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Haigis AC, Vergauwen L, LaLone CA, Villeneuve DL, O'Brien JM, Knapen D. Cross-species applicability of an adverse outcome pathway network for thyroid hormone system disruption. Toxicol Sci 2023; 195:1-27. [PMID: 37405877 DOI: 10.1093/toxsci/kfad063] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2023] Open
Abstract
Thyroid hormone system disrupting compounds are considered potential threats for human and environmental health. Multiple adverse outcome pathways (AOPs) for thyroid hormone system disruption (THSD) are being developed in different taxa. Combining these AOPs results in a cross-species AOP network for THSD which may provide an evidence-based foundation for extrapolating THSD data across vertebrate species and bridging the gap between human and environmental health. This review aimed to advance the description of the taxonomic domain of applicability (tDOA) in the network to improve its utility for cross-species extrapolation. We focused on the molecular initiating events (MIEs) and adverse outcomes (AOs) and evaluated both their plausible domain of applicability (taxa they are likely applicable to) and empirical domain of applicability (where evidence for applicability to various taxa exists) in a THSD context. The evaluation showed that all MIEs in the AOP network are applicable to mammals. With some exceptions, there was evidence of structural conservation across vertebrate taxa and especially for fish and amphibians, and to a lesser extent for birds, empirical evidence was found. Current evidence supports the applicability of impaired neurodevelopment, neurosensory development (eg, vision) and reproduction across vertebrate taxa. The results of this tDOA evaluation are summarized in a conceptual AOP network that helps prioritize (parts of) AOPs for a more detailed evaluation. In conclusion, this review advances the tDOA description of an existing THSD AOP network and serves as a catalog summarizing plausible and empirical evidence on which future cross-species AOP development and tDOA assessment could build.
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Affiliation(s)
- Ann-Cathrin Haigis
- Zebrafishlab, Veterinary Physiology and Biochemistry, Department of Veterinary Sciences, University of Antwerp, 2610 Wilrijk, Belgium
| | - Lucia Vergauwen
- Zebrafishlab, Veterinary Physiology and Biochemistry, Department of Veterinary Sciences, University of Antwerp, 2610 Wilrijk, Belgium
| | - Carlie A LaLone
- Great Lakes Toxicology and Ecology Division, United States Environmental Protection Agency, Duluth, Minnesota 55804, USA
| | - Daniel L Villeneuve
- Great Lakes Toxicology and Ecology Division, United States Environmental Protection Agency, Duluth, Minnesota 55804, USA
| | - Jason M O'Brien
- Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, Carleton University, Ottawa, Ontario K1S 5B6, Canada
| | - Dries Knapen
- Zebrafishlab, Veterinary Physiology and Biochemistry, Department of Veterinary Sciences, University of Antwerp, 2610 Wilrijk, Belgium
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Mohammadparast-Tabas P, Arab-Zozani M, Naseri K, Darroudi M, Aramjoo H, Ahmadian H, Ashrafipour M, Farkhondeh T, Samarghandian S. Polychlorinated biphenyls and thyroid function: a scoping review. REVIEWS ON ENVIRONMENTAL HEALTH 2023:reveh-2022-0156. [PMID: 37434382 DOI: 10.1515/reveh-2022-0156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 05/27/2023] [Indexed: 07/13/2023]
Abstract
