Endocrine control of diurnal oocyte maturation in the kyusen wrasse, Halichoeres poecilopterus

Michiya Matsuyama, Shin Onozato, Masaaki Kashiwagi

研究成果: ジャーナルへの寄稿学術誌査読

18 被引用数 (Scopus)


The present study examined diurnal cycles of oocyte development and maturation in the kyusen wrasse, Halichoeres poecilopterus, and investigated the sensitivity of oocytes to maturation-inducing hormone (MIH) and gonadotropic hormone (GTH). Female fish were sampled at fixed intervals throughout the day, revealing that final oocyte maturation and ovulation were completed by 6:00 hr, and that spawning occurred daily between 6:00 and 9:00 hr. In vitro experiments showed that the steroids 17,20β-dihydroxy-4-pregnen-3-one (17,20β-P) and 17,20β,21-trihydroxy-4-pregnen-3-one (20β-S) were equally potent and highly effective inducers of germinal vesicle breakdown (GVBD) in kyusen wrasse oocytes. Additionally, circulating levels of 17,20β-P and 20β-S increased around the rime of GVBD and ovulation, suggesting that 17,20β-P and 20β-S act as MIHs in the kyusen wrasse. Moreover, in vitro experiments clearly showed that kyusen wrasse oocytes had a daily developmental cycle of GTH and MIH sensitivity, and that oocytes that completed vitellogenesis acquired GTH-induced maturational competence. Ah endogenous GTH surge likely occurs between 12:00 and 15:00 hr, and this daily pre-maturational GTH surge probably controls the diurnal maturation cycles of kyusen wrasse oocytes.

ジャーナルZoological science
出版ステータス出版済み - 9月 1 2002

!!!All Science Journal Classification (ASJC) codes

  • 動物科学および動物学


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