飼育下におけるマイワシ雄の生殖年周期および性成熟に伴う血中ステロイドホルモン量の変動

書誌事項

タイトル別名
  • Testicular development and serum levels of gonadal steroeds during the annual reproductive cycle of captive Japanese sardine.

抄録

Gonad and blood samples were taken throughout the year from captive males of the Japanese sardine, Sardinops melanostictus, and changes in serum levels of gonadal steroids were examined in relation to the annual gonadal cycle. On the basis of testicular histology, the annual gonadal cycle was divisible into four periods: immature (July-September), spermatogenesis (October-December), spermiation (January-April), and post-spawning (May-June). The pattern of seasonal changes in the gonadosomatic index (GSI) was inversely correlated with that of water temperature, and reflected the degree of testicular maturity. The serum testosterone level was relatively low during spermatogenesis (2.2-2.5ng/ml), rose markedly around the time of spermiation (7.7-24.6ng/ml), and became low after spawning and during immature periods (0.6-0.7ng/ml). The serum 17α, 20/β-dihydroxy-4-pregnen-3-one level was high in males with spermatogenic or spermiating testes (0.6-1.0ng/ml), but became low (0.2ng/ ml) during the post-spawning period and was undetectable in immature fish. Although 11-ketotestosterone was detectable in some fish, the values obtained were thought to reflect cross-reactivity of the antiserum employed with testosterone. These findings are discussed in relation to male reproduction of the Japanese sardine and steroidal regulation of spermatogenesis and spermiation in other teleosts.

収録刊行物

  • 魚類学雑誌

    魚類学雑誌 37 (4), 381-390, 1991

    The Ichthyological Society of Japan

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詳細情報 詳細情報について

  • CRID
    1390282679740015872
  • NII論文ID
    130004019062
  • DOI
    10.11369/jji1950.37.381
  • ISSN
    18847374
    00215090
  • 本文言語コード
    en
  • データソース種別
    • JaLC
    • CiNii Articles
  • 抄録ライセンスフラグ
    使用不可

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