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Updated: Jun 1, 2026
04:14
In vivo Characterization of Endocrine Disrupting Chemical Effects via Thyroid Hormone Action Indicator Mouse
Published on: October 6, 2023
Thyroid function tests in persons with occupational exposure to fipronil.
Fabrice Herin1, Elisa Boutet-Robinet, Aude Levant
11 Inserm U558, National Institute of Health and Medical Research (INSERM) and The University Paul Sabatier, Toulouse, France.
Summary
This study found no evidence that occupational fipronil exposure increases thyroid abnormalities. However, fipronil may centrally inhibit thyroid-stimulating hormone (TSH) secretion in humans, warranting medical surveillance for exposed workers.
Area of Science:
- Endocrinology
- Occupational Health
- Toxicology
Background:
- Fipronil, an insecticide, targets the GABA receptor.
- Rodent studies link fipronil to thyroid tumors and elevated thyroid-stimulating hormone (TSH).
- Human TSH levels have also been associated with thyroid cancer risk.
Purpose of the Study:
- To investigate the association between chronic occupational fipronil exposure and abnormal thyroid function tests in factory workers.
Main Methods:
- Assessed 159 workers manufacturing fipronil-containing veterinary drugs.
- Measured serum concentrations of TSH, thyroxine, fipronil, and fipronil sulfone.
Main Results:
- Positive correlation between serum fipronil/fipronil sulfone and exposure duration.
- Negative correlation between serum fipronil sulfone and TSH levels.
- No significant increase in thyroid function test abnormalities observed.
Conclusions:
- Chronic fipronil exposure did not correlate with increased thyroid function abnormalities in this cohort.
- Fipronil may centrally inhibit TSH secretion in humans, unlike in rats.
- Occupational medical surveillance and further research into fipronil's thyroid-disrupting mechanisms are recommended.
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