Effect of castration and subsequent substitution with testosterone, dihydrotestosterone and oestradiol on sexual preference behaviour in the male rat.

In the present study effects of castration and subsequent hormonal substitution on the partner-preference behaviour of the male rat are investigated. For the determination of this behaviour a residential plus-maze is used. Castration of a male rat leads to the disappearance of preference behaviour after a few weeks. Subsequent administration of testosterone by means of a silastic implant restores this behaviour within a few weeks. Castrated male rats with a silastic implant containing dihydrotestosterone will not seek contact with the oestrous female rat. Oestradiol-implanted castrated male rats show the same behaviour in the residential plus-maze as do intact male rats. It is concluded that in the male rat gonadal hormones have an effect on the processing of the signals which an oestrous female rat emits to attract a male.