Description
Thyroid-stimulating hormone (TSH orthyrotropin), produced in humanpituitary glands, has a molecular mass of25kD. An Important indicator of thyroid function, TSH is used to monitor thyroid associated diseases. Thyroid-stimulating hormone is a hormone synthesized and secreted by thyrotrope cells in the anterior pituitary gland which regulates the endocrine function of the thyroidgland. TSH stimulates the thyroid gland to secrete the hormones thyroxine (T4)and triiodothyronine (T3). TSH production is controlled by a Thyrotropin Releasing Hormone (TRH), which ismanufactured in the hypothalamus andtransported to the anterior pituitarygland, where it increases TSH productionand release. Somatostatin is also produced by the hypothalamus, and hasan opposite effect on the pituitary production of TSH, decreasing or inhibiting its release. The level of Thyroid hormones (T3 and T4) in the blood have an additional effect on the pituitary release of TSH. When the levels of T3 and T4 are low, the production of TSH is increased, and conversely, when levels of T3 and T4 are high, then TSH production is decreased. This effect creates a regulatory negative feedback loop. TSH is a glycoprotein and consists of two subunits, the alpha and the beta subunit. The alpha subunit is identical to that of human chorionicgonadotropin (HCG), luteinizing hormone(LH), follicle-stimulating hormone (FSH).The beta subunit is unique to TSH, and therefore determines its function. Structure and charge of the three N-linked carbohydrate chains influence activity; the most complex forms have lower activity but longer half life. Bovine and porcine TSH bind human TSH receptors (TSHR) with high affinity. he hypothalamic peptide TRH stimulates production and secretion of TSH by thyrotrophs (basophile cells) in the anterior pituitary gland. TSH travels tothyroid TSHR to stimulate production of thyroxine (T4). In the tissues, T4 is converted to the active form of thyroidhormone, triiodothyronine (T3), which completes a feedback loop by inhibiting TSH production. Studies in mouse identify bone marrow as a secondary site of TSH production. In bone, TSH signaling through TSHR on osteoblast and osteoclast precursors negatively regulates skeletal remodeling.
Description: DNA sequences encoding human TSH-a(Ala25-Ser116, UniProt Accession:P01215) and human TSH-b(Phe21-Val138, UniProt Accession:P01222) were co-expressed in Chinese Hamster Ovary cells