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

Cognition and psychological wellbeing in hypopituitary patients

Hypopituitarism (HP) frequently occurs in patients presenting with sellar masses and despite recent advances in therapeutic options, HP patients consistently suffer from impaired quality of life due to psychological distress and cognitive dysfunction. These neurocognitive complications tend to persist in spite of surgical or biochemical remission of the disease making it especially challenging to segregate the effect of HP per se from other comorbidities such as the effect of tumour, surgery, radiation therapy, or complications caused by excess hormone production. Regardless, there is ample evidence to suggest that receptors for various pituitary hormones are abundantly expressed in key areas of central nervous system that are associated with memory and behaviour function and HP is also associated with poor sleep which can further exacerbate neurocognitive dysfunction. There is also evidence that hormonal replacement in HP patients partially restores these neurocognitive functions and improves sleep disorders. However, there is a need for creating better awareness among healthcare providers interacting with HP patients to enhance an earlier recognition of these disorder and their impact on quality of life despite initial remission. Importantly, there is a need to not only develop better and more cost-effective replacement therapies that would closely mimic the physiological hormonal release patterns, but also develop coping strategies for HP patients suffering from these complications.

The Mysterious Universe of the TSH Receptor

The thyroid-stimulating hormone receptor (TSH-R) is predominantly expressed in the basolateral membrane of thyrocytes, where it stimulates almost every aspect of their metabolism. Several extrathyroidal locations of the receptor have been found including: the pituitary, the hypothalamus, and other areas of the central nervous system; the periorbital tissue; the skin; the kidney; the adrenal; the liver; the immune system cells; blood cells and vascular tissues; the adipose tissue; the cardiac and skeletal muscles, and the bone. Although the functionality of the receptor has been demonstrated in most of these tissues, its physiological importance is still a matter of debate. A contribution to several pathological processes is evident in some cases, as is the case of Grave's disease in its multiple presentations. Conversely, in the context of other thyroid abnormalities, the contribution of the TSH-R and its ligand is still a matter of debate. This article reviews the several different sites of expression of the TSH-R and its potential role in both physiological and pathological processes.