title: Non-ovarian aromatization is required to activate female sexual motivation in testosterone-treated ovariectomized quail.
abstract: Although aromatase is expressed in both male and female brains, its functional significance in females remains poorly understood. In female quail, sexual receptivity is activated by estrogens. However it is not known whether sexual motivation is similarly estrogen-dependent and whether estrogens locally produced in the brain contribute to these behavioral responses. Four main experiments were designed to address these questions. In Experiment 1 chronic treatment of females with the anti-estrogen tamoxifen decreased their receptivity, confirming that this response is under the control of estrogens. In Experiment 2 chronic treatment with tamoxifen significantly decreased sexual motivation as treated females no longer approached a sexual partner. In Experiment 3 (a) ovariectomy (OVX) induced a significant decrease of time spent near the male and a significantly decreased receptivity compared to gonadally intact females, (b) treatment with testosterone (OVX+T) partially restored these responses and (c) this effect of T was prevented when estradiol synthesis was inhibited by the potent aromatase inhibitor Vorozole (OVX+T+VOR). Serum estradiol concentration was significantly higher in OVX+T than in OVX or OVX+T+VOR females. Together these data demonstrate that treatment of OVX females with T increases sexual motivation and that these effects are mediated at least in part by non-gonadal aromatization of the androgen. Finally, assays of aromatase activity on brain and peripheral tissues (Experiment 4) strongly suggest that brain aromatization contributes to behavioral effects observed here following T treatment but alternative sources of estrogens (e.g. liver) should also be considered.
authors.affiliation: GIGA Neurosciences, Research Group in Behavioral Neuroendocrinology, University of Liège, Avenue Hippocrate 15 (B36), 4000 Liège, Belgium.
authors.forename: Catherine
authors.initials: C
authors.lastname: de Bournonville
authors.affiliation: GIGA Neurosciences, Research Group in Behavioral Neuroendocrinology, University of Liège, Avenue Hippocrate 15 (B36), 4000 Liège, Belgium.
authors.forename: Jacques
authors.initials: J
authors.lastname: Balthazart
authors.affiliation: Department of Psychology, University of Maryland, 2141 Tydings Hall, College Park MD20742-7201, USA.
authors.forename: Gregory F
authors.initials: GF
authors.lastname: Ball
authors.affiliation: GIGA Neurosciences, Research Group in Behavioral Neuroendocrinology, University of Liège, Avenue Hippocrate 15 (B36), 4000 Liège, Belgium. Electronic address: charlotte.cornil@ulg.ac.be.
authors.forename: Charlotte A
authors.initials: CA
authors.lastname: Cornil
mesh_terms: D000818:Animals; D001141:Aromatase / Q000378:metabolism* / Q000502:physiology; D047072:Aromatase Inhibitors / Q000494:pharmacology; D003370:Coturnix / Q000097:blood / Q000502:physiology; D004958:Estradiol / Q000097:blood; D005260:Female; D008297:Male; D009042:Motivation / Q000187:drug effects / Q000502:physiology*; D010052:Ovariectomy / Q000662:veterinary; D010053:Ovary / Q000187:drug effects / Q000378:metabolism; D011784:Quail / Q000097:blood / Q000502:physiology; D012726:Sexual Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D013739:Testosterone / Q000494:pharmacology*; D014230:Triazoles / Q000494:pharmacology
chemical_list: D047072:Aromatase Inhibitors; D014230:Triazoles; C060523:vorozole; D013739:Testosterone; D004958:Estradiol; D001141:Aromatase
keywords: Approach behavior; Aromatase activity; Female sexual behavior; Japanese quail; Partner preference; Tamoxifen; Vorozole