Growthhormoneplaysamajorroleinregulatinggrowthduringchildhoodandadolescenceandalsoregulatesmetabolism.Defectsingrowthhormonesignalingcanresultindwarfismanddecreasesingrowthhormonelevelswithagehavebeensuggestedtoplayaroleinthereducedfunctionofsomephysiologicalsystems.Growthhormonesignalsaresponseincellsthroughthegrowthhormonereceptor,amemberofthecytokinereceptorgenefamily.Growthhormonecausesthereceptortodimerize,activatingtheJAK2proteinkinase.TheactivityofJAK2mediatesmanyofthedownstreamresponsestogrowthhormonethroughphosphorylationofSTATtranscriptionfactors,MAPkinases,otherkinasecascadesandmoleculesinvolvedinmetabolismlikeIRS-1.FactorslikeSOCSandSHP-1appeartoplayaroleinthedownregulationofsignalingbygrowthhormoneandcytokines.

Contributor:GlennCroston,PhD.

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