High Temperature Causes Masculinization of Genetically Female Medaka by Elevation of Cortisol
High Temperature Causes Masculinization of Genetically Female Medaka by Elevation of Cortisol
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DOI：
10.1002/mrd.21203
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发表时间：
2010-08-01
影响因子：
2.5
通讯作者：
Kitano, Takeshi
中科院分区：
文献类型：
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作者：
Hayashi, Yuki;Kobira, Hiroshi;Kitano, Takeshi
在变温脊椎动物中，性别决定有时受到温度等环境因素的影响。然而，人们对环境性别决定的分子机制知之甚少。medaka （Oryzias latipes）是一种硬骨鱼，具有XX/XY性别决定系统。最近有报道称，XX medaka在性别分化期通过高水温（HT; 32-34℃）处理，可实现性别逆转为表型雄性。在这里，我们报道了皮质醇导致雌性向雄性的性别逆转，而甲替拉酮（一种皮质醇合成抑制剂）抑制ht诱导的XX medaka雄性化。激素治疗引起全身皮质醇水平升高，而在性别分化过程中，美替拉酮抑制激素治疗引起的皮质醇升高。此外，皮质醇和33℃处理抑制了XX medaka性别分化过程中雌性型生殖细胞的增殖以及促卵泡激素受体（fshr） mRNA的表达。这些结果强烈提示，HT通过升高皮质醇水平诱导XX medaka雄性化，从而抑制生殖细胞增殖和fshr mRNA表达。
In poikilothermic vertebrates, sex determination is sometimes influenced by environmental factors such as temperature. However, little is known about the molecular mechanisms underlying environmental sex determination. The medaka (Oryzias latipes) is a teleost fish with an XX/XY sex determination system. Recently, it was reported that XX medaka can be sex-reversed into phenotypic males by high water temperature (HT; 32-34 degrees C) treatment during the sex differentiation period. Here we report that cortisol caused female-to-male sex reversal and that metyrapone (an inhibitor of cortisol synthesis) inhibited HT-induced masculinization of XX medaka. HT treatment caused elevation of whole-body levels of cortisol, while metyrapone suppressed the elevation by HT treatment during sexual differentiation. Moreover, cortisol and 33 degrees C treatments inhibited female-type proliferation of germ cells as well as expression of follicle-stimulating hormone receptor (fshr) mRNA in XX medaka during sexual differentiation. These results strongly suggest that HT induces masculinization of XX medaka by elevation of cortisol level, which, in turn, causes suppression of germ cell proliferation and of fshr mRNA expression.