The effects of testosterone, estradiol, and dihydrotestosterone on male mouse (Mus musculus) ultrasonic vocalizations

Two experiments examined the effects of the free forms of testosterone (T), dihydrotestosterone (DHT), and estradiol (E₂) upon male mouse (Mus musculus) courtship vocalizations and seminal vesicle weight. In the first experiment, administration of T to castrated males was associated with a large number of vocalizations and large seminal vesicle weights, DHT was associated with large seminal vesicle weights but very few vocalizations, whereas E₂ was associated with low measures of both vocalization and seminal vesicle weight. In the second experiment, T and DHT had effects highly similar to those of the previous experiment; however, in contrast to the previous experiment, both low and high dosages of E₂ were associated with large numbers of ultrasonic vocalizations but small seminal vesicles. A mixture of E₂ and DHT was very similar to T in its effect upon both measures. We suggest from these results that hormonal mechanisms similar to those reported for rat sex behavior may interact with situational variables to determine the expression of male mouse courtship.