thyroid hormone Articles
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Waterborne exposure to microcystin‐lr causes thyroid hormone metabolism disturbances in juvenile chinese rare minnow (Gobiocypris rarus)
Microcystin‐LR (MC‐LR) has the potential to disturb thyroid hormone (TH) homeostasis, but little is known of the underlying mechanisms of MC‐LR in fish. In the present study, juvenile Chinese rare minnows (Gobiocypris rarus) were exposed to various concentrations of MC‐LR (0, 50, 100, and 500 μg/L) for 7 d. The whole‐body content of THs, the histology of thyroid follicle epithelial cells, the ...
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Chronic exposure to pentachlorophenol alters thyroid hormones and thyroid hormone pathway mRNAs in zebrafish
Pentachlorophenol (PCP) is frequently detected in the aquatic environment and has been implicated as an endocrine disruptor in fish. In the present study, 4‐month‐old zebrafish (Danio rerio) were exposed to 1 of 4 concentrations of PCP (0.1, 1, 9, and 27 µg/L) for 70 d. The effects of PCP exposure on plasma thyroid hormone levels, and the expression levels of selected genes, were measured in ...
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Perfluorooctane sulfonate (PFOS) affects hormone receptor activity, steroidogenesis, and expression of endocrine‐related genes in vitro and in vivo
Perfluorooctane sulfonate (PFOS) is a widespread and persistent chemical in the environment. We investigated the endocrine‐disrupting effects of PFOS using a combination of in vitro and in vivo assays. Reporter gene assays were used to detect receptor‐mediated (anti‐)estrogenic, (anti‐)androgenic, and (anti‐)thyroid hormone activities. The effect of PFOS on steroidogenesis was assessed both at ...
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Developmental impairment in Eurasian dipper nestlings exposed to urban stream pollutants
Avian studies of endocrine disruption have focussed traditionally on reproductive impairment given that many environmental contaminants affect sex steroid hormones. There is also increasing interest in altered thyroid function, and associated early development, particularly in altricial species with extended developmental windows. Both types of effect are relevant under the complex pollutant ...
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Sex‐specific changes in thyroid gland function and circulating thyroid hormones in nestling American kestrels (Falco sparverius) following embryonic exposure to PBDEs by maternal transfer
High concentrations of polybrominated diphenyl ethers (PBDEs) accumulate in predatory birds. Several PBDE congeners are considered thyroid disruptors however avian studies are limited. Here, we examined circulating thyroid hormones, thyroid gland function of nestling American kestrels (Falco sparverius) at 17‐20 d of age, following embryonic exposure by maternal transfer only to ...
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Bisphenol S alters embryonic viability, development, gallbladder size, and mRNA expression in chicken embryos exposed via egg injection
Amid concerns about the toxicological effects and environmental prevalence of bisphenol A (BPA), efforts to find suitable, safer replacement alternatives are essential. Bisphenol S (BPS) is one potential chemical substitute for BPA; however, few studies are available confirming it has a more desirable ecotoxicological profile. In the present study, BPS was injected into the air cell of ...
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Gene expression, glutathione status, and indicators of hepatic oxidative stress in laughing gull (Larus atricilla) hatchlings exposed to methylmercury
Despite extensive studies of methylmercury (MeHg) toxicity in birds, molecular effects on birds are poorly characterized. To improve our understanding of toxicity pathways and identify novel indicators of avian exposure to Hg, the authors investigated genomic changes, glutathione status, and oxidative status indicators in liver from laughing gull (Larus atricilla) hatchlings that were exposed ...
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Exposure to a PBDE/OH‐BDE mixture alters juvenile zebrafish (Danio rerio) development
Polybrominated diphenyl ethers (PBDEs) and their metabolites (e.g. hydroxylated BDEs (OH‐BDEs)) are contaminants detected together frequently in human tissues, and are structurally similar to thyroid hormones (TH). THs partially mediate metamorphic transitions between life stages in zebrafish, making this a critical developmental window which may be vulnerable to chemicals disrupting thyroid ...
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Effects of triclocarban, deet and a mixture of pharmaceuticals and personal care products on fathead minnows (Pimephales promelas)
Pharmaceuticals and personal care products (PPCPs) have been detected widely in aquatic ecosystems, but little is known about their mechanisms of toxicity. We exposed adult fathead minnows (Pimephales promelas) for 48 hours to triclocarban (1.4 µg/L), DEET (0.6 µg/L) or to a PPCP mixture consisting of atenolol (1.5 µg/L), caffeine (0.25 µg/L), diphenhydramine (0.1 µg/L), gemfibrozil ...
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Enzyme induction and histopathology elucidate AhR vs. non‐AhR mediated effects of aroclor 1268 in American mink (Neovison vison)
Polychlorinated biphenyl (PCB) concentrations reported in preferred prey and blubber of bottlenose dolphins from the Turtle‐Brunswick River Estuary (TBRE, Georgia, USA) suggests the potential for adverse effects. However, PCBs in TBRE dolphins are primarily derived from Aroclor 1268, and predicting toxic effects of Aroclor 1268 is uncertain due to the mixture's unique composition and ...
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Implication of microRNA deregulation in the response of vertebrates to endocrine disrupting chemicals
MicroRNAs are recently discovered small regulatory molecules that control messenger RNA (mRNA) translation in plants and animals and have been implicated in a variety of hormone‐related physiological pathways. Estrogens, thyroid hormones, and gonadotropins all are known to act on miRNA abundance to cause major shifts in cellular activity, physiology, and homeostatic control mechanisms. ...
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A three‐generational study of in ovo exposure to PBDE‐99 in the zebra finch
Based on a literature review of avian data for polybrominated diphenyl ethers (PBDEs), ecologically relevant doses, low (10 ng/egg), medium (100 ng/egg), and high (1,000 ng/egg) of the 2,2',4,4',5‐pentabromodiphenyl ether (BDE‐99) congener along with dimethylsulfoxide (DMSO) control were injected into the yolk sac of un‐incubated eggs of zebra finch, Taeniopygia guttata. Offspring development ...
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