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Three forms of gonadotropin-releasing hormone characterized from brains of one species.
Department of Biology, University of Victoria, B.C. Canada.
Most vertebrate species have more than one form of gonadotropin-releasing hormone (GnRH) in their brains, but it is not clear whether each form has a distinct function. We report that sea bream (Sparus aurata) brains have three forms of GnRH, one of which is described herein and is called sea bream GnRH (sbGnRH). The primary structures of two forms were determined by Edman degradation and mass spectral analysis. The amino acid sequence of sbGnRH is pGlu-His-Trp-Ser-Tyr-Gly-Leu-Ser-Pro-Gly-NH2. The second peptide is identical to a form originally isolated from chicken brains (cGnRH-II): pGlu-His-Trp-Ser-His-Gly-Trp-Tyr-Pro-Gly-NH2. cGnRH-II is the most ancient form of GnRH identified to date in jawed fish and the most prevalent form throughout the vertebrates. The third form of GnRH has previously been identified as salmon GnRH by cDNA studies and is confirmed here by chromatographic and immunological studies. Phylogenetic distribution of GnRH peptides suggests sbGnRH arose in the perch-like fish as a gene duplication of the existing cGnRH-II or salmon GnRH genes. All three identified GnRH peptides were synthesized and shown to release gonadotropin in vivo in the sea bream. The dominant form of GnRH stored in the pituitary was sbGnRH. Not only was the content of sbGnRH 500-fold greater than that of salmon GnRH but also cGnRH-II was not detected in the pituitary. The latter evidence suggests that sbGnRH is the endogenous releaser of gonadotropin II.
PMID: 7991588 [PubMed - indexed for MEDLINE]
PMCID: PMC45380
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Cited by 3 PubMed Central articles
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In silico and in situ characterization of the zebrafish (Danio rerio) gnrh3 (sGnRH) gene.
Torgersen J, Nourizadeh-Lillabadi R, Husebye H, Aleström P.
BMC Genomics. 2002 Aug 21; 3(1):25. Epub 2002 Aug 21.
[BMC Genomics. 2002]
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Locust adipokinetic hormones: carrier-independent transport and differential inactivation at physiological concentrations during rest and flight.
Oudejans RC, Vroemen SF, Jansen RF, Van der Horst DJ.
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[Proc Natl Acad Sci U S A. 1996]
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Three gonadotropin-releasing hormone genes in one organism suggest novel roles for an ancient peptide.
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[Proc Natl Acad Sci U S A. 1995]