OBJECTIVE Numerous evidence indicates the association between polychlorinated biphenyls (PCBs), an endocrine disrupter, with thyroid hormone disruption, contradictory findings also exist. Herein, we tried to address this question by performing a scoping review. CONTENT The search was performed on PubMed, Scopus, Web of Science, and Google Scholar databases from 2010 onwards. Animal studies on PCBs' effect on thyroid function were searched. The SYRCLE's RoB scale assessed the risk of bias. I2 and Q tests are used for investigating heterogeneity. A random-effects model with the pooled standard means difference (SMD) and 95 % confidence interval (CI) was performed for the TSH, TT4, TT3, and FT4 outcomes using Comprehensive Meta-Analyses (CMA) Software version 3. Also, we conducted subgroup analyses based on the different types of PCB. The initial search identified 1,279 publications from the main databases 26 of them fulfilled our eligibility criteria for the study, and then five studies among selected studies had sufficient data for analysis. Meta-analysis of data revealed that Aroclor 1260 (SDM: -0.47, 95 % CI: -0.92, -0.01, p=0.044) and PCB 126 (SDM: 0.17, 95 % CI: -0.40, 0.75, p=0.559) significantly increased TSH concentration in the exposed groups vs. the control groups. Related to the effects of PCBs on the TT4, our findings indicated a significant reduction the TT4 concentration of animals exposed to Aroclor 1260 (SDM: -5.62, 95 % CI: -8.30, -2.94, p=0.0001), PCB 118 (SDM: -6.24, 95 % CI: -7.76, -4.72, p=0.0001), PCB 126 (SDM: -1.81, 95 % CI: -2.90, -0.71, p=0.001), and PCB 153 (SDM: -1.32, 95 % CI: -2.29, -0.35, p=0.007) vs. the controls. Our meta-analysis indicated a significant increase in TT3 concentration following exposure to PCB 118 and PCB 153 (SDM: -0.89, 95 % CI: -1.36, -0.42, p=0.0001, and SDM: -1.45, 95 % CI: -2.15, -0.75, p=0.0001, respectively). Aroclor 1254 and PCB 126 significantly decreased TT3 concentration (SDM: 1.25, 95 % CI: 0.29, 2.21, p=0.01 and SDM: 3.33, 95 % CI: 2.49, 4.18, p=0.0001, respectively). PCB 126 significantly decreased FT4 in the exposed groups vs. the control groups (SDM: -7.80, 95 % CI: -11.51, -5.35, p=0.0001). SUMMARY Our findings showed an association between PCBs exposure and hypothyroidism in rodents, fish, and chicken embryos. OUTLOOK Regarding to the most evidence of hypothyroidism effects of PCBs in animal species, it is necessary to consider large cohort studies to address the association between PCBs exposure and thyroid function impairment in humans.
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Affiliation(s)
| | - Morteza Arab-Zozani
- Social Determinants of Health Research Center, Birjand University of Medical Sciences, Birjand, Iran
| | - Kobra Naseri
- Department of Toxicology and Pharmacology, School of Pharmacy, Birjand University of Medical Sciences, Birjand, Iran
| | - Majid Darroudi
- Department of Basic Sciences, Neyshabur University of Medical Sciences, Neyshabur, Iran
| | - Hamed Aramjoo
- Student Research Committee, Birjand University of Medical Sciences, Birjand, Iran
| | - Hanie Ahmadian
- Student Research Committee, Birjand University of Medical Sciences, Birjand, Iran
| | - Mostafa Ashrafipour
- Department of Parasitology and Mycology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Tahereh Farkhondeh
- Department of Toxicology and Pharmacology, School of Pharmacy, Birjand University of Medical Sciences, Birjand, Iran
| | - Saeed Samarghandian
- Healthy Ageing Research Centre, Neyshabur University of Medical Sciences, Neyshabur, Iran
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Takaguchi K, Nishikawa H, Mizukawa H, Tanoue R, Yokoyama N, Ichii O, Takiguchi M, Nakayama SMM, Ikenaka Y, Kunisue T, Ishizuka M, Tanabe S, Iwata H, Nomiyama K. Effects of PCB exposure on serum thyroid hormone levels in dogs and cats. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 688:1172-1183. [PMID: 31726548 DOI: 10.1016/j.scitotenv.2019.06.300] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 06/19/2019] [Accepted: 06/19/2019] [Indexed: 06/10/2023]
