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Wang L, Miao J, Ding M, Zhang W, Pan L. Exploring the mechanism of nonylphenol-induced ovarian developmental delay of manila clams, Ruditapes philippinarum: Applying RNAi to toxicological analysis. CHEMOSPHERE 2024; 356:141905. [PMID: 38579946 DOI: 10.1016/j.chemosphere.2024.141905] [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: 01/14/2024] [Revised: 04/02/2024] [Accepted: 04/03/2024] [Indexed: 04/07/2024]
Abstract
Nonylphenol (NP) contamination in the coastal environment of China poses ecological risks to aquatic organisms. However, the endocrine disruptive impacts of NP on bivalves, particularly on ovarian development, remain poorly understood. In this study, Manila clams Ruditapes philippinarum at the developing stage of gonad were exposed to 1.0 μg/L NP for 21 days. Utilizing RNA interference (RNAi) to suppress ER gene expression, we observed a delay in ovarian development as evidenced by histological observations under both NP and NPRi (NP with ER-RNAi) treatment, with Vtg elevation exclusive to the NP group. Comprehensive analyses encompassing transcriptomics, real-time quantitative PCR, and steroid hormone measurement revealed significant alterations in aldosterone synthesis, estrogen signaling, and thyroid hormone synthesis. These pathways showed similar perturbations in both NP and NPRi groups compared to controls. Notably, the NPRi group exhibited distinct enrichment in PPAR and insulin signaling pathways, may implicating these in ER function suppression. Steroid hormone biosynthesis was notably reduced in both treatments, pointing to a profound impact on hormone synthesis. The contrast between in vivo and in vitro findings suggests that NP's detrimental effects on ovarian development may primarily involve neuroendocrine regulation of steroidogenesis. This investigation highlights the complex dynamics of NP-induced endocrine disruption in bivalves, emphasizing the pivotal role of ER and associated pathways.
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Affiliation(s)
- Lu Wang
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, 266003, PR China
| | - Jingjing Miao
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, 266003, PR China.
| | - Min Ding
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, 266003, PR China; Marine Environmental Monitoring Central Station of Qinhuangdao, SOA, PR China
| | - Wei Zhang
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, 266003, PR China
| | - Luqing Pan
- The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, Qingdao, 266003, PR China
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Mukherjee U, Das S, Ghosh S, Maitra S. Reproductive toxicity of bisphenol A, at environmentally relevant concentrations, on ovarian redox balance, maturational response, and intra-oocyte signalling events in Labeo bata. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167415. [PMID: 37777122 DOI: 10.1016/j.scitotenv.2023.167415] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 09/04/2023] [Accepted: 09/25/2023] [Indexed: 10/02/2023]
Abstract
Bisphenol A (BPA) is a widely used plastic monomer that potentially interferes with ovarian neuroendocrine, endocrine, and autocrine/paracrine factors, causing reproductive dysfunction. However, the influence of BPA on redox balance, estrogen receptor (ER) expression vis-à-vis meiotic cell cycle progression, and intra-oocyte signalling events has not been extensively investigated. The present study examines the impact of BPA on reproductive toxicity in female Labeo bata (Order Cypriniformes, Family Cyprinidae), a freshwater teleost preferred as a food fish in the Indian subcontinent. Our results show that while ovarian weight (gonadosomatic index, GSI) and dynamics of follicular growth undergo pronounced changes during the annual reproductive cycle, chronic BPA exposure at environmentally relevant concentrations promotes follicular atresia concomitant with reduced GSI during the spawning phase, the highest response being observed due to low-dose (0.1 μg/L, 0.438 nM) BPA exposure in vivo. Furthermore, BPA perturbation of ovarian StAR expression and ERα/ERβ homeostasis corroborates with elevated oxidative stress in BPA-treated ovary, FG follicles, and follicular cells. A sharp increase in ROS accumulation and nitric oxide (NO) levels in BPA-treated full-grown (FG) follicles coupled with loss of redox balance, elevated follicular cell death, and activation of apoptotic markers (caspase -8, -9, -3, Bax) indicate poor oocyte health and reproductive toxicity. Importantly, maturational steroid (MIS, 17,20β-P)-induced cyclin B-p34cdc2 activation and elevated GVBD (germinal vesicle breakdown) response require protein kinase A (PKA) inhibition and participation of Mos/MAPK- and cdc25-mediated signalling events. While the adenylate cyclase activator forskolin (FK) abrogates, priming with a PKA inhibitor (H89) promotes the meiotic G2-M1 transition, confirming the role of PKA in meiotic cell cycle progression in this species. Furthermore, the negative influence of BPA priming on 17,20β-P-induced oocyte maturation involves elevated PKAc phosphorylation (activation) and significant alteration in Mos/MAPK signalling, indicating derailed meiotic maturational competence and disrupted oocyte quality.
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Affiliation(s)
- Urmi Mukherjee
- Molecular and Cellular Endocrinology Laboratory, Department of Zoology, Visva-Bharati University, Santiniketan 731235, India
| | - Sriparna Das
- Molecular and Cellular Endocrinology Laboratory, Department of Zoology, Visva-Bharati University, Santiniketan 731235, India
| | - Soumyajyoti Ghosh
- Molecular and Cellular Endocrinology Laboratory, Department of Zoology, Visva-Bharati University, Santiniketan 731235, India
| | - Sudipta Maitra
- Molecular and Cellular Endocrinology Laboratory, Department of Zoology, Visva-Bharati University, Santiniketan 731235, India.
