Effects of Ammonium Perchlorate Exposure in Pregnant Rats: A Morphometric Analysis of the Thyroid Gland of Rat Pups
Final rept. Sep 1997-Dec 1998
AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH HUMAN EFFECTIVENESS DIRECTORATE
Pagination or Media Count:
Characterization of potential risks posed by perchlorate contamination of ground water by the partnered efforts of industry representative and federal and state regulatory agencies has been hindered by the paucity of reliable toxicology data. Our study, a byproduct of one of eight new studies recommended to fill the data gaps, addresses the effect of ammonium perchlorate on thyroid gland morphology and function in the developing fetus. Female rats were dosed orally with 10, 3, 1, 0.1, or 0 mgkg ammonium perchlorate daily during pregnancy and out to 10 days postpartum. Thyroids from offspring were collected at 5 and 81 days postpartum and fixed in 10 buffered formalin. Randomly selected 10 male and 10 female samples per dose group were processed by routine histologic techniques and stained with hematoxylin and eosin for morphometric assessment of follicular lumen areas. Male and female 5-day-old pups displayed a dose-related reduction in follicular lumen areas with significant differences at 10 mgkg in females and at 10, 3, and 0.1 mgkg in males when compared to controls. Thyroids of the recovery cohort, the 81-day-old rats, demonstrated no differences between dose groups and controls for either sex. The above data will contribute information for the generation of a reference dose based on relatively low dose levels in a sensitive subpopulation.
- Anatomy and Physiology
- Inorganic Chemistry