Plasma DHEA levels in wild, territorial red squirrels: Seasonal variation and effect of ACTH

Boonstra, R., Lane, J. E., Boutin, S., Bradley, A., Desantis, L., Newman, A. E. M. and Soma, K. K. (2008) Plasma DHEA levels in wild, territorial red squirrels: Seasonal variation and effect of ACTH. General and Comparative Endocrinology, 158 1: 61-67. doi:10.1016/j.ygcen.2008.05.004


Author Boonstra, R.
Lane, J. E.
Boutin, S.
Bradley, A.
Desantis, L.
Newman, A. E. M.
Soma, K. K.
Title Plasma DHEA levels in wild, territorial red squirrels: Seasonal variation and effect of ACTH
Journal name General and Comparative Endocrinology   Check publisher's open access policy
ISSN 0016-6480
Publication date 2008
Year available 2008
Sub-type Article (original research)
DOI 10.1016/j.ygcen.2008.05.004
Open Access Status
Volume 158
Issue 1
Start page 61
End page 67
Total pages 7
Editor Henderson, I W
Dores, R M
Place of publication United States
Publisher Academic Press
Collection year 2009
Language eng
Subject C1
060806 Animal Physiological Ecology
839899 Environmentally Sustainable Animal Production not elsewhere classified
Abstract In many species, territorial behavior is limited to the breeding season and is tightly coupled to circulating gonadal steroid levels. In contrast, both male and female red squirrels (Tamiasciurus hudsonicus) are highly aggressive in both the breeding and non-breeding seasons in defense of food Stores on their individual territories throughout the boreal and northern forests of North America. Dehydroepiandrosterone (DHEA), an androgen precursor, is secreted from the adrenal Cortex in some mammals, and DHEA has been linked to aggression in non-breeding songbirds. Here, we examined plasma DHEA levels in a natural population of red squirrels in the Yukon, Canada. Plasma DHEA levels in both males and females reached high concentrations (up to 16.952 ng/ml in males and 14.602 ng/ml in females), markedly exceeding plasma DHEA concentrations in laboratory rats and mice and similar to plasma DHEA concentrations in some primates. Circulating DHEA levels showed both seasonal and yearly variation. Seasonal variation in male plasma DHEA levels was negatively correlated with testes mass. Yearly variation in male DHEA levels was positively correlated with population density. In both males and females, circulating DHEA rapidly increased after ACTH treatment, implying an adrenal origin. This is the first examination of plasma DHEA concentrations in a wild rodent and the first field experiment on the regulation of plasma DHEA in any wild mammal. These data lay the foundation for future studies on the role of DHEA in non-breeding territoriality in this species and other mammals. (C) 2008 Elsevier Inc. All rights reserved.
Keyword ACTH
adrenal cortex
aggression
boreal forest
cortisol
DHEA
food
supply
population density
season
sex difference
stress
territorial
behavior
testosterone
winter
Q-Index Code C1
Q-Index Status Confirmed Code

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2009 Higher Education Research Data Collection
School of Biomedical Sciences Publications
Ecology Centre Publications
 
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Created: Wed, 18 Mar 2009, 12:10:20 EST