A competitive effect of androgen signaling on male mouse attraction to volatile female mouse odors

Olfaction plays an important role in animal communication. We hypothesized that males recognize the attractive volatile odors attributed to female reproductive ability. We measured the period during which a male mouse spent sniffing volatile odors from a sham-operated female mouse or an ovariectornized mouse without visual or tactile contact. Intact male mice spent more time sniffing volatile odors from proestrous, estrous or metestrous females than from ovariectornized females. There was no difference in castrated male mice. To investigate the involvement of sexual hormone in this behavior, castrated male mice were treated with 17 alpha-estradiol (E), dihydrotestosterone (DHT), or both. E-treatment did not affect sniffing behavior. Regardless of the estrous stages, DHT-treated castrated males spent less time sniffing the volatile odors from sham-operated than from ovariectornized female mice. Both E- and DHT-treated castrated males spent less time sniffing the volatile odors from proestrous or estrous females than from ovariectornized females. These results suggest that neither androgen nor estrogen is sufficient for reproducing male attraction to volatile female mouse odors, and that androgen signaling has a competitive effect against the attraction. (c) 2005 Elsevier Inc. All rights reserved.