Studies on genes relating to the formation of the testis-ovum in the testis of amphibians by the non-estrogenic action of environmental chemicals

本研究研究了双酚A （BPA）、壬基酚（NP）和雌二醇苯甲酸酯（EB）等环境化学物质对两栖动物睾丸-卵子形成的影响。首先，对三种两栖动物进行了暴露实验。雌雄蛙的蝌蚪和变性小蛙的睾丸异常比其他种类的更为明显。因此，在进一步的实验中，红毛鼠可作为实验动物的模型。其次，对暴露于环境化学物质中的蝌蚪的睾丸进行组织学分析，以了解睾丸-卵子的形成过程。最后，分析了暴露于BPA的蝌蚪在睾丸-卵子形成过程中的基因表达差异。编码卵黄原蛋白A1和ERRgamma的基因被分离出来，作为与环境化学物质非雌激素作用诱导的睾丸-卵子形成有关的候选基因。

In the present study, the formation of the testis-ovum has been investigated in amphibians exposed to environmental chemicals, such as bisphenol A (BPA), nonylphenol (NP), and estradiol benzoate (EB). Firstly, exposure experiments were performed using three species of amphibians. Abnormal testes were observed more remarkably in the tadpoles and metamorphosed froglets of the frog Rana rugosa than in those of the other species. Thus, R. rugosa was used as a model of an experimental animal in further experiments. Next, the testes were analyzed histologically in the tadpoles exposed to environmental chemicals to know the process of testis-ovum formation. Finally, genes expressed differentially in the tadpoles exposed to BPA were analyzed during the formation of the testis-ova. Genes encoding vitellogenin A1 and ERRgamma were isolated as candidates relating to the formation of testis-ova induced by the non-estrogenic action of the environmental chemical.