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Proc Natl Acad Sci U S A. May 15, 1991; 88(10): 4191–4194.

Brain is the major site of estrogen synthesis in a male songbird.


The neural system controlling song in passerine birds can undergo striking morphological and functional changes during both development and adulthood, and many of these changes are regulated by estrogenic hormones. Estrogens circulate at high levels in blood of male songbirds and persist after castration. We measured the activity of aromatase, the enzyme that converts androgens to estrogens, in various tissues from adult male and female zebra finches. As expected, aromatase activity was present in male hypothalamus/preoptic area and pituitary and female ovary, but aromatase was unusually active in whole telencephalon of males and females. By contrast, activity was undetected in testes, adrenals, or other tissues of males. These results suggest that brain is the source of circulating estrogens in the male zebra finch and that estrogen actions on the song system result from local rather than peripheral aromatization.

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  • Naftolin F, Ryan KJ, Davies IJ, Reddy VV, Flores F, Petro Z, Kuhn M, White RJ, Takaoka Y, Wolin L. The formation of estrogens by central neuroendocrine tissues. Recent Prog Horm Res. 1975;31:295–319. [PubMed]
  • MacLusky NJ, Naftolin F. Sexual differentiation of the central nervous system. Science. 1981 Mar 20;211(4488):1294–1302. [PubMed]
  • McEwen BS, Biegon A, Davis PG, Krey LC, Luine VN, McGinnis MY, Paden CM, Parsons B, Rainbow TC. Steroid hormones: humoral signals which alter brain cell properties and functions. Recent Prog Horm Res. 1982;38:41–92. [PubMed]
  • Callard G, Schlinger B, Pasmanik M. Nonmammalian vertebrate models in studies of brain-steroid interactions. J Exp Zool Suppl. 1990;4:6–16. [PubMed]
  • Gurney ME, Konishi M. Hormone-induced sexual differentiation of brain and behavior in zebra finches. Science. 1980 Jun 20;208(4450):1380–1383. [PubMed]
  • Gurney ME. Hormonal control of cell form and number in the zebra finch song system. J Neurosci. 1981 Jun;1(6):658–673. [PubMed]
  • Hutchison JB, Wingfield JC, Hutchison RE. Sex differences in plasma concentrations of steroids during the sensitive period for brain differentiation in the zebra finch. J Endocrinol. 1984 Dec;103(3):363–369. [PubMed]
  • Adkins-Regan E, Abdelnabi M, Mobarak M, Ottinger MA. Sex steroid levels in developing and adult male and female zebra finches (Poephila guttata). Gen Comp Endocrinol. 1990 Apr;78(1):93–109. [PubMed]
  • Marler P, Peters S, Ball GF, Dufty AM, Jr, Wingfield JC. The role of sex steroids in the acquisition and production of birdsong. Nature. 1988 Dec 22;336(6201):770–772. [PubMed]
  • Marler P, Peters S, Wingfield J. Correlations between song acquisition, song production, and plasma levels of testosterone and estradiol in sparrows. J Neurobiol. 1987 Nov;18(6):531–548. [PubMed]
  • Harding CF, Sheridan K, Walters MJ. Hormonal specificity and activation of sexual behavior in male zebra finches. Horm Behav. 1983 Mar;17(1):111–133. [PubMed]
  • Arnold AP. The effects of castration and androgen replacement on song, courtship, and aggression in zebra finches (Poephila guttata). J Exp Zool. 1975 Mar;191(3):309–326. [PubMed]
  • Adkins-Regan E, Ascenzi M. Sexual differentiation of behavior in the zebra finch: effect of early gonadectomy or androgen treatment. Horm Behav. 1990 Mar;24(1):114–127. [PubMed]
  • Schlinger BA, Callard GV. Localization of aromatase in synaptosomal and microsomal subfractions of quail (Coturnix coturnix japonica) brain. Neuroendocrinology. 1989 Apr;49(4):434–441. [PubMed]
  • Schlinger BA, Callard GV. A comparison of aromatase, 5 alpha-, and 5 beta- reductase activities in the brain and pituitary of male and female quail (C. c. japonica). J Exp Zool. 1987 May;242(2):171–180. [PubMed]
  • Schlinger BA, Fivizzani AJ, Callard GV. Aromatase, 5 alpha- and 5 beta-reductase in brain, pituitary and skin of the sex-role reversed Wilson's phalarope. J Endocrinol. 1989 Aug;122(2):573–581. [PubMed]
  • Bradford MM. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. [PubMed]
  • Wilson JD, Leshin M, George FW. The Sebright bantam chicken and the genetic control of extraglandular aromatase. Endocr Rev. 1987 Nov;8(4):363–376. [PubMed]
  • Vockel A, Pröve E, Balthazart J. Effects of castration and testosterone treatment on the activity of testosterone-metabolizing enzymes in the brain of male and female zebra finches. J Neurobiol. 1990 Jul;21(5):808–825. [PubMed]
  • Hutchison JB, Steimer T. Formation of behaviorally effective 17 beta-estradiol in the dove brain: steroid control of preoptic aromatase. Endocrinology. 1986 Jun;118(6):2180–2187. [PubMed]
  • Vockel A, Pröve E, Balthazart J. Sex- and age-related differences in the activity of testosterone-metabolizing enzymes in microdissected nuclei of the zebra finch brain. Brain Res. 1990 Mar 19;511(2):291–302. [PubMed]
  • RYAN KJ. Biological aromatization of steroids. J Biol Chem. 1959 Feb;234(2):268–272. [PubMed]
  • Schumacher M, Balthazart J. Neuroanatomical distribution of testosterone-metabolizing enzymes in the Japanese quail. Brain Res. 1987 Sep 29;422(1):137–148. [PubMed]
  • Watson JT, Abdelnabi M, Wersinger S, Ottinger MA, Adkins-Regan E. Circulating estradiol and the activation of male and female copulatory behavior in Japanese quail (Coturnix japonica). Gen Comp Endocrinol. 1990 Feb;77(2):229–238. [PubMed]
  • Arnold AP, Bottjer SW, Brenowitz EA, Nordeen EJ, Nordeen KW. Sexual dimorphisms in the neural vocal control system in song birds: ontogeny and phylogeny. Brain Behav Evol. 1986;28(1-3):22–31. [PubMed]
  • Toran-Allerand CD. Sex steroids and the development of the newborn mouse hypothalamus and preoptic area in vitro: implications for sexual differentiation. Brain Res. 1976 Apr 23;106(2):407–412. [PubMed]
  • MacLusky NJ, Naftolin F, Goldman-Rakic PS. Estrogen formation and binding in the cerebral cortex of the developing rhesus monkey. Proc Natl Acad Sci U S A. 1986 Jan;83(2):513–516. [PMC free article] [PubMed]

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