Cellular and molecular distribution of thyroid-specific proteins, thyroid-stimulating hormone receptor (TSH-R) and thyroglobulin (TG) in the central nervous system

The widespread extra-thyroidal localisation of thyroid-specific proteins, thyroid-stimulating hormone receptor (TSH-R) and thyroglobulin (TG), has been well documented. However, more recent years has seen the focus of this research area shift to the distribution of these thyroid-specific proteins, in the central nervous system (CNS). This is largely attributed to the well-known associations between thyroid auto-immunity and neuro-psychiatric disorders. Although these associations have not yet been well defined, there are several studies that demonstrate the presence of TSH-R and TG proteins in CNS regions and its cellular structures. In addition, there is an emerging body of evidence to describe the potential functional roles of these thyroid proteins in various regions of the CNS. In this review, the neural distribution of TSH-R and TG as well as their possible physiological implications in various regions of human and non-human brain is discussed.