Making sense with thyroid hormone--the role of T3 in auditory development.

The senses are our window to the world, our interface with the habitat in which we live in and the basis for our communication with each other. Although sensory systems are not generally viewed as major targets of endocrine regulation, sensory development is profoundly influenced by thyroid hormone (T3) signalling. In this article, we discuss this developmental role of T3 and highlight the auditory system as the best-studied example of the interplay between systemic and local tissue mechanisms by which T3 stimulates the onset of sensory function. Several genes that mediate the action of T3 are known to promote sensory development in mice, including genes that encode T3 receptors and deiodinase enzymes that amplify or deplete levels of T3. We also discuss the current knowledge of sensory defects in human genetic disorders in which T3 signalling is impaired. As sensory input provides the only means of acquiring information from the environment, the stimulation of sensory development is one of the most fundamental functions of T3 signalling. [ABSTRACT FROM AUTHOR]