[Influence of congenital hypothyroidism on the developing rat brain and improvement after thyroid replacement...

On the basis of rat model of congenital hypothyroidism, the following problems were investigated: (1) The biochemical changes of DNA amount in cerebrum, and increase of DNA concentration & decline of protein/DNA in cerebellum. (2) The mitochondria ATPase activity of the cells in cerebral cortex was significantly diminished in hypothyroidism, suggesting that energy metabolism of brain was affected by thyroid hormone. (3) The serum T4 level of hypothyroid offsprings was markedly decreased with increase of serum TSH concentration, while the serum T3 content showed no change. However, 131I uptake rate of thyroid was elevated with peak ahead of time in hypothyroid rats. (4) All the hypothyroid rats were accompanied with delayed body weight growth and decreased weight of brain and several other organs. (5) After replacement therapy with thyroid all the indices mentioned above were improved.