Mammalian protein found in humans
PTH Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 1BWX , 1ET1 , 1FVY , 1HPH , 1HPY , 1HTH , 1ZWA , 1ZWB , 1ZWD , 1ZWE , 1ZWF , 1ZWG , 2L1X , 3C4M
Identifiers Aliases PTH , PTH1, parathyroid hormone, Parathyroid hormone, FIH1External IDs OMIM : 168450 ; MGI : 97799 ; HomoloGene : 266 ; GeneCards : PTH ; OMA :PTH - orthologs Wikidata
Parathyroid hormone (PTH ), also known as parathormone or parathyrin , is a peptide hormone secreted by the parathyroid glands . It plays a critical role in regulating serum calcium and phosphate levels through its actions on bone , kidneys , and the small intestine . PTH increases serum calcium levels and is opposed by calcitonin . It also promotes the synthesis of calcitriol , the active form of vitamin D .[ 5]
PTH is secreted in response to low blood serum calcium (Ca2+ ) levels and is a key regulator of bone remodeling , the continuous process of bone resorption and formation. PTH indirectly stimulates osteoclast activity, promoting the release of calcium from the bone matrix to restore serum calcium levels. The bones serve as a reservoir of calcium, releasing it as needed to maintain homeostasis in the face of fluctuating metabolism , stress , and nutritional status.
Produced primarily by the chief cells of the parathyroid glands, PTH is a polypeptide prohormone consisting of 84 amino acids and has a molecular mass of approximately 9500 Da . Its gene is located on chromosome 11 .[ 6]
PTH exerts its biological effects via two main receptors. The Parathyroid hormone 1 receptor , activated by the 34 N-terminal amino acids of PTH, is highly expressed in bone and kidney cells. The Parathyroid hormone 2 receptor is predominantly found in the central nervous system , pancreas , testes , and placenta .[ 7] The hormone has a short half-life of approximately 4 minutes.[ 8] Dysregulation of PTH secretion, as seen in conditions like hypoparathyroidism , hyperparathyroidism , and paraneoplastic syndromes , can result in bone disease , hypocalcemia , or hypercalcemia .
^ a b c GRCh38: Ensembl release 89: ENSG00000152266 – Ensembl , May 2017
^ a b c GRCm38: Ensembl release 89: ENSMUSG00000059077 – Ensembl , May 2017
^ "Human PubMed Reference:" . National Center for Biotechnology Information, U.S. National Library of Medicine .
^ "Mouse PubMed Reference:" . National Center for Biotechnology Information, U.S. National Library of Medicine .
^ Khan M, Jose A, Sharma S (29 October 2022). "Physiology, Parathyroid Hormone" . StatPearls . Treasure Island (FL): StatPearls Publishing. PMID 29763115 . Retrieved 8 April 2025 .
^ Brewer HB, Fairwell T, Ronan R, Sizemore GW, Arnaud CD (1972). "Human parathyroid hormone: amino-acid sequence of the amino-terminal residues 1-34" . Proceedings of the National Academy of Sciences of the United States of America . 69 (12): 3585– 8. Bibcode :1972PNAS...69.3585B . doi :10.1073/pnas.69.12.3585 . PMC 389826 . PMID 4509319 .
^ Nosek TM. "Section 5/5ch6/s5ch6_11" . Essentials of Human Physiology . Archived from the original on 24 March 2016.
^ Bieglmayer C, Prager G, Niederle B (October 2002). "Kinetic analyses of parathyroid hormone clearance as measured by three rapid immunoassays during parathyroidectomy" . Clinical Chemistry . 48 (10): 1731– 8. doi :10.1093/clinchem/48.10.1731 . PMID 12324490 . Archived from the original on 7 June 2011. Retrieved 23 February 2009 .