成熟にともなうアユの血中ステロイド量の変動〔英文〕

概要

論文の詳細を見る
Plasma levels of estradiol-17β, 17α-hydroxyprogesterone and 17α, 20β-dihydroxy-4-pregnen-3-one (17α, 20β-diOHprog) were measured by radioimmunoassay during various stages of sexual maturation in female ayu Plecoglossus altivelis. Estradiol-17β increased during vitellogenesis and rapidly decreased prior to final oocyte maturation, followed by a second rise during ovulation and spawning. This second rise of estradiol-17β maybe associated with the remaining vitellogenic oocytes in the ovary. Plasma 17α-hydroxyprogesterone and 17α, 20β-diOHprog profiles were similar during most periods of ovarian maturation. Both steroids remained very low throughout the vitellogenic stages but were extremely elevated during ovulation and spawning, and thereafter rapidly decreased to basal levels. A significant rise of 17α-hydroxyprogesterone was already apparent in the plasma of females collected at final maturation; however, 17α, 20β-diOHprog did not increase significantly until the time of ovulation, suggesting a role of 17α-hydroxyprogesterone as a precursor of 17α, 20β-diOHprog. These results provide further evidence that 17α, 20β-diOHprog is the natural maturation-inducing steroid in ayu.
日本水産學會の論文