Effects of thyroid hormone on gonadotropin-induced steroid production in medaka, Oryzias latipes, ovarian follicles

Soyano, Kiyoshi; Saito, Toshihiko; Nagae, Masaki; Yamauchi, Kazuyo

doi:10.1007/bf00004574

Cited by 30 publications

(14 citation statements)

References 28 publications

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“…Since reproductive roles for GH (reviewed in LeGac et al 1993), IGFs (Huang et al 1998, Weber & Sullivan 2005, thyroid hormones (Soyano et al 1993, Tambets et al 1997 and F (reviewed in Mommsen et al 1999) have all been demonstrated in fish, gonadal changes in their expression further indicate multiple pathways of oestrogen effect on sexual development. Given the lack of knowledge on the function of locally produced GH and IGF-I, and of the roles of THRs and GRs in the gonad, however, it is difficult to interpret these effects.…”

Section: Discussionmentioning

confidence: 99%

Multiple molecular effect pathways of an environmental oestrogen in fish

Filby¹,

Thorpe²,

Tyler³

2006

Journal of Molecular Endocrinology

129

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Complex interrelationships in the signalling of oestrogenic effects mean that environmental oestrogens present in the aquatic environment have the potential to disrupt physiological function in fish in a more complex manner than portrayed in the present literature. Taking a broader approach to investigate the possible effect pathways and the likely consequences of environmental oestrogen exposure in fish, the effects of 17b-oestradiol (E 2 ) were studied on the expression of a suite of genes which interact to mediate growth, development and thyroid and interrenal function (growth hormone GH (gh), GH receptor (ghr ), insulin-like growth factor (IGF-I) (igf1), IGF-I receptor (igf1r ), thyroid hormone receptors-a (thra) and -b (thrb) and glucocorticoid receptor (gr )) together with the expression analyses of sex-steroid receptors and ten other genes centrally involved in sexual development and reproduction in fathead minnow (fhm; Pimephales promelas). Exposure of adult fhm to 35 ng E 2 /l for 14 days induced classic oestrogen biomarker responses (hepatic oestrogen receptor 1 and plasma vitellogenin), and impacted on the reproductive axis, feminising 'male' steroidogenic enzyme expression profiles and suppressing genes involved in testis differentiation. However, E 2 also triggered a cascade of responses for gh, ghr, igf1, igf1r, thra, thrb and gr in the pituitary, brain, liver, gonad and gill, with potential consequences for the functioning of many physiological processes, not just reproduction. Molecular responses to E 2 were complex, with most genes showing differential responses between tissues and sexes. For example, igf1 expression increased in brain but decreased in gill on exposure to E 2 , and responded in an opposite way in males compared with females in liver, gonad and pituitary. These findings demonstrate the importance of developing a deeper understanding of the endocrine interactions for unravelling the mechanisms of environmental oestrogen action and predicting the likely health consequences.

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Section: Discussionmentioning

confidence: 99%

Multiple molecular effect pathways of an environmental oestrogen in fish

Filby¹,

Thorpe²,

Tyler³

2006

Journal of Molecular Endocrinology

129

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“…Thus, thyroid hormones are undoubtedly involved in synergizing with gonadotropin during oocyte maturation. The existence of a thyroid hormone receptor in the gonad has also been proved in several teleosts such as perch (Chakraborti et al 1986) and medaka (Soyano et al 1993). This permits the enhancement of thyroid hormone on gonadotropin action.…”

mentioning

confidence: 91%

Cloning of the cDNA for thyroid stimulating hormone beta subunit and changes in activity of the pituitary-thyroid axis during silvering of the Japanese eel, Anguilla japonica

Han

Liao²,

Tzeng³

et al. 2004

Journal of Molecular Endocrinology

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The purposes of this study were: (1) to clone the cDNA encoding pituitary thyroid-stimulating hormone beta subunit (TSH ) of the Japanese eel, Anguilla japonica, together with its genomic DNA sequence, for phylogenetic analysis, and to study the regulation of the TSH gene expression in cultured pituitaries; and (2) to investigate the transcript levels of pituitary TSH mRNA and the serum thyroxine profiles at different stages of ovarian development before and during silvering in the wild female eels. The maturity of female eels was divided into four stages, juvenile, sub-adult, pre-silver, and silver, based on skin color and oocyte diameter. The genomic DNA of the TSH subunit contains two introns and three exons, and the TSH protein possesses a putative signal peptide of 20 amino acids and a mature peptide of 127 amino acids. The amino acid sequence identities of TSH mature peptide of Japanese eel compared with those of teleosts and other vertebrates are: European eel (98·4%), salmonids (60·6 -61·3%), carps (52·0 -56·7%), sturgeon (48·4%), and tetrapods (42·9 -45·2%). In in vitro studies of the regulation of TSH mRNA it was found that thyrotropin-releasing hormone increased while thyroxine decreased its expression. RT-PCR and real-time quantitative PCR analysis showed that the transcript levels of TSH subunit increased during eel silvering. The serum thyroxine levels also increased in parallel with TSH mRNA expression during silvering, supporting the hypothesis that the hypothalamus-pituitary-thyroid axis is correlated to silvering in the wild female Japanese eels.

