The Highly Conserved Gonadotropin-Releasing Hormone-2 Form Acts as a Melatonin-Releasing Factor in the Pineal of a Teleost Fish, the European Sea Bass Dicentrarchus labrax

• DOI: 10.1210/en.2009-1207
• Publication Date: 2010-03-10T03:23:52Z
• Authors: Arianna Servili; Christèle Lethim...; Jean-Jacques Lareyre; José Fernando Lo...; Francisco Javier ...; Olivier Kah; José Antonio Mun...
• Keywords: Dicentrarchus; Sea bass; Kisspeptin; Gonadotropin

With the exception of modern mammals, most vertebrate species possess two GnRH genes, GnRH-1 and GnRH-2. In addition, in many teleost fish, there is a third gene called GnRH-3. If main function unambiguously to stimulate gonadotropin release, other forms still lack clear functions. This particularly true for highly conserved GnRH-2 that encodes chicken GnRH-II. variant consistently expressed neurons dorsal synencephalon groups but has no functions supported by anatomical, pharmacological, physiological data. this study performed on perciform European sea bass, we show first time pineal organ receives GnRH-2-immunoreactive fibers originating from synencephalic neurons. was shown through combination retrograde tracing immunohistochemistry, using specific antibodies. Supporting presence functional targets, RT-PCR data together with situ hybridization studies showed bass gland strongly receptor (dlGnRHR-II-2b) selectivity and, lesser extent, dlGnRHR-II-1a subtype. Finally, vitro vivo experiments demonstrate stimulatory effects nocturnal melatonin secretion organ. Altogether, these provide, species, converging evidence supporting role modulation fish