The effect of testosterone and cyproterone acetate on the concentration of gamma-aminobutyric acid in brain areas of aggressive and non-aggressive mice.

Mice which had been housed in groups were introduced into the home cages of isolated mice and the aggressive defensive behaviour assessed. The grouped mice were chronically treated with testosterone, cyproterone acetate or arachis oil. The concentration of GABA was determined in 10 regions following the last behavioural assessment. The grouped mice which were treated with testosterone or with the anti-androgen, cyproterone acetate, were subjected to fewer aggressive attacks by the isolated mice thatn the grouped controls. The concentration of GABA in particular brain areas appears to depend on the degree of aggressive behaviour exhibited, the type of environment into which the mouse is introduced, the hormone treatment, and the housing conditions.