Abstract
Polychlorinated biphenyls (PCBs) and their hydroxylated metabolites (OH-PCBs) might disrupt thyroid function. However, there is no clear evidence of PCB exposure disrupting thyroid hormone (TH) homeostasis in dogs and cats. The present study conducted in vivo experiments to evaluate the effects of a mixture of 12 PCB congeners (CB18, 28, 70, 77, 99, 101, 118, 138, 153, 180, 187 and 202, each congener 0.5 mg/kg BW, i.p. administration) on serum TH levels in male dogs (Canis lupus familiaris) and male cats (Felis silvestris catus). In PCB-exposed dogs, the time courses of higher-chlorinated PCBs and L-thyroxine (T4)-like OH-PCBs (4-OH-CB107 and 4-OH-CB202) concentrations were unchanged or tended to increase, whereas those of lower-chlorinated PCBs and OH-PCBs tended to decrease after 24 h. In PCB-exposed cats, concentrations of PCBs increased until 6 h and then remained unchanged. The levels of lower-chlorinated OH-PCBs including 4'-OH-CB18 increased until 96 h and then decreased. In PCB-exposed dogs, free T4 concentrations were higher than those in the control group at 48 and 96 h after PCB administration and positively correlated with the levels of T4-like OH-PCBs, suggesting competitive binding of T4 and T4-like OH-PCBs to a TH transporter, transthyretin. Serum levels of total T4 and total 3,3',5-triiodo-L-thyronine (T3) in PCB-exposed dogs were lower than in the control group at 24 and 48 h and negatively correlated with PCB concentrations, implying that PCB exposure enhanced TH excretion by increasing TH uptake and TH conjugation enzyme activities in the dog liver. In contrast, no obvious changes in TH levels were observed in PCB-exposed cats. This could be explained by the lower levels of T4-like OH-PCBs and lower hepatic conjugation enzyme activities in cats compared with dogs. Different effects on serum TH levels in PCB-exposed dogs and cats are likely to be attributable to species-specific PCB and TH metabolism.
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Affiliation(s)
- Kohki Takaguchi
- Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577, Japan
| | - Hiroyuki Nishikawa
- Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577, Japan
| | - Hazuki Mizukawa
- Department of Science and Technology for Biological Resources and Environment, Graduate School of Agriculture, Ehime University, Tarumi 3-5-7, Matsuyama, Ehime 790-8566, Japan
| | - Rumi Tanoue
- Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577, Japan
| | - Nozomu Yokoyama
- Faculty of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo, Hokkaido 060-0818, Japan
| | - Osamu Ichii
- Faculty of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo, Hokkaido 060-0818, Japan
| | - Mitsuyoshi Takiguchi
- Faculty of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo, Hokkaido 060-0818, Japan
| | - Shouta M M Nakayama
- Faculty of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo, Hokkaido 060-0818, Japan
| | - Yoshinori Ikenaka
- Faculty of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo, Hokkaido 060-0818, Japan; Unit for Environmental Sciences and Management, Potchefstroom Campus, North-West University, X6001, Potchefstroom 2520, South Africa
| | - Tatsuya Kunisue
- Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577, Japan
| | - Mayumi Ishizuka
- Faculty of Veterinary Medicine, Hokkaido University, Kita 18, Nishi 9, Kita-ku, Sapporo, Hokkaido 060-0818, Japan
| | - Shinsuke Tanabe
- Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577, Japan
| | - Hisato Iwata
- Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577, Japan
| | - Kei Nomiyama
- Center for Marine Environmental Studies (CMES), Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577, Japan.
