TY - JOUR
T1 - Testosterone induction of song in photosensitive and photorefractory male sparrows
AU - Nowicki, Stephen
AU - Ball, Gregory F.
N1 - Funding Information:
We thank Tamia Rudnicky and Mary Lou Sotanskif or technicala ssistance,S usan Peters and Peter Marler for providing the subjects, William Searcy for helpful discussion, and Peter Marler and Fernando Nottebohm for commentso n the manuscript.T his work was supportedb y U.S.P.H.S. Grant NS24651,a wards from the Mary Flagler Cary Trust, the Irma T. Hirsch1 Trust, and the Revson Foundation, and Biomedical Research Support Grant SO7R R07065.
Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 1989/12
Y1 - 1989/12
N2 - Song in male songbirds is activated by the sex steroid testosterone (T). Using male song sparrows (Melospiza melodia), we compared effects of T in the normal spring state of photosensitivity (i.e., when the pituitary-gonadal axis is sensitive to stimulation by increasing daylength) and in the late summer-early fall state of photorefractoriness (i.e., when they are insensitive to increasing daylength). Photosensitive males experienced short days for 8 weeks and then long days for another 22 weeks to induce photorefractoriness. T implants were given to the birds twice, first when on short days and photosensitive, and second when on long days and photorefractory. Song rates were compared among 5 conditions: (1) photosensitive, short days, low T titers; (2) photosensitive, short days, high T titers; (3) photosensitive, long days, high T titers; (4) photorefractory, long days, low T titers; and (5) photorefractory, long days, high T titers. Plasma levels of T were monitored throughout the experiment by radioimmunoassay. T was equally effective in inducing song in both the photosensitive and photorefractory conditions. Thus, no seasonal change was found in the sensitivity to hormone action of the neural target sites mediating this behavior in song sparrows. Photosensitive birds sang at a higher rate when on long days than when on short days, however, even though there was no concomitant increase in plasma levels of T. This finding suggests that environmental factors can alter the expression of song activated by similar levels of T.
AB - Song in male songbirds is activated by the sex steroid testosterone (T). Using male song sparrows (Melospiza melodia), we compared effects of T in the normal spring state of photosensitivity (i.e., when the pituitary-gonadal axis is sensitive to stimulation by increasing daylength) and in the late summer-early fall state of photorefractoriness (i.e., when they are insensitive to increasing daylength). Photosensitive males experienced short days for 8 weeks and then long days for another 22 weeks to induce photorefractoriness. T implants were given to the birds twice, first when on short days and photosensitive, and second when on long days and photorefractory. Song rates were compared among 5 conditions: (1) photosensitive, short days, low T titers; (2) photosensitive, short days, high T titers; (3) photosensitive, long days, high T titers; (4) photorefractory, long days, low T titers; and (5) photorefractory, long days, high T titers. Plasma levels of T were monitored throughout the experiment by radioimmunoassay. T was equally effective in inducing song in both the photosensitive and photorefractory conditions. Thus, no seasonal change was found in the sensitivity to hormone action of the neural target sites mediating this behavior in song sparrows. Photosensitive birds sang at a higher rate when on long days than when on short days, however, even though there was no concomitant increase in plasma levels of T. This finding suggests that environmental factors can alter the expression of song activated by similar levels of T.
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U2 - 10.1016/0018-506X(89)90039-1
DO - 10.1016/0018-506X(89)90039-1
M3 - Article
C2 - 2606465
AN - SCOPUS:0024833874
SN - 0018-506X
VL - 23
SP - 514
EP - 525
JO - Hormones and Behavior
JF - Hormones and Behavior
IS - 4
ER -