Melanokortin

Šablon:POMC Melanokortini su grupa peptidnih hormona koji uključuju adrenokortikotropni hormon (ACTH) i različite oblike melanocit-stimulirajućeg hormona (MSH),^[1] a izvedeni su iz proopiomelanokortina (POMC) u hipofizi.^[2] Melanokortini ostvaruju svoje efekte vezanjem i aktiviranjem melanokortinskih receptora.^[1]

Postoji pet receptora za melanokortin (MCR) i svi su G-protein spregnuti receptori. U mozgu se eksprimiraju samo MC3R i MC4R i njihov endogeni ligand je α-MSH. Agouti-srosni peptid (AgRP) je endogeni antagonist.^[3]

Derivati proopiomelanokortina

POMC
- γ-MSH
- ACTH
  - α-MSH
  - CLIP
- β-lipotropin
  - γ-lipotropin
  - β-endorfin
- β-MSH

Funkcija

Sistem melanokortina jedan je od alata organizma sisara koji na dvotaktni način regulira unos hrane.^[4] Jedini neuroni za koje je poznato da oslobađaju melanokortine nalaze se u lučnom jezgru hipotalamusa. U skladu s tim, postoji subpopulacija neurona koja se naziva POMC i ona koja se naziva AgRP neuroni.^[5] Kada POMC neuroni oslobode α-MSH, apetit se smanjuje. S druge strane, oslobađanje AgRP u AgRP neuronima, stimulira se apetit.

Leptin, hormon viška energije i grelin, hormon gladi, uzvodni su regulatori sistema melanokortina u mozgu.^[5] Ovi hormoni također regulišu oslobađanje peptida koji nisu melanokortini. Poremećaj puta leptin-melanokortin može dovesti do gojaznosti s ranim početkom, kao i do različitih metaboličkih poremećaja i potiskanja imunske funkcije.^[6]

Reference

^ ^a ^b Gantz I, Fong TM (mart 2003). "The melanocortin system". American Journal of Physiology. Endocrinology and Metabolism. 284 (3): E468–74. doi:10.1152/ajpendo.00434.2002. PMID 12556347.
^ Raffin-Sanson ML, de Keyzer Y, Bertagna X (august 2003). "Proopiomelanocortin, a polypeptide precursor with multiple functions: from physiology to pathological conditions". European Journal of Endocrinology. 149 (2): 79–90. doi:10.1530/eje.0.1490079. PMID 12887283.
^ Yoon YR, Baik JH (decembar 2015). "Melanocortin 4 Receptor and Dopamine D2 Receptor Expression in Brain Areas Involved in Food Intake". Endocrinology and Metabolism (jezik: English). 30 (4): 576–83. doi:10.3803/enm.2015.30.4.576. PMC 4722414. PMID 26790386.CS1 održavanje: nepoznati jezik (link)
^ Zhou Y, Rui L (juni 2013). "Leptin signaling and leptin resistance". Frontiers of Medicine. 7 (2): 207–22. doi:10.1007/s11684-013-0263-5. PMC 4069066. PMID 23580174.
^ ^a ^b Klok MD, Jakobsdottir S, Drent ML (januar 2007). "The role of leptin and ghrelin in the regulation of food intake and body weight in humans: a review". Obesity Reviews. 8 (1): 21–34. doi:10.1111/j.1467-789x.2006.00270.x. PMID 17212793.
^ Nunziata A, Borck G, Funcke JB, Kohlsdorf K, Brandt S, Hinney A, Moepps B, Gierschik P, Debatin KM, Fischer-Posovszky P, Wabitsch M (novembar 2017). "Estimated prevalence of potentially damaging variants in the leptin gene". Molecular and Cellular Pediatrics. 4 (1): 10. doi:10.1186/s40348-017-0074-x. PMC 5670095. PMID 29101506.

Vanjski linkovi

Melanocortins na US National Library of Medicine Medical Subject Headings (MeSH)

Šablon:Neuropeptidi Šablon:Modulatori receptora melanokortina

[Gantz_2003-1] Gantz I, Fong TM (mart 2003). "The melanocortin system". American Journal of Physiology. Endocrinology and Metabolism. 284 (3): E468–74. doi:10.1152/ajpendo.00434.2002. PMID 12556347.

[2] Raffin-Sanson ML, de Keyzer Y, Bertagna X (august 2003). "Proopiomelanocortin, a polypeptide precursor with multiple functions: from physiology to pathological conditions". European Journal of Endocrinology. 149 (2): 79–90. doi:10.1530/eje.0.1490079. PMID 12887283.

[3] Yoon YR, Baik JH (decembar 2015). "Melanocortin 4 Receptor and Dopamine D2 Receptor Expression in Brain Areas Involved in Food Intake". Endocrinology and Metabolism (jezik: English). 30 (4): 576–83. doi:10.3803/enm.2015.30.4.576. PMC 4722414. PMID 26790386.CS1 održavanje: nepoznati jezik (link)

[4] Zhou Y, Rui L (juni 2013). "Leptin signaling and leptin resistance". Frontiers of Medicine. 7 (2): 207–22. doi:10.1007/s11684-013-0263-5. PMC 4069066. PMID 23580174.

[Klok_2007-5] Klok MD, Jakobsdottir S, Drent ML (januar 2007). "The role of leptin and ghrelin in the regulation of food intake and body weight in humans: a review". Obesity Reviews. 8 (1): 21–34. doi:10.1111/j.1467-789x.2006.00270.x. PMID 17212793.

[6] Nunziata A, Borck G, Funcke JB, Kohlsdorf K, Brandt S, Hinney A, Moepps B, Gierschik P, Debatin KM, Fischer-Posovszky P, Wabitsch M (novembar 2017). "Estimated prevalence of potentially damaging variants in the leptin gene". Molecular and Cellular Pediatrics. 4 (1): 10. doi:10.1186/s40348-017-0074-x. PMC 5670095. PMID 29101506.

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