title: Characterization of Gnrh/Gnih elements in the olfacto-retinal system and ovary during zebrafish ovarian maturation.
abstract: Gonadotropin releasing hormone (GnRH) is one of the key players of brain-pituitary-gonad axis, exerting overall control over vertebrate reproduction. In zebrafish, two variants were characterized and named as Gnrh2 and Gnrh3. In this species, Gnrh3, the hypohysiotropic form, is expressed by neurons of the olfactory-retinal system, where it is related with food detection, intra/interspecific recognition, visual acuity and retinal processing modulation. Previous studies have reported the presence of Gnrh receptors in the zebrafish retina, but not yet in the zebrafish olfactory epithelium. The current study analyzed the presence of gnrh2 and gnrh3, their receptors (gnrhr 1,2,3 and 4) and gnih (gonadotropin inhibitory hormone) transcripts, as well as the Gnrh3 protein in the olfactory epithelium (OE), olfactory bulb (OB), retina and ovary during zebrafish ovarian maturation. We found an increase of gnrh receptors transcripts in the OE at the final stages of ovarian maturation. In the OE, Gnrh3 protein was detected in the olfactory receptor neurons cilia and in the olfactory nerve fibers. Interestingly, in the OB, we found an inverse expression pattern between gnih and gnrh3. In the retina, gnrhr4 mRNA was found in the nuclei of amacrine, bipolar, and ganglion cells next to Gnrh3 positive fibers. In the ovary, gnrh3, gnrhr2 and gnrhr4 transcripts were found in perinucleolar oocytes, while gnih in oocytes at the cortical alveolus stage. Our results suggested that Gnrh/Gnih elements are involved in the neuromodulation of the sensorial system particularly at the final stages of maturation, playing also a paracrine role in the ovary.
authors.affiliation: Aquaculture Center of São Paulo State University (CAUNESP), Jaboticabal, São Paulo, Brazil.
authors.forename: Sheryll
authors.initials: S
authors.lastname: Corchuelo
authors.affiliation: Reproductive and Molecular Biology Group, Department of Morphology, Institute of Bioscience of Botucatu, São Paulo State University, Botucatu, São Paulo, Brazil.
authors.forename: Emanuel R M
authors.initials: ERM
authors.lastname: Martinez
authors.affiliation: Aquaculture Center of São Paulo State University (CAUNESP), Jaboticabal, São Paulo, Brazil; Reproductive and Molecular Biology Group, Department of Morphology, Institute of Bioscience of Botucatu, São Paulo State University, Botucatu, São Paulo, Brazil.
authors.forename: Arno J
authors.initials: AJ
authors.lastname: Butzge
authors.affiliation: Reproductive and Molecular Biology Group, Department of Morphology, Institute of Bioscience of Botucatu, São Paulo State University, Botucatu, São Paulo, Brazil.
authors.forename: Lucas B
authors.initials: LB
authors.lastname: Doretto
authors.affiliation: Reproductive and Molecular Biology Group, Department of Morphology, Institute of Bioscience of Botucatu, São Paulo State University, Botucatu, São Paulo, Brazil.
authors.forename: Juliana M B
authors.initials: JMB
authors.lastname: Ricci
authors.affiliation: Aquaculture Center of São Paulo State University (CAUNESP), Jaboticabal, São Paulo, Brazil.
authors.forename: Fernanda N
authors.initials: FN
authors.lastname: Valentin
authors.affiliation: Department of Animal Morphology and Physiology, São Paulo State University (UNESP), Jaboticabal, São Paulo, Brazil. Electronic address: laurankg@yahoo.com.br.
authors.forename: Laura S O
authors.initials: LSO
authors.lastname: Nakaghi
authors.affiliation: Laboratorio de Ictiofisiología y Acuicultura, Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús (CONICET-UNSAM), Chascomús, Argentina.
authors.forename: Gustavo M
authors.initials: GM
authors.lastname: Somoza
authors.affiliation: Reproductive and Molecular Biology Group, Department of Morphology, Institute of Bioscience of Botucatu, São Paulo State University, Botucatu, São Paulo, Brazil. Electronic address: biorhn@yahoo.com.br.
authors.forename: Rafael H
authors.initials: RH
authors.lastname: Nóbrega
mesh_terms: D000818:Animals; D005260:Female; D018507:Gene Expression Regulation, Developmental; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007028:Hypothalamic Hormones / Q000378:metabolism*; D008297:Male; D008954:Models, Biological; D009831:Olfactory Mucosa / Q000166:cytology / Q000378:metabolism*; D010053:Ovary / Q000254:growth & development* / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011966:Receptors, LHRH / Q000235:genetics / Q000378:metabolism; D012160:Retina / Q000378:metabolism*; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics* / Q000378:metabolism; D029961:Zebrafish Proteins / Q000378:metabolism
chemical_list: D007028:Hypothalamic Hormones; D012333:RNA, Messenger; D011966:Receptors, LHRH; D029961:Zebrafish Proteins; D007987:Gonadotropin-Releasing Hormone
keywords: Gnih; Gnrh; Olfactory bulb; Ovarian maturation; Sensorial systems; Zebrafish