Hormonal regulation of brain development I. The effect of neonatal thyroidectomy upon nucleic acids, protein and two enzymes in developing cerebral cortex and cerebellum of the rat

The changes in protein, nucleic acids, aspartate amino transferase, and aspartate transcarbamoylase during postnatal development of the cerebral cortex and cerebellum of the rat have been studied. With the exception of nucleic acids, the patterns of change are similar in both tissues. Neonatal thyroidectomy produced a significant increase in the DNA content of the cerebral cortex, but only slightly affected that of the cerebellum. This condition led to a substantial decrease of RNA and protein in both tissues. The lack of thyroid function from birth produced a marked depression of mitochondrial aspartate amino transferase, but did not affect the level of the soluble enzyme. This condition also led to a slight increase of cerebellar aspartate transcarbamoylase, but did not affect its level in the cerebral cortex.