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Published on: January 17, 2016
Androgens regulate gene expression in avian skeletal muscles.
Matthew J Fuxjager1, Julia Barske, Sienmi Du
1Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, California, United States of America. mfoxhunter@gmail.com
Plos One
|January 4, 2013
Summary
Androgens, like testosterone, can up-regulate gene expression in avian wing muscles, potentially enhancing physical performance for reproduction. This androgen receptor-mediated effect is conserved across passerine species.
Area of Science:
- Endocrinology
- Comparative Physiology
- Molecular Biology
Background:
- Circulating androgens impact multiple organ systems in male vertebrates.
- Androgen receptors (AR) are present in skeletal muscles of several bird species.
- Wing muscles constitute a significant portion of a bird's body mass, suggesting potential for widespread androgen effects.
Purpose of the Study:
- To investigate the influence of androgens on gene expression in avian wing musculature.
- To determine if androgen action in skeletal muscle is conserved across passerine species.
Main Methods:
- Quantitative PCR (qPCR) was used to measure mRNA expression levels.
- Gene expression of parvalbumin (PV) and insulin-like growth factor I (IGF-I) was analyzed in wing muscles.
- Experiments involved wild golden-collared manakins and captive zebra finches, with some treated with testosterone and an anti-androgen (flutamide).
Main Results:
- Testosterone (T) up-regulated PV and IGF-I expression in manakin wing muscles.
- In zebra finches, flutamide counteracted the effects of T on PV and IGF-I expression.
- PV and IGF-I expression varied across species (manakins, zebra finches, ochre-bellied flycatchers) in a manner consistent with AR-dependent regulation.
Conclusions:
- Androgen action via AR influences gene expression in passerine skeletal muscle.
- These findings suggest androgens can modulate avian muscle to enhance physical capacity for reproduction.
- Transcriptional effects of androgens on skeletal muscle are conserved in birds.
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