DISSERTATION RESEARCH: Assessment of Endocrine Disruptor Effects in Anurans

两栖动物被认为是环境变化的生物指标。两栖动物的数量可能在世界范围内迅速下降，原因尚不清楚。造成这种下降的一个原因是化学物质的广泛污染，这些化学物质会破坏激素系统。本研究旨在评估测试生态雌激素对青蛙和蟾蜍（无尾蟾蜍）影响的方法。生态雌激素包括主要为农业和工业用途而设计的化学品，这些化学品被提议模仿雌激素的作用。pi将使用anurans来检查自然产生的（内源性）雌激素的效果，并将内源性雌激素的效果与生态雌激素的效果进行比较。PIs发现内源雌激素的作用因物种和发育阶段而异。pi正在测试多个物种和多个生命阶段，以确定特定的生态雌激素在我们所有的测试中是否始终像内源性雌激素一样起作用。内源性雌激素使成年雌性青蛙和蟾蜍产生蛋黄成分（卵黄原蛋白）。雄性通常不产生卵黄原蛋白，因为它们通常不产卵。然而，在暴露于内源性和生态雌激素的雄性中，卵黄原蛋白的产生可以被诱导。在生成卵黄原蛋白之前，必须先生成生成卵黄原蛋白的遗传指令（卵黄原蛋白mRNA）。pi将在加州各地调查野生雄性青蛙和蟾蜍，以确定它们的卵黄原蛋白基因是否被激活。pi应将此信息作为开发可靠系统以检测非实验室动物雌激素暴露的第一步。

Amphibians have been proposed as bio-indicators of environmental change. Amphibian populations may be in rapid worldwide decline for reasons that are still unclear. One proposed contributor to this decline is widespread contamination with chemicals that disrupt hormone systems. This study is designed to evaluate ways of testing the effects that eco-estrogens have on frogs and toads (anurans). Eco-estrogens include chemicals mostly designed for agricultural and industrial use and that have been proposed to mimic the effects of estrogens. The PIs will use anurans to examine the effects of naturally produced (endogenous) estrogens and compare the effects of endogenous estrogens to the effects of eco-estrogens. The PIs found that the endogenous estrogen effects vary according to species and developmental stage. The PIs are testing multiple species and multiple life stages to determine if specific eco-estrogens consistently act like endogenous estrogens throughout all of our tests.Endogenous estrogens cause adult female frogs and toads to produce egg yolk components (vitellogenin). Males do not normally produce vitellogenin because they do not normally make eggs. However, vitellogenin production can be induced in males exposed to both endogenous and eco-estrogens. Before vitellogenin can be produced, the genetic instructions to produce vitellogenin (vitellogenin mRNA) must be made. The PIs will survey wild male frogs and toads at sites throughout California to determine if their vitellogenin genes are turned on. The PIs shall use this information as the first step in developing a reliable system for detecting estrogen exposure in non-laboratory animals.