Androgens and the immunocompetence handicap hypothesis: Unraveling direct and indirect pathways of immunosuppression in song sparrows
(2004) In American Naturalist 164(4). p.490-505- Abstract
- The immunocompetence handicap hypothesis proposes that testosterone (T)-dependent sexual signals are honest indicators of male health or genetic quality because only high-quality males are able to withstand the obligate effects of T-induced immunosuppression. In birds, the basic assumption that T suppresses immune function is equivocal, and the physiological mechanisms underlying T-induced immunosuppression remain to be investigated. We explored the proximate pathways of T-induced immunosuppression in song sparrows (Melospiza melodia) by treating captive nonbreeding males with different androgens and measuring several components of acquired immune function. Males implanted with T suppressed cell-mediated and humoral immune responses... (More)
- The immunocompetence handicap hypothesis proposes that testosterone (T)-dependent sexual signals are honest indicators of male health or genetic quality because only high-quality males are able to withstand the obligate effects of T-induced immunosuppression. In birds, the basic assumption that T suppresses immune function is equivocal, and the physiological mechanisms underlying T-induced immunosuppression remain to be investigated. We explored the proximate pathways of T-induced immunosuppression in song sparrows (Melospiza melodia) by treating captive nonbreeding males with different androgens and measuring several components of acquired immune function. Males implanted with T suppressed cell-mediated and humoral immune responses compared to males implanted with 5proportional to-dihydrotestosterone (DHT), dehydroepiandrosterone, or control ( empty) implants. Furthermore, T treatment increased plasma levels of corticosterone and decreased body mass and fat stores in relation to other treatments. The failure of DHT to depress immune function suggests that T-induced immunosuppression does not occur through a direct pathway because both T and DHT bind to androgen receptors on target cells. Instead, we outline indirect pathways that are likely responsible for suppression of the avian immune system that include stress-induced immunosuppression, aromatization to estrogen, and alterations in energy allocation that constrain expenditures toward immune system activation. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/136894
- author
- Owen-Ashley, N T ; Hasselquist, Dennis LU and Wingfield, J C
- organization
- publishing date
- 2004
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- immunosuppression, song sparrow, testosterone, corticosterone, androgens, immunocompetence
- in
- American Naturalist
- volume
- 164
- issue
- 4
- pages
- 490 - 505
- publisher
- University of Chicago
- external identifiers
-
- wos:000224079900008
- scopus:6344265162
- ISSN
- 0003-0147
- language
- English
- LU publication?
- yes
- id
- 35d99101-0856-4dcb-94ff-2401f544c41c (old id 136894)
- alternative location
- http://proquest.umi.com/pqdlink?index=4&did=729955661&SrchMode=2&sid=6&Fmt=6&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1209455076&clientId=53681
- date added to LUP
- 2016-04-01 12:01:35
- date last changed
- 2025-10-14 11:00:25
@article{35d99101-0856-4dcb-94ff-2401f544c41c,
abstract = {{The immunocompetence handicap hypothesis proposes that testosterone (T)-dependent sexual signals are honest indicators of male health or genetic quality because only high-quality males are able to withstand the obligate effects of T-induced immunosuppression. In birds, the basic assumption that T suppresses immune function is equivocal, and the physiological mechanisms underlying T-induced immunosuppression remain to be investigated. We explored the proximate pathways of T-induced immunosuppression in song sparrows (Melospiza melodia) by treating captive nonbreeding males with different androgens and measuring several components of acquired immune function. Males implanted with T suppressed cell-mediated and humoral immune responses compared to males implanted with 5proportional to-dihydrotestosterone (DHT), dehydroepiandrosterone, or control ( empty) implants. Furthermore, T treatment increased plasma levels of corticosterone and decreased body mass and fat stores in relation to other treatments. The failure of DHT to depress immune function suggests that T-induced immunosuppression does not occur through a direct pathway because both T and DHT bind to androgen receptors on target cells. Instead, we outline indirect pathways that are likely responsible for suppression of the avian immune system that include stress-induced immunosuppression, aromatization to estrogen, and alterations in energy allocation that constrain expenditures toward immune system activation.}},
author = {{Owen-Ashley, N T and Hasselquist, Dennis and Wingfield, J C}},
issn = {{0003-0147}},
keywords = {{immunosuppression; song sparrow; testosterone; corticosterone; androgens; immunocompetence}},
language = {{eng}},
number = {{4}},
pages = {{490--505}},
publisher = {{University of Chicago}},
series = {{American Naturalist}},
title = {{Androgens and the immunocompetence handicap hypothesis: Unraveling direct and indirect pathways of immunosuppression in song sparrows}},
url = {{https://lup.lub.lu.se/search/files/2749044/624616.pdf}},
volume = {{164}},
year = {{2004}},
}