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'''پيراٿائرائڊ ھارمون'''{{ٻيا نالا|انگريزي= ''' Parathyroid hormone'''}}, مختصرن '''پي ٽي ايڇ'''('''PTH''') جن کي '''پيرٿارمون'''{{ٻيا نالا|انگريزي= '''parathormon '''}} يا '''پيراٿائرن'''{{ٻيا نالا|انگريزي= '''parathyrin '''}} به چوندا آهن، ھڪ ھارمون جو نالو آهي جيڪو [[پيراٿائرائڊ غدود]] خارج ڪندو آهي ۽ جيڪو ھڏن، بڪين ۽ آنڊي تي اثرانداز ٿي [[سيرم ڪيلشيم]] کي برقرار رکندو آهي.<ref name="pmid15180028">{{cite journal | vauthors = Coetzee M, Kruger MC | title = Osteoprotegerin-receptor activator of nuclear factor-kappaB ligand ratio: a new approach to osteoporosis treatment? | journal = Southern Medical Journal | volume = 97 | issue = 5 | pages = 506–11 | date = May 2004 | pmid = 15180028 | doi = 10.1097/00007611-200405000-00018 }}</ref> پي ٽي ايڇ رسيپٽر ٻن قسمن جا ھوندا آھن جن مان [[پيراٿائرائڊ ھارمون 1 رسيپٽر]] 34 اين - ٽرمينل پي ٽي ايڇ جا امينو ائسڊ بڪين ۽ ھڏن جي گھرڙن جي مٿئين سطح تي موجود ھوندا آھن. [[پيراٿائرائڊ ھارمون 2 رسيپٽر]] [[مرڪزي تنتي نظام]]، [[لبلبو|لبلبي]] ، آنورن ۽ [[اؤر]] جي گھرڙن جي مٿئين سطح تي موجود ھوندا آھن .<ref>{{GeorgiaPhysiology|5/5ch6/s5ch6_11}}</ref>پيراٿائرائڊ ھارمون جي اڌ عمر چئن منٽن جي لڳ ڀڳ ھوندي آھي. <ref name="pmid12324490">{{cite journal | vauthors = Bieglmayer C, Prager G, Niederle B | title = Kinetic analyses of parathyroid hormone clearance as measured by three rapid immunoassays during parathyroidectomy | journal = Clinical Chemistry | volume = 48 | issue = 10 | pages = 1731–8 | date = Oct 2002 | pmid = 12324490 | doi = | url = http://www.clinchem.org/cgi/content/abstract/48/10/1731 }}</ref>
==حوالا==
PTH influences [[bone remodeling]], which is an ongoing process in which [[bone tissue]] is alternately [[bone resorption|resorbed]] and [[ossification|rebuilt]] over time. PTH is secreted in response to low blood serum [[Calcium in biology|calcium]] (Ca<sup>2+</sup>) levels. PTH indirectly stimulates [[osteoclast]] activity within the bone matrix ([[osteon]]), in an effort to release more ionic calcium (Ca<sup>2+</sup>) into the blood to elevate a low serum calcium level. The [[bone]]s act as a (metaphorical) "[[bank]] of calcium" from which the body can make "withdrawals" as needed to keep [[calcium in biology#Measurement|the amount of calcium in the blood]] at appropriate [[concentration|levels]] despite the ever-present challenges of [[metabolism]], [[stress (biology)|stress]], and [[nutrition]]al variations. PTH is "a key that unlocks the bank vault" to remove the calcium.
PTH is secreted primarily by the [[parathyroid chief cell|chief cells]] of the parathyroid glands. It is a [[polypeptide]] containing 84 [[amino acids]], which is a [[prohormone]]. It has a molecular mass around 9500 [[Dalton (unit)|Da]].<ref name="pmid4509319">{{cite journal | vauthors = Brewer HB, Fairwell T, Ronan R, Sizemore GW, Arnaud CD | title = Human parathyroid hormone: amino-acid sequence of the amino-terminal residues 1-34 | journal = Proceedings of the National Academy of Sciences of the United States of America | volume = 69 | issue = 12 | pages = 3585–8 | year = 1972 | pmid = 4509319 | pmc = 389826 | doi = 10.1073/pnas.69.12.3585}}</ref> Its action is opposed by the hormone [[calcitonin]].
There are two types of PTH receptors. [[Parathyroid hormone 1 receptor]]s, 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 receptor]]s are present at high levels on the cells of central nervous system, pancreas, testes, and placenta.<ref>{{GeorgiaPhysiology|5/5ch6/s5ch6_11}}</ref> The half-life of PTH is about 4 minutes.<ref name="pmid12324490">{{cite journal | vauthors = Bieglmayer C, Prager G, Niederle B | title = Kinetic analyses of parathyroid hormone clearance as measured by three rapid immunoassays during parathyroidectomy | journal = Clinical Chemistry | volume = 48 | issue = 10 | pages = 1731–8 | date = Oct 2002 | pmid = 12324490 | doi = | url = http://www.clinchem.org/cgi/content/abstract/48/10/1731 }}</ref>
Disorders that yield too little or too much PTH, such as [[hypoparathyroidism]], [[hyperparathyroidism]], and [[paraneoplastic syndrome]]s can cause [[bone disease]], [[hypocalcaemia]], and [[hypercalcaemia]].
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