Gonadotropin-oslobađajući hormon

Gonadotropin-oslobađajući hormon (GnRH) je hormon koji oslobađaju neuroni u hipotalamusu u sistemu krvnih sudova portalnog sistema u hipofizi. To je dekapeptid koji stimulra prednji režanj hipofize za oslobađanje gonadotropina (luteinizirajući hormon, LH i folikul-stimulirajući hormon, FSH).

GNRH1
Identifikatori
Aliasi	GNRH1
Vanjski ID-jevi	OMIM: 152760 MGI: 95789 HomoloGene: 641 GeneCards: GNRH1
Lokacija gena (čovjek) Hrom. Hromosom 8 (čovjek) Bend 8p21.2 Početak 25,419,258 bp Kraj 25,424,654 bp
Lokacija gena (miš) Hrom. Hromosom 14 (miš) Bend 14|14 D1 Početak 67,982,630 bp Kraj 67,986,888 bp
Obrazac RNK ekspresije Više referentnih podataka o ekspresiji
Ontologija gena Molekularna funkcija • hormone activity • gonadotropin hormone-releasing hormone activity • gonadotropin-releasing hormone receptor binding Ćelijska komponenta • axon terminus • perikaryon • Golgi-associated vesicle • extracellular region • neurosecretory vesicle • dendrit • mitohondrija • neuron projection • cytoplasmic side of rough endoplasmic reticulum membrane • Vanćelijsko Biološki proces • negative regulation of immature T cell proliferation • response to prolactin • negative regulation of neuron migration • response to potassium ion • GO:1904578 response to organic cyclic compound • response to testosterone • estrous cycle • female pregnancy • cell-cell signaling • response to steroid hormone • GO:0010260 Starenje • response to peptide hormone • negative regulation of apoptotic process • male sex determination • multicellular organism development • response to prostaglandin E • response to lipopolysaccharide • response to corticosteroid • Regulacija ekspresije gena • ovulation cycle • response to ethanol • regulation of ovarian follicle development • GO:0072468 Transdukcija signala • negative regulation of cell population proliferation • regulation of signaling receptor activity • G protein-coupled receptor signaling pathway • razmnožavanje Izvori:Amigo / QuickGO
Ortolozi
Vrste	Čovjek	Miš
Entrez	2796	14714
Ensembl	ENSG00000147437	ENSMUSG00000015812
UniProt	P01148	P13562
RefSeq (mRNK)	NM_001083111 NM_000825	NM_008145
RefSeq (bjelančevina)	NP_000816 NP_001076580	NP_032171
Lokacija (UCSC)	Chr 8: 25.42 – 25.42 Mb	Chr 14: 67.98 – 67.99 Mb
PubMed pretraga
Wikipodaci
Pogledaj/uredi – čovjek Pogledaj/uredi – miš

Struktura

Prekursor ovog hormona sadrži 92 aminokiseline. GnRH sastoji se od 10 aminokiselina: p Glu – His – Trp – Ser – Tyr – Gly – Leu – Arg – Pro – Gly · NH2.

Struktura i genetika GnRH

GNRH1 gen, prekursor GnRH, nalazi se na hromosomu 8. Kod sisara se linearni dekapeptid koji je konačni proizvod sintetizira iz prehormona 92 aminokiseline u preoptičkom dijelo prednjeg hipotalamusa

Identitet GnRH otkrili su 1977. Roger Guillemin i Andrew Schally, dobitnici Nobelove nagrade za fiziologiju ili medicinu:

piroGlu –His – Trp –Ser –Tyr – Gly – Leu – Arg –Pro –Gly CONH₂;

PiroGlu – Su –Trp –Ser –Tyr –Gly –Leu –Arg –Pro –Gly CONH₂.

Funkcija

Neuronska soma za izlučivanja GnRH nalaze se uglavnom u medijalnom dijelu prednjeg području preoptičkog dijela hipotalamusa i ispred zglobnog jezgra (infundibulski) i njegovi nervni završeci, raspodijeljeni su u obliku mreže prema srednjem uzvišenju, pored hipofizne drške.

Lučenje GnRH, kod svih kičmenjaka je neophosno za normalne spolne funkcije. Dakle, jedan hormon, GnRH1, kontrolira složen proces rasta folikula rasta, ovulacije, održavanje corpus luteum u ženki i spermatogeneze u mužjaka.

Postoje razlike u izlučivanju GnRH između žena i muškaraca. Kod muškaraca GnRH izlučuje se u impulsima konstantnom frekvencijom; međutim, kod žena frekvencija pulsa varira tokom menstrualnog ciklusa, a javlja se i velik porast GnRH neposredno prije ovulacije

GnRH se oslobađa na pulsilrajući, to jest naizmjenično, s razdobljima izlučivanja s razdobljima u kojima se hormon ne luči, iako se u preovulatornom periodu pojavljuje prividno kontinuirana razina proizvodnje.

Pulsativnoi obrazac izlučivanja GnRH ključan je u regulaciji ženskog spolnog ciklusa. Brzina pulsiranja luteinirajućeg hormona, koja vjerovatno odražava brzinu pulsa GnRH, u lutealnoj fazi je niska i maksimalno se povećava u folikulskoj i preovulacijskoj fazi

Razinu sekrecije hormona koji oslobađa gonadotropin (GnRH) regulira kispeptin proizveden u kispeptinskim neuronima, koji su zauzvrat regulirani nivoom spolnih steroida.

Medicinska upotreba

GnRH je dostupan u obliku gonadorelin-hidrohlorida (Factrel) za injekcijsku upotrebu. Koristi se putem sistema za perfuzijsku pumpu za indukciju ovulacije kod pacijenata sa hipotalamusnim hipogonadizmom.

Analog GnRH, leuprolid, koristi se kontinuiranom infuzijom za liječenje karcinoma dojke, endometrioze, [[karcinom prostate|karcinoma prostate i prijevremenog puberteta.

Također pogledajte

• Steroidni hormoni
• Hipotalamus

Dopunska literatura

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