Metamorphic inhibition of Xenopus laevis by sodium perchlorate: Effects on development and thyroid histology

doi:10.1897/04-105R.1

Paper

Metamorphic inhibition of Xenopus laevis by sodium perchlorate: Effects on development and thyroid histology

Published Apr 1, 2005 · J. Tietge, G. Holcombe, K. Flynn

Environmental Toxicology and Chemistry

Q1 SJR score

105

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13

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Abstract

The perchlorate anion inhibits thyroid hormone (TH) synthesis via inhibition of the sodium‐iodide symporter. It is, therefore, a good model chemical to aid in the development of a bioassay to screen chemicals for affects on thyroid function. Xenopus laevis larvae were exposed to sodium perchlorate during metamorphosis, a period of TH‐dependent development, in two experiments. In the first experiment, stage 51 and 54 larvae were exposed for 14 d to 16, 63, 250, 1,000, and 4,000 μg perchlorate/L. In the second experiment, stage 51 larvae were exposed throughout metamorphosis to 8, 16, 32, 63, and 125 μg perchlorate/L. Metamorphic development and thyroid histology were the primary endpoints examined. Metamorphosis was retarded significantly in the first study at concentrations of 250 μg/L and higher, but histological effects were observed at 16 μg/L. In the second study, metamorphosis was delayed by 125 μg/L and thyroid size was increased significantly at 63 μg/L. These studies demonstrate that inhibition of metamorphosis readily can be detected using an abbreviated protocol. However, thyroid gland effects occur at concentrations below those required to elicit developmental delay, demonstrating the sensitivity of this endpoint and suggesting that thyroidal compensation is sufficient to promote normal development until perchlorate reaches critical concentrations.

Non-RCT

Animal Study

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Study Snapshot

Sodium perchlorate can inhibit metamorphosis in Xenopus laevis larvae, with thyroid gland effects occurring at concentrations below those required to delay developmental delay, suggesting thyroidal compensation is sufficient for normal development.

PopulationOlder adults (50-71 years)

Sample size24

MethodsObservational

OutcomesBody Mass Index projections

ResultsSocial networks mitigate obesity in older groups.

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Paper

Metamorphic inhibition of Xenopus laevis by sodium perchlorate: Effects on development and thyroid histology

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References

Citations

Testing the sensitivity of the medaka Transgenic Eleuthero-embryonic THYroid-Specific assay (TETHYS) to different mechanisms of action.

The TETHYS assay effectively detects thyroid active chemicals, providing a new OECD test for assessing the impact of chemicals on thyroid activity.

How the Xenopus eleutheroembryonic thyroid assay compares to the amphibian metamorphosis assay for detecting thyroid active chemicals.

The XETA and amphibian metamorphosis assays are highly concordant in detecting thyroid-active chemicals, with the exception of NIS inhibition.

Historical control histopathology data from amphibian metamorphosis assays and fathead minnow fish short term reproductive assays: A tool for data interpretation.

Historical control data from amphibian metamorphosis assays and fathead minnow fish short term reproductive assays can aid in interpreting future study outcomes and refining current testing paradigms.

Effects of perchlorate and exogenous T4 on growth, development and tail resorption of Rana chensinensis.

NaClO4 and exogenous T4 exposure negatively affect tail resorption in Rana chensinensis, affecting their adaptation to terrestrial life and affecting environmental protection.

A biologically based computational model for the hypothalamic-pituitary-thyroid (HPT) axis in Xenopus laevis larvae.

This computational model of the hypothalamic-pituitary-thyroid axis in Xenopus laevis larvae can help predict the effects of chemical toxicants on thyroid hormone-mediated metamorphosis and help understand thyroid hormone-mediated metamorphosis mechanisms.