TSH is a member of the glycoprotein hormone family, constituting a subset of the cystine-knot growth factor superfamily. TSH is produced by the pituitary thyrotrophs and released into circulation in a pulsatile manner. It stimulates thyroid functions using a specific membrane TSH receptor (TSHR) that belongs to the superfamily of G protein-coupled receptors (GPCRs). TSH beta is the beta subunit of thyroid stimulating hormone. This TSH antibody labels normal and neoplastic thyrotropic cells. It may be useful in classification of pituitary tumors.