Maintenance of male sexual behavior by combined treatment with oestrogen and dihydrotestosterone in CD-1 mice.

After castration, adult male sexually experienced CD-1 strain mice were treated with dihydrotestosterone (200 mug/day, DHT), oestradiol benzoate (1 mug/day, OB) or DHT (200 mug/day) plus OB (1 mug/day). Oestradiol benzoate and the combined treatment DHT + OB maintained male sexual behaviour at levels comparable to a group of intact control mice, while DHT m maintained behaviour at a lower level. Having all hormone dosages resulted in a decrease in the number of OB-treated animals mating and a complete loss of mating in the DHT-treated animals. The decrease in dosage did not result in any change in the behavior of the mice receiving both hormones. Adrenalectomy was found to have no effect on the mating behaviour of the OB-treated and untreated animals, but it did reduce the number of DHT+ OB-treated animals mating. Thus, both OB alone and combined DHT+OB treatment can maintain male mating behaviour in castrated CD-1 strain mice and these effects do not appear to be due to the effects of oestradiol on the adrenal.