Dissertation Research: Hormonal regulation of immune function in seasonally-breeding birds

论文研究：免疫功能的荷尔蒙调节季节性繁殖的BIRDS诺亚·T·欧文-阿什利和约翰·C·温菲尔德西雅图华盛顿大学的类固醇激素睾酮(T)被认为对许多脊椎动物的健康有双向影响。T在协调男性的生殖和攻击性行为，以及促进许多对女性选择重要的第二性特征的发展方面是重要的。另一方面，高水平的T被认为会抑制免疫功能。许多对鸟类的研究发现，T抑制免疫系统的某些成分(S)，但尚不清楚这种机制是通过直接还是间接途径发生的。本研究的主要目的是了解这些途径在调节T诱导的免疫抑制中对西北歌雀和白冠麻雀的作用。在许多鸟类中，T的实验性升高会改变其他荷尔蒙的水平，如皮质酮和雌二醇，这些荷尔蒙也调节免疫力。因此，鸟类的免疫功能可能是通过这些中间激素而不是直接通过睾酮来改变的。将在这两个物种上进行一系列实验，涉及使用激素植入和/或药物阻滞剂，以梳理这些对生理和行为免疫功能的直接和间接影响。这些研究将为季节性繁殖鸟类的荷尔蒙免疫调节提供新的见解，并协调现有的理论，这些理论假定T在调节雄性脊椎动物免疫活性和繁殖成功之间的权衡中起直接作用。

DISSERTATION RESEARCH:HORMONAL REGULATION OF IMMUNE FUNCTIONIN SEASONALLY-BREEDING BIRDSNoah T. Owen-Ashley & John C. WingfieldUniversity of Washington, Seattle The steroid hormone testosterone (T) is thought to have bidirectional effects on fitness in many vertebrates. T is important in orchestrating reproductive and aggressive behavior in males, and promoting the development of many secondary sex characters important for female choice. On the other hand, high levels of T are thought to suppress immune function. Many studies in birds have found that T suppresses some component(s) of the immune system, but it is not known if this mechanism occurs through direct or indirect pathways. The main goal of this research is to understand the contributions of these pathways in regulating T-induced immunosuppression in the Northwestern Song Sparrow (Melospiza melodia morphna) and the White-crowned Sparrow (Zonotrichia leucophrys). Experimental elevation of T in many bird species alters the levels of other hormones, such as corticosterone and estradiol, which also regulate immunity. Therefore, avian immune function may be altered through these intermediary hormones, rather than by testosterone directly. A suite of experiments will be conducted on both species involving the use of hormone implants and/or pharmacological blockers to tease apart these direct and indirect effects on physiological and behavioral immune function. These studies will provide new insights into hormonal regulation of immunity in seasonally-breeding birds, and reconcile existing theories which assume a direct role of T in regulating a tradeoff between immunocompetence and reproductive success in male vertebrates.