Gonadal Malformations in Whitefish from Lake Thun: Defining the Case and Evaluating the Role of EDCs
The objectives of this project were to evaluate i) whether the gonad alterations of whitefish (Coregonus lavaretus spp.) in Lake Thun represent abnormal morphological variations specific to this lake, and, if so, ii) whether the malformations are related to chemical exposure, in particular...
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Swiss Chemical Society
2008-05-01
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| Series: | CHIMIA |
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| Online Access: | https://chimia.ch/chimia/article/view/4499 |
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| author | Daniel Bernet Thomas Wahli Marc J.-F. Suter Carlo R. Largiader Christoph Küng Sibylle Kipfer Rik I. L. Eggen David Bittner Anja Liedtke Helmut Segner |
| author_facet | Daniel Bernet Thomas Wahli Marc J.-F. Suter Carlo R. Largiader Christoph Küng Sibylle Kipfer Rik I. L. Eggen David Bittner Anja Liedtke Helmut Segner |
| author_sort | Daniel Bernet |
| collection | DOAJ |
| description |
The objectives of this project were to evaluate i) whether the gonad alterations of whitefish (Coregonus lavaretus spp.) in Lake Thun represent abnormal morphological variations specific to this lake, and, if so, ii) whether the malformations are related to chemical exposure,
in particular to exposure to endocrine-disrupting compounds (EDCs). Large-scale monitoring data revealed that, although whitefish in other lakes display some background variation of gonad morphology, the situation in Lake Thun, is unique because of the significantly higher prevalence of gonad
malformations. The abnormal variations of whitefish gonad morphology include aplasias, compartmentations, fusions, and intersex. In the search for the factor(s) causing the gonad malformations, coregonids were exposed from fertilization up to maturity to Lake Thun water and plankton or to
contaminants possibly being present in the lake, including trinitrotoluenes, and naphtalene sulfonates. Since these experiments are still ongoing, a conclusive answer cannot be given yet, but initial observations point to a role of the lake plankton. The possible presence of EDCs in Lake Thun
was assessed using bioanalytics and biomarkers. The bioanalytical studies found estrogenic activities in concentrated plankton extracts of Lake Thun, however, estrogenic activities occurred also in plankton extracts of reference lakes. Bioassay-directed fractionation of the plankton samples
points to degradation products of natural substances as a cause of the estrogenic activity. Examination of Lake Thun whitefish for EDC biomarkers such as vitellogenin, sex steroid levels or intersex frequency yielded no indications of exposure to EDCs, neither in fish with normal nor in fish
with abnormal gonad morphology. Long-term laboratory exposure of developing coregonids to the prototype estrogenic compound, 17?-estradiol, resulted in an increased frequency of intersex gonads, but did not induce the other gonad malformations typical for Lake Thun coregonids. In summing
up, the currently available evidence does not support an EDC or chemical etiology of the gonad malformations, however, this preliminary conclusion needs to be substantiated in the ongoing investigations. The project also highlights the need for more detailed knowledge of natural variation
in wildlife populations to be able to recognize anthropogenically caused variation.
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| first_indexed | 2024-04-11T07:48:16Z |
| format | Article |
| id | doaj.art-5b0b6066820b429eac035210f75b0de3 |
| institution | Directory Open Access Journal |
| issn | 0009-4293 2673-2424 |
| language | deu |
| last_indexed | 2024-04-11T07:48:16Z |
| publishDate | 2008-05-01 |
| publisher | Swiss Chemical Society |
| record_format | Article |
| series | CHIMIA |
| spelling | doaj.art-5b0b6066820b429eac035210f75b0de32022-12-22T04:36:10ZdeuSwiss Chemical SocietyCHIMIA0009-42932673-24242008-05-0162510.2533/chimia.2008.383Gonadal Malformations in Whitefish from Lake Thun: Defining the Case and Evaluating the Role of EDCsDaniel BernetThomas WahliMarc J.-F. SuterCarlo R. LargiaderChristoph KüngSibylle KipferRik I. L. EggenDavid BittnerAnja LiedtkeHelmut Segner The objectives of this project were to evaluate i) whether the gonad alterations of whitefish (Coregonus lavaretus spp.) in Lake Thun represent abnormal morphological variations specific to this lake, and, if so, ii) whether the malformations are related to chemical exposure, in particular to exposure to endocrine-disrupting compounds (EDCs). Large-scale monitoring data revealed that, although whitefish in other lakes display some background variation of gonad morphology, the situation in Lake Thun, is unique because of the significantly higher prevalence of gonad malformations. The abnormal variations of whitefish gonad morphology include aplasias, compartmentations, fusions, and intersex. In the search for the factor(s) causing the gonad malformations, coregonids were exposed from fertilization up to maturity to Lake Thun water and plankton or to contaminants possibly being present in the lake, including trinitrotoluenes, and naphtalene sulfonates. Since these experiments are still ongoing, a conclusive answer cannot be given yet, but initial observations point to a role of the lake plankton. The possible presence of EDCs in Lake Thun was assessed using bioanalytics and biomarkers. The bioanalytical studies found estrogenic activities in concentrated plankton extracts of Lake Thun, however, estrogenic activities occurred also in plankton extracts of reference lakes. Bioassay-directed fractionation of the plankton samples points to degradation products of natural substances as a cause of the estrogenic activity. Examination of Lake Thun whitefish for EDC biomarkers such as vitellogenin, sex steroid levels or intersex frequency yielded no indications of exposure to EDCs, neither in fish with normal nor in fish with abnormal gonad morphology. Long-term laboratory exposure of developing coregonids to the prototype estrogenic compound, 17?-estradiol, resulted in an increased frequency of intersex gonads, but did not induce the other gonad malformations typical for Lake Thun coregonids. In summing up, the currently available evidence does not support an EDC or chemical etiology of the gonad malformations, however, this preliminary conclusion needs to be substantiated in the ongoing investigations. The project also highlights the need for more detailed knowledge of natural variation in wildlife populations to be able to recognize anthropogenically caused variation. https://chimia.ch/chimia/article/view/4499CoregonusEndocrine disruptionGonad malformationIntersex |
| spellingShingle | Daniel Bernet Thomas Wahli Marc J.-F. Suter Carlo R. Largiader Christoph Küng Sibylle Kipfer Rik I. L. Eggen David Bittner Anja Liedtke Helmut Segner Gonadal Malformations in Whitefish from Lake Thun: Defining the Case and Evaluating the Role of EDCs CHIMIA Coregonus Endocrine disruption Gonad malformation Intersex |
| title | Gonadal Malformations in Whitefish from Lake Thun: Defining the Case and Evaluating the Role of EDCs |
| title_full | Gonadal Malformations in Whitefish from Lake Thun: Defining the Case and Evaluating the Role of EDCs |
| title_fullStr | Gonadal Malformations in Whitefish from Lake Thun: Defining the Case and Evaluating the Role of EDCs |
| title_full_unstemmed | Gonadal Malformations in Whitefish from Lake Thun: Defining the Case and Evaluating the Role of EDCs |
| title_short | Gonadal Malformations in Whitefish from Lake Thun: Defining the Case and Evaluating the Role of EDCs |
| title_sort | gonadal malformations in whitefish from lake thun defining the case and evaluating the role of edcs |
| topic | Coregonus Endocrine disruption Gonad malformation Intersex |
| url | https://chimia.ch/chimia/article/view/4499 |
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