Effects of Ammonium Perchlorate on the Thyroid Hormone Levels of the Sprague-Dawley Rat.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
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The purpose of this research was to determine the threshold dose for ammonium perchlorate AP in the Sprague-Dawley rat. No dose response data exist for AP and the EPA has studied literature on the subject of perchlorates to determine a provisional reference dose. The Perchiorate Group, a consortium of DoD and industry representatives, believes this provisional reference dose is too conservative. This experiment was executed to provide dose response data on which to base a more accurate reference dose. The study consisted of eight groups of 12 Sprague-Dawley rats, six male and six female, which were exposed to incremental doses of AP in their drinking water. The results indicated that Triiodothyronine T3 levels in male and female rats fell, Thyroxine T4 levels in male rats remained relatively unchanged. Reverse Triiodothyronine rT3, Thyrotropin TSH, and Thyroglobulin Tg all increased in both males and females. These results imply that the AP anion blocked the uptake of iodine in the thyroid. Although an estimated threshold could not be determined, the NOAEL for AP on the TSH levels was .44 mgkgday for the male rats and .124 mgkglday for the female rats. These NOAELs are consistent with the assumptions made by the EPA, which estimated a NOAEL of .14 mgkgday for perchlorates.
- Inorganic Chemistry