γ-Endorphin (''gamma''-endorphin) is an
opioid peptide
Opioid peptides are peptides that bind to opioid receptors in the brain; opiates and opioids mimic the effect of these peptides. Such peptides may be produced by the body itself, for example endorphins. The effects of these peptides vary, but t ...
that is characterized by the presence of 17
amino acids. The first 16 amino acids are identical to
α-endorphin
α-Endorphin is an endogenous opioid peptide with a length of 16 amino acids, and the amino acid sequence: Tyr- Gly-Gly- Phe- Met- Thr- Ser- Glu- Lys-Ser- Gln-Thr- Pro- Leu- Val-Thr. With the use of mass spectrometry, Nicholas Ling was able to ...
;
leucine
Leucine (symbol Leu or L) is an essential amino acid that is used in the biosynthesis of proteins. Leucine is an α-amino acid, meaning it contains an α- amino group (which is in the protonated −NH3+ form under biological conditions), an α- ...
added at the end. In addition, γ-endorphin is identical to the first 17 amino acids of
β-endorphin
''beta''-Endorphin (β-endorphin) is an endogenous opioid neuropeptide and peptide hormone that is produced in certain neurons within the central nervous system and peripheral nervous system. It is one of three endorphins that are produced ...
. Similar to other
endorphins, research focusing upon γ-endorphin has been ongoing since its discovery in the 1970s. Yet, most of the information about the substance's exact role within the body is speculation that has yet to be proven. Some studies have indicated, however, that the polypeptide has antipsychotic effects on a certain category of patients with
schizophrenia
Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social wit ...
, while others suggest that γ-endorphin may act to help regulate
blood pressure. Further research is needed, but if γ-endorphin does indeed possess such characteristics, the substance could eventually be utilized as a useful means of medical treatment.
It has been hypothesized that γ-endorphin may play a role in substance abuse, as well a neurological problems. The DRD2 gene regulates dopamine to which any mutation in this gene can lead to neurological and psychological disorders. It has been shown in a that a lack of γ-endorphin ''
in utero
''In Utero'' is the third and final studio album by American rock band Nirvana. It was released on September 21, 1993, by DGC Records. After breaking into the mainstream with their second album, ''Nevermind'' (1991), Nirvana hired Steve Albin ...
'' leads to the DRD2-A2 allele over-expression. the DRD2-A1 allele increases the desire for alcohol and has been shown to be associated with a low γ-endorphin count. The argument of γ-endorphin relating to psychological issues is strong; however, more testing would need to be done to confirm this.
γ-Endorphin resides in the pituitary gland of humans, as well as in other animals such as rats. An experiment was preformed where two human pituitary glands where made available, and through various procedures like gel filtration chromatography and high-performance chromatography, 0.7 nmol of gamma-endorphin was found.
References
{{DEFAULTSORT:Endorphin, gamma-
Neuropeptides
Opioid peptides