Studies on endocrine system of amphioxus in comparison with vertebrates

为了考虑内分泌机制向脊椎动物的进化，对文昌鱼与脊椎动物属于同一门脊索动物的内分泌机制进行了研究。文昌鱼有一种常见的性激素合成途径，主要是5-α还原的类固醇。此外，糖蛋白激素、神经垂体激素、雌激素受体和促性腺激素释放激素受体的基因表达也显示在神经索的神经细胞中。这些结果表明，文昌鱼的许多内分泌物质与脊椎动物的内分泌物质同源，但作为神经内分泌系统在神经索中合成。

In order to consider the evolution of the endocrine mechanism to vertebrates, the endocrine mechanism of amphioxus belonging to the same phylum Chordata as vertebrates was investigated. There is a common sex steroidogenic pathway and 5α-reduced steroids is main in amphioxus. Furthermore, gene expressions of glycoprotein hormones, neurohypophyseal hormone, estrogen receptor and gonadotropin-releasing hormone receptors were shown in nerve cells of a nerve cord. These results suggest that many endocrine substances of amphioxus are homologous to those of vertebrates, but synthesized in a nerve cord as a neuroendocrine system.