Species and Strain

Exposure Conditions

Fluoride Concentration or Dosea

Exposure Duration

Effects

Reference

Cows (3 years old with chronic fluorosis, 10 controls without fluorosis, from different regions of Turkey)

Drinking water Iodine intakes not specifically stated

5.7-15.2 mg/L in drinking water (approximate doses, 0.7-1.8 mg/kg/day)h

Lifelong

Mean values of T4, T3, and PBI in fluorotic animals were below the normal ranges and also significantly less than in controls.

Low concentrations of bioavailable iodine in fluorosis region might be a factor.

TSH not measured.

Cinar and Selcuk 2005

aInformation in parentheses was calculated from information given in the papers or as otherwise noted.

bBased on water consumption of about 10% of body weight.

cATSDR (2003) stated that an intermediate-duration minimal risk level (MRL) derived from this study of thyroid effects in rats would have been lower (more protective) than the chronic-duration MRL derived from a human study of bone effects (0.05 mg/kg/day).

dBased on feed consumption of 16 kg/day (dry weight) and body weight of 500 kg.

eBased on water consumption of about 10% of body weight and feed consumption of about 8% of body weight.

fText says “triiodiothyronine uptake” and table says “thyroxine uptake.” Data for different treatment groups were not given.

gIn many mammalian species, maternal fluoride exposures are not well reflected by fluoride concentrations in milk; therefore, the impacts of fetal exposure and of reduced milk production by the mothers must also be considered.

hBased on water consumption of 60 L/day and body weight of 500 kg.

ABBREVIATIONS: GH, growth hormone; PBI, protein-bound iodine; TSH, thyroid-stimulating hormone.



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