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 Seasonal Changes of Gonadal Histology and Serum Steroid Hormone Levels in the Bambooleaf Wrasse Pseudolabrus japonicus
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.
日本水産学会誌 63(5), 694-700, 1997-09-15