Overexpression of transforming growth factor alpha in transgenic mice alters nonreproductive, sex-related behavioral differences: interaction with gonadal hormones.

Sexually dimorphic differences in voluntary sodium intake, locomotor activity, immobility in the swim test, and aggressive behavior were found to be altered in transgenic CD-1 mice that overexpressed transforming growth factor alpha (TGF alpha). In contrast to nontransgenic CD-1 mice, immobility in the swim test was longer and sodium intake higher in the male TGF alpha mice than in the female TGF alpha mice. These findings indicate that the male TGF alpha mice exhibited feminization of some behaviors. Furthermore, the male TGF alpha mice were highly aggressive. Castration reversed the behavioral effects in the adult male transgenic mice, but ovariectomy did not reverse the behavioral effects in the adult female transgenic mice. Thus the feminizing effect of TGF alpha on some nonreproductive behaviors and increased aggressive behavior in male mice may be mediated through an interaction between this growth factor and gonadal hormones.