The Role of Activin in Spermatogenesis in Fish

摘要: Spermatogenesis is an extended process of differentiation and maturation germ cells resulting in haploid spermatozoa. Although it generally accepted that the principal stimuli for vertebrate spermatogenesis are pituitary gonadotropins androgens, specific role played by individual hormones has not been clarified (1–4). Progress this field hampered complex organization testis higher vertebrates, which seminiferous tubules contain several successive generations cells. In contrast, certain teleosts, such as eel salmonid fishes, advantageous studying regulation a result synchronous development (5, 6). Within lobules, spermatogonia undergo numerous mitotic divisions produce cysts, each containing spermatogonia. During maturation, all within cyst at approximately same stage development. As then spermiogenesis proceed, cysts expand eventually rupture, liberating spermatozoa into lobular lumen continuous with sperm duct. This chapter summarizes current view on testes, particular emphasis activin B initiation spermatogenesis. Most data presented still unpublished.