title: Distribution of LPXRFa, a gonadotropin-inhibitory hormone ortholog peptide, and LPXRFa receptor in the brain and pituitary of the tilapia.
abstract: In vertebrates, gonadotropin-releasing hormone (GnRH) and gonadotropin-inhibitory hormone (GnIH), respectively, regulate reproduction in positive and negative manners. GnIH belongs to the LPXRFa family of peptides previously identified in mammalian and nonmammalian vertebrates. Studying the detailed distribution of LPXRFa as well as its receptor (LPXRFa-R) in the brain and pituitary is important for understanding their multiple action sites and potential functions. However, the distribution of LPXRFa and LPXRFa-R has not been studied in teleost species, partially because of the lack of fish-specific antibodies. Therefore, in the present study, we generated specific antibodies against LPXRFa and its receptor from Nile tilapia (Oreochromis niloticus), and examined their distributions in the brain and pituitary by immunohistochemistry. Tilapia LPXRFa-immunoreactive neurons lie in the posterior ventricular nucleus of the caudal preoptic area, whereas LPXRFa-R-immunoreactive cells are distributed widely. Double immunofluorescence showed that neither LPXRFa-immunoreactive fibers nor LPXRFa-R is closely associated or coexpressed with GnRH1, GnRH3, or kisspeptin (Kiss2) neurons. In the pituitary, LPXRFa fibers are closely associated with gonadotropic endocrine cells [expressing luteinizing hormone (LH) and follicle-stimulating hormone (FSH)], with adrenocorticomelanotropic cells [corticotropin (ACTH) and α-melanotropin (α-MSH)], and with somatolactin endocrine cells. In contrast, LPXRFa-R are expressed only in LH, ACTH, and α-MSH cells. These results suggest that LPXRFa and LPXRFa-R signaling acts directly on the pituitary cells independent from GnRH or kisspeptin and could play multiple roles in reproductive and nonreproductive functions in teleosts. J. Comp. Neurol. 524:2753-2775, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Selangor, Malaysia.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ogawa
authors.affiliation: Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Selangor, Malaysia.
authors.forename: Mageswary
authors.initials: M
authors.lastname: Sivalingam
authors.affiliation: Department of Animal Sciences, The Robert H Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, Rehovot 76100, Israel.
authors.forename: Jakob
authors.initials: J
authors.lastname: Biran
authors.affiliation: Department of Animal Sciences, The Robert H Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, Rehovot 76100, Israel.
authors.forename: Matan
authors.initials: M
authors.lastname: Golan
authors.affiliation: Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Selangor, Malaysia.
authors.forename: Rachel Shalini
authors.initials: RS
authors.lastname: Anthonysamy
authors.affiliation: Department of Animal Sciences, The Robert H Smith Faculty of Agriculture, Food, and Environment, Hebrew University of Jerusalem, Rehovot 76100, Israel.
authors.forename: Berta
authors.initials: B
authors.lastname: Levavi-Sivan
authors.affiliation: Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Selangor, Malaysia.
authors.forename: Ishwar S
authors.initials: IS
authors.lastname: Parhar
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D001923:Brain Chemistry / Q000502:physiology; D007987:Gonadotropin-Releasing Hormone / Q000032:analysis* / Q000096:biosynthesis; D007028:Hypothalamic Hormones / Q000032:analysis* / Q000096:biosynthesis; D008297:Male; D010902:Pituitary Gland / Q000737:chemistry* / Q000378:metabolism; D011967:Receptors, Gonadotropin / Q000032:analysis* / Q000096:biosynthesis; D011966:Receptors, LHRH / Q000032:analysis* / Q000096:biosynthesis; D017210:Tilapia
chemical_list: D007028:Hypothalamic Hormones; C000588859:RFamide-related peptide-3, rat; D011967:Receptors, Gonadotropin; D011966:Receptors, LHRH; D007987:Gonadotropin-Releasing Hormone
keywords: GPR147; GnRH; RRID:AB_2490075; RRID:AB_2493182; RRID:AB_2493183; cichlid; kisspeptin; reproduction