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Li Y, Li J, Shen Y, Xiong Y, Li X, Qin Z. Identification of estrogen receptor target genes involved in gonadal feminization caused by estrogen in Xenopus laevis. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2021; 232:105760. [PMID: 33515924 DOI: 10.1016/j.aquatox.2021.105760] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/10/2021] [Accepted: 01/15/2021] [Indexed: 06/12/2023]
Abstract
Estrogens and estrogenic endocrine disrupting chemicals can cause gonadal feminization in some vertebrates mainly through estrogen receptor (ER), but the underlying molecular mechanisms are unclear. The present study aimed to identify ER target genes involved in estrogen-caused gonadal feminization in Xenopus laevis. Based on our recent transcriptomic data that 10 nM 17β-estradiol (E2) altered gene transcription in feminizing gonads of male X. laevis at NF stages 48, 50, and 52, we searched estrogen response element (ERE) using the Dragon ERE Finder software in the promoter region of all the E2-regulated genes. As a result, 163 genes containing ERE sequence were identified as predicted ER target genes at NF stage 50 (on the 14th day postfertilization), a crucial stage for gonadal feminization. Then, some of these predicted ER target genes were further investigated, mainly including the genes that were suggested to be involved in E2-caused gonadal feminization and genes being dramatically up or down-regulated by E2. Fifteen genes were demonstrated to be responsive to E2, in turn ER antagonist blocked the E2-regulated transcription. Finally, we identified 10 genes that can bind to ERα by a chromatin immunoprecipitation-qPCR. Taken together, we identified the 10 genes that contain predicted ERE sequences, are responsive to estrogen and ER antagonist, and have ability to bind to ER as ER target genes, including pglyrp2, apoa1, fgb, tdo2, ca6, nags, cpb2, tmprss6, nudc, zwilch. Our results could help to improve the understanding of the molecular mechanisms for gonadal feminization caused by estrogenic endocrine disrupting chemicals in X. laevis, and even in other species.
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Affiliation(s)
- Yuanyuan Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jinbo Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yanping Shen
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yiming Xiong
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xinghong Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhanfen Qin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
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Li Y, Shen Y, Li J, Cai M, Qin Z. Transcriptomic analysis identifies early cellular and molecular events by which estrogen disrupts testis differentiation and causes feminization in Xenopus laevis. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2020; 226:105557. [PMID: 32645606 DOI: 10.1016/j.aquatox.2020.105557] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 06/23/2020] [Accepted: 06/26/2020] [Indexed: 06/11/2023]
Abstract
Extensive studies have shown that estrogenic endocrine-disrupting chemicals (EDCs) can disrupt testis differentiation and even cause feminization in vertebrates. However, little is known about the mechanisms by which estrogenic EDCs disrupt testis differentiation. Here, we employed Xenopus laevis, a model amphibian species sensitive to estrogenic EDCs, to explore the molecular and cellular events by which 17β-estradiol (E2) disrupts testis differentiation and causes feminization. Following waterborne exposure to E2 from stage 45/46, genetically male X. laevis were confirmed to undergo testis differentiation inhibition and ovary differentiation activation at stages 52 and 53, ultimately displaying gonadal feminization at stage 66. Using a time-course RNA sequencing approach, we then identified thousands of differentially expressed transcripts (DETs) in genetically male gonad-mesonephros complexes at stages 48, 50 and 52 (the window for testis differentiation) between E2 treatment and the control. Enrichment analysis suggests alterations in cell proliferation, extracellular matrix, and cell motility following E2 exposure. Further verification by multiple methods demonstrated that E2 inhibited cell proliferation, disrupted extracellular matrix, and altered cell motility in the genetically male gonads compared with controls, implying that these events together contributed to testis differentiation disruptions and feminization in X. laevis. This study for the first time uncovered some of the early molecular and cellular events by which estrogen disrupts testicular differentiation and causes feminization in X. laevis. These new findings improve our understanding of the mechanisms by which estrogenic EDCs disrupt testicular differentiation in vertebrates.
