Department of Zoology, University of British Columbia, Vancouver, BC, Canada.
Horm Behav. 2013 Mar;63(3):462-74. doi: 10.1016/j.yhbeh.2012.12.010. Epub 2012 Dec 26.
Wild zebra finches form long-term monogamous pair-bonds that are actively maintained year-round, even when not in breeding condition. These desert finches are opportunistic breeders, and breeding is highly influenced by unpredictable rainfall. Their high levels of affiliation and complex breeding patterns make zebra finches an excellent model in which to study the endocrine regulation of affiliation. Here, we compared zebra finch pairs that were provided with water ad libitum (control) or water restricted. We examined (1) reproductive physiology, (2) pair-maintenance behaviors in several contexts, and (3) circulating and brain steroid levels. In females, water restriction profoundly reduced largest ovarian follicle size, ovary size, oviduct size, and egg laying. In males, water restriction had no effect on testes size but decreased systemic testosterone levels. However, in the hypothalamus, local testosterone and estradiol levels were unaffected by water restriction in both sexes. Systemic and local levels of the androgen precursor dehydroepiandrosterone (DHEA) were also unaffected by water restriction. Lastly, in three different behavioral paradigms, we examined a variety of pair-maintenance behaviors, and none were reduced by water restriction. Taken together, these correlational data are consistent with the hypothesis that local production of sex steroids in the brain promotes the expression of pair-maintenance behaviors in non-breeding zebra finches.
野生斑胸草雀形成长期的一夫一妻制，全年都积极维持这种关系，即使在非繁殖期也是如此。这些沙漠雀是机会主义繁殖者，繁殖高度受不可预测的降雨影响。它们高度的亲密关系和复杂的繁殖模式使斑胸草雀成为研究附属内分泌调节的理想模型。在这里，我们比较了给予自由饮水（对照）或限制饮水的斑胸草雀对。我们检查了（1）生殖生理学，（2）几种情况下的维持行为，（3）循环和大脑类固醇水平。在雌性中，限水严重降低了最大卵巢滤泡大小、卵巢大小、输卵管大小和产卵。在雄性中，限水对睾丸大小没有影响，但降低了系统睾丸激素水平。然而，在两性的下丘脑，局部睾丸激素和雌二醇水平不受限水影响。雄激素前体脱氢表雄酮（DHEA）的系统和局部水平也不受限水影响。最后，在三个不同的行为范式中，我们检查了各种维持行为，限水都没有减少这些行为。综上所述，这些相关数据与局部脑内产生性类固醇促进非繁殖期斑胸草雀维持行为表达的假设一致。
