Related Experiment Video
Updated: Jul 10, 2026
07:08
Long-term Behavioral and Reproductive Consequences of Embryonic Exposure to Low-dose Toxicants
Published on: March 6, 2018
Developmental exposure to low-dose PBDE-99: tissue distribution and thyroid hormone levels
Sergio Noboru Kuriyama1, Antonia Wanner, Antonio Augusto Fidalgo-Neto
1Institute of Clinical Pharmacology and Toxicology, Department of Toxicology, Charité University Medical School Berlin, Campus Benjamin Franklin, Berlin, Germany.
Toxicology
|October 30, 2007
Summary
Low doses of 2,2
Area of Science:
- Environmental Toxicology
- Endocrinology
- Pharmacokinetics
Background:
- Polybrominated diphenyl ethers (PBDEs) are flame retardants with known environmental persistence.
- PBDEs are suspected endocrine disruptors, potentially affecting thyroid hormone homeostasis.
- Previous studies indicate PBDEs can alter thyroid hormone levels, but low-dose effects require further investigation.
Purpose of the Study:
- To evaluate the effects of low-dose 2,2',4,4',5-pentabromodiphenyl ether (PBDE-99) exposure on thyroid hormone concentrations in Wistar rats.
- To assess the persistence and tissue distribution of PBDE-99 following single low-dose administration.
- To investigate potential endocrine disruption by PBDE-99 at environmentally relevant concentrations.
Main Methods:
- Wistar rat dams were administered a single oral dose of 60 or 300 microg PBDE-99/kg body weight on gestation day 6.
- Thyroid hormone (T4) levels were measured in dams and offspring at various time points post-exposure.
- Tissue concentrations of PBDE-99 were analyzed to determine its persistence and distribution, particularly in adipose tissue.
Main Results:
- PBDE-99 was persistent in rodent tissues, with significant adipose tissue concentrations detected 37 days post-exposure.
- A dose of 300 microg PBDE-99/kg bw reduced maternal thyroxine (T4) at lactation onset and showed a non-significant reduction later.
- Offspring exhibited reduced T4 levels at postnatal day 22, suggesting cumulative exposure effects during lactation.
Conclusions:
- Single low-dose exposure to PBDE-99 can lead to persistent tissue accumulation and disrupt thyroid hormone homeostasis in Wistar rats.
- These findings demonstrate endocrine-disrupting potential of PBDE-99 at low doses, relevant to human exposure levels.
- The study highlights the need for further research into the long-term health consequences of low-level PBDE exposure, including reproductive and behavioral effects.
More Related Videos
04:14In vivo Characterization of Endocrine Disrupting Chemical Effects via Thyroid Hormone Action Indicator Mouse
Published on: October 6, 2023
08:28Assessment of the Effects of Endocrine Disrupting Compounds on the Development of Vertebrate Neural Network Function Using Multi-electrode Arrays
Published on: April 26, 2018
Related Concept Videos
01:18Functions of Thyroid Hormones
The thyroid hormone (TH) plays a pivotal role in the intricate orchestration of physiological processes, exerting profound effects on development, metabolism, and homeostasis throughout different life stages.
TH is indispensable for the normal development and maturation of the skeletal, muscular, and nervous systems during fetal and childhood growth. It facilitates bone mineral turnover and regulates protein synthesis in developing tissues, contributing significantly to overall growth and...
TH is indispensable for the normal development and maturation of the skeletal, muscular, and nervous systems during fetal and childhood growth. It facilitates bone mineral turnover and regulates protein synthesis in developing tissues, contributing significantly to overall growth and...
01:23Toxicity Testing in Animals
Toxicity tests in animals are grounded on two main assumptions: first, the effects observed in laboratory animals can be extrapolated to humans, especially when adjusted for body surface area; second, high-dose exposure in animals is essential to identify potential human hazards from lower doses. This is based on the quantal dose-response concept, which faces the challenge of extrapolating results from relatively few test animals to much larger human populations. For example, a 0.01% incidence...
01:20Synthesis and Regulation of Thyroid Hormones
Low blood levels of the thyroid hormones — triiodothyronine (T3) and thyroxine (T4) — signal the hypothalamus to release the thyrotropin-releasing hormone (TRH). TRH then reaches the pituitary gland and stimulates the release of thyroid-stimulating hormone(TSH) into the bloodstream.
Upon reaching the thyroid gland, TSH stimulates the follicular cells' active uptake of iodide ions from the blood. The ions diffuse to the apical surface of the cells and are oxidized to iodine. The iodine is then...
Upon reaching the thyroid gland, TSH stimulates the follicular cells' active uptake of iodide ions from the blood. The ions diffuse to the apical surface of the cells and are oxidized to iodine. The iodine is then...
01:17Pharmacokinetics in Pediatric Patients: Drug Distribution
Drug distribution in the pediatric population exhibits unique challenges and considerations due to the physiological differences between children, particularly neonates and infants, and adults. A crucial aspect of pediatric pharmacology is understanding how these differences impact the pharmacokinetics of various drugs, necessitating age-specific dosing strategies to ensure efficacy and safety.Neonates and infants have a higher total body water content, ~75%–90% of their body weight, compared...
01:26Toxic Reactions: Overview
When toxic substances penetrate the human body, they disseminate to various tissues, undergoing metabolic changes. This process yields reactive metabolites that may covalently bind with specific target molecules, resulting in toxicity.
Toxicity falls into two primary categories: local and systemic.
Local toxicity appears at the exposure site, such as protein denaturation caused by caustic substances.
In contrast, systemic toxicity requires the toxic agent's absorption and distribution,...
Toxicity falls into two primary categories: local and systemic.
Local toxicity appears at the exposure site, such as protein denaturation caused by caustic substances.
In contrast, systemic toxicity requires the toxic agent's absorption and distribution,...
02:59Biological Effects of Radiation
All radioactive nuclides emit high-energy particles or electromagnetic waves. When this radiation encounters living cells, it can cause heating, break chemical bonds, or ionize molecules. The most serious biological damage results when these radioactive emissions fragment or ionize molecules. For example, α and β particles emitted from nuclear decay reactions possess much higher energies than ordinary chemical bond energies. When these particles strike and penetrate matter, they produce ions...