[Thyroid homeostasis in animals with iodine deficiency]

The content of total iodine, its hormonal and nonhormonal fractions as well the level of protein-bound iodine in blood and basic tissue targets in representatives of 4 classes of animals: Esox lucius L., Rana esculenta, Streptopelia decaocto Priv., Lepus europaeus Pall. inhabiting the mountain regions with iodine deficiency in environment and in the lowlands of Transcarpathia with higher iodine provision have been investigated. A considerable decrease of general and hormone iodine level in the animal tissues of the mountain area accompanied by the suppression of the thyroid function has been stated. The utilization of thyroid hormones under the iodine deficiency condition is increased in the majority of cases and the level of protein-bound iodine is lowered that testifies to the transition of animal organism in the iodine-deficient areas to the lower level of thyroid homeostasis.