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Zhang Y, Guan T, Wang L, Ma X, Zhu C, Wang H, Li J. Metamifop as an estrogen-like chemical affects the pituitary-hypothalamic-gonadal (HPG) axis of female rice field eels ( Monopterus albus). Front Physiol 2023; 14:1088880. [PMID: 36744025 PMCID: PMC9892845 DOI: 10.3389/fphys.2023.1088880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 01/09/2023] [Indexed: 01/21/2023] Open
Abstract
Metamifop (MET) is a widely used herbicide. It is likely for it to enter water environment when utilized, thus potential impacts may be produced on aquatic animals. Little information is available about its effects on the endocrine system of fish to date. In the current study, female rice field eels (Monopterus albus) were exposed to different MET concentrations (0, 0.2, 0.4, 0.6, 0.8 mg L -1) for 96 h to examine the effect of MET on the hypothalamic-pituitary-gonadal (HPG) axis and sexual reversal. The results showed that high concentrations of MET exposure increased vitellogenin (VTG) levels in liver and plasma, but plasma sex hormone levels were not affected by MET exposure. MET exposure increased the expression of CYP19A1b and CYP17 that regulate sex hormone production in the brain, but the expression of genes (CYP19A1a, CYP17, FSHR, LHCGR, hsd11b2, 3β-HSD) associated with sex hormone secretion in the ovary and the estrogen receptor genes (esr1, esr2a, esr2b) in the liver were all suppressed. In addition, the expression of sex-related gene (Dmrt1) was suppressed. This study revealed for the first time that MET has estrogen-like effects and has a strong interference with the expression of HPG axis genes. MET did not show the ability to promote the sexual reversal in M. albus, on the contrary, the genes expression showed that the occurrence of male pathway was inhibited.
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Affiliation(s)
- Yi Zhang
- School of Life Science, Huaiyin Normal University, Huai’an, China,Key Laboratory of Freshwater Aquatic Genetic Resources Ministry of Agriculture, Shanghai Ocean University, Shanghai, China
| | - Tianyu Guan
- School of Life Science, Huaiyin Normal University, Huai’an, China,Key Laboratory of Freshwater Aquatic Genetic Resources Ministry of Agriculture, Shanghai Ocean University, Shanghai, China
| | - Long Wang
- School of Life Science, Huaiyin Normal University, Huai’an, China,Key Laboratory of Freshwater Aquatic Genetic Resources Ministry of Agriculture, Shanghai Ocean University, Shanghai, China
| | - Xintong Ma
- School of Life Science, Huaiyin Normal University, Huai’an, China
| | - Chuankun Zhu
- School of Life Science, Huaiyin Normal University, Huai’an, China
| | - Hui Wang
- School of Life Science, Huaiyin Normal University, Huai’an, China,*Correspondence: Hui Wang,
| | - Jiale Li
- Key Laboratory of Freshwater Aquatic Genetic Resources Ministry of Agriculture, Shanghai Ocean University, Shanghai, China
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Blanco M, Rizzi J, Fernandes D, Colin N, Maceda-Veiga A, Porte C. Assessing the impact of waste water effluents on native fish species from a semi-arid region, NE Spain. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 654:218-225. [PMID: 30445323 DOI: 10.1016/j.scitotenv.2018.11.115] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 11/07/2018] [Accepted: 11/08/2018] [Indexed: 06/09/2023]
Abstract
Mediterranean rivers are strongly affected by pollution and water scarcity. Over the summer period, urban and industrial effluents arrive into the rivers with little dilution. In order to assess the water quality, two native fish species, Barbus meridionalis and Squalius laietanus, were collected from six sites along the Ripoll River (Spain). PAH metabolites, alkylphenols (nonylphenol and octylphenol) and the musk galaxolide levels were determined in bile. 7-Ethoxyresorufin-O-deethylase (EROD) and 7-benzyloxy-4-trifluoromethyl-coumarin O-debenzyloxylase (BFCOD) were measured as metabolic biomarkers, and the activity of CYP19 aromatase was determined in the ovaries of B. meridionalis as a biomarker of endocrine disruption. The analysis of bile indicated that fish from the lower course of the river were highly exposed to different pollutants. Accordingly, a significant induction of EROD (9 to 10-fold) and BFCOD (3 to 5-fold) activities were detected in both fish species together with an increased aromatase activity in females of B. meridionalis from the most polluted sites. Considering that sewage treatment plant (STP) effluents are essential for maintaining environmental flows in small Mediterranean rivers, this study highlights the need to improve the efficiency of STPs to protect fish health.
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Affiliation(s)
- Maria Blanco
- Environmental Chemistry Department, IDAEA-CSIC, Jordi Girona 18, 08034 Barcelona, Spain
| | - Juliane Rizzi
- PhD Program in Water Resources and Environmental Engineering, Federal University of Paraná, 81531-980 Curitiba, Paraná, Brazil
| | - Denise Fernandes
- Environmental Chemistry Department, IDAEA-CSIC, Jordi Girona 18, 08034 Barcelona, Spain
| | - Nicole Colin
- Department of Evolutionary Biology, Ecology and Environmental Sciences- IRBio, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain; Departamento de Ecología, Facultad de Ciencias y Centro de Investigación en Biodiversidad y Ambientes Sustentables (CIBAS), Universidad Católica de la Santísima Concepción, Concepción, Chile
| | - Alberto Maceda-Veiga
- Department of Evolutionary Biology, Ecology and Environmental Sciences- IRBio, Faculty of Biology, University of Barcelona, 08028 Barcelona, Spain
| | - Cinta Porte
- Environmental Chemistry Department, IDAEA-CSIC, Jordi Girona 18, 08034 Barcelona, Spain.
