Reference : Relationships between aromatase activity in the brain and gonads and behavioural defi...
Scientific journals : Article
Social & behavioral sciences, psychology : Neurosciences & behavior
Human health sciences : Endocrinology, metabolism & nutrition
http://hdl.handle.net/2268/11637
Relationships between aromatase activity in the brain and gonads and behavioural deficits in homozygous and heterozygous aromatase knockout mice
English
Bakker, Julie mailto [Université de Liège - ULg > Département des sciences biomédicales et précliniques > Biologie de la différenciation sexuelle du cerveau >]
Baillien, M. [> > > >]
Honda, S. [> > > >]
Harada, N. [> > > >]
Balthazart, Jacques mailto [Université de Liège - ULg > Département des sciences biomédicales et précliniques > Biologie de la différenciation sexuelle du cerveau >]
May-2004
Journal of Neuroendocrinology
Blackwell Publishing Ltd
16
5
483-490
Yes (verified by ORBi)
International
0953-8194
Oxford
[en] aromatase ; oestradiol ; brain ; sexual differentiation
[en] The present study was carried out to determine whether aromatase knockout (ArKO) mice are completely devoid of aromatase activity in their brain and gonads and to compare aromatase activity in wild-type and ArKO mice, as well as in heterozygous (HET) mice of both sexes that were previously shown to display a variety of reproductive behaviours; at levels intermediate between wild-type and ArKO mice. Aromatase activity was extremely low, and undetectable by the tritiated water assay, in homogenates of the preoptic area-hypothalamus of adult wild-type mice, but was induced following a 12-day treatment with testosterone. The induction of aromatase activity by testosterone was significantly larger in males than in females. Even after 12 days exposure to testosterone, no aromatase activity was detected in the brain of ArKO mice of either sex whereas HET mice showed intermediate levels of activity between ArKO and wild-type. Aromatase activity was also undetectable in the ovary of adult ArKO females but was very high in the wildtype ovary and intermediate in the HET ovary. In wild-type mice, a high level of aromatase activity was detected on the day of birth even without pretreatment with testosterone. This neonatal activity was higher in males than in females, but females nevertheless appear to display a substantial level of oestrogen production in their brain. Aromatase activity was undetectable in the brain of newborn ArKO males and females and was intermediate between wild-type and ArKO in HET mice. In conclusion, the present study confirms that ArKO mice are unable to synthesize any oestrogens, thereby validating the ArKO mouse as a valuable tool in the study of the physiological roles of oestradiol. In addition, it demonstrates that the intermediate behaviour of HET mice presumably reflects the effect of gene dosage on aromatase expression and activity, that aromatase activity is sexually differentiated in mice during the neonatal period as well as in adulthood and, finally, that the neonatal female brain produces substantial amounts of oestrogens that could play a significant role in the sexual differentiation of the female brain early in life.
http://hdl.handle.net/2268/11637
10.1111/j.1365-2826.2004.01191.x

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