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Kato Y, Tamaki S, Haraguchi K, Ikushiro SI, Fujii Y, Ohta C, Atobe K, Kimura O, Endo T, Koga N, Yamada S, Degawa M. Kanechlor 500-mediated changes in serum and hepatic thyroxine levels primarily occur in a transthyretin-unrelated manner. J Appl Toxicol 2019; 39:1701-1709. [PMID: 31498458 DOI: 10.1002/jat.3895] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 07/19/2019] [Accepted: 07/24/2019] [Indexed: 11/08/2022]
Abstract
The effects of Kanechlor-500 (KC500) on the levels of serum total thyroxine (T4 ) and hepatic T4 in wild-type C57BL/6 (WT) and its transthyretin (TTR)-deficient (TTR-null) mice were comparatively examined. Four days after a single intraperitoneal injection with KC500 (100 mg/kg body weight), serum total T4 levels were significantly decreased in both WT and TTR-null mice. The KC500 pretreatment also promoted serum [125 I]T4 clearance in both strains of mice administrated with [125 I]T4 , and the promotion of serum [125 I]T4 clearance in WT mice occurred without inhibition of the [125 I]T4 -TTR complex formation. Furthermore, the KC500 pretreatment led to significant increases in liver weight, steady-state distribution volume of [125 I]T4 , hepatic accumulation level of [125 I]T4 , and concentration ratio of the liver to serum in both strains of mice. The present findings indicate that the KC500-mediated decrease in serum T4 level occurs in a TTR-unrelated manner and further suggest that KC500-promoted T4 accumulation in the liver occurs through the development of liver hypertrophy and the promotion of T4 transportation from serum to liver.
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Affiliation(s)
- Yoshihisa Kato
- Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki, Kagawa, Japan
| | - Sekihiro Tamaki
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | | | | | - Yukiko Fujii
- Daiichi College of Pharmaceutical Sciences, Fukuoka, Japan
| | - Chiho Ohta
- Faculty of Nutritional Sciences, Nakamura Gakuen University, Fukuoka, Japan
| | - Kazutaka Atobe
- Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki, Kagawa, Japan
| | - Osamu Kimura
- Faculty of Pharmaceutical Sciences, Health Science University of Hokkaido, Hokkaido, Japan
| | - Tetsuya Endo
- Faculty of Pharmaceutical Sciences, Health Science University of Hokkaido, Hokkaido, Japan
| | - Nobuyuki Koga
- Faculty of Nutritional Sciences, Nakamura Gakuen University, Fukuoka, Japan
| | - Shizuo Yamada
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
| | - Masakuni Degawa
- School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka, Japan
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Dirinck E, Dirtu AC, Malarvannan G, Covaci A, Jorens PG, Van Gaal LF. A Preliminary Link between Hydroxylated Metabolites of Polychlorinated Biphenyls and Free Thyroxin in Humans. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2016; 13:421. [PMID: 27089353 PMCID: PMC4847083 DOI: 10.3390/ijerph13040421] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 04/06/2016] [Accepted: 04/11/2016] [Indexed: 01/07/2023]
Abstract
BACKGROUND Polychlorinated biphenyls (PCBs) and their hydroxylated metabolites (HO-PCBs) interfere with thyroid hormone action both in vitro and in vivo. However, epidemiologic studies on the link between PCB exposure and thyroid function have yielded discordant results, while very few data are available for HO-PCBs. OBJECTIVES Our study aimed at investigating the relationship between clinically available markers of thyroid metabolism and serum levels of both PCBs and HO-PCBs. SUBJECTS AND METHODS In a group of 180 subjects, thyroid-stimulating hormone (TSH) and free thyroxin (fT4), 29 PCBs (expressed both in lipid weight and in wet weight) and 18 HO-PCBs were measured in serum. RESULTS In regression models, adjusted for gender, age, current smoking behavior, BMI and total lipid levels, serum levels of 3HO-PCB118 and 3HO-PCB180, and PCB95(lw), PCB99(lw) and PCB149(lw) were independent, significant predictors of fT4. A stepwise, multiple regression with gender, age, current smoking behavior, BMI and total lipid levels and all five previously identified significant compounds retained age, BMI, PCB95(lw), PCB99(lw) and 3HO-PCB180 as significant predictors of fT4. TSH levels were not predicted by serum levels of any of the PCBs or HO-PCBs. CONCLUSIONS Our study indicates that in vivo, circulating fT4 levels can be linked to serum levels of several PCBs and hydroxylated PCB metabolites.
