Androgen effects on responsiveness to aggression and stress-related odors of male mice

Abstract

The effect of male gonadal hormones on responsiveness to the aggression and stress-related odors of male mice was examined. The initial experiment indicated that intact male mice would avoid an area of an open field that had been spotted with the urine of aggressive male donors, while castration of the subjects eliminated the response. Hormone replacement was effective in reinstating the aversion, clearly demonstrating the androgen-dependent nature of the response. A second experiment determined that the effects of castration do not generalize to another type of aversive odor, namely the alarm odors of castrate donors. That is, both intact and castrate males exhibited a pronounced aversion to the urine odors of castrates that had been subjected to a prolonged period of stress. These results suggest that gonadal hormone effects on olfactory responsivity are somewhat specific, and more interestingly, that the mechanism behind the effects of gonadal hormones on rodent aggression may lie in their influence on the nature of the response to the relevant olfactory stimuli.