Lipotropinis the name for twohormonesproduced by the cleavage ofpro-opiomelanocortin(POMC). Theanterior pituitary glandproduces thepro-hormonePOMC, which is then cleaved again to formadrenocorticotropin(ACTH) and β-lipotropin (β-LPH).
| pro-opiomelanocortin | |||||||
|---|---|---|---|---|---|---|---|
| Identifiers | |||||||
| Symbol | POMC | ||||||
| NCBI gene | 5443 | ||||||
| HGNC | 9201 | ||||||
| OMIM | 176830 | ||||||
| RefSeq | NM_000939 | ||||||
| UniProt | P01189 | ||||||
| Other data | |||||||
| Locus | Chr. 2p23 | ||||||
| |||||||
β-Lipotropin
editβ-Lipotropin is a 90-amino acidpolypeptidethat is thecarboxy-terminalfragment of POMC. It was initially reported to stimulatemelanocytesto producemelanin.It was also reported to perform lipid-mobilizing functions such aslipolysis[1]andsteroidogenesis.However, no subsequent studies have been published that support these early findings and no receptor has been identified for β-lipotropin.
β-Lipotropin can be cleaved into smaller peptides. In humans, γ-lipotropin,β-MSH,andβ-endorphin,are all possible fragments of β-lipotropin.[2]β-endorphin is the predominant opioid of the anterior human and rat pituitary gland. Birdsall and Hulme demonstrated that the C-fragment of lipotropin (β-endorphin) has a high affinity for opiate receptors in the brain, and the binding was reversed by naloxone, a classical antagonist of the opiates (Bradbury et al. 1976a). Alongside this, Feldberg found that β-endorphin administered in cat ventricles was 100 times more potent than morphine as an analgesic agent (Feldberg & Smyth 1976, 1977) and the analgesia persisted for several hours. Feldberg concluded that β-endorphin was the most potent analgesic agent known. β-Lipotropin is found in essentially equimolar concentrations to that ofcorticotropin.Evidence shows that β-Lipotropin is metabolized intoendorphinsthat can greatly affect mood and behavior and is thus regarded as aprohormone.[3]
γ-Lipotropin
editγ-lipotropin is theamino-terminalpeptide fragment of β-lipotropin. In humans, it has 56 amino acids. Gamma lipotropin is identical to the first 56 amino acid sequences of β-lipotropin. It can be cleaved toβ-melanocyte stimulating hormone.
In sheep, gamma-lipotropic hormone is a 58-amino-acid long pituitary polypeptide formed from the first 58 residues of beta-lipotropic hormone. Thecarboxyl-terminalof gamma-lipotropic hormone is identical to the structure of beta-melanophore-stimulating hormone.[4]
Use in pain relief
editβ-endorphin has been determined to have an analgesic effect. It produces effects similar to or characteristic of morphine.[5]
Use in sport
editLipotropin is on the Prohibited List of substances by the World Anti Doping Agency.[6]Lipotropin has also, under its alternate name AOD-9604 (Anti-Obesity Drug-9604),[7]been connected with controversies inAustralian Rules Football.Allegations have arisen around the use of the drug and its administration to players of theEssendon Football Clubin theEssendon Football Club supplements saga,including weekly administration to players in the 2012 season.[8]The matters are currently under investigation due to the relationship between Lipotropin and growth hormones, as noted by club medical staff.[9]
Clinical trials
editIn 2020 AOD-9604 underwent clinical trials into its use for the treatment of pain.[10]
References
edit- ^Li CH, Chung D (April 1976)."Isolation and structure of an untriakontapeptide with opiate activity from camel pituitary glands".Proceedings of the National Academy of Sciences of the United States of America.73(4): 1145–8.Bibcode:1976PNAS...73.1145L.doi:10.1073/pnas.73.4.1145.PMC430217.PMID1063395.
- ^Spiess J, Mount CD, Nicholson WE, Orth DN (August 1982)."NH2-terminal amino acid sequence and peptide mapping of purified human beta-lipotropin: comparison with previously proposed sequences".Proceedings of the National Academy of Sciences of the United States of America.79(16): 5071–5.Bibcode:1982PNAS...79.5071S.doi:10.1073/pnas.79.16.5071.PMC346829.PMID6956916.
- ^Lazarus LH, Ling N, Guillemin R (June 1976)."beta-Lipotropin as a prohormone for the morphinomimetic peptides endorphins and enkephalins".Proceedings of the National Academy of Sciences of the United States of America.73(6): 2156–9.Bibcode:1976PNAS...73.2156L.doi:10.1073/pnas.73.6.2156.PMC430469.PMID1064883.
- ^Chrétien M, Lis M, Gilardeau C, Benjannet S (June 1976). "In vitro biosynthesis of gamma-lipotropic hormone".Canadian Journal of Biochemistry.54(6): 566–570.doi:10.1139/o76-083.PMID1276982.
- ^Smyth DG (2016-05-01)."60 YEARS OF POMC: Lipotropin and beta-endorphin: a perspective".Journal of Molecular Endocrinology.56(4): T13–T25.doi:10.1530/JME-16-0033.ISSN1479-6813.PMID26903509.
- ^"The Prohibited List".World Anti Doping Agency.Retrieved2023-11-15.
- ^Peptides Direct information page, accessed 26 August 2013
- ^Le Grand C (2016).The straight dope: the inside story of sport's biggest drug scandal(Updated full story ed.). Carlton, Victoria.ISBN978-0-522-87028-2.OCLC942533247.
{{cite book}}:CS1 maint: location missing publisher (link) - ^Dillon A (13 August 2013)."Statement of Charges against James Hird and Essendon Football Club"(PDF).Australian Football League.Archived fromthe original(PDF)on 2013-09-03.Retrieved26 August2013.
- ^"Lateral Pharma | LAT8881".Retrieved2021-03-27.
External links
edit- beta-Lipotropinat the U.S. National Library of MedicineMedical Subject Headings(MeSH)
- gamma-Lipotropinat the U.S. National Library of MedicineMedical Subject Headings(MeSH)
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