[Thyroid hormone metabolism and the functional activity of the thyroid gland in mother and fetus].

The functional activity of the thyroid glands of the pregnant rats and their foetuses prior to the birth and the deiodizing ability of the liver of the mother and the foetus on the 18-th day of pregnancy were studied. The reliable differences were shown between the levels of protein bound iodine in the blood serum of the pregnant rats as compared with the control ones, as well as the high content of thyroid hormones in the blood serum of the foetuses. The process of thyroxin and diiodothyrosine deiodizing in the foetal liver was more active than in the mother. The results obtained suggest the increase of functional activity of the thyroid gland in the mother by the end of pregnancy and the presence of such an activity in the foetus, as well as the high activity of the deiodizing system in the foetal liver during the last days of prenatal development.