Acute and chronic effects of an aromatase inhibitor on territorial aggression in breeding and nonbreeding male song sparrows

被引:0
|
作者
Kiran K. Soma
Kim A. Sullivan
Anthony D. Tramontin
Colin J. Saldanha
Barney A. Schlinger
John C. Wingfield
机构
[1] Department of Zoology,
[2] Box 351800,undefined
[3] University of Washington,undefined
[4] Seattle,undefined
[5] WA 98195,undefined
[6] USA,undefined
[7] Department of Biology,undefined
[8] Utah State University,undefined
[9] Logan,undefined
[10] UT 84322,undefined
[11] USA,undefined
[12] Department of Physiological Science and Laboratory of Neuroendocrinology,undefined
[13] Brain Research Institute,undefined
[14] University of California,undefined
[15] Los Angeles,undefined
[16] CA 90095,undefined
[17] USA,undefined
[18] Present address: The Rockefeller University,undefined
[19] Box 210,undefined
[20] 1230 York Avenue,undefined
[21] New York,undefined
[22] NY 10021,undefined
[23] USA,undefined
来源
关键词
Estradiol Reproduction Songbird Testosterone Territory;
D O I
暂无
中图分类号
学科分类号
摘要
Many studies have demonstrated that male aggression is regulated by testosterone. The conversion of testosterone to estradiol by brain aromatase is also known to regulate male aggression in the breeding season. Male song sparrows (Melospiza melodia morphna) are territorial not only in the breeding season, but also in the nonbreeding season, when plasma testosterone and estradiol levels are basal. Castration has no effect on nonbreeding aggression. In contrast, chronic (10 day) aromatase inhibitor (fadrozole) treatment decreases nonbreeding aggression, indicating a role for estrogens. Here, we show that acute (1 day) fadrozole treatment decreases nonbreeding territoriality, suggesting relatively rapid estrogen effects. In spring, fadrozole decreases brain aromatase activity, but acute and chronic fadrozole treatments do not significantly decrease aggression, although trends for some behaviors approach significance. In gonadally intact birds, fadrozole may be less effective at reducing aggression in the spring. This might occur because fadrozole causes a large increase in plasma testosterone in intact breeding males. Alternatively, estradiol may be more important for territoriality in winter than spring. We hypothesize that sex steroids regulate male aggression in spring and winter, but the endocrine mechanisms vary seasonally.
引用
收藏
页码:759 / 769
页数:10
相关论文
共 50 条