Effects of age at castration on testosterone induced aggression-promoting cues in groups of male mice

Abstract

Groups of five male albino mice were set up in observation cages so that each contained one individual from each of the following five categories: trained fighters (T.F.); mice castrated pre-pubertally and implanted with testosterone in adulthood (P.I.); mice castrated pre-pubertally but sham-implanted in adulthood (P.S.); mice castrated in adulthood and implanted (A.I.) and mice castrated in adulthood but sham-implanted (A.S.). T.F's. became dominant to all these mice but did not distribute their attacks uniformly among the four categories of opponent. A.I. mice were attacked significantly more than P.I. mice which in turn were attacked significantly more than either P.S. or A.S. mice. It was concluded that the age at castration affected the response of mice to testosterone in terms of the production of aggression-eliciting olfactory cues. This effect seems likely to be a consequence of the duration of time between castration and hormonal treatment rather than an effect of age per se.