Ghrelin
| Ghrelin | ||
|---|---|---|
|
||
| Preproghrelin with ghrelin (green) according to PDB 1P7X | ||
| Properties of human protein | ||
| Mass / length primary structure | 28 aa; 3.24 kD | |
| Precursor | Preproghrelin | |
| Isoforms | des-Gln14-ghrelin | |
| Identifier | ||
| Gene names | GHRL ; MTLRP; Ghrelin-28 | |
| External IDs | ||
| Occurrence | ||
| Homology family | HBG018522 | |
| Parent taxon | Euteleostomi | |
| Orthologue | ||
| human | mouse | |
| Entrez | 51738 | 58991 |
| Ensemble | ENSG00000157017 | ENSMUSG00000064177 |
| UniProt | Q9UBU3 | Q9EQX0 |
| Refseq (mRNA) | NM_016362 | NM_021488 |
| Refseq (protein) | NP_057446 | NP_067463 |
| Gene locus | Chr 3: 10.3 - 10.31 Mb | Chr 6: 113.68 - 113.69 Mb |
| PubMed search | 51738 |
58991
|
Ghrelin ( acronym , English G rowth H ormone Rel ease In ducing "growth hormone releasing introduction") is an appetizing peptide that in the gastric mucosa and the pancreas is produced. In addition to stimulating the appetite, the hormone has a number of other effects.
education
Ghrelin is mainly produced in the parietal cells in the epithelium of the gastric fundus , but also by the ε-cells of the pancreas and converted into the active form in a preliminary stage in the hypothalamus and pituitary gland and by splitting off some amino acids .
structure
Ghrelin is a peptide hormone , consisting of 28 amino acids, which is formed from the precursor protein preproghrelin (117 amino acids) through post-translational modification . At the same time, a molecule of obestatin is created . The third amino acid serine in ghrelin is esterified with octanoic acid . This modification is essential for the hormone to work. The molecular mass of the precursor is 12.91 kDa, that of ghrelin 3.24 kDa.
physiology
Ghrelin is a hormone that regulates food intake and the secretion of growth hormone . The level of ghrelin in the blood rises during periods of hunger and falls after a meal. Lack of sleep induces increased ghrelin secretion and in this way probably contributes to the development of obesity .
Other hormones that control the feeling of hunger or satiety are leptin , orexin and cortisol .
Effects
hunger
In the experiment , ghrelin infusions increase food intake. In the fasting state the ghrelin secretion is increased, after eating the ghrelin level decreases.
It stimulates the secretion of neuropeptide Y in the hypothalamus , which is known to increase food intake, and of agouti-related peptide hormones (AGRP) in the arcuate nucleus .
Most species of birds also have a functional gene (GHRL) that codes for ghrelin , but ghrelin inhibits feeding in birds. In a 2015 study it was also shown that the "ghrelin gene" is inoperable in saker falcons and peregrine falcons ; this ensures that hunting and feeding behavior is increased in these species.
Depression relief
In addition, ghrelin has a calming effect in the mouse experiment . A study from 2008 suggests the antidepressant effects of ghrelin and sheds light on the question of why chronic stress and depression can lead to obesity .
Associated with alcohol addiction
The hypothesis that ghrelin is partly responsible for the development of alcohol dependence was at least confirmed in the mouse experiment.
Growth hormone
Ghrelin is an endogenous ligand for a receptor that regulates the release of growth hormone in the pituitary gland. It binds to the GHS receptor ( Growth Hormone Secretagogue Receptor ) on special cells of the anterior pituitary gland ( acidophilic cells) and thus stimulates the release of growth hormone.
Pathophysiology
The rare Prader-Willi syndrome sometimes shows massive increases in ghrelin levels. It is characterized by a lack of satiety .
literature
- Cummings DE, Weigle DS, Frayo RS, et al. : Plasma ghrelin levels after diet-induced weight loss or gastric bypass surgery . In: N. Engl. J. Med. . 346, No. 21, May 2002, pp. 1623-30. doi : 10.1056 / NEJMoa012908 . PMID 12023994 .
- Garcia JM, Garcia-Touza M, Hijazi RA, et al. : Active ghrelin levels and active to total ghrelin ratio in cancer-induced cachexia . In: J. Clin. Endocrinol. Metab. . 90, No. 5, May 2005, pp. 2920-6. doi : 10.1210 / jc.2004-1788 . PMID 15713718 .
- Zhang JV, Ren PG, Avsian-Kretchmer O, et al. : Obestatin, a peptide encoded by the ghrelin gene, opposes ghrelin's effects on food intake . In: Science . 310, No. 5750, November 2005, pp. 996-9. doi : 10.1126 / science.1117255 . PMID 16284174 .
Individual evidence
- ↑ UniProt Q9UBU3
- ^ Yildiz BO, Suchard MA, Wong ML, McCann SM, Licinio J: Alterations in the dynamics of circulating ghrelin, adiponectin, and leptin in human obesity . In: Proc. Natl. Acad. Sci. USA . 101, No. 28, July 2004, pp. 10434-9. doi : 10.1073 / pnas.0403465101 . PMID 15231997 . PMC 478601 (free full text).
- ↑ Entry on Leptin in Flexikon , a wiki from DocCheck , accessed on November 26, 2015.
- ↑ Inge Seim, Penny L. Jeffery, Adrian C. Herington and Lisa K. Chopin: Comparative analysis reveals loss of the appetite-regulating peptide hormone ghrelin in falcons. In: General and comparative endocrinology. Volume 216, 2015, pp. 98-102, doi: 10.1016 / j.ygcen.2014.11.016 , PMID 25500363 .
- ↑ Hunger hormone drives away anxiety and depression - but makes you fat ( memento of the original from May 13, 2009 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. aerzteblatt.de
- ↑ Michael Lutter, Ichiro Sakata, Sherri Osborne-Lawrence, Sherry A Rovinsky, Jason G Anderson, Saendy Jung, Shari Birnbaum, Masashi Yanagisawa, Joel K Elmquist, Eric J Nestler, Jeffrey M Zigman: The orexigenic hormone ghrelin defends against depressive symptoms of chronic stress. In: Nature Neuroscience . 11, 2008, pp. 752-753, doi: 10.1038 / nn.2139 .
- ↑ Elisabet Jerlhag, Emil Egecioglu, Sara Landgren, Nicolas Salomé, Markus Heilig, Diederik Moechars, Rakesh Datta, Daniel Perrissoud, Suzanne L. Dickson, Jörgen A. Engel: Requirement of central ghrelin signaling for alcohol reward . In: Proc. Natl. Acad. Sci. USA . 106, No. 27, July 2009, pp. 11318-5. doi : 10.1073 / pnas.0812809106 .
- ↑ Kojima M, Hosoda H, Date Y, Nakazato M, Matsuo H, Kangawa K: Ghrelin is a growth-hormone-releasing acylated peptide from stomach . In: Nature . 402, No. 6762, December 1999, pp. 656-660. doi : 10.1038 / 45230 . PMID 10604470 . (Discovery and first publication on ghrelin).
