SGER: Characterization of Hermaphroditism in Rana Pipiens

SGER：Rana Pipiens 雌雄同体的特征

• 批准号: 0315274
• 负责人: Tyrone Hayes
• 金额: $ 10万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-15 至 2005-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0315274&HistoricalAwards=false
• 关键词: SGER; Characterization; Hermaphroditism; Rana; Pipiens

Previous laboratory studies showed that the herbicide, atrazine, induced sexual abnormalities in both African clawed frogs (Xenopus laevis) and American leopard frogs (Rana pipiens). Hermaphroditism (animals with both testes and ovaries or testes with developing eggs) was the most severe abnormality observed. Later studies showed that similar abnormalities were found in the wild in populations exposed to atrazine via agricultural runoff. Although the cause-effect hypothesis is supported by laboratory data, it is possible that hermaphroditism occurs naturally and that the correlation with atrazine contamination in the wild may be coincidental. The current study will address the possibility in two ways: 1) Animals from populations in the wild that show hermaphroditism will be reared in the laboratory to determine if hermaphroditism occurs in the absence of exposure to atrazine-contaminated water. Development of animals from these populations will be compared with animals from populations that do not show hermaphroditism in the wild. 2) Animals from populations that do not show hermaphroditism in the wild will be reared in atrazine-contaminated water collected from areas where hermaphroditism was observed in the wild to determine if it will induce hermaphroditism in animals that do not normally show this developmental pattern.The two aims outlined above will determine if hermaphroditism occurs naturally, or is the result of contaminant exposure. These studies are important for several reasons: 1) atrazine is the most common contaminant in ground and drinking water; 2) laboratory studies showed that atrazine is active at levels as low as 0.1 parts per billion, a level that can be exceeded even in rain water; 3) atrazine and other pesticides may be involved in amphibian declines; 4) the proposed endocrine mechanisms by which atrazine affects amphibians have been documented in fish, reptiles, and mammals; 5) the same mechanisms may be responsible for cancers produced in rats by atrazine and observed in humans occupationally exposed to atrazine (breast and prostate cancer).

先前的实验室研究表明，除草剂阿特拉津会诱导非洲爪蛙（非洲爪蟾）和美国豹蛙（蛙）的性异常。雌雄同体（同时具有睾丸和卵巢或睾丸中有发育中卵子的动物）是观察到的最严重异常。后来的研究表明，在通过农业径流接触阿特拉津的野生种群中也发现了类似的异常。虽然因果假说得到了实验室数据的支持，但两性畸形可能是自然发生的，与野生阿特拉津污染的相关性可能是巧合。目前的研究将从两个方面解决这种可能性：1）将在实验室中饲养来自野生种群的显示两性畸形的动物，以确定在没有暴露于阿特拉津污染的水的情况下是否会发生两性畸形。这些种群的动物发育将与野生动物中不显示雌雄同体的种群的动物进行比较。2)来自野生动物中没有表现出雌雄同体的动物将被饲养在阿特拉津污染的水中，这些水是从在野生动物中观察到雌雄同体的地区收集的，以确定它是否会在通常不表现出这种发育模式的动物中诱导雌雄同体。上述两个目标将确定雌雄同体是自然发生的还是污染物暴露的结果。这些研究之所以重要，有几个原因：1）阿特拉津是地下水和饮用水中最常见的污染物; 2）实验室研究表明，阿特拉津的活性水平低至十亿分之0.1，即使在雨水中也可能超过这一水平; 3）阿特拉津和其他农药可能与两栖动物数量的减少有关; 4）阿特拉津影响两栖动物的拟议内分泌机制已在鱼类、爬行动物和哺乳动物中得到证实; 5）同样的机制可能是导致阿特拉津在大鼠体内产生癌症的原因，也可能是在职业性接触阿特拉津的人类中观察到的原因。（乳腺癌和前列腺癌）。