Testosterone upregulates lipoprotein status to control sexual attractiveness in a colorful songbird

Kevin McGraw, Stephanie M. Correa, Elizabeth Adkins-Regan

Research output: Contribution to journalArticlepeer-review

99 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)117-122
Number of pages6
JournalBehavioral Ecology and Sociobiology
Issue number2
StatePublished - Jun 2006


  • Androgen
  • Carotenoid pigmentation
  • Cholesterol
  • Flutamide
  • Plasma carotenoids
  • Sexual selection
  • Taeniopygia guttata
  • Zebra finch

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Animal Science and Zoology


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