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Affiliation(s)
- Eveline Dirinck
- Department of Endocrinology, Diabetology and Metabolism, Antwerp University Hospital, University of Antwerp, Wilrijkstraat 10, Edegem 2650, Belgium.
| | - Alin C Dirtu
- Toxicology Centre, University of Antwerp, Wilrijk 2610, Belgium.
| | | | - Adrian Covaci
- Toxicology Centre, University of Antwerp, Wilrijk 2610, Belgium.
| | - Philippe G Jorens
- Department of Clinical Pharmacology, Antwerp University Hospital, University of Antwerp, Edegem 2650, Belgium.
| | - Luc F Van Gaal
- Department of Endocrinology, Diabetology and Metabolism, Antwerp University Hospital, University of Antwerp, Wilrijkstraat 10, Edegem 2650, Belgium.
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6
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Ohta C, Haraguchi K, Kato Y, Endo T, Kimura O, Koga N. Distribution and excretion of 2,2',3,4',5,5',6-heptachlorobiphenyl (CB187) and its metabolites in rats and guinea pigs. CHEMOSPHERE 2015; 118:5-11. [PMID: 25433397 DOI: 10.1016/j.chemosphere.2014.05.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 05/08/2014] [Accepted: 05/09/2014] [Indexed: 06/04/2023]
Abstract
4-Hydroxy (OH)-2,2',3,4',5,5',6-heptachlorobiphenyl (CB187) is a polychlorinated biphenyl (PCB) metabolite present in human serum at the highest concentration of the PCB metabolites. Our previous study demonstrated that CB187 was metabolized by rat and guinea pig liver microsomes to the major metabolite 4'-OH-2,2',3,3',5,5',6-heptachlorobiphenyl (CB178), and the two minor metabolites 4-OH-CB187 and 4'-OH-2,2',3,5,5',6-hexachlorobiphenyl (CB151). In this study, the distribution of these metabolites in serum, liver and kidney, and their fecal excretion, were examined in rats and guinea pigs intraperitoneally dosed with CB187. Similarly to the in vitro study, 4'-OH-CB178 was a major metabolite in the liver, serum and feces of both animal species on day 4 after CB187 injection, and the level in the liver was about 20 times higher in untreated guinea pigs than in untreated rats. In addition, 4-OH-CB187, a minor metabolite, was detected in the serum and kidneys, but not in the feces, of both guinea pigs and rats. Another minor metabolite, 4'-OH-CB151, was detected at a lower level only in guinea pig feces; little was found in the serum or liver of either animals. Over the 30d following CB187 injection into guinea pigs, 4'-OH-CB178 and 4-OH-CB187 in the serum was observed at higher level on day 4 and day 16 after injection, respectively. The majority of the 4'-OH-CB178 was rapidly excreted to the feces following unmetabolized CB187, whereas 4-OH-CB187 was not found in guinea pig feces and liver during 30d. These results support previous reports that 4-OH-CB187 is retained persistently in animal blood.
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Affiliation(s)
- Chiho Ohta
- Faculty of Nutritional Sciences, Nakamura Gakuen University, 5-7-1 Befu, Jonan-ku, Fukuoka 814-0198, Japan.
| | - Koichi Haraguchi
- Daiichi College of Pharmaceutical Sciences, 22-1 Tamagawa-cho, Minami-ku, Fukuoka 815-8511, Japan.
| | - Yoshihisa Kato
- Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, 1314-1 Shido, Sanuki, Kagawa 769-2193, Japan.
| | - Tetsuya Endo
- Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, 1757 Ishikari-Tobetsu, Hokkaido 061-0293, Japan.
| | - Osamu Kimura
- Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, 1757 Ishikari-Tobetsu, Hokkaido 061-0293, Japan.
| | - Nobuyuki Koga
- Faculty of Nutritional Sciences, Nakamura Gakuen University, 5-7-1 Befu, Jonan-ku, Fukuoka 814-0198, Japan.
