Thyroid Research is an online journal that aims to present the newest knowledge related to thyroid hormones, thyroid diseases and any related fields. The journal’s regular readership includes researchers, clinicians and healthcare providers across the world.
Thyroid Research encompasses a wide range of thyroidology topics including, diagnosis, pharmacological and other treatment methods, invasive treatment, physiological mechanisms of thyroid hormone action and regulation, immunological aspects, genetics, new guidelines in disease management, thyroid related diseases and complications.
Thyroid disease is common, affecting around 2% of women and 0.2% of men in the UK. Our understanding of the effects of thyroid hormones under physiological circumstances, as well as in pathological conditions, has increased dramatically during the last two centuries and it has become clear that overt thyroid dysfunction is associated with significant morbidity and mortality. Both hypo-and hyperthyroidism and their treatments have been linked with increased risk from cardiovascular disease and the adverse effects of thyrotoxicosis in terms of osteoporosis risk are well established. Although the evidence suggests that successful treatment of overt thyroid dysfunction significantly improves overall survival, the issue of treating mild or subclinical hyper- and hypothyroidism remains controversial. Furthermore, the now well-established effects of thyroid hormones on neurodevelopment have sparked a whole new debate regarding the need to screen pregnant women for thyroid function abnormalities. This review describes the current evidence of the effects of thyroid hormone on the cardiovascular, skeletal and neurological systems, as well as the influence of thyroid diseases and their treatments on the development of malignancy. Furthermore we will describe some recent developments in our understanding of the relationship between thyroid status and health.
Thyroid hormones are key regulators of metabolism and development and are known to have pleiotropic effects in many different organs. The thyroid gland synthesises and releases triiodothyronine (T3) and thyroxine (T4), which represent the only iodine-containing hormones in vertebrates. T4 is the main product of thyroid secretion and local deiodination in peripheral tissues produces T3, the biologically active thyroid hormone. T3 and T4 are bound to thyroglobulin, providing a matrix for their synthesis and a vehicle for their subsequent storage in the thyroid. More than 99% of the circulating T3 and T4 is protein bound, mainly to T4-binding globulin and to a lesser extent to transthyretin and albumin. Thyroid hormones can rapidly be released from these proteins, this process facilitating their entry into cells. The production of thyroid hormones is controlled by serum thyrotrophin (TSH) synthesised by the anterior pituitary gland in response to TSH-releasing hormone (TRH), which is secreted by the hypothalamus. Unbound or free T3 and T4 (fT3 and fT4 respectively) exert a negative feedback on the synthesis and release of TSH and TRH in order to maintain circulating thyroid hormone levels within the required range.