title: An evolutionarily conserved form of gonadotropin-releasing hormone coordinates energy and reproductive behavior.
abstract: GnRH is the master neuropeptide that coordinates and regulates reproduction in all vertebrates and in some nonvertebrate species. Sixteen forms of GnRH have been isolated in brain. In the vast majority of species, two or more forms occur in anatomically and developmental distinct neuronal populations. In mammalian brain, two GnRH forms, mammalian (GnRH-I) and chicken-II (GnRH-II), exist. The distribution and functions of GnRH-I have been well characterized and intensively studied. However, the function of GnRH-II, which is the most evolutionarily conserved form of GnRH, has been elusive. Here we demonstrate that in a primitive mammal, the musk shrew (Suncus murinus), GnRH-II activates mating behavior in nutritionally challenged females within a few minutes after administration. In addition GnRH-II immunoreactive cell numbers and fibers increase in food-restricted females. Furthermore, GnRH type II receptor immunoreactivity was detected in musk shrew brain in regions associated with mating behavior. Our results lead us to hypothesize that the role of the evolutionarily conserved GnRH-II peptide is to coordinate reproductive behavior as appropriate to the organism's energetic condition.
authors.affiliation: Program in Neuroscience, University of Virginia Medical School, Charlottesville, Virginia 22908, USA.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Temple
authors.forename: Robert P
authors.initials: RP
authors.lastname: Millar
authors.forename: Emilie F
authors.initials: EF
authors.lastname: Rissman
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology / Q000502:physiology; D001923:Brain Chemistry; D002452:Cell Count; D017124:Conserved Sequence; D004734:Energy Metabolism; D019143:Evolution, Molecular; D005260:Female; D005508:Food Deprivation; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D011966:Receptors, LHRH / Q000032:analysis; D012098:Reproduction / Q000502:physiology*; D012726:Sexual Behavior, Animal / Q000187:drug effects / Q000502:physiology; D012788:Shrews / Q000502:physiology*; D014018:Tissue Distribution
chemical_list: C427484:GNRHR2 protein, human; D011966:Receptors, LHRH; D007987:Gonadotropin-Releasing Hormone; C047717:LHRH, His(5)-Trp(7)-Tyr(8)-