title: Sequence analysis, tissue distribution and molecular physiology of the GnRH preprogonadotrophin in the South American plains vizcacha (Lagostomus maximus).
abstract: Gonadotropin-releasing hormone (GnRH) is the regulator of the hypothalamic-hypophyseal-gonadal (HHG) axis. GnRH and GAP (GnRH-associated protein) are both encoded by a single preprohormone. Different variants of GnRH have been described. In most mammals, GnRH is secreted in a pulsatile manner that stimulates the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH). The South-American plains vizcacha, Lagostomus maximus, is a rodent with peculiar reproductive features including natural poly-ovulation up to 800 oocytes per estrous cycle, pre-ovulatory follicle formation throughout pregnancy and an ovulatory process which takes place at mid-gestation and adds a considerable number of secondary corpora lutea. Such features should occur under a special modulation of the HHG axis, guided by GnRH. The aim of this study was to sequence hypothalamic GnRH preprogonadotrophin mRNA in the vizcacha, to compare it with evolutionarily related species and to identify its expression, distribution and pulsatile pattern of secretion. The GnRH1variant was detected and showed the highest homology with that of chinchilla, its closest evolutionarily related species. Two isoforms of transcripts were identified, carrying the same coding sequence, but different 5' untranslated regions. This suggests a sensitive equilibrium between RNA stability and translational efficiency. A predominant hypothalamic localization and a pulsatile secretion pattern of one pulse of GnRH every hour were found. The lower homology found for GAP, also among evolutionarily related species, depicts a potentially different bioactivity.
authors.affiliation: Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: Santiago Elías
authors.initials: SE
authors.lastname: Charif
authors.affiliation: Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: Pablo Ignacio Felipe
authors.initials: PI
authors.lastname: Inserra
authors.affiliation: Laboratorio de Neuroendocrinología, Instituto de Biología y Medicina Experimental (IByME)-CONICET, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: Noelia Paula
authors.initials: NP
authors.lastname: Di Giorgio
authors.affiliation: Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: Alejandro Raúl
authors.initials: AR
authors.lastname: Schmidt
authors.affiliation: Laboratorio de Neuroendocrinología, Instituto de Biología y Medicina Experimental (IByME)-CONICET, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: Victoria
authors.initials: V
authors.lastname: Lux-Lantos
authors.affiliation: Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina.
authors.forename: Alfredo Daniel
authors.initials: AD
authors.lastname: Vitullo
authors.affiliation: Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico (CEBBAD), Universidad Maimónides, Ciudad Autónoma de Buenos Aires, Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina. Electronic address: dorfman.veronica@maimonides.edu.
authors.forename: Verónica Berta
authors.initials: VB
authors.lastname: Dorfman
mesh_terms: D000818:Animals; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D011247:Pregnancy; D017421:Sequence Analysis; D013020:South America; D014018:Tissue Distribution
chemical_list: D007987:Gonadotropin-Releasing Hormone
keywords: GAP; GnRH; Plains vizcacha; Reproductive axis