Hirohiko Kagawa

TL;DR: Repeated injections of salmon pituitary extract induced vitellogenesis in feminized, cultivated Japanese eels, and many fertilized eggs from cultivated eels are obtained using these techniques developed for female and male eels.

TL;DR: A two-cell-type model for the production of follicular estrogens, the thecal layer possibly contributing to estradiol-17β production by synthesizing androgens which are transferred to the granulosa layer and aromatized to est radiol- 17β is suggested.

TL;DR: It is found that a slurry-type diet made from shark egg powder is suitable feed for captive-bred eel larvae and revealed for the first time the transition from the preleptocephalus to the leptocephali stage of the eel.

TL;DR: Levels of plasma estradiol-17β, testosterone, progesterone, 17α-hydroxyprogesterone,17α-OHprog and 17α, 20β-dihydroxy-4-pregnen-3-one and 17β-diOH Progestogens were assayed during gonadal maturation in female goldfish Carassius auratus which have an asynchronous ovary in which oocytes are found at various stages of development.

TL;DR: Evidence is provided that gonadotropin directly controls estradiol-17β production in amago salmon follicles, and this work is the first to demonstrate that in vitro gonadotropic activity in oocytes surrounded by follicle layers of amago Salmon is regulated by a single substance.