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Affiliation(s)
- Yuanyuan Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yanping Shen
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jinbo Li
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Man Cai
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China
| | - Zhanfen Qin
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
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Zhang W, Chen L, Xu Y, Deng Y, Zhang L, Qin Y, Wang Z, Liu R, Zhou Z, Diao J. Amphibian (Rana nigromaculata)exposed to cyproconazole: Changes in growth index, behavioral endpoints, antioxidant biomarkers, thyroid and gonad development. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2019; 208:62-70. [PMID: 30639745 DOI: 10.1016/j.aquatox.2018.12.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 12/18/2018] [Accepted: 12/18/2018] [Indexed: 06/09/2023]
Abstract
Pesticides are a major cause of reduction in the global population of amphibians. This study investigates the effect of varying concentrations of cyproconazole (1 and 10 mg/L) on Rana nigromaculata during a chronic 90 days exposure period. High levels of cyproconazole (10 mg/L) induced declined body weight, short snout-vent length, slow metamorphic development and abnormal behavioral endpoints in R. nigromaculata tadpoles. Tadpoles exposed to 10 mg/L did not survive beyond 42 days. Abnormal behaviors were observed more frequently with exposure to the highest concentration of cyproconazole. Compared with controls, the concentrations of dismutase (SOD), catalase (CAT) and glutathione (GSH) were significantly increased in tadpoles exposed to 1 mg/L cyproconazole. However, when the concentration of cyproconazole increased to 10 mg/L, concentrations of SOD, GSH and CAT activity began to decline. In addition, thyroid and gonad development were also affected at the gene and hormone level, with varied effects observed with different exposure levels and days. Exposure to cyproconazole at the lower level of 1 mg/L induced damage to histological structures of the thyroid gland. Stereoselective tissue distribution and bioaccumulation of cyproconazole was observed in tadpoles. The ranked order of bioaccumulation was: enantiomer -4 > 3> 2 > 1, with the level of cyproconazole highest in the gut. These findings reflect the toxicity of cyproconazole to R. nigromaculata and further our understanding of the effects of pesticide exposure on global amphibian population declines.
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Affiliation(s)
- Wenjun Zhang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Yuanmingyuan West Road 2, Beijing, 100193, China; Department of Applied Chemistry, China Agricultural University, Yuanmingyuan West Road 2, Beijing, 100193, China
| | - Li Chen
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Yuanmingyuan West Road 2, Beijing, 100193, China; Department of Applied Chemistry, China Agricultural University, Yuanmingyuan West Road 2, Beijing, 100193, China
| | - Yuanyuan Xu
- ICU, Binzhou City People's Hospital, Wenhua Road, Binzhou, Shandong, 256800, China
| | - Yue Deng
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Yuanmingyuan West Road 2, Beijing, 100193, China; Department of Applied Chemistry, China Agricultural University, Yuanmingyuan West Road 2, Beijing, 100193, China
| | - Luyao Zhang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Yuanmingyuan West Road 2, Beijing, 100193, China; Department of Applied Chemistry, China Agricultural University, Yuanmingyuan West Road 2, Beijing, 100193, China
| | - Yinan Qin
- Department of Applied Chemistry, China Agricultural University, Yuanmingyuan West Road 2, Beijing, 100193, China
| | - Zikang Wang
- Department of Applied Chemistry, China Agricultural University, Yuanmingyuan West Road 2, Beijing, 100193, China
| | - Rui Liu
- Department of Applied Chemistry, China Agricultural University, Yuanmingyuan West Road 2, Beijing, 100193, China
| | - Zhiqiang Zhou
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Yuanmingyuan West Road 2, Beijing, 100193, China; Department of Applied Chemistry, China Agricultural University, Yuanmingyuan West Road 2, Beijing, 100193, China
| | - Jinling Diao
- Department of Applied Chemistry, China Agricultural University, Yuanmingyuan West Road 2, Beijing, 100193, China.
