TY - JOUR
T1 - Testosterone upregulates lipoprotein status to control sexual attractiveness in a colorful songbird
AU - McGraw, Kevin
AU - Correa, Stephanie M.
AU - Adkins-Regan, Elizabeth
N1 - Funding Information:
Acknowledgements We thank K. Navara and M. Mendonca for help running T assays; V. Johnson at Polymedco Inc. for answering questions about cholesterol assays; T. van Deusen, D. Sheils, and P. Smith for assistance with animal care; and P. Deviche, R. Parker, and D. Winkler for constructive comments on the manuscript. This research was supported by the National Science Foundation (IBN 9514088 and 0130986 to EAR) and the Environmental Protection Agency (graduate STAR fellowship to KJM). All reported procedures were approved by the Institutional Animal Care and Use Committee at Cornell University (protocol # 99–89).
PY - 2006/6
Y1 - 2006/6
N2 - A salient feature of many secondary sexual characteristics in animals is that their expression is controlled by sex-steroid hormones. However, for only a few types of ornaments do we know the precise molecular mechanism by which androgens like testosterone (T) enhance trait production. We studied the red carotenoid-based beak of male zebra finches (Taeniopygia guttata), which serves as a sexually selected trait and is thought to be T dependent. In previous research, we demonstrated that the extent to which male finches produce lipoproteins in the bloodstream, which bind carotenoid pigments acquired from the diet and transport them to peripheral tissues, regulates the accumulation of carotenoids in the body and beak pigmentation. Here we show that T acts to upregulate lipoprotein production and allows male zebra finches to display flashy, sexually attractive coloration. Levels of circulating T in blood positively and significantly predicted lipoprotein profile (as measured by cholesterol levels), blood carotenoid concentration, and beak color. Exogenous T administration elevated cholesterol and carotenoid status as well as beak redness. Last, experimental inhibition of T (using the anti-androgen flutamide) downregulated lipoprotein production and carotenoid circulation and faded the beak. This androgen- and lipoprotein-mediated system represents one of the more detailed physiological mechanisms underlying the development of a sex-steroid-dependent trait in animals.
AB - A salient feature of many secondary sexual characteristics in animals is that their expression is controlled by sex-steroid hormones. However, for only a few types of ornaments do we know the precise molecular mechanism by which androgens like testosterone (T) enhance trait production. We studied the red carotenoid-based beak of male zebra finches (Taeniopygia guttata), which serves as a sexually selected trait and is thought to be T dependent. In previous research, we demonstrated that the extent to which male finches produce lipoproteins in the bloodstream, which bind carotenoid pigments acquired from the diet and transport them to peripheral tissues, regulates the accumulation of carotenoids in the body and beak pigmentation. Here we show that T acts to upregulate lipoprotein production and allows male zebra finches to display flashy, sexually attractive coloration. Levels of circulating T in blood positively and significantly predicted lipoprotein profile (as measured by cholesterol levels), blood carotenoid concentration, and beak color. Exogenous T administration elevated cholesterol and carotenoid status as well as beak redness. Last, experimental inhibition of T (using the anti-androgen flutamide) downregulated lipoprotein production and carotenoid circulation and faded the beak. This androgen- and lipoprotein-mediated system represents one of the more detailed physiological mechanisms underlying the development of a sex-steroid-dependent trait in animals.
KW - Androgen
KW - Carotenoid pigmentation
KW - Cholesterol
KW - Flutamide
KW - Plasma carotenoids
KW - Sexual selection
KW - Taeniopygia guttata
KW - Zebra finch
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U2 - 10.1007/s00265-005-0135-3
DO - 10.1007/s00265-005-0135-3
M3 - Article
AN - SCOPUS:33744929652
SN - 0340-5443
VL - 60
SP - 117
EP - 122
JO - Behavioral Ecology and Sociobiology
JF - Behavioral Ecology and Sociobiology
IS - 2
ER -