Parathyroid hormone

Parathyroid hormone (PTH), also called parathormone or parathyrin, is a peptide hormone secreted by the parathyroid glands that regulates the serum calcium concentration through its effects on bone, kidney, and intestine.

PTH
Available structures
PDBOrtholog search: PDBe RCSB
Identifiers
AliasesPTH, PTH1, parathyroid hormone, Parathyroid hormone, FIH1
External IDsOMIM: 168450 MGI: 97799 HomoloGene: 266 GeneCards: PTH
Orthologs
SpeciesHumanMouse
Entrez

5741

19226

Ensembl

ENSG00000152266

ENSMUSG00000059077

UniProt

P01270

Q9Z0L6

RefSeq (mRNA)

NM_000315
NM_001316352

NM_020623

RefSeq (protein)

NP_000306
NP_001303281

NP_065648

Location (UCSC)Chr 11: 13.49 – 13.5 MbChr 7: 112.98 – 112.99 Mb
PubMed search
Wikidata
View/Edit HumanView/Edit Mouse

PTH influences bone remodeling, which is an ongoing process in which bone tissue is alternately resorbed and rebuilt over time. PTH is secreted in response to low blood serum calcium (Ca2+) levels. PTH indirectly stimulates osteoclast activity within the bone matrix (osteon), in an effort to release more ionic calcium (Ca2+) into the blood to elevate a low serum calcium level. The bones act as a (metaphorical) "bank of calcium" from which the body can make "withdrawals" as needed to keep the amount of calcium in the blood at appropriate levels despite the ever-present challenges of metabolism, stress, and nutritional variations. PTH is "a key that unlocks the bank vault" to remove the calcium.

PTH is secreted primarily by the chief cells of the parathyroid glands. The gene for PTH is located on chromosome 11. It is a polypeptide containing 84 amino acids, which is a prohormone. It has a molecular mass around 9500 Da. Its action is opposed by the hormone calcitonin.

There are two types of PTH receptors. Parathyroid hormone 1 receptors, activated by the 34 N-terminal amino acids of PTH, are present at high levels on the cells of bone and kidney. Parathyroid hormone 2 receptors are present at high levels on the cells of central nervous system, pancreas, testes, and placenta. The half-life of PTH is about 4 minutes.

Disorders that yield too little or too much PTH, such as hypoparathyroidism, hyperparathyroidism, and paraneoplastic syndromes can cause bone disease, hypocalcemia, and hypercalcemia.

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