Co-localization of GnRH ligands and their receptors in the European sea bass, Dicentrarchus labrax.

MONCAUT, N.P.; SOMOZA, G.M.; POWER, D.; CANÁRIO, A.V.M.

Boston. USA

Congreso; 15th International Congress on Comparative Endocrinology; 2005

ISCE

Co-localization of GnRH ligands and their receptors in the European sea bass, Dicentrarchus labrax Natalia Moncaut, Gustavo Somoza, Deborah M. Power and Adelino V.M. Canário Centre of Marine Sciences, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal. E-mail: acanario@ualg.pt Laboratorio de Ictiofisiologia y Acuicultura, Instituto de Investigaciones Biotecnologicas-Instituto Tecnologico de Chascomus (IIB-INTECH), Camino de Circunvalacion Laguna Km. 6 (B7130IWA). Chascomus, Provincia de Buenos Aires, Argentina. The number of known gonadotrophin releasing hormone (GnRH) family members has now reached a total of 23, generally named after the species where they were first isolated, and this number is likely to grow as new species are investigated. Like most perciform teleost fish species, the European sea bass synthesizes three GnRH ligands: salmon GnRH, sea bream GnRH and chicken II GnRH. These peptides exert their actions through GnRH receptors (GnRHRs) belonging to the rhodopsin-like G-protein coupled receptor family. Recently, we reported the isolation of 5 sea bass GnRHRs, grouped in two subtypes by phylogenetic analysis and named accordingly dlGnRHR-1A and -1B, and dlGnRHR-2A, -2B and -2C. dlGnRHs mRNAs were differentially expressed in peripheral tissues related to reproduction (gonads), chemical senses (eye and olfactory epithelium) and osmoregulation (kidney and gill). Co-localized mRNA expression with ligands was observed in different parts of the brain, in the gonads and in the eyes. This suggests that, in addition to the neuroendocrine regulation of gonadotrophins secretion from the anterior pituitary, the GnRH system is likely to play a role in the regulation of a wide range of cellular functions in an autocrine/paracrine manner. Acknowledgment: N.M. is in receipt of financial support from Fundação para a Ciência e Tecnologia, Portugal (BD6083/2002) and Consejo Nacional de Investigaciones Cientificas y Técnicas, Argentina.