Thyroxine and Seasonality in American Tree Sparrows

美国树麻雀的甲状腺素和季节性

• 批准号: 9982281
• 负责人: Fred Wilson
• 金额: $ 16.1万
• 依托单位: Kansas State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-04-01 至 2003-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9982281&HistoricalAwards=false
• 关键词: Thyroxine; Seasonality; American; Tree; Sparrows

The common observation that thyroidectomy blocks the transition from the breeding season to the nonbreeding season has led to the concept that thyroid hormone plays a key role in the termination of seasonal reproduction. Dr. Wilson's conceptual model, based on extensive studies on the obligately photoperiodic American tree sparrow (Spizella arborea), envisions a more pervasive role of thyroid hormone in seasonality and includes thyroid hormone-dependent control of gonadal growth and postnuptial molt as well as thyroid hormone-dependent control of gonadal regression. Recent data from his laboratory support the hypothesis that thyroxine (is the tissue-active thyroid hormone that) acts in the brain to program photostimulated American tree sparrows for seasonality. Thyroxine-dependent programming occurs early during photostimulation and resembles an organizational-like process in that thyroxine is not later required for expression of seasonality. Knowing where thyroxine acts in the brain is essential for advancing understanding of the physiological basis of seasonality. Using an acute model system, wherein a single injection of thyroxine on the first day of photostimulation programs thyrodectomized male American tree sparrows for seasonality, coupled with immunocytochemical and autoradiographic techniques, he expects to reveal potential "programmable" cells. Revealing such cells will provide a starting point for exploring the neural networks and/or glial connections that facilitate thyroxine-dependent programming of seasonality and for studying the cellular mechanism of thyroid hormone action.

甲状腺切除术阻断了从繁殖季节到非繁殖季节的过渡，这一普遍观察导致了甲状腺激素在季节性繁殖终止中起关键作用的概念。威尔逊博士的概念模型基于对专性光周期美国树雀（Spizella arborea）的广泛研究，设想了甲状腺激素在季节性中更普遍的作用，包括甲状腺激素对性腺生长和婚后蜕皮的依赖控制，以及甲状腺激素对性腺退化的依赖控制。他实验室的最新数据支持了他的假设，即甲状腺素（一种组织活性甲状腺激素）在大脑中起作用，使受光刺激的美国树麻雀具有季节性。甲状腺素依赖性编程发生在光刺激早期，类似于一个组织样的过程，甲状腺素不需要晚些时候表达季节性。了解甲状腺素在大脑中的作用位置对于提高对季节性生理基础的理解至关重要。使用急性模型系统，其中在光刺激计划的第一天单次注射甲状腺素以去除季节性的雄性美洲树麻雀，再加上免疫细胞化学和放射自显影技术，他希望揭示潜在的“可编程”细胞。揭示这些细胞将为探索神经网络和/或神经胶质连接提供一个起点，这些神经网络和/或神经胶质连接促进甲状腺素依赖性的季节性编程，并为研究甲状腺激素作用的细胞机制提供一个起点。