TSH Recombinant Rabbit mAb (SDT-1595-21)

Thyroid-stimulating hormone (TSH) is a 28 kDa heterodimeric glycoprotein secreted by the anterior pituitary, composed of a common α-subunit (92 amino acids shared with LH, FSH, and hCG) and a unique β-subunit (118 amino acids) that confers specificity; it binds to the Gs-coupled TSH receptor on thyroid follicular cells to activate adenylyl cyclase, up-regulate iodine uptake, thyroglobulin iodination, and proteolysis, thereby stimulating synthesis and release of thyroxine (T4) and triiodothyronine (T3), and its circulating level is regulated by negative feedback from free T4/T3 and by hypothalamic TRH, making TSH the central sensor and effector of the hypothalamic–pituitary–thyroid axis. Therefore, TSH in the blood is a sensitive test reflecting the function of the hypothalamic-pituitary-thyroid axis, especially significant for the diagnosis of subclinical hyperthyroidism and subclinical hypothyroidism.