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5
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Rutherford R, Lister A, MacLatchy D. Comparison of steroidogenic gene expression in mummichog (Fundulus heteroclitus) testis tissue following exposure to aromatizable or non-aromatizable androgens. Comp Biochem Physiol B Biochem Mol Biol 2018; 227:39-49. [PMID: 30218714 DOI: 10.1016/j.cbpb.2018.09.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 09/06/2018] [Indexed: 02/08/2023]
Abstract
Androgens are a recognized class of endocrine disrupting compounds with the ability to impact reproductive status in aquatic organisms. The current study utilized in vitro exposure of mummichog (Fundulus heteroclitus) testis tissue to either the aromatizable androgen 17α-methyltestosterone (MT) or the non-aromatizable androgen 5α-dihydrotestosterone (DHT) over the course of 24 h to determine if there were differential effects on steroidogenic gene expression. Testis tissue was exposed to androgen concentrations of 10-12 M, 10-9 M and 10-6 M for 6, 12, 18 or 24 h, after which a suite of steroidogenic genes, including steroidogenic acute regulatory protein, 3β-hydroxysteroid dehydrogenase (3βhsd) and cytochrome P450 17A1 (cyp17a1), were quantified using real-time polymerase chain reaction. Both androgens affected steroidogenic gene expression, with most alterations occurring at the 24-hour time point. The gene with the highest fold-change, and shortest interval to expression alteration, was 3βhsd for both androgens. Potential differences between the two model androgens were observed in increased expression of cyp17a1 and 11β-hydroxysteroid dehydrogenase (11βhsd), which were only altered after exposure to DHT and in expression levels of cytochrome P450 11A1 (cyp11a1), which was upregulated by MT but not altered by DHT. Results from this study show both androgens interact at the gonadal level of the hypothalamus-pituitary-gonadal axis and may possess some distinct gene expression impacts. These data strengthen the current research initiatives of establishing in vitro test systems that allow toxic potential of untested chemicals to be predicted from molecular perturbations.
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Affiliation(s)
- Robert Rutherford
- Department of Biology, Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON N2L 3C5, Canada.
| | - Andrea Lister
- Department of Biology, Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON N2L 3C5, Canada
| | - Deborah MacLatchy
- Department of Biology, Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON N2L 3C5, Canada
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Das S, Majumder S, Gupta S, Dutta S, Mukherjee D. Effects of phenol on ovarian P450arom gene expression and aromatase activity in vivo and antioxidant metabolism in common carp Cyprinus carpio. FISH PHYSIOLOGY AND BIOCHEMISTRY 2016; 42:275-286. [PMID: 26403910 DOI: 10.1007/s10695-015-0135-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Accepted: 09/19/2015] [Indexed: 06/05/2023]
Abstract
Ovarian cyp19a mRNA expression and P450 aromatase activity were measured in vivo in common carp Cyprinus carpio exposed to phenol for 96 h. Production of reactive oxygen species (ROS) and parameters of antioxidant defense system in serum ovary and liver of this fish after long-term phenol exposure were also studied. In vivo exposure of fish to sublethal dose of phenol for 96 h caused marked attenuation of ovarian cyp19a1a gene expression and P450 aromatase activity. Production of ROS like hydrogen peroxide and hydroxyl radicals in serum, liver and ovary in fish exposed to phenol for 15 days elevated significantly from day 1 to day 7 with no further significant increase thereafter compared to their respective control values. Total superoxide dismutase (SOD) and catalase activities in serum and ovary decreased gradually and significantly from day 1 to day 4, which then increased significantly for the rest of the exposure days. Liver SOD activity seemed to be distinctly responsive to phenol. SOD activity in liver of phenol-exposed fish started to increase gradually from day 1 to 4 with no further increase thereafter. Catalase activities in all the tissues showed significant inhibition up to day 4 which then increased gradually and significantly up to day 15 of phenol exposure compared to their respective control values. From our results, it appears that sublethal dose of phenol has the endocrine disruptive potential and effect is mediated via inhibition of ovarian P450arom gene expression and aromatase activity in vivo. Sublethal dose of phenol also caused oxidative stress, and antioxidant systems are very much effective to prevent the damages caused by the generation of ROS.
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Affiliation(s)
- Sumana Das
- Department of Zoology, Krishnanagar Government College, Krishnanagar, West Bengal, 741101, India.
| | - Suravi Majumder
- Endocrinology Laboratory, Department of Zoology, Kalyani University, Kalyani, West Bengal, 741235, India
| | - Shreyasi Gupta
- Endocrinology Laboratory, Department of Zoology, Kalyani University, Kalyani, West Bengal, 741235, India
| | - Sharmistha Dutta
- Department of Zoology, Maulana Azad College, Kolkata, West Bengal, 700013, India
| | - Dilip Mukherjee
- Endocrinology Laboratory, Department of Zoology, Kalyani University, Kalyani, West Bengal, 741235, India.
