ササノハベラの生殖腺と血中ステロイドホルモン量の季節変化 [in Japanese] Seasonal Changes of Gonadal Histology and Serum Steroid Hormone Levels in the Bambooleaf Wrasse Pseudolabrus japonicus [in Japanese]
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Seasonal gonadal develpment and changes in serum sex steroid hormone levels were investigated in female and secondary male bambooleaf wrasse, <i>Pseudolabrus japonicus</i>, from Ago Bay in Mie Prefecture from May to December 1991.<br>Seasonal changes of GSI and gonadal histology indicated that the gonadal maturation occurred during October and November. In females, serum 20β-S levels increased only during the spawning season (1, 560pg/m<i>l</i>), but 17, 20β-P showed high and constant levels (450-850pg/m<i>l</i>), suggesting that 20β-S may be involved in final oocyte maturation. The serum level of 11-KT in the secondary males showed a positive correlation with the testicular development; it peaked (2, 930pg/m<i>l</i>) in August when spermatogenesis actively proceeded, but decreased during the spawning season (960-1, 300pg/m<i>l</i>) when spermiation occurred. Serum 17, 20β-P in the secondary males fluctuated at low levels (160-420pg/m<i>l</i>) throughout the experimental period.
NSUGAF 63(5), 694-700, 1997-09-15
The Japanese Society of Fisheries Science