N-acetylation and C-terminal proteolysis of beta-endorphin in the anterior lobe of the horse pituitary.
Abstract: beta-Endorphin is post-translationally processed to both N-acetylated and C-terminally shortened derivatives in the anterior lobe of the horse pituitary, a processing pattern qualitatively different from that of the rat and virtually every other mammalian species. Thus, separation of the molecular forms of beta-endorphin using gel filtration and ion exchange chromatography showed that the horse anterior lobe primarily contains beta-endorphin-1-31 and N-acetyl-beta-endorphin-1-27 along with smaller amounts of beta-lipotropin, beta-endorphin-1-27, and N-acetyl-beta-endorphin-1-31 and -1-26, in contrast to the rat anterior lobe, which contains approximately equal amounts of beta-lipotropin and beta-endorphin-1-31. Immunohistochemical experiments using an antiserum which specifically recognizes N-acetylated beta-endorphin peptides confirmed that N-acetyl-beta-endorphin immunoreactivity is present in the anterior lobe of the horse, but not the rat. The intermediate lobe of both species primarily synthesizes N-acetylated, C-terminally shortened beta-endorphin peptides, and while distinct species differences do occur, they were relatively minor, consisting of quantitative differences in the relative proportion of each peptide. These results are consistent with earlier reports that beta-endorphin processing in the rat pituitary is tissue specific; the anterior and intermediate lobes produce entirely different sets of beta-endorphin peptides. In the equine pituitary, however, both pituitary lobes produce the same multiple beta-endorphin forms, possessing both opioid and nonopioid properties, although their relative amounts differ.
Publication Date: 1992-02-01 PubMed ID: 1601261DOI: 10.1016/0016-6480(92)90014-bGoogle Scholar: Lookup
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- Comparative Study
- Journal Article
- Research Support
- Non-U.S. Gov't
- Research Support
- U.S. Gov't
- Non-P.H.S.
- Research Support
- U.S. Gov't
- P.H.S.
Summary
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The research article presents an in-depth study on the post-translational processing of beta-endorphin in the anterior lobe of the horse pituitary. The researchers discovered that the processing pattern in horses shows a qualitative difference when compared to rats or other mammals.
Post-translational Processing of Beta-Endorphin
- The research paper revolves around the study of beta-Endorphin, a peptide hormone. This hormone undergoes ‘post-translational processing’—modifications after protein synthesis—in the anterior lobe of the horse pituitary.
- Two primary processes followed in horses are N-acetylation and C-terminal proteolysis, leading to the generation of N-acetylated and C-terminally shortened derivatives of beta-endorphin.
Difference in Processing Pattern with Other Species
- The researchers noted a unique processing pattern that is qualitatively different from other mammalian species and, specifically, the rat.
- Studies using gel filtration and ion exchange chromatography show that the horse anterior lobe primarily contains beta-endorphin-1-31 and N-acetyl-beta-endorphin-1-27. Only smaller amounts of other variants were found in the horse pituitary, unlike the rat anterior lobe that contains equal amounts of beta-lipotropin and beta-endorphin-1-31.
Immunohistochemical Experiments
- In order to verify these findings, immunohistochemical experiments were carried out using antisera that can specifically recognize N-acetylated beta-endorphins.
- Advancing the study, it was confirmed that N-acetyl-beta-endorphin is present in the horse’s anterior lobe, but not in the rat.
May Lead to Multiple Beta-Endorphin Forms
- Apart from different processing pattern in various species, the presence of N-acetylated, C-terminally shortened beta-endorphin peptides indicates that both species primarily synthesize these peptides in their intermediate lobes, even though the proportion varies.
- In equine pituitary, both the anterior and intermediate lobes produce multiple beta-endorphin forms, which possess both opioid and nonopioid properties, although their relative amounts differ.
Cite This Article
APA
Millington WR, Dybdal NO, Mueller GP, Chronwall BM.
(1992).
N-acetylation and C-terminal proteolysis of beta-endorphin in the anterior lobe of the horse pituitary.
Gen Comp Endocrinol, 85(2), 297-307.
https://doi.org/10.1016/0016-6480(92)90014-b Publication
Researcher Affiliations
- School of Basic Life Sciences, University of Missouri, Kansas City 64108.
MeSH Terms
- Acetylation
- Animals
- Chromatography, Gel
- Chromatography, Ion Exchange
- Horses / metabolism
- Immunoenzyme Techniques
- Male
- Pituitary Hormones, Anterior / metabolism
- Protein Processing, Post-Translational / physiology
- Radioimmunoassay
- Rats
- Rats, Inbred Strains
- Species Specificity
- beta-Endorphin / metabolism
Grant Funding
- DA04598 / NIDA NIH HHS
- NS28019 / NINDS NIH HHS
Citations
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