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Degger N, Tse ACK, Wu RSS. Silver nanoparticles disrupt regulation of steroidogenesis in fish ovarian cells. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2015; 169:143-151. [PMID: 26546908 DOI: 10.1016/j.aquatox.2015.10.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 10/23/2015] [Accepted: 10/23/2015] [Indexed: 06/05/2023]
Abstract
Despite the influx of silver nanoparticles (nAg) into the marine environment, their effects on fish reproduction remain completely unexplored. Using ovarian primary cells from marine medaka (Oryzias melastigma), in vitro studies were carried out to evaluate the effects of two differently coated nAg particles (Oleic Acid, (OA) nAg and Polyvinylpyrrolidone, (PVP) nAg) on fish ovarian tissues, using AgNO3 as a positive control. Cytotoxicity was evaluated by MTT assay and expression of key genes regulating steroidogenesis (StAR, CYP 19a, CYP 11a, 3βHSD and 20βHSD) were determined by Q-RT-PCR. EC50 values for PVP nAg, OA nAg and AgNO3 were 7.25μgL(-1), 924.4μgL(-1), and 42.0μgL(-1) respectively, showing that toxicity of silver was greatly enhanced in the PVP coated nano-form. Down regulation of CYP 19a was observed in both nAg and AgNO3 treatments, while down regulation of 3βHSD was only found in the OA nAg and AgNO3 treatments. For the first time, our results demonstrated that nAg can affect specific genes regulating steroidogenesis, implicating nAg as a potential endocrine disruptor.
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Affiliation(s)
- Natalie Degger
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong Special Administrative Region
| | - Anna C K Tse
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong Special Administrative Region
| | - Rudolf S S Wu
- School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong Special Administrative Region.
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8
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Sridevi P, Chaitanya RK, Prathibha Y, Balakrishna SL, Dutta-Gupta A, Senthilkumaran B. Early exposure of 17α-ethynylestradiol and diethylstilbestrol induces morphological changes and alters ovarian steroidogenic pathway enzyme gene expression in catfish, Clarias gariepinus. ENVIRONMENTAL TOXICOLOGY 2015; 30:439-51. [PMID: 24273110 DOI: 10.1002/tox.21920] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 10/19/2013] [Accepted: 10/26/2013] [Indexed: 05/21/2023]
Abstract
Environmental estrogens are major cause of endocrine disruption in vertebrates, including aquatic organisms. Teleosts are valuable and popular models for studying the effects of endocrine disrupting chemicals (EDCs) in the environment. In the present study, we investigated the changes caused by exposure to the synthetic estrogens 17α-ethynylestradiol (EE2 ) and diethylstilbesterol (DES) during early stages of growth and sex differentiation of air-breathing catfish, Clarias gariepinus, at the morphological, histological, and molecular levels. Catfish hatchlings, 0 day post hatch (dph) were exposed continuously to sublethal doses of EE2 (50 ng/L) and DES (10 ng/L) until 50 dph and subsequently monitored for ovarian structural changes and alteration in the gene expression of steroidogenic enzymes till adulthood. Treated fish exhibited morphological deformities such as spinal curvature, stunted growth, and yolk-sac fluid retention. In addition to ovarian atrophy, DES-treated fish showed either rudimentary or malformed ovaries. Detailed histological studies revealed precocious oocyte development as well as follicular atresia. Further, transcript levels of various steroidogenic enzyme and transcription factor genes were altered in response to EE2 and DES. Activity of the rate-limiting enzyme of estrogen biosynthesis, aromatase, in the ovary as well as the brain of treated fish was in accordance with transcript level changes. These developmental and molecular effects imparted by EE2 and DES during early life stages of catfish could demonstrate the deleterious effects of estrogen exposure and provide reliable markers for estrogenic EDCs exposure in the environment.
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Affiliation(s)
- P Sridevi
- Department of Animal Sciences, School of Life Sciences, University of Hyderabad, P O Central University, Hyderabad, 500 046, India
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9
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Puy-Azurmendi E, Olivares A, Vallejo A, Ortiz-Zarragoitia M, Piña B, Zuloaga O, Cajaraville MP. Estrogenic effects of nonylphenol and octylphenol isomers in vitro by recombinant yeast assay (RYA) and in vivo with early life stages of zebrafish. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 466-467:1-10. [PMID: 23892017 DOI: 10.1016/j.scitotenv.2013.06.060] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 04/29/2013] [Accepted: 06/13/2013] [Indexed: 06/02/2023]
Abstract
Commercial OP and NP are complex isomer mixtures that can be individually present in the environment, showing different estrogenic potencies. The aims of this study were to establish the estrogenic potency of some AP isomers in comparison to the commercial NP (cNP) mixture in vitro and to investigate in vivo their possible effects during the embryo and larval development of zebrafish. An in vitro estrogen receptor-based recombinant yeast assay was used to test the estrogenicity of specific AP isomers (22-OP, 33-OP, 22-NP, 33-NP and 363-NP) and cNP. The EC₅₀ was in the range of 0.6-7.7 mg/L. Both OP isomers and 363-NP exhibited higher estrogenic activity than cNP. For in vivo experiments, one-day postfertilisation (dpf) embryos were exposed to cNP (50, 250 and 500 μg/L), 363-NP and 33-OP (50 μg/L), 17β-estradiol (100 ng/L) and DMSO (0.01% v/v) for 4weeks. After exposure fish were maintained for 2 weeks in clean water in order to evaluate a possible recovery. Fish of groups exposed to cNP and 363-NP were the last to hatch. Histological alterations were not observed after 7, 28 or 42 dpf. Exposure to 33-OP increased transcriptional levels of erα, vtg and cyp19a1b genes. However, transcriptional response in E2 exposure was observed at later stages and with higher fold induction levels. Exposure to cNP decreased levels of erα whereas increased levels of rxrγ and cyp19a1b. Exposure to 363-NP did not cause changes in transcriptional levels of studied genes. The differences in response of the OP isomer compared to the NP isomer in zebrafish could be related to the rapid decay in concentration of the latter.