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Ruiz P, Myshkin E, Quigley P, Faroon O, Wheeler JS, Mumtaz MM, Brennan RJ. Assessment of hydroxylated metabolites of polychlorinated biphenyls as potential xenoestrogens: a QSAR comparative analysis∗. SAR AND QSAR IN ENVIRONMENTAL RESEARCH 2013; 24:393-416. [PMID: 23557136 DOI: 10.1080/1062936x.2013.781537] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Alternative methods, including quantitative structure-activity relationships (QSAR), are being used increasingly when appropriate data for toxicity evaluation of chemicals are not available. Approximately 40 mono-hydroxylated polychlorinated biphenyls (OH-PCBs) have been identified in humans. They represent a health and environmental concern because some of them have been shown to have agonist or antagonist interactions with human hormone receptors. This could lead to modulation of steroid hormone receptor pathways and endocrine system disruption. We performed QSAR analyses using available estrogenic activity (human estrogen receptor ER alpha) data for 71 OH-PCBs. The modelling was performed using multiple molecular descriptors including electronic, molecular, constitutional, topological, and geometrical endpoints. Multiple linear regressions and recursive partitioning were used to best fit descriptors. The results show that the position of the hydroxyl substitution, polarizability, and meta adjacent un-substituted carbon pairs at the phenolic ring contribute towards greater estrogenic activity for these chemicals. These comparative QSAR models may be used for predictive toxicity, and identification of health consequences of PCB metabolites that lack empirical data. Such information will help prioritize such molecules for additional testing, guide future basic laboratory research studies, and help the health/risk assessment community understand the complex nature of chemical mixtures.
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Affiliation(s)
- P Ruiz
- Division of Toxicology and Human Health Sciences, Agency for Toxic Substances and Disease Registry, Atlanta, USA.
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8
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Miyawaki I, Tamura A, Matsumoto I, Inada H, Kunimatsu T, Kimura J, Funabashi H. The effects of clobazam treatment in rats on the expression of genes and proteins encoding glucronosyltransferase 1A/2B (UGT1A/2B) and multidrug resistance-associated protein-2 (MRP2), and development of thyroid follicular cell hypertrophy. Toxicol Appl Pharmacol 2012; 265:351-9. [PMID: 22982618 DOI: 10.1016/j.taap.2012.09.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 09/05/2012] [Accepted: 09/06/2012] [Indexed: 11/17/2022]
Abstract
Clobazam (CLB) is known to increase hepatobiliary thyroxine (T4) clearance in Sprague-Dawley (SD) rats, which results in hypothyroidism followed by thyroid follicular cell hypertrophy. However, the mechanism of the acceleration of T4-clearance has not been fully investigated. In the present study, we tried to clarify the roles of hepatic UDP-glucronosyltransferase (UGT) isoenzymes (UGT1A and UGT2B) and efflux transporter (multidrug resistance-associated protein-2; MRP2) in the CLB-induced acceleration of T4-clearance using two mutant rat strains, UGT1A-deficient mutant (Gunn) and MRP2-deficient mutant (EHBR) rats, especially focusing on thyroid morphology, levels of circulating hormones (T4 and triiodothyronine (T3)) and thyroid-stimulating hormone (TSH), and mRNA or protein expressions of UGTs (Ugt1a1, Ugt1a6, and Ugt2b1/2) and MRP2 (Mrp). CLB induced thyroid morphological changes with increases in TSH in SD and Gunn rats, but not in EHBR rats. T4 was slightly decreased in SD and Gunn rats, and T3 was decreased in Gunn rats, whereas these hormones were maintained in EHBR rats. Hepatic Ugt1a1, Ugt1a6, Ugt2b1/2, and Mrp2 mRNAs were upregulated in SD rats. In Gunn rats, UGT1A mRNAs (Ugt1a1/6) and protein levels were quite low, but UGT2B mRNAs (Ugt2b1/2) and protein were prominently upregulated. In SD and Gunn rats, MRP2 mRNA and protein were upregulated to the same degree. These results suggest that MRP2 is an important contributor in development of the thyroid cellular hypertrophy in CLB-treated rats, and that UGT1A and UGT2B work in concert with MRP2 in the presence of MRP2 function to enable the effective elimination of thyroid hormones.
