Induction of female-to-male sex change in the honeycomb grouper (Epinephelus merra) by 11-ketotestosterone treatments
Induction of female-to-male sex change in the honeycomb grouper (Epinephelus merra) by 11-ketotestosterone treatments
复制标题
DOI：
10.2108/zsj.23.65
复制
发表时间：
2006-01-01
影响因子：
0.9
通讯作者：
Nakamura, Masaru
中科院分区：
文献类型：
--
作者：
Bhandari, Ramji Kumar;Alam, Mohammad Ashraful;Nakamura, Masaru
蜂窝石斑鱼（Epinephelus merra）是一种雌雄同体的鱼类。性类固醇激素在该物种的性别变化中起关键作用。内源性雌二醇-17 β (E2)水平的显著下降就会引发女性向男性的性别变化，随后11-酮睾酮（11KT）水平的升高与精子发生的进展有关。为了阐明雄激素在性别变化中的作用，我们尝试通过外源性11KT处理诱导雌性向雄性的性别变化。11KT处理75 d可使产卵前雌鱼100%雄性化。对照（载体处理）鱼的卵巢在卵发生的各个阶段都有卵母细胞，而11kt处理的鱼的性腺已经转化为睾丸；这些精子含有不同阶段的生精生殖细胞，包括精子在精子管中的积累。在变性鱼中，血浆E2水平显著降低，而睾酮(T)和11KT均显著升高。我们的结果表明11KT在蜂窝石斑鱼的性别变化中起着重要的作用。11kt诱导雌变雄的机制是通过直接刺激卵巢内精子发生，还是通过抑制雌激素合成，目前尚不清楚。
The honeycomb grouper, Epinephelus merra, is a protogynous hermaphrodite fish. Sex steroid hormones play key roles in sex change of this species. A significant drop in endogenous estradiol-17 beta (E2) levels alone triggers female-to-male sex change, and the subsequent elevation of 11-ketotestosterone (11KT) levels correlates with the progression of spermatogenesis. To elucidate the role of an androgen in sex change, we attempted to induce female-to-male sex change by exogenous 11KT treatments. The 75-day 11KT treatment caused 100% masculinization of pre-spawning females. Ovaries of the control (vehicle-treated) fish had oocytes at various stages of oogenesis, while the gonads of the 11KT-treated fish had transformed into testes; these contained spermatogenic germ cells at various stages, including an accumulation of spermatozoa in the sperm duct. In the sex-changed fish, plasma levels of E2 were significantly low, while both testosterone (T) and 11KT were significantly increased. Our results suggest that 11KT plays an important role in sex change in the honeycomb grouper. Whether the mechanism of 11 KT-Induced female-to-male sex change acts through direct stimulation of spermatogenesis in the ovary or via the inhibition of estrogen synthesis remains to be clarified.