A dose-response study of estradiol's effects on the developing zebra finch song system.
To gauge the sensitivity of the female zebra finch song system to estradiol (E2), we used subcutaneous implants to administer various doses of E2 to hatchling female zebra finches. Four different doses of E2 were administered: 50, 15, 5 and 0-microg via subcutaneous silicon "ropes" at hatching, and the brains were examined in adulthood. Further, we examined whether masculinization was all-or-none once a threshold was reached or if the morphology of the song system would show a graded response to the various doses of E2. Finally, we asked if the various dependent measures - volume of song nuclei, neuron size, and neuron number - would show differential sensitivity to E2. Fifteen micrograms was sufficient to masculinize many aspects of the song system and was often as effective as 50-microg, causing a dramatic difference relative to the 0-microg group. Different aspects of the song system seemed differentially sensitive to the effects of E2: volumes of song control nuclei, the size of RA neurons, and the number of HVC neurons were significantly masculinized by 15-microg E2, but the number of RA neurons and HVC and lMAN soma sizes required 50-microg. The results suggest that several developmental processes are influenced by E2, possibly because of multiple sites of action or multiple processes that respond to E2.
Grisham
William
W
Department of Psychology and Laboratory of Neuroendocrinology of the Brain Research Institute, University of California, UCLA, 1285 Franz Hall, P.O. Box 951563, Los Angeles, CA 90095-1563, United States. wgrisham@ucla.edu
Lee
Janet
J
Park
Sun Hee
SH
Mankowski
Jennifer L
JL
Arnold
Arthur P
AP
D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001522:Behavior, Animal / Q000187:drug effects; D001921:Brain / Q000033:anatomy & histology* / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000494:pharmacology*; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D046369:Finches; D009474:Neurons / Q000187:drug effects; D012727:Sex Characteristics; D014828:Vocalization, Animal / Q000187:drug effects*
D004967:Estrogens; D004958:Estradiol
J Neurosci. 1994 Nov;14(11 Pt 1):6532-43
7965057
Horm Behav. 2002 Mar;41(2):236-41
11855909
J Neurobiol. 1997 Nov;33(5):572-84
9369460
Nat Neurosci. 2001 Feb;4(2):170-5
11175878
J Neurobiol. 1991 Oct;22(7):777-93
1765783
J Neurosci. 1981 Jun;1(6):658-73
7346574
J Neurobiol. 1994 Feb;25(2):185-96
8021647
J Neurobiol. 1995 Aug;27(4):513-9
7561830
Proc Biol Sci. 2005 Jan 22;272(1559):173-7
15695208
Neuron. 2002 Jun 13;34(6):945-60
12086642
J Neurobiol. 1991 Jan;22(1):29-39
2010748
Ann N Y Acad Sci. 2004 Jun;1016:540-59
15313794
J Exp Zool A Comp Exp Biol. 2006 Sep 1;305(9):743-8
16902969
Brain Res. 1982 Jan 7;231(1):153-72
7055672
J Neurobiol. 1991 Oct;22(7):755-76
1765782
J Comp Neurol. 1998 Jun 29;396(2):186-92
9634141
Am J Physiol. 1963 Nov;205(5):842-4
5896305
J Neurobiol. 1995 Feb;26(2):163-70
7707040
J Comp Neurol. 2004 Feb 16;469(4):535-47
14755534
Brain Res. 1985 Jun 17;336(2):381-3
4005597
Proc Natl Acad Sci U S A. 1999 Jul 6;96(14):8241-6
10393979
Proc Natl Acad Sci U S A. 1998 Sep 15;95(19):11429-34
9736753
Science. 1976 Oct 8;194(4261):211-3
959852
Proc Natl Acad Sci U S A. 1994 Dec 20;91(26):12413-7
7809051
Nat Rev Neurosci. 2004 Sep;5(9):701-8
15322528
Proc Natl Acad Sci U S A. 2005 May 24;102(21):7730-5
15894627
Gen Comp Endocrinol. 1990 Apr;78(1):93-109
2332151
J Comp Neurol. 1987 May 15;259(3):393-9
3584563
Proc Natl Acad Sci U S A. 1988 Sep;85(18):7006-7
3413131
J Neurobiol. 2002 Apr;51(1):1-8
11920723
Brain Res Dev Brain Res. 1995 Apr 18;85(2):220-4
7600669