Effects of nitrate on thyroid function in rabbits

Kim, Jin-sang; Han, Jeong-hee; Kim, Kye-soo

Korean Journal of Veterinary Research 1989;29(2):25-31.

Jin-sang Kim¹, Jeong-hee Han¹, Kye-soo Kim²

¹College of Veterinary Medicine, Chunbuk National University
²Kimje Agricultural High School

Nitrate가 가토 갑상선 기능에 미치는 영향

김진상¹, 한정희¹, 김기수²

¹전북대학교 수의과대학
²김제농고

Abstract

The present study was carried out to investigate the effects of nitrate ($KNO_3$) on the thyroid glands in rabbits which were administrated $KNO_3$ of 1g/kg/day for 6 weeks. Growth rate, and serum levels for $T_4$, $T_3$ and TSH were observed every weeks. The histological changes and the weights of the thyroid glands were observed in 6 weeks. The results obtained were summarized as follows: 1. The mean growth rates of experiments were decreased significantly in the 1st week, but were increased a little from the 5th to 6th week compared with those of controls. 2. The serum levels for $T_4$ of the experimental group manifested significantly decreased values than those of control through the experimental term consistently and the serum levels for $T_3$ were greatly decreased in the 3rd and 4th weeks. 3. TSH contents of the serum were not changed through the experimental term. 4. The mean weight of the thyroid gland in the experiment was decreased significantly after 6 weeks compared with that of control. 5. In the experimental group, the color of colloid in the thyroid follicles revealed deeper eosinophilic and the heights of the follicular epithelial cells were taller than those of controls. The colloid in the thyroid follicles revealed depletion. As summarized above, the observations suggest that nitrate can be an antithyroid substance in rabbits and it leads the thyroid glands to hypofunctional state.

Key Words: nitrate, thyroid gland, thyroxine($T_4$), hypothyroidism, rabbit