Hormonal regulation of oocyte development and maturation of amphioxus.

Using the electron microscopic technique and radioimmunoassay, the hormonal regulation of the oocyte development and maturation of the amphioxus has been investigated. The results indicate that the exogenous GnRH-A can stimulate the oocyte development and maturation as well as the spawning of the amphioxus. It has further been revealed by radioimmunoassay that GnRH-A can increase the context of sex steroid hormone, especially, estradiol-17 beta, by 1-3 times. The increase of estradiol-17 beta coordinates with the synthesis of oocyte into yolk substance. The results further justify that the hormonal regulation in the oocyte development and maturation of amphioxus is similar to that of vertebrates. This is of great theoretical significance for reproductive endocrine physiology of amphioxus.