title: Sex difference in attraction thresholds for volatile odors from male and estrous female mouse urine.
abstract: Volatile urinary odors from opposite sex conspecifics contribute to mate recognition in numerous mammalian species, including mice. We used a simple habituation/dishabituation testing procedure to ask whether the capacity to detect and investigate decreasing concentrations of volatile urinary odors is sexually differentiated in mice. Beginning 2 months after gonadectomy and in the absence of any sex steroid treatment, adult, sexually naive male and female CBA x C57Bl/6 F1 hybrid mice received two series of daily tests that involved the presentation of different dilutions of urine from C57Bl/6 males followed by urine from estrous females. Each test session began with three consecutive presentations of deionized water (10 microl on filter paper for 2 min, behind a mesh barrier which prevented direct physical access, in the home cage at 1-min intervals) followed by three presentations of one of five different dilutions of urine (a different dilution on each test day). Males and females showed equivalent, significant habituation/dishabituation responses (low investigation times for successive water presentations; increased investigation of the first urine stimulus, followed by a decline in successive urine investigation times) to both male and female urine/water dilutions of 1:1, 1:10, and 1:20. However, only female mice responded reliably to 1:40 and 1:80 dilutions of both types of urine, pointing to a sex dimorphism in the detection and/or processing of biologically relevant, volatile urinary odors by the main olfactory system.
authors.affiliation: Subdepartment of Animal Behaviour, University of Cambridge, Cambridge, CB3 8AA, United Kingdom.
authors.forename: M J
authors.initials: MJ
authors.lastname: Baum
authors.forename: E B
authors.initials: EB
authors.lastname: Keverne
mesh_terms: D000818:Animals; D005260:Female; D006185:Habituation, Psychophysiologic / Q000502:physiology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D009812:Odorants; D009919:Orchiectomy; D010052:Ovariectomy; D012684:Sensory Thresholds / Q000502:physiology*; D012727:Sex Characteristics; D012726:Sexual Behavior, Animal / Q000502:physiology*; D014556:Urine / Q000502:physiology*