Lipotropin

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pro-opiomelanocortin
Identifiers
Symbol POMC
Entrez 5443
HUGO 9201
OMIM 176830
RefSeq NM_000939
UniProt P01189
Other data
Locus Chr. 2 p23

Lipotropin is a hormone produced by the cleavage of pro-opiomelanocortin (POMC). The anterior pituitary gland produces the pro-hormone POMC, which is then cleaved again to form adrenocorticotropin (ACTH) and β-lipotropin (β-LPH).

β-Lipotropin[edit]

β-Lipotropin is a 90-amino acid polypeptide that is the carboxy-terminal fragment of POMC. It was initially reported to stimulate melanocytes to produce melanin. It was also reported to perform lipid-mobilizing functions such as lipolysis[1] and steroidogenesis. 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, and β-endorphin, are all possible fragments of β-lipotropin.[2] β-Lipotropin is the predominant opioid of the anterior human and rat pituitary gland. It is found in essentially equimolar concentrations to that of corticotropin. Evidence shows that β-Lipotropin is metabolized into endorphins that can greatly affect mood and behavior and is thus regarded as a prohormone.[3]

γ-Lipotropin[edit]

γ-lipotropin is the amino-terminal peptide 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 to β-melanocyte stimulating hormone.

Use in sport[edit]

Lipotropin has also, under its alternate name AOD-9604 (Anti-Obesity Drug-9604),[4] been connected with controversies in Australian Rules Football. Allegations have arisen around the use of the drug and its administration to players of the Essendon Football Club as a supplement, including weekly administration to players in the 2012 season. The matters are currently under investigation due to the relationship between Lipotropin and growth hormones, as noted by club medical staff.[5]

References[edit]

  1. ^ 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. PMC 430217Freely accessible. PMID 1063395. 
  2. ^ Joachim Spiess; Charles D. Mount; Wendell E. Nicholson; David N. Orth (1982), "NH2-Terminal amino acid sequence and peptide mapping of purified human β-lipotropin: Comparison with previously proposed sequences", Proc. Natl. Acad. Sci. USA, 79 (16): 5071–5, Bibcode:1982PNAS...79.5071S, doi:10.1073/pnas.79.16.5071, PMC 346829Freely accessible, PMID 6956916 
  3. ^ 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. PMC 430469Freely accessible. PMID 1064883. 
  4. ^ Peptides Direct information page, accessed 26 August 2013
  5. ^ AFL Statement of Charges against James Hird and Essendon Football Club, accessed 26 August 2013 [1]

External links[edit]