Mechanistic aspects of ingested chlorine dioxide on thyroid function: impact of oxidants on iodide metabolism
Toxicological studies dealing with recent findings of health effects of drinking water disinfectants are reviewed. Experiments with monkeys and rodents indicate that the biological activity of ingested disinfectants is expressed via their chemical interaction with the mucosal epithelia, secretory products, and nutritional contents of the alimentary tract. Evidence exists that a principal partner of this redox interaction is the iodide of nutritional origin that is ubiquitous in the gastrointestinal tract. Thus the observation that subchronic exposure to chlorine dioxide (ClO/sub 2/) in drinking water decreases serum thyroxine levels in mammalian species can be best explained with changes produced in the chemical form of the bioavailable iodide. Ongoing and previously reported mechanistic studies indicate that oxidizing agents such as chlorine-based disinfectants oxidize the basal iodide content of the gastrointestinal tract. The resulting reactive iodine species readily attaches to organic matter by covalent bonding. Evidence suggests that the extent to which such iodinated organics are formed is proportional to the magnitude of the electromotive force and stoichiometry of the redox couple between iodide and the disinfectant. Because the extent of thyroid uptake of the bioavailable iodide does not decrease during ClO/sub 2/ ingestion, it seems that ClO/sub 2/ does not cause iodide deficiency of sufficient magnitude to account for the decease in hormonogenesis. Absorption of one or more of iodinated molecules, e.g., nutrient, hormones, or cellular constituents of the alimentary tract having thyromimetic or thyroid inhibitory properties, is a better hypothesis for the effects seen.
- Research Organization:
- Environmental Protection Agency, Cincinnati, OH
- OSTI ID:
- 5749813
- Journal Information:
- Environ. Health Perspect.; (United States), Vol. 69
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
62 RADIOLOGY AND NUCLEAR MEDICINE
CHLORINE OXIDES
BIOLOGICAL EFFECTS
MUCOUS MEMBRANES
IODINATION
PATHOLOGICAL CHANGES
NUTRIENTS
TONGUE
SCANNING ELECTRON MICROSCOPY
DISINFECTANTS
DRINKING WATER
EPITHELIUM
IODINE 125
MONKEYS
OXIDATION
RATS
SODIUM IODIDES
THYROID
THYROXINE
WATER TREATMENT
ALKALI METAL COMPOUNDS
AMINO ACIDS
ANIMAL TISSUES
ANIMALS
BETA DECAY RADIOISOTOPES
BODY
CARBOXYLIC ACIDS
CHALCOGENIDES
CHEMICAL REACTIONS
CHLORINE COMPOUNDS
DAYS LIVING RADIOISOTOPES
DIGESTIVE SYSTEM
ELECTRON CAPTURE RADIOISOTOPES
ELECTRON MICROSCOPY
ENDOCRINE GLANDS
GERMICIDES
GLANDS
HALIDES
HALOGEN COMPOUNDS
HALOGENATION
HORMONES
HYDROGEN COMPOUNDS
INORGANIC PHOSPHORS
INTERMEDIATE MASS NUCLEI
IODIDES
IODINE COMPOUNDS
IODINE ISOTOPES
ISOTOPES
MAMMALS
MEMBRANES
MICROSCOPY
NUCLEI
ODD-EVEN NUCLEI
ORAL CAVITY
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC IODINE COMPOUNDS
ORGANS
OXIDES
OXYGEN COMPOUNDS
PEPTIDE HORMONES
PHOSPHORS
PRIMATES
RADIOISOTOPES
RODENTS
SODIUM COMPOUNDS
THYROID HORMONES
TISSUES
VERTEBRATES
WATER
560300* - Chemicals Metabolism & Toxicology
550601 - Medicine- Unsealed Radionuclides in Diagnostics