Title Reproduction and GnRH in Teleost Fish
Authers Masafumi AMANO
Keywords GnRH,GTH,water temperature,photoperiod,brain,pituitary
Citation Bull. Fish. Res. Agen. supplement No. 4, 71-73, 2006
Abstract
Gonadal maturation in teleost fish is primarily regulated by the brainpituitary-gonadal axis. Gonadotropin-releasing hormone (GnRH) stimulates the synthesis and release of pituitary gonadotropin (GTH), and GTH stimulates the secretion of steroid hormones from the gonads. Recent study has shown that in teleosts, two or three molecular forms of GnRH exist even within the same species. Three GnRH neuronal systems exist in teleost fish judging from the location of GnRH neuronal somata and their projections; the preoptic area GnRH system (GnRH-Ⅰ), the midbrain tegmentum GnRH system (GnRH-II), and the terminal nerve GnRH system (GnRH-III). Among the three GnRH systems, GnRH-Ⅰsystem is considered to regulate GTH secretion, because it is the main system that projects directly to the pituitary. GnRH-IIand GnRH-III systems are suggested to function as neuromodulators in the brain.
URI http://www.fra.affrc.go.jp/bulletin/bull/bull-b4/11.pdf