Early androgenization and aggression pheromone in inbred mice

Three experiments were conducted to investigate the effects of early androgenization on the social interactions in mice. Results of Expt 1 indicated that neonatally testosterone propionate (TP) treated females, when mature, were attacked faster, more frequently, and for longer durations by trained fighters than females treated neonatally with oil. Experiment 2 showed that male castrates coated with urine from neonatally TP-treated females were attacked more often and for longer durations than castrates coated with urine from neonatally oil-treated females. The results implicated a urinary pathway of pheromonal output. Experiment 3 was conducted to investigate the relatively long-term social interactions between a naive male and a female treated at birth with TP or between a naive male and a female treated at birth with oil. The androgenized females showed a greater number of wounds after 5 days of pair housing than the control females. Five out of seven androgenized females were killed. Six control females gave birth, and none of the remaining two androgenized females did.