The influence of androgens on hibernation phenology of free-living male arctic ground squirrels
Free-living ground squirrel species are sexually dimorphic in hibernation phenology. The underlying causes of these differences are not yet known. Androgens, testosterone (T) in particular, inhibit hibernation. To determine the influence of endogenous androgens on annual timing of hibernation we fir...
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ftpubmed:oai:pubmedcentral.nih.gov:5359051 2023-05-15T14:59:15+02:00 The influence of androgens on hibernation phenology of free-living male arctic ground squirrels Richter, M.M. Barnes, B.M. O’Reilly, K.M. Fenn, A.M. Buck, C.L. 2016-12-13 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5359051/ http://www.ncbi.nlm.nih.gov/pubmed/27986541 https://doi.org/10.1016/j.yhbeh.2016.12.007 en eng http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5359051/ http://www.ncbi.nlm.nih.gov/pubmed/27986541 http://dx.doi.org/10.1016/j.yhbeh.2016.12.007 Article Text 2016 ftpubmed https://doi.org/10.1016/j.yhbeh.2016.12.007 2018-03-04T01:13:51Z Free-living ground squirrel species are sexually dimorphic in hibernation phenology. The underlying causes of these differences are not yet known. Androgens, testosterone (T) in particular, inhibit hibernation. To determine the influence of endogenous androgens on annual timing of hibernation we first measured circulating levels of T and dehydroepiandrosterone (DHEA), an adrenal androgen implicated in non-mating season aggression in other species, in free-living male arctic ground squirrels (Urocitellus parryii, AGS). We also manipulated endogenous androgen levels by surgical castration, and consequently compared body temperature records from intact (n = 24) and castrated (n = 9) males to elucidate the influence of endogenous androgens on annual body temperature cycles. The highest T levels (0.53 ± 0.10 ng/mL) were in reproductively mature male AGS in spring; whereas, both immature males in spring and all males in late summer had T levels an order of magnitude lower (0.07 ± 0.01 and 0.06 ± 0.00 ng/mL, respectively). DHEA levels were higher in males during the late summer compared to reproductively mature males in spring (120.6 ± 18.9 and 35.9 ± 2.3 pg/mL, respectively). Eliminating gonadal androgens via castration resulted in males delaying euthermy by extending heterothermy significantly in spring (Apr 22 ± 2.9) than reproductive males (Mar 28 ± 3.9) but did not change the timing of hibernation onset (castrate: Oct 12 ± 1.0 vs. intact: Oct 3 ± 3.1). We conclude that while androgens play a significant role in spring hibernation phenology of males, their role in fall hibernation onset is unclear. Text Arctic Urocitellus parryii PubMed Central (PMC) Arctic Hormones and Behavior 89 92 97 |
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Article Richter, M.M. Barnes, B.M. O’Reilly, K.M. Fenn, A.M. Buck, C.L. The influence of androgens on hibernation phenology of free-living male arctic ground squirrels |
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Free-living ground squirrel species are sexually dimorphic in hibernation phenology. The underlying causes of these differences are not yet known. Androgens, testosterone (T) in particular, inhibit hibernation. To determine the influence of endogenous androgens on annual timing of hibernation we first measured circulating levels of T and dehydroepiandrosterone (DHEA), an adrenal androgen implicated in non-mating season aggression in other species, in free-living male arctic ground squirrels (Urocitellus parryii, AGS). We also manipulated endogenous androgen levels by surgical castration, and consequently compared body temperature records from intact (n = 24) and castrated (n = 9) males to elucidate the influence of endogenous androgens on annual body temperature cycles. The highest T levels (0.53 ± 0.10 ng/mL) were in reproductively mature male AGS in spring; whereas, both immature males in spring and all males in late summer had T levels an order of magnitude lower (0.07 ± 0.01 and 0.06 ± 0.00 ng/mL, respectively). DHEA levels were higher in males during the late summer compared to reproductively mature males in spring (120.6 ± 18.9 and 35.9 ± 2.3 pg/mL, respectively). Eliminating gonadal androgens via castration resulted in males delaying euthermy by extending heterothermy significantly in spring (Apr 22 ± 2.9) than reproductive males (Mar 28 ± 3.9) but did not change the timing of hibernation onset (castrate: Oct 12 ± 1.0 vs. intact: Oct 3 ± 3.1). We conclude that while androgens play a significant role in spring hibernation phenology of males, their role in fall hibernation onset is unclear. |
format |
Text |
author |
Richter, M.M. Barnes, B.M. O’Reilly, K.M. Fenn, A.M. Buck, C.L. |
author_facet |
Richter, M.M. Barnes, B.M. O’Reilly, K.M. Fenn, A.M. Buck, C.L. |
author_sort |
Richter, M.M. |
title |
The influence of androgens on hibernation phenology of free-living male arctic ground squirrels |
title_short |
The influence of androgens on hibernation phenology of free-living male arctic ground squirrels |
title_full |
The influence of androgens on hibernation phenology of free-living male arctic ground squirrels |
title_fullStr |
The influence of androgens on hibernation phenology of free-living male arctic ground squirrels |
title_full_unstemmed |
The influence of androgens on hibernation phenology of free-living male arctic ground squirrels |
title_sort |
influence of androgens on hibernation phenology of free-living male arctic ground squirrels |
publishDate |
2016 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5359051/ http://www.ncbi.nlm.nih.gov/pubmed/27986541 https://doi.org/10.1016/j.yhbeh.2016.12.007 |
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Arctic |
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Arctic |
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Arctic Urocitellus parryii |
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Arctic Urocitellus parryii |
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5359051/ http://www.ncbi.nlm.nih.gov/pubmed/27986541 http://dx.doi.org/10.1016/j.yhbeh.2016.12.007 |
op_doi |
https://doi.org/10.1016/j.yhbeh.2016.12.007 |
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Hormones and Behavior |
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89 |
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92 |
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97 |
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