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“…This criterion can be challenging to meet with females of fish species that are asynchronous, fractional spawners, as inter-individual variation in ovarian weight can be high during the spawning cycle. Two approaches researchers have used to overcome this limitation are synchronization of spawning cycles through environmental manipulations (Soyano et al, 1993; Van den Belt et al, 2001), and more commonly, simply including sufficient numbers of replicates in an exposure tank to "average" out the variation across individuals.…”

mentioning

confidence: 99%

“…With regard to medaka and zebrafish, the limited data make it difficult to make comparisons with fathead minnows, other than evidence for cyclic levels of E2 in females. For example, in the medaka, E2 plasma concentrations appear to oscillate during the spawning cycle, with peak concentrations occurring approximately 8 hours before spawning (Soyano et al, 1993). No published data on E2, T, or 11-KT levels in zebrafish could be found.…”

mentioning

confidence: 99%

“…Average plasma E2 concentrations are in the range of 6 ng E2/mL and 0.5 ng E2/mL in mature females and males, respectively. One study reports plasma E2 levels measured by RIA in mature female medaka during the daily period of vitellogenesis and spawning (Soyano et al, 1993). These data show low levels of 4 ng E2/mL plasma at 16 hours before spawning, with a peak of 16 ng E2/mL plasma at 8 hours prior to spawning before levels decrease again.…”

mentioning

confidence: 99%

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Detailed Review Paper on Fish Screening Assays for the Detection of Endocrine Active Substances

2004

OECD Series on Testing and Assessment

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LIST OF TABLES ACKNOWLEDGMENTSThe OECD Secretariat would like to acknowledge the contributions of national experts who provided extensive comments on the draft version of this detailed review paper:• US Environmental Protection Agency, Office of Science Coordination and Policy, who prepared the original version of this document; • Brunel University, Department Biological Sciences, United Kingdom;• US Environmental Protection Agency, Mid-Continent Ecology Division (Duluth, MN);• University of Heidelberg, Zoological Institute, Aquatic Ecotoxicology, Germany;• Fraunhofer Institute for Molecular Biology and Applied Ecology (Schmallenberg) Germany;• ECT Ecotoxicology (Flörsheim), Germany;• Laboratory for Aquatic Organisms, Bayer CropScience (Monheim), Germany;• DHI Water & Environment, Environmental Risk Assessment (Hørsholm), Denmark, who assisted the OECD Secretariat in finalising the Detailed Review Paper; • Schering AG, Experimental Toxicology (Berlin), Germany;• University of Southern Denmark, Institute of Biology (Odenske), Denmark;• European Commission, ECB European Chemicals Bureau (Ispra) Italy;• Institut National de l'Environnement Industriel et des Risques (Verneuil-en-Halatte), France;• CEFAS -Centre for Environment Fisheries and Aquaculture Science, United Kingdom;• Department of the Army Corps of Engineers, United States;• Waterways Experiment Station, Environmental Laboratory (Vicksburg/MS, US). ENV/JM/MONO(2004)18 13 PREAMBLEIn 1998, a Task Force on Endocrine Disrupter Testing and Assessment (EDTA) was established at the request of OECD member countries. The EDTA Task Force is a Special Activity of the Test Guidelines Programme and its main objectives are to:identify the needs and prioritize the development of new and enhanced guidelines for the detection and characterization of endocrine disrupting chemicals;• develop a harmonized testing strategy for the screening and testing of endocrine disrupters;• manage validation work for newly developed and enhanced Test Guidelines as appropriate;and, • provide practical tools for sharing testing results and assessments.The need for new and updated test methods to detect and characterise endocrine disrupting chemicals has been expressed by the Task Force for the assessment of human health effects and environmental effects. At early meetings of the EDTA Task Force, it appeared that existing OECD Test Guidelines would insufficiently cover for endocrine-related effects, especially for the environment. Member countries decided to list test methods which could potentially cover effects of chemicals on the reproductive system (estrogen agonists/antagonists and androgen agonists/antagonists) and on the development (thyroid system), and proposed enhancements where needed. Fish screening assays have been developed for the detection of (anti-) estrogenic and (anti-)androgenic compounds in oviparous animals living in aquatic ecosystems, as there is good evidence that fish in the field are being impacted by endocrine active substances. This Detailed Review Paper (DRP) is...

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Effects of thyroid hormone on gonadotropin-induced steroid production in medaka, Oryzias latipes, ovarian follicles

Cited by 30 publications

References 28 publications

Multiple molecular effect pathways of an environmental oestrogen in fish

Multiple molecular effect pathways of an environmental oestrogen in fish

Cloning of the cDNA for thyroid stimulating hormone beta subunit and changes in activity of the pituitary-thyroid axis during silvering of the Japanese eel, Anguilla japonica

Detailed Review Paper on Fish Screening Assays for the Detection of Endocrine Active Substances

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