Eel Biology pp 351-372 | Cite as

GTH and GnRH Molecules and Their Expression in the Japanese Eel

  • Hiroaki Suetake
  • Kataaki Okubo
  • Yasutoshi Yoshiura
  • Katsumi Aida


Many aspects in the reproductive cycle of the wild Japanese eel Anguilla japonica remain unclear. Female Japanese eels cultivated in freshwater ponds normally possess immature ovaries in which most developed oocytes are at the previtellogenic stage. Silver eels migrating in rivers or coastal areas toward their spawning grounds (Yamamoto et al. 1974) and eels reared for long terms in seawater ponds (Kagawa et al. 1998) exhibit oocytes at the early vitellogenic stage. However, under ordinary rearing conditions, further development of oocytes is not observed in the Japanese eel. The same phenomenon occurs in the European eel, Anguilla anguilla. The fact that eels do not mature spontaneously under captive conditions is considered to be related to a deficiency of pituitary gonadotropic function (Dufour et al. 1988).


Chum Salmon GnRH Receptor GnRH Neuron Ovarian Maturation GnRH Form 
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Copyright information

© Springer-Verlag Tokyo 2003

Authors and Affiliations

  • Hiroaki Suetake
    • 1
  • Kataaki Okubo
    • 2
  • Yasutoshi Yoshiura
    • 2
  • Katsumi Aida
    • 2
  1. 1.Fisheries Laboratory, Graduate School of Agricultural and Life SciencesThe University of TokyoMaisaka, Hamana, ShizuokaJapan
  2. 2.Department of Aquatic Bioscience, Graduate School of Agricultural and Life SciencesThe University of TokyoBunkyo-ku, TokyoJapan

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