Effects of nitrate on thyroid function in rabbits

Kim, J.S.; Han, J.H. . Coll. of Veterinary Medicine; Kim, K.S.

Effects of nitrate on thyroid function in rabbits

1989

Kim, J.S. | Han, J.H. (Chonbuk National Univ., Chonju (Korea R.). Coll. of Veterinary Medicine) | Kim, K.S. (Kimje Agricultural High School, Kimje (Korea R.))

The present study was carried out to investigate the effects of nitrate (KNO3) on the thyroid glands in rabbits which were administrated KNO3 of 1g/kg/day for 6 weeks. Growth rate, and serum levels for T4, T3 and TSH were observed every week. The histological changes and the weights of the thyroid glands were observed in 6 weeks. 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. The serum levels for T4 of the experimental group manifested significantly decreased values than those of control through the experimental term consistently and the serum levels for T3 were greatly decreased in the 3rd and 4th weeks. TSH contents of the serum were not changed through the experimental term. The mean weight of the thyroid gland in the experiment was decreased significantly after 6 weeks compared with that of cotrol. 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

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