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Affiliation(s)
- E Puy-Azurmendi
- Laboratory of Cell Biology and Histology, Department of Zoology and Animal Cell Biology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Sarriena z/g, E-48940 Leioa, Basque Country, Spain; Research Centre for Experimental Marine Biology and Biotechnology PIE, University of the Basque Country (UPV/EHU), Areatza z/g, E-48620 Plentzia, Basque Country, Spain
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10
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Geraudie P, Nahrgang J, Forget-Leray J, Minier C, Camus L. In vivo effects of environmental concentrations of produced water on the reproductive function of polar cod (Boreogadus saida). JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2014; 77:557-573. [PMID: 24754392 DOI: 10.1080/15287394.2014.887420] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Offshore oil and gas drilling processes generate operational discharges such as produced water (PW), a complex mixture of seawater with polycyclic aromatic hydrocarbons (PAH) and alkylphenols (AP). Some of these compounds may interact with the endocrine system of marine organisms and alter reproductive functions. In this study, polar cod were exposed for up to 28 d to a mixture of PAH, alkylated PAH, and AP simulating the composition of North Sea PW, at low and high concentrations (1:2000 and 1:1000 dilution of the original concentrate, respectively). Potential adverse effects of PW on polar cod physiology were investigated through biomarkers of biotransformation (hepatic ethoxyresorufin O-deethylase [EROD] activity and bile PAH metabolites), endocrine disruption (plasma vitellogenin [VTG] levels and sex steroid concentrations), and gonad histology. Plasma sexual steroid levels in fish were not markedly affected by PW exposure, while higher plasma VTG concentrations were measured in females exposed to the high PW treatment for 7 and 28 d. In males exposed to the higher PW concentration, inhibition of spermatogenesis was observed after 28 d in addition to increase of melano-macrophage occurrence in testis. Females exposed to the high PW treatment for 21 d showed a significant increase of atresia incidence. Finally, a significant decrease in oocyte number was observed in high PW exposed female ovaries after 28 d of exposure.
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Affiliation(s)
- P Geraudie
- a UMR SEBIO - SFR 4116 SCALE, University of Le Havre. ComUE Normandie University
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11
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Arukwe A, Olufsen M, Cicero N, Hansen MD. Effects on development, growth responses and thyroid-hormone systems in eyed-eggs and yolk-sac larvae of Atlantic salmon (Salmo salar) continuously exposed to 3,3',4,4'-tetrachlorobiphenyl (PCB-77). JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2014; 77:574-586. [PMID: 24754393 DOI: 10.1080/15287394.2014.887422] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Thyroid hormones (triiodothyronine, T3; and thyroxine, T4) play significant roles in development, metamorphosis, metabolism, homeostasis, cellular proliferation, and differentiation, for which the effects are mediated through thyroid hormone receptors (TRα and TRβ). Similarly, the insulin-like growth factor (IGF) is involved in growth and development through regulation of somatic growth. This study was designed to examine the effects of the dioxin-like 3,3',4,4'-tetrachlorobiphenyl (PCB-77) on responses related to growth and thyroid hormone system in eyed eggs and yolk-sac larvae of Atlantic salmon. Salmon eggs were continuously exposed to two waterborne concentrations of PCB-77 (1 or 10 ng/L) over a period of 50 d covering hatching and through yolk-sac absorption stages. Sampling was performed regularly throughout the exposure period and at different time intervals. Gene expression patterns were performed on whole-body homogenate at age 500, 548, 632, 674, and 716 dd (dd: day degrees) using quantitative polymerase chain reaction (PCR). Total T3 (TT3) and total T4 (TT4) were measured using radioimmunoassay (RIA). Data showed that 10 ng PCB-77 increased dioiodinase 2 (Dio2) at 500 dd and both PCB-77 concentrations decreased dio2 expression at 548 dd. PCB-77 elevated cellular TT3 at 500 dd and was lowered at 548 dd only at 10 ng. Otherwise, time-related reduction was not affected by PCB-77 exposure as observed for the rest of the exposure period. For TT4, 1 ng PCB-77 produced a rise at 500 dd, and an apparent concentration decrease at 548 dd, before a total inhibition at 632 dd. The IGF-1 and IGF-1R were variably affected by PCB-77. For IGF-2, PCB-77 produced a concentration-dependent increase at 548 dd, and thereafter an elevation (1 ng) and fall (10 ng) at 632 dd. TRβ mRNA demonstrated PCB-77 related increases during the exposure period, and this effect returned to control levels at 716 dd. For TRα, a rise was noted only after exposure to 10 ng PCB-77 at 500 dd. Overall, the present study demonstrates some possible growth and developmental consequences following exposure to PCB-77 during early life stages of Atlantic salmon.
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Affiliation(s)
- Augustine Arukwe
- a Department of Biology , Norwegian University of Science and Technology (NTNU) , Trondheim , Norway
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Tse ACK, Lau KYT, Ge W, Wu RSS. A rapid screening test for endocrine disrupting chemicals using primary cell culture of the marine medaka. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2013; 144-145:50-58. [PMID: 24140634 DOI: 10.1016/j.aquatox.2013.09.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 09/16/2013] [Accepted: 09/22/2013] [Indexed: 06/02/2023]
Abstract
While endocrine disrupting chemicals (EDCs) pose a significant threat to wildlife worldwide, their diverse chemical structures present a major challenge to their detection, particularly since they are present at very low concentrations in the environment. We here report the development of an in vitro system for rapid screening of EDCs, using primary cell cultures (pituitary, ovarian follicular and testicular cells) of the marine medaka (Oryzias melastigma). Pituitary, testis and ovary cell cultures were developed and challenged by environmentally relevant concentrations of three well known EDCs (viz. estradiol, 2,2',4,4'-tetrabromodiphenyl ether, and 4-n-nonylphenol) as well as hypoxia (which has been shown to be a potent endocrine disruptor). In general, the mRNA expression levels of gonadotropins, their receptors and steroidogenic enzymes exhibited dose response relationships to the four endocrine disruptors in different tissues. The sensitivity and responses were also comparable to in vivo responses of whole fish and in vitro responses of the H295R human adrenocortical cell line. Our results suggest that the use of marine medaka primary cultured cells can serve as a cost effective tool for rapid screening of EDCs in the marine environment, and at the same time, sheds light on the underlying mechanisms of EDCs by deciphering their specific target sites along the hypothalamus-pituitary-gonad axis of vertebrates.