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Delos Santos N, Azmat S, Cuenca Y, Drenth J, Lauper J, Tseng AS. Effects of the biocide methylisothiazolinone on Xenopus laevis wound healing and tail regeneration. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2016; 181:37-45. [PMID: 27810491 DOI: 10.1016/j.aquatox.2016.10.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 10/18/2016] [Accepted: 10/19/2016] [Indexed: 06/06/2023]
Abstract
The South African clawed frog, Xenopus laevis, has a strong history as a suitable model for environmental studies. Its embryos and transparent tadpoles are highly sensitive to the environment and their developmental processes are well described. It is also amenable for molecular studies. These characteristics enable its use for rapid identification and understanding of exposure-induced defects. To investigate the consequences of chemical exposure on aquatic animals, Xenopus laevis embryos and tadpoles were exposed to the biocide, methylisothiazolinone (MIT). Frog tadpoles exposed to MIT following tail amputation lost their natural regenerative ability. This inhibition of regeneration led to a failure to regrow tissues including the spinal cord, muscle, and notochord. This MIT-dependent regenerative defect is due to a failure to close the amputation wound. A wound healing assay revealed that while untreated embryos close their wounds within one day after injury, MIT-treated animals maintained open wounds that did not reduce in size and caused lethality. Concomitant exposure of MIT with chemicals containing thiol groups such as glutathione and N-acetyl cysteine restored normal wound healing and regeneration responses in tadpoles. Together these results indicate that exposure to MIT impairs developmental wound repair and tissue regeneration in Xenopus laevis. Thus, this study reveals new aspects of MIT activity and demonstrates that Xenopus laevis is a well-suited model for facilitating future research into chemical exposure effects on injury responses.
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Affiliation(s)
- Nicole Delos Santos
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154, USA
| | - Summer Azmat
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154, USA
| | - Yesenia Cuenca
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154, USA
| | - Jessica Drenth
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154, USA
| | - Julia Lauper
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154, USA
| | - Ai-Sun Tseng
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV 89154, USA.
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Brinkmann M, Koglin S, Eisner B, Wiseman S, Hecker M, Eichbaum K, Thalmann B, Buchinger S, Reifferscheid G, Hollert H. Characterisation of transcriptional responses to dioxins and dioxin-like contaminants in roach (Rutilus rutilus) using whole transcriptome analysis. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 541:412-423. [PMID: 26410716 DOI: 10.1016/j.scitotenv.2015.09.087] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Revised: 09/16/2015] [Accepted: 09/16/2015] [Indexed: 05/10/2023]
Abstract
There is significant concern regarding the contamination of riverine sediments with dioxins and dioxin-like compounds (DLCs), including polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and some polycyclic aromatic hydrocarbons (PAHs). The majority of studies investigating the ecotoxicology of DLCs in fish have focused on a few standard model species. However, there is significant uncertainty as to whether these model species are representative of native river fish, particularly in Europe. In this study, the transcriptional responses following exposure to equipotent concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), PCB 156 or the dioxin-like PAH, benzo[k]fluoranthene (BkF), were investigated in juvenile roach (Rutilus rutilus), a fish species that constitutes a large proportion of the fish biomass in freshwater bodies throughout Europe. To this end, RNA sequencing analysis was used to comprehensively characterise the molecular mechanisms and pathways of toxicity of these DLCs. Whole transcriptome analyses using ClueGO software revealed that DLCs have the potential to disrupt a number of important processes, including energy metabolism, oogenesis, the immune system, apoptosis and the response to oxidative stress. However, despite using equipotent concentrations, there was very little conservation of the transcriptional responses observed in fish exposed to different DLCs. TCDD provoked significant specific changes in the levels of transcripts related to immunotoxicity and carbohydrate metabolism, while PCB 156 caused virtually no specific effects. Exposure to BkF affected the most diverse suite of molecular functions and biological processes, including blood coagulation, oxidative stress responses, unspecific responses to organic or inorganic substances/stimuli, cellular redox homeostasis and specific receptor pathways. To our knowledge, this is the first study of the transcriptome-wide effects of different classes of DLCs in fish. These findings represent an important step towards describing complete toxicity pathways of DLCs, which will be important in the context of informing risk assessments of DLC toxicity in native fish species.
