title: Non-breeding gonadal testosterone production of male and female northern cardinals (Cardinalis cardinalis) following GnRH challenge.
abstract: Yearly, testosterone (T) levels fluctuate as many vertebrates cycle through reproductive and non-reproductive periods. Among many temperate birds, it is well established that levels of T peak as gonads recrudesce for breeding and then fall as gonads regress prior to the non-breeding season. While the tissues producing breeding season T are well studied, the tissues responsible for non-breeding T have received less investigative attention. We examined the ability of male and female Northern Cardinals (Cardinalis cardinalis) to elevate gonadal T following standardized injections of gonadotropin-releasing hormone (GnRH) across three non-breeding seasons. Males and females were capable of significantly elevating gonadal T production following GnRH injections during periods of reproductive quiescence. The magnitude of T elevation varied across the non-breeding season, but not between sexes. To our knowledge, this is the first report of a significant increase in gonadal T production following GnRH injections administered in the non-breeding season.
authors: Department of Biological Sciences, The University of Southern Mississippi, 118 College Drive # 5018, Hattiesburg, MS 39406, USA. Margaret.Devries@eagles.usm.edu
authors: M Susan
authors: MS
authors: DeVries
authors: Aaron L
authors: AL
authors: Holbrook
authors: Caitlin P
authors: CP
authors: Winters
authors: Jodie M
authors: JM
authors: Jawor
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D003345:Corticosterone / Q000097:blood / Q000378:metabolism; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D006066:Gonads / Q000187:drug effects* / Q000378:metabolism*; D006234:Handling, Psychological; D008297:Male; D046109:Passeriformes / Q000097:blood / Q000378:metabolism*; D012098:Reproduction / Q000502:physiology; D012621:Seasons; D013739:Testosterone / Q000097:blood / Q000378:metabolism*; D013997:Time Factors
chemical_list: D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D003345:Corticosterone