title: Dicamba affects sex steroid hormone level and mRNA expression of related genes in adult rare minnow (Gobiocypris rarus) at environmentally relevant concentrations.
abstract: Dicamba is a benzoic acid herbicide that has been detected in surface and ground water. The herbicide has been shown to have cytogeneic and DNA damaging effects and to cause organ damage in mammals; however, little is known about the endocrine disrupting effects of dicamba in fish. In this study, histological changes, plasma vitellogenin (VTG) and sex hormone levels, and mRNA expression of sex steroid hormone-related genes were determined in adult rare minnow exposed to environmentally relevant concentrations of dicamba (0, 0.05, 0.5, 5, and 50 μg/L) for 40 days. The results showed inhibition of spermatogenesis in male testes and ovarian degeneration in females. Plasma 17β-estradiol (E2) levels were significantly increased in both genders, and plasma VTG levels were significantly increased in males (p<0.05). These results indicate that sex hormone homeostasis and normal reproduction of fish could be affected by dicamba. Moreover, the mRNA levels of vtg were significantly upregulated in the livers and gonads of both male and female rare minnows (p < 0.05). The downregulation of cytochrome P450c19a (cyp19a) and steroidogenic acute regulatory protein (star) mRNA levels, and the upregulation of cytochrome P450c17 (cyp17) mRNA levels were observed in the livers and ovaries (p<0.05). The results of the mRNA analysis suggest that changes in steroid hormone-related gene expression could serve as a regulatory mechanism to maintain sex hormone homeostasis. Overall, dicamba exposure could result in histological lesions, plasma VTG increases, changes in sex hormone levels, and alterations of hormone-related gene expression. Therefore, dicamba should be considered to be a potential endocrine disruptor.
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Shuangqing Rd 18, Haidian District, Beijing, 100085, People's Republic of China.
authors.forename: Lifei
authors.initials: L
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Shuangqing Rd 18, Haidian District, Beijing, 100085, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Shuangqing Rd 18, Haidian District, Beijing, 100085, People's Republic of China.
authors.forename: Jinmiao
authors.initials: J
authors.lastname: Zha
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Shuangqing Rd 18, Haidian District, Beijing, 100085, People's Republic of China.
authors.forename: Zijian
authors.initials: Z
authors.lastname: Wang
mesh_terms: D000818:Animals; D003530:Cyprinidae / Q000378:metabolism; D003996:Dicamba / Q000633:toxicity; D052244:Endocrine Disruptors / Q000633:toxicity; D005260:Female; D012739:Gonadal Steroid Hormones / Q000097:blood*; D006066:Gonads / Q000187:drug effects; D006540:Herbicides / Q000633:toxicity; D006801:Humans; D008099:Liver / Q000187:drug effects; D008297:Male; D010053:Ovary / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D013091:Spermatogenesis; D013737:Testis / Q000187:drug effects; D014819:Vitellogenins / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000097:blood / Q000633:toxicity*
chemical_list: D052244:Endocrine Disruptors; D012739:Gonadal Steroid Hormones; D006540:Herbicides; D012333:RNA, Messenger; D014819:Vitellogenins; D014874:Water Pollutants, Chemical; D003996:Dicamba
keywords: dicamba; endocrine disruptor; rare minnow (Gobiocypris rarus); sex steroid hormone; vitellogenin (VTG)