2 0 0 0 キンギョ1年魚の精巣活動と関連ホルモンに及ぼす環境の影響
- 著者
- ラザニ ホセイン 羽生 功 会田 勝美
- 出版者
- 日本水産學會
- 雑誌
- 日本水産学会誌 (ISSN:00215392)
- 巻号頁・発行日
- vol.54, no.9, pp.1513-1520, 1988
- 被引用文献数
- 3 10
Under natural condition, yearling male goldfish <i>Carassius auratus</i> started regression by late July and completed in August. Then gonadal development commenced and proceeded to milting by October. Spermatogenesis was arrested in winter. However, milting fish appeared again in March.<br> When transferred to 24°C, the male fish matured within a short period at both 12L and 16L in off breeding seasons. However, the minimum time needed for reaching milting was shorter at 16L than at 12L. On both regimes, the spawning stage did not last long but passed to the post-spawning stage. Conversely, males matured and stayed in milting condition at 16°C regardless of photoperiod. The speed of maturation was slower at 16°C than at 24°C regimes.<br> Plasma testosterone levels were high when the fish was maturing or matured but low in immature fish. Plasma gonadotropin levels were more dependent on the water temperature than on the maturation stages. Plasma thyroxine levels did not show clear relationship to the testicular activity at both 16°C and 24°C regimes.
1 0 0 0 OA HCG投与によるキンギョの排卵誘発時における血中GtHおよびステロイドホルモン濃度の変化
- 著者
- 森脇 俊尚 小林 牧人 会田 勝美 羽生 功
- 出版者
- 公益社団法人 日本水産学会
- 雑誌
- 日本水産学会誌 (ISSN:00215392)
- 巻号頁・発行日
- vol.57, no.1, pp.41-43, 1991-01-25 (Released:2008-02-29)
- 参考文献数
- 12
- 被引用文献数
- 8 9
Changes in plasma gonadotropin (GtH) and steroid hormone levels were investigated during ovulation induced by human chorionic gonadotropin (HCG) in female goldfish. Sexually mature female goldfish maintained at 20°C under 14L10D (lights on at 0430hr) were injected with HCG at a dose of 10IU/g BW at 2100hr. Twenty-one fish out of 28 ovulated between 9 and 18 hours (0600 to 1500hr) after injection. In ovulatory fish, there was neither a significant increase nor surge in plasma GtH levels after the injection, whereas plasma testosterone and 17α, 20β-dihydroxy-4-pregnen-3-one levels showed changes similar to those occurring in spontaneous ovulation. These results suggest that injected HCG acts directly on the ovary without accelerating endogenous GtH secretion, and therefore induces ovulation in a similar manner as does the ovulatory GtH surge in spontaneous ovulation.