性类固醇激素对黄颡鱼雌雄生长二态性的影响

为了研究性类固醇激素在雌雄生长二态性中(Sexual Size Dimorphism, SSD)的作用, 文章分析了性类固醇激素对雌雄生长、性腺发育和能量代谢的影响。结果显示: 17β-雌二醇(17β-estradiol, E₂)显著抑制黄颡鱼的生长, 且E₂显著促进能量在肝脏中的分配, 但在摄食量上无显著影响, 所以E2对黄颡鱼生长的抑制是能量分配的差异引起, 而不是能量获取差异引起。17α-甲基睾丸酮(17α-Methyltestosterone, MT)显著促进雌鱼生长, 但抑制雄鱼生长, MT能显著促进黄颡鱼摄食和肝脏的能量分配, 显著抑制卵母细胞的发育和卵巢的能量投入。本研究发现MT通过促进摄食, 抑制卵巢发育并且减少性腺发育的能量投入, 从而促进雌鱼生长; E₂能够显著增加雌雄鱼在肝脏中能量的投入, 最终抑制雌雄生长。实验结果只能部分解释实验中观察到的生长差异现象, 因此我们需要更进一步从能量的摄入、分配及消耗三方面来研究雌雄生长的二态性。

EFFECTS OF SEX STEROID HORMONES ON SEXUAL SIZE DIMORPHISM IN YELLOW CATFISH (TACHYSURUS FULVIDRACO)

Sexual size dimorphism (SSD) is the evolutionary result of choosing different sizes for males and females, which is widely found in the animal kingdom. In the past few years, the yellow catfish (Tachysurus fulvidraco) has been studied in many fields as an important economic fish. Males grow faster and larger than females, but the mechanism is still unclear. In order to investigate the role of sex steroid hormones on the SSD in yellow catfish, we studied the effects of estrogen and androgen on the growth, gonadal development, energy acquisition, and allocation. Results showed that 17β-estradiol (E₂) administration significantly inhibited the growth of both males and females, and promoted energy allocation to the liver without significantly impacting food intake, suggesting that the growth suppression of E₂ are induced by different energy allocation rather than the acquisition of food intake. Treatment with synthetic androgen 17α-Methyltestosterone (MT) significantly increased food intake, promoted energy allocation to the liver, and reduced energy allocation to the ovary in females, which may explain the significantly increased growth in MT-treated group. These results only partially explain the different growth of the experiment group, and further study on the dimorphism may focus on the three aspects of energy absorption, distribution and consumption.