Estrogenic control of reproductive behavior in the male zebra finch.
Item
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Title
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Estrogenic control of reproductive behavior in the male zebra finch.
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Identifier
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AAI8820908
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identifier
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8820908
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Creator
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Walters, Michael Joseph.
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Contributor
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Adviser: Cheryl F. Harding
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Date
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1988
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Language
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English
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Publisher
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City University of New York.
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Subject
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Psychology, Psychobiology
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Abstract
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This study consists of three experiments examining aromatization and reproductive behavior in male zebra finches. In the first experiment, castrated males were treated with androstenedione (AE), an aromatizable androgen, and their sexual and aggressive behavior compared with that of castrates treated with AE plus 1,4,6-androstatriene-3,17-dione (ATD), an aromatization inhibitor. Males treated with AE + ATD showed less courtship activity than AE-treated males, less copulatory behavior, and were unlikely to have nests. Estradiol (E), when given concurrently with AE + ATD, restored levels of courtship and copulation to those observed in AE-treated males. Aggressive behaviors were displayed exclusively by AE- and AE + ATD + E-treated males.;The second experiment examined the relationship between aromatization and two types of vocal behavior: courtship song and 'undirected' song. Castrated males were treated with AE, AE + ATD, or AE + ATD + E. Courtship songs were then recorded from individual males paired with a female, and undirected songs recorded from males grouped together in isolation from females. AE + ATD-treated males exhibited significantly fewer courtship songs than males treated with AE or AE + ATD + E, and they were of longer duration. In contrast, the frequency and duration of undirected songs were not affected by ATD treatment.;The third experiment examined estrogen receptor concentrations in brain regions involved in the control of sexual and vocal behavior. Cytosolic ({dollar}\sp3{dollar}H) estrogen binding was measured in castrated males and, to minimize competition from endogenously formed estrogen, in ATD-treated castrates. Specific, high-affinity ({dollar}\sp3{dollar}H) estrogen binding was detected in both untreated castrates and castrates treated with ATD. Although ATD treatment had no effect on estrogen receptor levels in hypothalamic-preoptic tissue, ATD-treated males has significantly higher levels of ({dollar}\sp3{dollar}H) estrogen binding in three vocal control nuclei: the dorsomedial portion of the intercollicular nucleus (DM), the magnocellular nucleus of the anterior neostriatum (MAN), and Area X. Low levels of estrogen binding were also detected in cytosol from the caudal portion of the ventral hyperstriatum (HVc) and the robust nucleus of the archistriatum (RA) of both untreated and ATD-treated castrates.;These experiments clearly demonstrate the importance of estrogen in the control of reproductive activities in male zebra finches and indicate that aromatization appears necessary for maintaining normal levels of sexual and aggressive behavior.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
