Alterations of Thyroid Morphology and Function After Long-Term Exposure to Low Doses of Endocrine Disruptor Dichlorodiphenyltrichloroethane

The aim of the investigation was to evaluate changes in thyroid morphology and function after different long-term exposure to low doses of endocrine disruptor dichlorodiphenyltrichloroethane (DDT) under the maximum permissible levels in food products.

Materials and Methods. The experiment was performed on adult male Wistar rats (n=62). Drinking water was substituted for water solution of o,p-DDT 20 and 80 μg/L. Mean daily consumption of DDT was 1.89±0.86 and 7.77±0.17 µg/kg body weight, respectively. Rat serum thyroid hormone content and histology of the thyroid glands were studied after 6 and 10 weeks of exposure to DDT.

Results. 6-week exposure to DDT caused inhibition of thyroid function followed by reactive increase of thyroid stimulating hormone secretion and triiodothyronine production. These symptoms were similar to those of the early stage of iodine deficiency. Restoration of rat thyroid status after 10 weeks of exposure was achieved due to diffuse microfollicular transformation of thyroid parenchyma.

Conclusion. Exposure to low doses of DDT inhibits thyroid function. Reactive increase of thyroid hormone production after exposure to DDT and in iodine deficiency is similar, but early changes in thyroid histology are different. Long-term exposure to DDT is supposed to aggravate iodine deficiency and to be a risk factor of thyroid tumors.

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Yaglov V.V., Yaglova N.V. Alterations of Thyroid Morphology and Function After Long-Term Exposure to Low Doses of Endocrine Disruptor Dichlorodiphenyltrichloroethane. Sovremennye tehnologii v medicine 2014; 6(4): 55