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Affiliation(s)
- Anna C K Tse
- School of Biological Sciences, The University of Hong Kong, Hong Kong
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Xu X, Yekeen TA, Xiao Q, Wang Y, Lu F, Huo X. Placental IGF-1 and IGFBP-3 expression correlate with umbilical cord blood PAH and PBDE levels from prenatal exposure to electronic waste. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2013; 182:63-9. [PMID: 23900036 DOI: 10.1016/j.envpol.2013.07.005] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 07/03/2013] [Accepted: 07/06/2013] [Indexed: 02/05/2023]
Abstract
Electronic waste recycling produces Polycyclic Aromatic Hydrocarbons (PAHs) and Polybrominated Diphenyl Ethers (PBDEs) which may affect fetal growth and development by altering the insulin-like-growth factor (IGF) system. Questionnaires were administered to pregnant women (Guiyu, an e-waste site, n = 101; control, n = 53), and umbilical cord blood (UCB) and placentas were collected upon delivery. PBDEs and PAHs in UCB and placental IGF-1 and IGFBP-3 mRNA levels were analyzed using GC-MS and real-time PCR, respectively. Infant birth length and Apgar scores were lower in Guiyu. All PAHs (except Fl, Chr, IP, BbF and BP), total 16-PAHs, total/individual PBDEs, placental IGF-1 (median 0.23 vs 0.19; P < 0.05) and IGFBP-3 (median 1.91 vs 0.68; P < 0.001) levels were significantly higher in Guiyu. Spearman correlation showed that BDE-154, BDE-209 and ∑5ring-PAHs positively correlate with IGF-1 while PBDEs, 4 rings and total PAHs correlate with IGFBP-3 expression. Increased placental IGF-1 level might indirectly affect fetal growth and development.
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Affiliation(s)
- Xijin Xu
- Analytical Cytology Laboratory, Shantou University Medical College, 22 Xinling Rd., Shantou 515041, Guangdong, China; Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou 515041, China; Department of Cell Biology and Genetics, Shantou University Medical College, Shantou 515041, China
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Das S, Majumder S, Mukherjee D. Effect of phenol on ovarian secretion of 17β-estradiol in common carp Cyprinus carpio. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2013; 65:132-141. [PMID: 23423282 DOI: 10.1007/s00244-013-9875-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 01/15/2013] [Indexed: 06/01/2023]
Abstract
Phenol is a common substance present in many industrial wastewaters and in nonspecific pesticides. Due to its solubility and volatility phenol is often found in marine and freshwater environment. It is lipophilic compound and has a high potential for accumulating along the trophic chain. Phenol thus is not only a threat to natural environment but also to human health. The effects of phenol on the secretion of 17β-estradiol were examined in female common carp Cyprinus carpio. Vitellogenic stage fish were exposed to physiological safe dose of phenol for 0, 24, 48 and 96 h. In the in vitro experiments, vitellogenic follicles were incubated with phenol and dose- and time-course effects on leuteinising hormone (LH) induced steroid production were examined. Exposure of fish with phenol gradually attenuated serum and ovarian 17β-estradiol levels with increasing time and maximum inhibition was noticed after 96 h. Administration of phenol significantly inhibited LH-induced secretion of 17β-estradiol by the ovarian follicles in vitro. To clarify the mechanism of attenuated production of 17β-estradiol in phenol-treated follicles, stimulated by LH, in vitro effect phenol and LH on aromatase activity (conversion of testosterone to 17β-estradiol) and cytochrome P450arom gene expression in carp ovarian follicles were investigated. Physiological safe dose of phenol significantly inhibited LH-stimulated aromatase activity and P450arom gene expression in ovarian follicles. The present study further demonstrated that LH-induced activation of ovarian steroidogenic factor-1 (SF-1) is strongly inhibited by phenol treatment. These results suggest that physiological safe dose of phenol as endocrine disruption (ED) potential and the effect can be mediated via several cellular pathways including the inhibition of SF-1 activity, aromatase activity and P450arom gene expression.
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Affiliation(s)
- Sumana Das
- Department of Zoology, Maulana Azad College, Kolkata 700013, West Bengal, India.
