• Study conducted by Dr. Braverman, Harvard University. Sponsored by the PSG. Male volunteers were exposed to one dose level of perchlorate in drinking water for 14 days. Thyroid hormones and radioactive iodine uptake were measured. Exposure to a dose of 0.14 mg/kg-day resulted in significant inhibition of radioactive iodine uptake compared with controls, but had no effect on thyroid hormone levels. A second phase of the study will examine the same endpoints at two lower doses (0.01 and 0.04 mg/kg-day). Study in progress.
  • Study results for dose of 0.14 mg/kg day
  • Letter to the Editor - Low Dose Perchlorate (3 mg daily) and Thyroid Function  Thyroid.  1999.  11:3, pg. 295
• Kinetic studies in humans to support the development of a PBPK model.  Conducted by Dr. Brabant, Germany. Healthy male volunteers exposed to 0.1, 1.0, or 12 mg/kg-day perchlorate in drinking water (daily dosed divided into 3, one every 8 hours) for 14 days. Thyroid hormones and perchlorate in sera and urine will be measured. This study provides the first phase of kinetics data in humans that will be used to develop a PBPK model in humans. When combined with similar data that are being collected in animals, this study will provide a basis for extrapolating risk assessment in animals to human exposure to perchlorate, and it will reduce uncertainty in derived standards for perchlorate. Study in progress.
• Pharmacokinetics and radioactive iodine uptake study in humans. Conducted by Dr. Monte Greer of the Oregon Health Sciences University, Portland, OR. Sponsored by the PSG. Healthy male and female volunteers were exposed to either 0.01, 0.02, 0.1 or 0.5 mg/kg-day perchlorate in drinking water for 14 days. Thyroid hormones, inhibition of radioactive iodine uptake, and elimination rate of perchlorate from blood and urine were measured. This study provided kinetic data needed to complete a PBPK model for humans that can be used to reduce uncertainty in the risk assessment extrapolation from animals to humans. In addition, it may provide dose response information about the effect of perchlorate on iodine uptake into the thyroid in healthy humans.

  • Protocol for a Study of the Pharmacokinetics of Fourteen-Day Drinking-Water Exposure to Perchlorate in Human Volunteers, Including Analysis of the Inhibition of Radioactive Iodine Uptake (PDF file)  Part A    Part B

  • Results of Study of Pharmacokinetics and radioactive iodine uptake study in humans

    • Inhibition of Radioactive Iodine Uptake

    • Recovery from Perchlorate Exposure

For further information, contact Ms. Joan Strawson at 910-692-7752 or Strawson@tera.org