Brain Aromatase in the guppy, Poecilia reticulata: Distribution, control and role in behaviour
2009 (English)Doctoral thesis, comprehensive summary (Other academic)
Oestrogens are produced by aromatisation of androgens by the aromatase enzyme. In the vertebrate brain this synthesis has vital functions in nerve protection, cell proliferation and nerve development during injury respectively brain development. Brain oestrogens are also crucial in activating certain reproductive and aggressive behaviours in mammals and birds. Teleosts have remarkably high activity of brain aromatase (bAA) compared to mammals and birds; 100-1000 times higher in brain regions like the hypothalamus, pre-optic area and optic tectum. The role of brain oestrogens in teleost behaviour is, however, less clear than in e.g. songbirds and rodents. This thesis studies the potential role of brain aromatase and brain oestrogens in the reproductive behaviour of the guppy male (Poecilia reticulata), how guppy brain aromatase responds to steroids and is distributed in the adult brain.
The thesis shows that male behaviour can be affected by brain aromatase. Reduction of bAA by aromatase inhibitor treatment reduced the sexual behaviours sigmoid display and gonopodium swinging (I) and oestrogen receptor blocking with an oestrogen antagonist reduced the number of successful mating attempts (II). The anatomical study (IV) showed that brain aromatase is distributed in areas of the adult guppy brain that are connected to reproductive control and behaviour in vertebrates.
Guppy bAA is stimulated by both androgens and oestrogens (III) but is more sensitive to oestrogens, especially in males, and could thus be used as an indicator of endocrine disruption at low concentrations found in the environment.
The thesis can also conclude that females possess more brain aromatase than males, and that although it is expressed in the same pattern throughout the brain in both genders the enzymatic activity is differently distributed between the sexes.
Place, publisher, year, edition, pages
Stockholm: Department of Zoology, Stockholm University , 2009. , 41 p.
Södertörn Doctoral Dissertations, ISSN 1652-7399 ; 36
Oestrogen production, behaviour, anatomy, endocrinology, bio markers, endocrine disruption
Research subject Functional Zoomorphology
IdentifiersURN: urn:nbn:se:su:diva-26942ISBN: 978-91-86069-03-2ISBN: 978-91-7155-870-1OAI: oai:DiVA.org:su-26942DiVA: diva2:211967
2009-05-26, MA624, Södertörns högskola, Alfred Nobels allé 7, Huddinge, 10:00 (English)
Bakker, Julie, Ph.D.
Olsén, Håkan, Professor. Ph.D.Borg, Bertil, Professor. Ph.D.
ProjectsAromatase and androgens in fish reproductive behaviour
List of papers