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Nair PMG, Choi J. Effects of cadmium chloride and nonylphenol on the expression of StAR-related lipid transfer domain containing protein (START1) gene in aquatic midge, Chironomus riparius. Comp Biochem Physiol C Toxicol Pharmacol 2012; 155:369-74. [PMID: 22056801 DOI: 10.1016/j.cbpc.2011.10.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2011] [Revised: 10/20/2011] [Accepted: 10/20/2011] [Indexed: 11/22/2022]
Abstract
We identified and characterized a partial cDNA of StAR-related lipid transfer domain containing protein gene from Chironomus riparius (CrSTART1) having homology with human MLN64 and Drosophila melanogaster START1 (DmSTART1) and evaluated the effects of cadmium chloride (Cd) and nonylphenol (NP) on its expression. Pfam analysis identified the presence of two StAR-related lipid transfer (START) domains in CrSTART1 having several conserved amino acid residues, characteristic of the MLN64 and DmSTART1. The mRNA expression of CrSTART1 was observed in all developmental stages. The modulation in the mRNA expression of CrSTART1 was investigated after exposure to different concentrations Cd (0, 2, 10, and 20 mg/L) and NP (0, 10, 50, and 100 μg/L) for different time intervals in fourth instar larvae of C. riparius. Significant downregulation of CrSTART1 mRNA was observed after exposure to 2, 10 and 20 mg/L of Cd for 24, 48 and 72 h. Significant upregulation of CrSTART1 was observed after exposure to 10 and 50 μg/L of NP for 24, and 48 h period. At 100 μg/L of NP significant upregulation of CrSTART1 was observed after 12 h and downregulated after 24, 48 and 72 h.
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Affiliation(s)
- Prakash M Gopalakrishnan Nair
- School of Environmental Engineering, Graduate School of Energy and Environmental System Engineering, University of Seoul, 90 Jeonnong-dong, Dongdaemun-gu, Seoul 130-743, Republic of Korea
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Spachmo B, Arukwe A. Endocrine and developmental effects in Atlantic salmon (Salmo salar) exposed to perfluorooctane sulfonic or perfluorooctane carboxylic acids. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2012; 108:112-124. [PMID: 22265611 DOI: 10.1016/j.aquatox.2011.07.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Revised: 07/25/2011] [Accepted: 07/29/2011] [Indexed: 05/31/2023]
Abstract
In this study, we have investigated the effect of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) on endocrine signalling, growth and development in Atlantic salmon (Salmo salar) embryos and larvae. Expression of genes related to the hypothalamic-pituitary-thyroid (HPT) axis, growth-hormone/insulin-like growth factor (GH/IGF) axis and the steroid hormone axis were used as indicators of endocrine disruption. We also studied bone development in larvae, both by observing skeletal structure formation and by investigating expression of genes involved in ossification process. Atlantic salmon embryos, kept in plastic tanks at 5-7°C, were exposed to 100 μg/L PFOA or PFOS from egg stage for a period of 52 days, followed by one-week recovery period. Sampling was performed at day 21, 35, 49 and 56 representing age 549, 597, 679 and 721 dd (dd or day degrees = number of days × temperature in degree Celsius:°C). Note that day 56 or 721 dd is the end of the 1-week recovery period. Larvae were divided into designated head and body regions for the purpose of gene expression analysis, except for genes that regulate ossification that were analyzed in whole larvae. Expression of thyroid receptor α and β (TRα and TRβ), thyroid-stimulating hormone β (TSHβ), T(4) outer-ring deiodinase (T(4)ORD), growth hormone (GH), insulin-like growth factor-I and II (IGF-I and II), insulin-like growth factor I receptor (IGF-IR), and estrogen receptor α and β (ERα and ERβ) were investigated using quantitative PCR. Both PFOS and PFOA exposure produced non-significant alterations in larvae weight (except after the recovery period when a decrease was observed), while larvae length was unaffected. PFOS and PFOA exposure produced body- and head region-specific alterations in expression of all the investigated gene transcripts. Expression of IGF-I and IGF-IR paralleled that of GH, indicating that perturbation of GH expression is a possible end point for disruption of the GH-IGF axis. We did not observe developmental changes related to angiogenesis, ossification and chondrogenesis after exposure to PFOS and PFOA. Transcriptional abnormalities may serve as indicators of chronic exposure, although the concrete mechanisms causing the observed effects remain ambiguous. The implications of these findings for the complete lifecycle, including other developmental and/or reproductive damage, are areas of future study.
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Affiliation(s)
- Bård Spachmo
- Department of Biology, Norwegian University of Science and Technology (NTNU), 7491 Trondheim, Norway
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Meier S, Morton HC, Andersson E, Geffen AJ, Taranger GL, Larsen M, Petersen M, Djurhuus R, Klungsøyr J, Svardal A. Low-dose exposure to alkylphenols adversely affects the sexual development of Atlantic cod (Gadus morhua): acceleration of the onset of puberty and delayed seasonal gonad development in mature female cod. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2011; 105:136-150. [PMID: 21722617 DOI: 10.1016/j.aquatox.2011.06.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 05/24/2011] [Accepted: 06/02/2011] [Indexed: 05/31/2023]
Abstract
Produced water (PW), a by-product of the oil-production process, contains large amount of alkylphenols (APs) and other harmful oil compounds. In the last 20 years, there have been increasing concerns regarding the environmental impact of large increases in the amounts of PW released into the North Sea. We have previously shown that low levels of APs can induce disruption of the endocrine and reproductive systems of Atlantic cod (Gadus morhua). The aims of this follow-up study were to: (i) identify the lowest observable effect concentration of APs; (ii) study the effects of exposure to real PW, obtained from a North Sea oil-production platform; and (iii) study the biological mechanism of endocrine disruption in female cod. Fish were fed with feed paste containing several concentrations of four different APs (4-tert-butylphenol, 4-n-pentylphenol, 4-n-hexylphenol and 4-n-heptylphenol) or real PW for 20 weeks throughout the normal period of vitellogenesis in Atlantic cod from October to January. Male and female cod, exposed to AP and PW, were compared to unexposed fish and to fish fed paste containing 17β-oestradiol (E(2)). Approximately 60% of the females and 96% of the males in the unexposed groups were mature at the end of the experiment. Our results show that exposure to APs and E(2) have different effects depending on the developmental stage of the fish. We observed that juvenile females are advanced into puberty and maturation, while gonad development was delayed in both maturing females and males. The AP-exposed groups contained increased numbers of mature females, and significant differences between the untreated group and the AP-treated groups were seen down to a dose of 4 μg AP/kg body weight. In the high-dose AP and the E(2) exposed groups, all females matured and no juveniles were seen. These results suggest that AP-exposure can affect the timing of the onset of puberty in fish even at extremely low concentrations. Importantly, similar effects were not seen in the fish that were exposed to real PW.
