title: Sex steroid profiles in zebra finches: Effects of reproductive state and domestication.
abstract: The zebra finch is a common model organism in neuroscience, endocrinology, and ethology. Zebra finches are generally considered opportunistic breeders, but the extent of their opportunism depends on the predictability of their habitat. This plasticity in the timing of breeding raises the question of how domestication, a process that increases environmental predictability, has affected their reproductive physiology. Here, we compared circulating steroid levels in various "strains" of zebra finches. In Study 1, using radioimmunoassay, we examined circulating testosterone levels in several strains of zebra finches (males and females). Subjects were wild or captive (Captive Wild-Caught, Wild-Derived, or Domesticated). In Study 2, using liquid chromatography-tandem mass spectrometry (LC-MS/MS), we examined circulating sex steroid profiles in wild and domesticated zebra finches (males and females). In Study 1, circulating testosterone levels in males differed across strains. In Study 2, six steroids were detectable in plasma from wild zebra finches (pregnenolone, progesterone, dehydroepiandrosterone (DHEA), testosterone, androsterone, and 5α-dihydrotestosterone (5α-DHT)). Only pregnenolone and progesterone levels changed across reproductive states in wild finches. Compared to wild zebra finches, domesticated zebra finches had elevated levels of circulating pregnenolone, progesterone, DHEA, testosterone, androstenedione, and androsterone. These data suggest that domestication has profoundly altered the endocrinology of this common model organism. These results have implications for interpreting studies of domesticated zebra finches, as well as studies of other domesticated species.
authors.affiliation: Zoology Department, University of British Columbia, Vancouver, BC, Canada. Electronic address: nhprior@umd.edu.
authors.forename: Nora H
authors.initials: NH
authors.lastname: Prior
authors.affiliation: Psychology Department, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Kang Nian
authors.initials: KN
authors.lastname: Yap
authors.affiliation: Department of Biological Sciences, Macquarie University, North Ryde, New South Wales, Australia.
authors.forename: Mark C
authors.initials: MC
authors.lastname: Mainwaring
authors.affiliation: The Prostate Centre at Vancouver General Hospital, Vancouver, BC, Canada.
authors.forename: Hans H
authors.initials: HH
authors.lastname: Adomat
authors.affiliation: Department of Biological Sciences, Macquarie University, North Ryde, New South Wales, Australia; School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia.
authors.forename: Ondi L
authors.initials: OL
authors.lastname: Crino
authors.affiliation: Psychology Department, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Chunqi
authors.initials: C
authors.lastname: Ma
authors.affiliation: The Prostate Centre at Vancouver General Hospital, Vancouver, BC, Canada.
authors.forename: Emma S
authors.initials: ES
authors.lastname: Guns
authors.affiliation: Department of Biological Sciences, Macquarie University, North Ryde, New South Wales, Australia.
authors.forename: Simon C
authors.initials: SC
authors.lastname: Griffith
authors.affiliation: School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia.
authors.forename: Katherine L
authors.initials: KL
authors.lastname: Buchanan
authors.affiliation: Zoology Department, University of British Columbia, Vancouver, BC, Canada; Psychology Department, University of British Columbia, Vancouver, BC, Canada; Graduate Program in Neuroscience, University of British Columbia, Vancouver, BC, Canada; Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Kiran K
authors.initials: KK
authors.lastname: Soma
mesh_terms: D000818:Animals; D000071278:Domestication; D005260:Female; D046369:Finches / Q000097:blood / Q000502:physiology*; D012739:Gonadal Steroid Hormones / Q000097:blood*; D008297:Male; D012098:Reproduction / Q000502:physiology*
chemical_list: D012739:Gonadal Steroid Hormones
keywords: Australia; Domestic; Opportunistic breeding; Songbird; Steroid profiling