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Affiliation(s)
- Markus Brinkmann
- Department of Ecosystem Analysis, Institute for Environmental Research, ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Sven Koglin
- Department of Ecosystem Analysis, Institute for Environmental Research, ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Bryanna Eisner
- Toxicology Centre, University of Saskatchewan, 44 Campus Drive, Saskatoon, SK S7N 5B3, Canada
| | - Steve Wiseman
- Toxicology Centre, University of Saskatchewan, 44 Campus Drive, Saskatoon, SK S7N 5B3, Canada
| | - Markus Hecker
- Toxicology Centre, University of Saskatchewan, 44 Campus Drive, Saskatoon, SK S7N 5B3, Canada; School of the Environment & Sustainability, University of Saskatchewan, 44 Campus Drive, Saskatoon, SK S7N 5B3, Canada
| | - Kathrin Eichbaum
- Department of Ecosystem Analysis, Institute for Environmental Research, ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Beat Thalmann
- Department of Ecosystem Analysis, Institute for Environmental Research, ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - Sebastian Buchinger
- Federal Institute of Hydrology (BfG), Department G3: Biochemistry, Ecotoxicology, Am Mainzer Tor 1, 56068 Koblenz, Germany
| | - Georg Reifferscheid
- Federal Institute of Hydrology (BfG), Department G3: Biochemistry, Ecotoxicology, Am Mainzer Tor 1, 56068 Koblenz, Germany
| | - Henner Hollert
- Department of Ecosystem Analysis, Institute for Environmental Research, ABBt - Aachen Biology and Biotechnology, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany; College of Resources and Environmental Science, Chongqing University, 1 Tiansheng Road Beibei, Chongqing 400715, China; College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, 1239 Siping Road, Shanghai, China; State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, China.
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Xu K, Wen M, Duan W, Ren L, Hu F, Xiao J, Wang J, Tao M, Zhang C, Wang J, Zhou Y, Zhang Y, Liu Y, Liu S. Comparative Analysis of Testis Transcriptomes from Triploid and Fertile Diploid Cyprinid Fish1. Biol Reprod 2015; 92:95. [DOI: 10.1095/biolreprod.114.125609] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 03/03/2015] [Indexed: 02/02/2023] Open
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Tompsett AR, Higley E, Pryce S, Giesy JP, Hecker M, Wiseman S. Transcriptional changes in African clawed frogs (Xenopus laevis) exposed to 17α-ethynylestradiol during early development. ECOTOXICOLOGY (LONDON, ENGLAND) 2015; 24:321-329. [PMID: 25427717 DOI: 10.1007/s10646-014-1380-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/02/2014] [Indexed: 06/04/2023]
Abstract
Although the past two decades have witnessed a significant increase in the number of studies investigating effects of estrogenic chemicals on amphibians, to date little is known about specific molecular interactions of estrogens with the hypothalamus-pituitary-gonadal-hepatic axis in developing amphibians. Here, tissue-specific functional sets of genes, derived previously from studies of fishes exposed to endocrine active chemicals, were evaluated in Xenopus laevis exposed to 17α-ethynylestradiol (EE2) throughout their early development. Specifically, transcriptional responses of X. laevis exposed to 0.09, 0.84, or 8.81 µg EE2/L were characterized during sexual differentiation [31 day post hatch (dph)] and after completion of metamorphosis during the juvenile stage (89 dph). While at 31 dph there were no consistent effects of EE2 on abundances of transcripts,at 89 dph X. laevis exhibited significant alterations in expression of genes involved in steroid signaling and metabolism, synthesis of cholesterol, and vitellogenesis. Specifically, expression of androgen receptor, farnesyl diphosphate synthase, estrogen receptor α, and vitellogenin A2 was significantly greater (>2-fold) than in controls while expression of farnesoid x-activated receptors α and β was significantly less (>2-fold reduction) than in controls. These results support the hypothesis that sets of genes derived from studies in teleost fish can be extrapolated for use in amphibians during the juvenile stage but not in sexually undifferentiated individuals. Furthermore, changes in abundances of transcripts of the here utilized sets of genes in animals sampled post sexual differentiation were in accordance with developmental effects and alterations of gonadal histology reported in a parallel study. This set of genes might be useful for predicting potential adverse outcomes at later life-stages.