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Rhee JS, Kim BM, Lee CJ, Yoon YD, Lee YM, Lee JS. Bisphenol A modulates expression of sex differentiation genes in the self-fertilizing fish, Kryptolebias marmoratus. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2011; 104:218-229. [PMID: 21632026 DOI: 10.1016/j.aquatox.2011.04.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2010] [Revised: 04/21/2011] [Accepted: 04/30/2011] [Indexed: 05/30/2023]
Abstract
Endocrine disrupting chemicals (EDCs) have been a major concern in the normal reproduction and development of aquatic organisms. In the teleost, steroid hormones are synthesized via the steroidogenesis pathway, and play a key physiological role in the regulation of gonadal sex differentiation. The protogynous hermaphroditic fish, Kryptolebias marmoratus is the only vertebrate capable of reproducing through internal self-fertilization. To uncover the effect of bisphenol A (BPA) on sex differentiation genes on transcription, we investigated the expression patterns of several sex differentiation-related genes such as dax1, dmrt1, mis, sf1, figlα, StAR and wt1 after BPA exposure with controls (E2 and TMX). In response to 17β-estradiol (E2) exposure, a testis-specific gene, dmrt1 mRNA was down-regulated in the gonad of the secondary male but the expression of the female-specific gene, dax1 mRNA was significantly elevated in the brain and gonad. A high level of StAR mRNA was detected in the brain and gonad of both hermaphrodite and secondary males, suggesting that the elevated expression of dax1 and StAR genes would be involved in E2 exposure. As expected, upon BPA exposure, the dmrt1 and MIS mRNA level decreased in both hermaphrodite and secondary males, while the female-specific gene, figlα mRNA level increased in the gonad of both genders. BPA showed an opposite mode of action on the expression of dax1 (induction, P>0.05) and sf1 mRNA (inhibition, P>0.05) in the brain and gonad against both genders. The sensitivity of dax1 to BPA on expression was relatively high in the secondary male. The wt1 mRNA was up-regulated in most tissues except in the liver of BPA-exposed secondary males. Regarding the time course study, the figlα mRNA level increased at 6 h after BPA exposure. In addition, BPA elevated the expression of StAR, dax1, and wt1 mRNA but repressed sf1 mRNA. In this paper, we demonstrated that BPA may modulate the expression of sex differentiation and steroidogenesis pathway genes, and this finding would provide a better understanding on the modulation of transcription upon BPA exposure in steroidogenesis and sex differentiation in the hermaphroditic fish, K. marmoratus.
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Affiliation(s)
- Jae-Sung Rhee
- Department of Molecular and Environmental Bioscience, Graduate School, Hanyang University, Seoul 133-791, South Korea
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Sandhu N, Vijayan MM. Cadmium-mediated disruption of cortisol biosynthesis involves suppression of corticosteroidogenic genes in rainbow trout. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2011; 103:92-100. [PMID: 21396343 DOI: 10.1016/j.aquatox.2011.02.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 02/10/2011] [Accepted: 02/12/2011] [Indexed: 05/30/2023]
Abstract
Cadmium is widely distributed in the aquatic environment and is toxic to fish even at sublethal concentrations. This metal is an endocrine disruptor, and one well established role in teleosts is the suppression of adrenocorticotrophic hormone (ACTH)-stimulated cortisol biosynthesis by the interrenal tissue. However the mechanism(s) leading to this steroid suppression is poorly understood. We tested the hypothesis that cadmium targets genes encoding proteins critical for corticosteroid biosynthesis, including melanocortin 2 receptor (MC2R), steroidogenic acute regulatory protein (StAR) and cytochrome P450 side chain cleavage enzyme (P450scc), in rainbow trout (Oncorhynchus mykiss). To test this, head kidney slices (containing the interrenal tissues) were incubated in vitro with cadmium chloride (0, 10, 100 and 1000nM) for 4h either in the presence or absence of ACTH (0.5IU/mL). In the unstimulated head kidney slices, cadmium exposure did not affect basal cortisol secretion and the mRNA levels of MC2R and P450scc, while StAR gene expression was significantly reduced. Cadmium exposure significantly suppressed ACTH-stimulated cortisol production in a dose-related fashion. This cadmium-mediated suppression in corticosteroidogenesis corresponded with a significant reduction in MC2R, StAR and P450scc mRNA levels in trout head kidney slices. The inhibition of ACTH-stimulated cortisol production and suppression of genes involved in corticosteroidogenesis by cadmium were completely abolished in the presence of 8-Bromo-cAMP (a cAMP analog). Overall, cadmium disrupts the expression of genes critical for corticosteroid biosynthesis in rainbow trout head kidney slices. However, the rescue of cortisol production as well as StAR and P450scc gene expressions by cAMP analog suggests that cadmium impact occurs upstream of cAMP production. We propose that MC2R signaling, the primary step in ACTH-induced cortocosteroidogenesis, is a key target for cadmium-mediated disruption of cortisol production in trout.
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Affiliation(s)
- Navdeep Sandhu
- Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1, Canada
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