all demonstrated that immunoreactive entactin is present in both the inner and outer basal laminae of the mouse seminiferous tubules and is co-localized with laminin. These results are consistent with previous work that demonstrated entactin is synthesized and secreted by both Sertoli and peritubular myoid cells. Because both Sertoli cells and peritubular myoid cells are androgen-responsive cells, we wanted to determine if hypophysectomy alters the testicular distribution of entactin. Changes in immunoreactive entactin and laminin in the basal laminae were observed in semi-thin cryosections of the testes from hypophysectomized mice up to 6 weeks after surgery. The results demonstrated that during this time period, while most of the spermatogenic cells degenerated, the intensity of immunoreactive entactin and laminin remained nearly unchanged, as the seminiferous tubule basal laminae took on an increasingly wavy appearance. This suggests that the relative concentration of entactin and laminin in the basal lamina is stable, and not dependent on the presence of normal spermatogenesis and pituitary hormones.