|
|
||||||||
Centre of Marine Sciences, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
1 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.
(Requests for offprints should be addressed to A V M Canário; Email: acanario{at}ualg.pt)
Gonadotrophin-releasing hormone (GnRH) is the main neurohormone controlling gonadotrophin release in all vertebrates, and in teleost fish also of growth hormone and possibly of other adenohypophyseal hormones. Over 20 GnRHs have been identified in vertebrates and protochoordates and shown to bind cognate G-protein couple receptors (GnRHR). We have searched the puffer fish, Fugu rubripes, genome sequencing database, identified five GnRHR genes and proceeded to isolate the corresponding complementary DNAs in European sea bass, Dicentrachus labrax. Phylogenetic analysis clusters the European sea bass, puffer fish and all other vertebrate receptors into two main lineages corresponding to the mammalian type I and II receptors. The fish receptors could be subdivided in two GnRHR1 (A and B) and three GnRHR2 (A, B and C) subtypes. Amino acid sequence identity within receptor subtypes varies between 70 and 90% but only 5055% among the two main lineages in fish. All European sea bass receptor mRNAs are expressed in the anterior and mid brain, and all but one are expressed in the pituitary gland. There is differential expression of the receptors in peripheral tissues related to reproduction (gonads), chemical senses (eye and olfactory epithelium) and osmoregulation (kidney and gill). This is the first report showing five GnRH receptors in a vertebrate species and the gene expression patterns support the concept that GnRH and GnRHRs play highly diverse functional roles in the regulation of cellular functions, besides the "classical" role of pituitary function regulation.
This article has been cited by other articles:
![]() |
P. Singh, A. Krishna, and R. Sridaran Localization of gonadotrophin-releasing hormone I, bradykinin and their receptors in the ovaries of non-mammalian vertebrates Reproduction, May 1, 2007; 133(5): 969 - 981. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |