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Effects of testosterone and corticosterone on immunocompetence in the zebra finch
journal contribution
posted on 2007-01-01, 00:00 authored by M Roberts, Kate BuchananKate Buchanan, D Hasselquist, M EvansThe original immunocompetence handicap hypothesis (ICHH) suggested that testosterone has a handicapping effect in males by both promoting the development of sexual signals and suppressing immune function. A modified version, the stress-linked ICHH, has recently proposed that testosterone is immunosuppressive indirectly by increasing production of corticosterone. To test both the original and stress-mediated versions of the ICHH, we implanted male zebra finches taken from lines selected for divergent maximum stress-induced levels of corticosterone (high, low and control) with either empty or testosterone-filled implants. Their humoral and cell-mediated immune responses were then assessed by challenge with diphtheria:tetanus vaccine and phytohemagglutinin respectively. We found no effect of the hormone manipulations on either PHA or tetanus antibody responses, but found a significant interaction between titers of both testosterone and corticosterone on diphtheria secondary antibody response; antibody response was greatest in individuals with high levels of both hormones. There was also a significant interactive effect between testosterone treatment group and corticosterone titer on body mass; the body mass of males in the elevated testosterone treatment group decreased with increasing corticosterone titer. These results suggest that, contrary to the assumption of the stress-mediated version of the ICHH, high plasma levels of corticosterone are not immunosuppressive, but are in fact immuno-enhancing in the presence of high levels of plasma testosterone. Equally, the central assumption of the ICHH that testosterone is obligately immunosuppressive is also not supported. The same individuals with the highest levels of both hormones and consequently the most robust antibody response also possessed the lowest body mass.
History
Journal
Hormones and behaviorVolume
51Issue
1Pagination
126 - 134Publisher
ElsevierLocation
Amsterdam, The NetherlandsPublisher DOI
ISSN
0018-506XeISSN
1095-6867Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
2006, ElsevierUsage metrics
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corticosteronediphtheria:tetanusPHAimmunocompetence handicap hypothesisstressimmunocompetencezebra finchglucocorticoidtestosteroneScience & TechnologyLife Sciences & BiomedicineBehavioral SciencesEndocrinology & Metabolismdiphtheria : tetanusMALE HOUSE SPARROWSDARK-EYED JUNCOSBASAL METABOLIC-RATEADRENOCORTICAL-RESPONSEBODY CONDITIONHANDICAP HYPOTHESISSEASONAL-CHANGESIMMUNE FUNCTIONPLASMA-CORTICOSTERONESEXUAL ATTRACTIVENESS
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