Interaction of the Plasma Melatonin Rhythm with other Hormone Rhythms During Development and on Various Light/Dark Cycles

两栖动物蝌蚪的变态是一个主要由甲状腺激素分泌增加驱动的发育过程，尽管其他激素，如肾上腺皮质激素、催乳素和褪黑激素可能加速或抑制其进程。许多激素表现出节律性，并在一天中的特定时间在血液中达到峰值。不同激素峰值水平的时间差异可能对变态的调节至关重要。然而，蝌蚪血浆中激素的节律尚不清楚。本项目将利用放射免疫分析法研究蝌蚪发育早期至后期血浆中上述变质激素的昼夜节律性。蝌蚪的发育速度也取决于光/暗周期，就像血浆褪黑激素水平一样，在黑暗中褪黑激素水平更高。褪黑素抑制蝌蚪的甲状腺，以及组织对甲状腺素的反应。这项研究还将关注昼夜周期与甲状腺素和褪黑素水平和节律之间的关系。这项工作将进一步了解激素在发育中的作用，特别是褪黑激素的影响。由于褪黑激素的分泌与光线和黑暗有关，因此这项研究也将有助于我们了解环境对两栖动物的影响。鉴于最近出现的青蛙异常，这是一个非常值得关注的问题，其中一些似乎是发育起源。这项工作将在一所本科院校与本科生研究人员合作完成，他们将被介绍到科学过程中，为专业和科学事业做准备。

Metamorphosis of the amphibian tadpole is a developmental program driven mainly by an increased secretion of thyroid hormones, although other hormones, such as adrenal corticoids, prolactin, and melatonin may accelerate or inhibit its progress. Many hormones exhibit rhythmicity, and peak in the blood at specific times of the day. Differences in the timing of the peak level of various hormones could be critical to the regulation of metamorphosis. However, the rhythm of hormones in the plasma of tadpoles is not known. Using radioimmunoassay, this project will study the circadian rhythmicity of the metamorphic hormones mentioned above in the plasma of tadpoles from early to late stages of development. Tadpole development rate is also dependent on the light/dark cycle, as are plasma melatonin levels, which are higher in the dark. Melatonin inhibits the thyroid gland of tadpoles, as well as the tissue response to thyroxine. This research will also focus on the relationship between the light/dark cycle and thyroxine and melatonin levels and rhythms. This work will further understanding of the role of hormones in development, especially the influence of melatonin. Since the secretion of melatonin is related to light and darkness, the research will also help us to understand the influence of the environment on amphibians. This is a problem of much concern in view of the recent appearance of frog abnormalities, some of which appear to be developmental in origin. The work will be done at an undergraduate institution with the collaboration of undergraduate researchers, who will be introduced to the scientific process in preparation for professional and scientific careers.