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Affiliation(s)
- Izuru Miyawaki
- Safety Research Laboratories, Dainippon Sumitomo Pharma Co., Ltd., 3-1-98, Kasugade Naka, Konohanaku, Osaka 554-0022, Japan.
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Akiyoshi S, Sai G, Yamauchi K. Species-dependent effects of the phenolic herbicide ioxynil with potential thyroid hormone disrupting activity: modulation of its cellular uptake and activity by interaction with serum thyroid hormone-binding proteins. J Environ Sci (China) 2012; 24:949-55. [PMID: 22893975 DOI: 10.1016/s1001-0742(11)60819-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Ioxynil, a phenolic herbicide, is known to exert thyroid hormone (TH) disrupting activity by interfering with TH-binding to plasma proteins and a step of the cellular TH-signaling pathway in restricted animal species. However, comparative studies are still lacking on the TH disruption. We investigated the interaction of [125I]ioxynil with serum proteins from rainbow trout, bullfrog, chicken, pig, rat, and mouse, using native polyacrylamide gel electrophoresis. Candidate ioxynil-binding proteins, which included lipoproteins, albumin and transthyretin (TTR), differed among the vertebrates tested. Rainbow trout and bullfrog tadpole serum had the lowest binding activity for ioxynil, whereas the eutherian serum had the highest binding activity. The cellular uptake of, and response to, ioxynil were suppressed by rat serum greater than by tadpole serum. The cellular uptake of [125I]ioxynil competed strongly with phenols with a single ring, but not with THs. Our results suggested that ioxynil interferes with TH homeostasis in plasma and with a step of cellular TH-signaling pathway other than TH-uptake system, in a species-specific manner.
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Affiliation(s)
- Sakura Akiyoshi
- Department of Biological Science, Faculty of Science, Shizuoka University, Shizuoka 422-8529, Japan
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Yamauchi K, Sai G. Characterization of plasma triiodophenol binding proteins in vertebrates and tissue distribution of triiodophenol in Rana catesbeiana tadpoles. Comp Biochem Physiol C Toxicol Pharmacol 2011; 153:328-35. [PMID: 21147258 DOI: 10.1016/j.cbpc.2010.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2010] [Revised: 11/29/2010] [Accepted: 12/06/2010] [Indexed: 12/22/2022]
Abstract
We investigated the interaction of 2,4,6-triiodophenol (TIP), a potent thyroid hormone disrupting chemical, with serum proteins from rainbow trout (Onchorhynchus mykiss), bullfrog (Rana catesbeiana), chicken (Gallus gallus), pig (Sus scrofa domesticus), and rat (Rattus norvegicus) using a [(125)I]TIP binding assay, gel filtration chromatography, and native polyacrylamide gel electrophoresis. [(125)I]TIP bound non-specifically to proteins in trout serum, specifically but weakly to proteins in bullfrog serum, and specifically and strongly to proteins in chicken, pig, and rat serum samples. Candidate TIP-binding proteins included lipoproteins (220-320kDa) in trout, albumin in bullfrog, albumin and transthyretin (TTR) in chicken and pig, and TTR in rat. TTR in the chicken, pig, and rat serum samples was responsible for the high-affinity, low-capacity binding sites for TIP (dissociation constant 2.2-3.5×10(-10)M). In contrast, a weak interaction of [(125)I]TIP with tadpole serum proteins accelerated [(125)I]TIP cellular uptake in vitro. Intraperitoneal injection of [(125)I]TIP in tadpoles revealed that the radioactivity was predominantly accumulated in the gallbladder and the kidney. The differences in the molecular and binding properties of TIP binding proteins among vertebrates would affect in part the cellular availability, tissue distribution and clearance of TIP.
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Affiliation(s)
- Kiyoshi Yamauchi
- Department of Biological Science, Faculty of Science, Shizuoka University, Shizuoka 422-8529, Japan.
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