Thyroid hormones and the brain - Commentary

Significant progress has been made over the past 2 decades toward understan ding the molecular basis of thyroid hormone action. It is now widely accept ed that thyroid hormones play predominantly a nuclear role and function by regulating the transcription of specific target genes. Understanding thyroi d hormone action at the tissue and organismic level requires assessment of the thyroid hormone response apparatus and identification of specific targe t genes. Progress toward uncovering the molecular basis of thyroid hormone action during mammalian brain development is advancing rapidly. This commen tary provides a brief overview of the molecular basis of thyroid hormone ac tion followed by three sections detailing thyroid hormone regulation of bra in development at the functional, cellular, and molecular levels. Each sect ion is followed by a discussion of unresolved issues and an analysis of our current level of understanding of each topic. (C) 2001 Academic Press.