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Affiliation(s)
- Amber R Tompsett
- Toxicology Centre, University of Saskatchewan, 44 Campus Drive, Saskatoon, SK, S7N 5B3, Canada
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Säfholm M, Ribbenstedt A, Fick J, Berg C. Risks of hormonally active pharmaceuticals to amphibians: a growing concern regarding progestagens. Philos Trans R Soc Lond B Biol Sci 2014; 369:20130577. [PMID: 25405966 PMCID: PMC4213589 DOI: 10.1098/rstb.2013.0577] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Most amphibians breed in water, including the terrestrial species, and may therefore be exposed to water-borne pharmaceuticals during critical phases of the reproductive cycle, i.e. sex differentiation and gamete maturation. The objectives of this paper were to (i) review available literature regarding adverse effects of hormonally active pharmaceuticals on amphibians, with special reference to environmentally relevant exposure levels and (ii) expand the knowledge on toxicity of progestagens in amphibians by determining effects of norethindrone (NET) and progesterone (P) exposure to 0, 1, 10 or 100 ng l(-1) (nominal) on oogenesis in the test species Xenopus tropicalis. Very little information was found on toxicity of environmentally relevant concentrations of pharmaceuticals on amphibians. Research has shown that environmental concentrations (1.8 ng l(-1)) of the pharmaceutical oestrogen ethinylestradiol (EE2) cause developmental reproductive toxicity involving impaired spermatogenesis in frogs. Recently, it was found that the progestagen levonorgestrel (LNG) inhibited oogenesis in frogs by interrupting the formation of vitellogenic oocytes at an environmentally relevant concentration (1.3 ng l(-1)). Results from the present study revealed that 1 ng NET l(-1) and 10 ng P l(-1) caused reduced proportions of vitellogenic oocytes and increased proportions of previtellogenic oocytes compared with the controls, thereby indicating inhibited vitellogenesis. Hence, the available literature shows that the oestrogen EE2 and the progestagens LNG, NET and P impair reproductive functions in amphibians at environmentally relevant exposure concentrations. The progestagens are of particular concern given their prevalence, the range of compounds and that several of them (LNG, NET and P) share the same target (oogenesis) at environmental exposure concentrations, indicating a risk for adverse effects on fertility in exposed wild amphibians.
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Affiliation(s)
- Moa Säfholm
- Department of Organismal Biology, Environmental Toxicology, Uppsala University, Norbyvägen 18A, 75236 Uppsala, Sweden
| | - Anton Ribbenstedt
- Department of Organismal Biology, Environmental Toxicology, Uppsala University, Norbyvägen 18A, 75236 Uppsala, Sweden
| | - Jerker Fick
- Department of Chemistry, Umeå University, KBC 6A, Linnaeus väg 6, 90187 Umeå, Sweden
| | - Cecilia Berg
- Department of Organismal Biology, Environmental Toxicology, Uppsala University, Norbyvägen 18A, 75236 Uppsala, Sweden
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