Thyroid hormone has numerous functions both in development and in adult homeostasis, the body’s ability to maintain internal stability. In humans, thyroid hormone abnormalities in development cause mental and physical retardation, whereas abnormalities in adulthood lead to other forms of impairment (for example, in metabolism and in cardiac function). Although thyroid hormone is known to produce powerful responses in the body, we do not fully understand how this happens. We use genetic approaches to clarify the mechanisms that control where, when, and how thyroid hormone acts. We also seek to uncover new functions for this hormone that are not yet known.
Thyroid hormone receptors are proteins in the cell nucleus that control how thyroid hormone produces a response. When thyroid hormone binds to the receptor triggers a change in the receptor, which allows it to switch on or off the expression of specific genes in the nucleus. Questions we address include the following:
- How do thyroid hormone receptors mediate specialized functions in different tissues?
- What is the role of deiodinase enzymes that control the availability of thyroid hormone in the development of different tissues?
- What role do other types of nuclear receptors, including retinoid-related orphan receptors, play in the developmental program in mammals?