mmunohistochemical localization of gonadotropin-releasing hormone receptors (GnRHR) in the nervous system, Hatschek's pit and gonads of amphioxus, Branchiostoma belcheri

Using gonadotropin-releasing hormone (GnRH) anti-idiotypic antibodies and APA im-munohistochemical method, the immunoreactivity of GnRHR in the nervous system, Hatschek's pit and gonads of amphioxus has been located. It is found for the first time that the immunoreactivity of GnRHR exists in the nerve cells and fibers in the amphioxus's brain and nerve tube and the epithelial cells of Hatschek's pit at the different stages of gonadal development. At the same time, it is also found that GnRHR also exists in the ovary and testis of different developed stages. These findings provide morphological new proof for the informative transfer and regulation between brain and Hatschek's pit mediation by GnRHR, and for the understanding of the mechanism of action on the reproductive endocrine control axis among brain-Hatschek's pit-go-nads.