TSH beta/CGa

TSH (thyroid stimulating hormone), also known as thyrotropin, is a member of the cystine knot growth factor superfamily. It is a heterodimer of a 15 kDa unique subunit, TSH beta, with a 14 kDa alpha subunit, CGa (common glycoprotein hormone alpha) that is shared with lutropin (LH), follitropin (FSH) and chorionic gonadotropin (CG). Production of TSH by the anterior pituitary gland is stimulated by the hypothalamic peptide TRH, and inhibited by feedback from the thyroid hormones triiodothyronine (T3) and thyroxine (T4). Studies in the mouse identify bone marrow as a secondary site of TSH production.