title: The emission of stress-induced 22-kHz calls in female rats is independent of testosterone levels.
abstract: Although emission of ultrasonic calls in rats induced by stress, referred to as "22-kHz calls," is dependent on circulating testosterone levels in males, it is still unknown whether the same testosterone-based regulation is applicable to female rats. In this study, we investigated the sex difference in the emission of air-puff-induced 22-kHz calls in rats on the basis of the hypothesis that female rats would emit fewer 22-kHz calls, and assessed whether male-like circulating testosterone levels can also influence the emission of 22-kHz calls in females. The experimental results showed that female rats emit significantly fewer 22-kHz calls than male rats. However, male-like circulating testosterone levels have little effect on the emission of 22-kHz calls in females. Hence, it is suggested that there is a sex difference in stress-induced 22-kHz calls in rats and, in contrast to male rats, the emission of 22-kHz calls in female rats may be independent of circulating testosterone levels, as tested in response to air-puff stimulation.
authors.affiliation: Laboratory of Veterinary Ethology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan. Electronic address: inagaki@care.nagoya-u.ac.jp.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Inagaki
authors.affiliation: Laboratory of Veterinary Ethology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Mori
mesh_terms: D000818:Animals; D005260:Female; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012737:Sex Factors; D013315:Stress, Psychological / Q000097:blood / Q000503:physiopathology; D013739:Testosterone / Q000097:blood*; D014465:Ultrasonics; D014828:Vocalization, Animal / Q000502:physiology*
chemical_list: D013739:Testosterone
keywords: Sex difference; Sex hormone; Stress response; Ultrasonic vocalization; Vocal communication