TSH R (Thyroid Stimulating Hormone Receptor) confers responsiveness to the endocrine hormones Thyrotropin/TSH and Thyrostimulin. TSH is produced by the anterior pituitary and triggers the thyroid gland to release thyroxine (T4). T4 is then converted to triiodothyronine (T3) which exerts wide-ranging effects on growth and metabolism. The heterodimeric TSH R is primarily expressed by epithelial cells of the thyroid (thyrocytes). TSH R is the dominant target of autoreactive agonistic antibodies in Gravesâ disease but is a more rare target in Hashimotoâs thyroiditis. The activation of TSH R in brown adipose tissue can trigger the upregulation of UCP-1 as well as thermogenesis.