中华绒螯蟹大颚器激素生物合成与性早熟的关系

The relationship between hormone biosynthesis of mandibular organ and precociousness in Eriocheir sinensis

运用放射化学方法跟踪测定中华绒螯蟹早熟个体和正常发育个体的大颚器合成和分泌的激素—甲基法尼酯(methylfarnesoate,MF),发现早熟雌、雄蟹当年9月的MF合成速率约为正常蟹的2倍,早熟蟹的MF在当年秋季(10月或11月)均达到峰值,之后MF合成速率显著降低,而成熟系数继续升高。正常发育的雌、雄幼蟹,当年至翌年4月的MF合成速率始终维持较低水平,翌年6月开始,MF合成速率迅速增大,至翌年10月的MF合成速率已超过早熟蟹的峰值,11月的MF合成速率明显降低,性腺发育至Ⅳ期末。研究结果表明:早熟蟹大颚器的提早发育,大量合成和分泌促性腺激素—MF,刺激卵巢或精巢发育成熟是导致性早熟的内分泌因素。

Methyl farnesoate (MF) biosynthesized and secreted by mandibular organ(MO) in Chinese mitten crab(Eriocheir sinensis), including precocious and normal crabs, was investigated by using in vitro radiochemical method. It was found that MF biosynthesis rates of precocious crabs (female and male) in September were about two times higher normal juvenile crabs, and reached the peak levels in October or November(1st autumn). After that, it decreased significantly, but GSI continued to increase during the winter. In normal crabs, MF biosynthetic rates maintained much lower levels from September(1st year) to April(2nd year) with undeveloped gonads. Since June (2nd year), MF biosynthetic rate increased rapidly. In October (2nd year), MF biosynthetic rates in both female and male were beyond the peak levels of precocious crab. In November, MF decreased significantly, while gonads reached the end of stage Ⅳ. The results indicated that MO development in advance in the precocious crabs(female and male), made large amount of MF to be biosynthesized and secreted and then stimulated ovaries and testes development and maturation. That is the endocrine factor for causing precociousness of crab.