Changes in aggressive and sexual responsiveness of male golden hamsters after neonatal androgen administration

On day 1 after birth, male golden hamsters received either 300 microng of an androgen (testosterone propionate, testosterone, dihydrotestosterone or androstenedione) in 0-03 ml arachis oil, or oil alone. As intact adults, their aggressiveness towards unreceptive females was measured. After this, all animals were castrated. At least 3 weeks after the operation all animals received oestradiol benzoate (10 microng) + progesterone (500 microng), after which their capacity to show patterns of female sexual behaviour towards a stud male was tested. Control hamsters which had received oil as neonates showed less aggression than the females with which they interacted; these controls also readily assumed lordosis after castration and priming with ovarian steroids. Conversely, animals which had received testosterone propionate or androstenedione neonatally were as aggressive as the female hamsters, and showed a markedly decreased ability to display lordotic behaviour after castration. The behaviour of male hamsters which received testosterone or dihydrotestosterone was unaffected. Thus, at the level of treatment used, increased aggressiveness appeared to co-vary with a decreased capacity to show female sexual behaviour patterns. However, within each treatment there was little evidence of such a relationship at the level of the individual animal.