Dehydroepiandrosterone heightens aggression and increases androgen receptor and aromatase mRNA expression in the brain of a male songbird

Douglas W. Wacker, Sahar Khalaj, Lindsey Jones, Tara Champion, Jason E Davis, Simone Meddle, J. C. Wingfield

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

Dehydroepiandrosterone (DHEA) is a testosterone/oestrogen precursor and known modulator ofvertebrate aggression. Male song sparrows ( Melospiza melodia morphna) show high aggressionduring breeding and nonbreeding life-history stages when circulating DHEA levels are high, andlow aggression during molt when DHEA levels are low. We previously showed that androgenreceptor and aromatase mRNA expression are higher during breeding and/or nonbreeding inbrain regions associated with reproductive and aggressive behaviour, although the potential roleof DHEA in mediating these seasonal changes remained unclear. In the present study, nonbreed-ing male song sparrows were captured and held in the laboratory under short days (8 : 16 hlight/dark cycle) and implanted with s.c. DHEA-filled or empty (control) implants for 14 days.DHEA implants increased aggression in a laboratory-based simulated territorial intrusion. Brainsof DHEA-implanted birds showed higher aromatase mRNA expression in the preoptic area (POA)and higher androgen receptor mRNA expression in the periventricular nucleus of the medialstriatum (pvMSt) and ventromedial nucleus of the hypothalamus. The DHEA-induced increasesin aromatase expression in the POA and androgen receptor expression in the pvMSt are consis-tent with previously reported seasonal increases in these markers associated with naturally ele-vated DHEA levels. This suggests that DHEA facilitates seasonal increases in aggression innonbreeding male song sparrows by up-regulating steroid signalling/synthesis machinery in abrain region-specific fashion.
Original languageEnglish
JournalJournal of Neuroendocrinology
Volume28
Issue number12
Early online date2 Nov 2016
DOIs
Publication statusPublished - Dec 2016

Keywords / Materials (for Non-textual outputs)

  • DHEA
  • aromatase
  • androgen receptor
  • aggression
  • sparrow

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