EFFECTS OF TREATMENTS WITH TESTOSTERONE AND ESTRADIOL ON THE ATTACK DIRECTED BY GROUPS OF GONADECTOMIZED MALE AND FEMALE MICE TOWARDS LACTATING INTRUDERS

Both intact female and castrated male group-housed mice direct high incidences of attack to lactating female intruders. This type of attack is not shown by intact, group-housed males, suggesting that androgens inhibit this behaviour. It was consequently thought to be of interest to assess the influences of testosterone (T) and oestradiol (O) on the attack directed by gonadectomized groups of male and female mice towards lactating female intruders. Compared with cholesterol implanted counterparts, T implanted females and both T and O implanted males evidenced reduced attack on lactating intruders. These results confirm that sex steroids inhibit this form of attack. It should also be noted that fighting was evident between members of groups when the intruders were present but increased intra-group fighting does not appear to account for the steroid-mediated suppression of attack on lactating intruders. © 1979.