title: Hypothalamic inhibition of socio-sexual behaviour by increasing neuroestrogen synthesis.
abstract: Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic neuropeptide that inhibits gonadotropin secretion and socio-sexual behaviours. Oestrogen (neuroestrogen) synthesized in the brain from androgen by aromatase regulates male socio-sexual behaviours. Here we show that GnIH directly activates aromatase and increases neuroestrogen synthesis in the preoptic area (POA) and inhibits socio-sexual behaviours of male quail. Aromatase activity and neuroestrogen concentration in the POA are low in the morning when the birds are active, but neuroestrogen synthesis gradually increases until the evening when the birds become inactive. Centrally administered GnIH in the morning increases neuroestrogen synthesis in the POA and decreases socio-sexual behaviours. Centrally administered 17β-oestradiol at higher doses also inhibits socio-sexual behaviours in the morning. These results suggest that GnIH inhibits male socio-sexual behaviours by increasing neuroestrogen synthesis beyond its optimum concentration for the expression of socio-sexual behaviours. This is the first demonstration of any hypothalamic neuropeptide that directly regulates neuroestrogen synthesis.
authors.affiliation: Department of Biology, Waseda University, 2-2 Wakamatsu-cho, Shinjuku, Tokyo 162-8480, Japan.
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Ubuka
authors.affiliation: Department of Biology, Waseda University, 2-2 Wakamatsu-cho, Shinjuku, Tokyo 162-8480, Japan.
authors.forename: Shogo
authors.initials: S
authors.lastname: Haraguchi
authors.affiliation: Department of Biology, Waseda University, 2-2 Wakamatsu-cho, Shinjuku, Tokyo 162-8480, Japan.
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Tobari
authors.affiliation: Department of Biology, Waseda University, 2-2 Wakamatsu-cho, Shinjuku, Tokyo 162-8480, Japan.
authors.forename: Misato
authors.initials: M
authors.lastname: Narihiro
authors.affiliation: Department of Biology, Waseda University, 2-2 Wakamatsu-cho, Shinjuku, Tokyo 162-8480, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Ishikawa
authors.affiliation: Department of Biochemistry, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Hayashi
authors.affiliation: Department of Biochemistry, Fujita Health University School of Medicine, Toyoake, Aichi 470-1192, Japan.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Harada
authors.affiliation: Department of Biology, Waseda University, 2-2 Wakamatsu-cho, Shinjuku, Tokyo 162-8480, Japan.
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Tsutsui
mesh_terms: D000728:Androgens / Q000378:metabolism; D000818:Animals; D001141:Aromatase / Q000378:metabolism; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology; D003370:Coturnix / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000494:pharmacology; D004967:Estrogens / Q000378:metabolism*; D006023:Glycoproteins / Q000008:administration & dosage / Q000494:pharmacology; D007028:Hypothalamic Hormones / Q000008:administration & dosage / Q000494:pharmacology; D007031:Hypothalamus / Q000502:physiology*; D057967:Infusions, Intraventricular; D008297:Male; D023421:Models, Animal; D011301:Preoptic Area / Q000378:metabolism*; D012726:Sexual Behavior, Animal / Q000187:drug effects / Q000502:physiology*
chemical_list: D000728:Androgens; D004967:Estrogens; D006023:Glycoproteins; D007028:Hypothalamic Hormones; C014995:gonadotropin inhibitor; D004958:Estradiol; D001141:Aromatase