Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Beta-endorphin-like immunoreactivity (beta-ELIR) blood levels in control subjects and in patients with different carcinoma and non-Hodgkin's lymphoma tumor types, were found within the same range, with the exception of one carcinoma type. This pertained to a group of patients with small cell lung cancer who had a significantly higher median beta-ELIR level compared to controls. This finding, and the fact that proopiomelanocortin expression is enhanced in tissues of this cancer type, suggest that the latter might secrete elevated beta-ELIR amounts into the blood of the affected patients.
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PMID:Beta-endorphin-like immunoreactivity: assessment of blood levels in patients with tumors of different origin. 180 94

Beta-endorphin is a peptide with morphine-like effects produced primarily in the anterior lobe of the pituitary gland. After its cleavage from the parent molecule, proopiomelanocortin, beta-endorphin is circulated via the blood stream to interact with specific opioid receptors located throughout the body. The peptide produces analgesia by inhibiting the firing of peripheral somatosensory fibers. It also affects other senses, such as vision, hearing, and smell. Whereas the ability to increase beta-endorphin secretion during times of surgical stress is positively correlated with amelioration of pain, the administration of exogenous opioids, such as fentanyl, reduces plasma beta-endorphin. Decreased beta-endorphin concentrations may play a role in trigeminal neuralgia, migraine headache, and rheumatoid arthritis.
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PMID:Peripheral beta-endorphin and pain modulation. 181 47

Plasma adrenocorticotropin (ACTH) levels increase after acute cold exposure. The purpose of this study was to determine if there were parallel changes in pituitary proopiomelanocortin (POMC) mRNA. Male rats were exposed to cold (3-5 degrees C) or a novel environment for 15 or 30 min. Others were unstressed. POMC mRNAs in frozen sections or dissociated cells were hybridized with a photobiotinylated oligonucleotide probe which was detected in situ by streptavidin-alkaline phosphatase. The percentage of area labeled for POMC mRNA was quantified by the Cue-3 color image analysis system. In frozen sections, 24-fold increases in the percentage of area labeled for POMC mRNA were evident in intermediate lobes (IL) 30 min after stress. No change was seen in anterior lobes (AL). If the ALs were dissociated, a 66-99% increase in percentage of labeled cells was detected 2-3 hr after the cold exposure. Fifteen min of cold stress (CS) also caused a 117% increase in the area of label for POMC mRNA per corticotrope. No change was seen after 30 min. Exposure to a novel environment caused a 73% increase in the percentage of area labeled for POMC mRNA per AL corticotrope and an 11-fold increase in the IL. These results indicate that both AL corticotropes and IL melanotropes are stimulated by acute exposure to cold and novel environments.
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PMID:Changes in rat pituitary POMC mRNA after exposure to cold or a novel environment, detected by in situ hybridization. 185 78

Many neuroendocrine precursor proteins, such as proopiomelanocortin (POMC), are cleaved in a tissue specific manner at distinct pairs of basic amino acids. Elucidating the specificity of the prohormone endoprotease(s) is essential to understanding cleavage specificity. However, isolation of these enzymes has been difficult, due to the inability to distinguish authentic maturation enzyme from the many other trypsin-like activities present in tissue homogenates. Recently, a "signature" of the insulin cell endoprotease(s) was defined in vivo by assessing the processing of a series of mutant cleavage sites in a model prohormone, mouse POMC (mPOMC) (Thorne, B. A., and Thomas, G. (1990) J. Biol. Chem. 265, 8436-8443. To investigate mechanisms of tissue-specific processing, we sought to identify the endoprotease signature of a cell having a processing phenotype distinct from insulinoma cells. In this report, the cleavage site specificity of the endoprotease(s) expressed in bovine adrenal chromaffin cells is examined. High levels of mPOMC (1.6 pmol/10(6) cells) were expressed in these cells using a vaccinia virus vector, and the precursor was targeted to the regulated secretory pathway. Analysis of POMC-derived peptides revealed that chromaffin cells processed the prohormone to a set of peptides highly similar to anterior pituitary corticotrophs, including adrenocorticotropin hormone (ACTH) and beta-lipotropin, gamma-lipotropin, and beta-endorphin. This processing contrasted with the pattern of cleavage site utilization in Rin m5F insulinoma cells, which more closely resembled that of the intermediate pituitary melanotrophs. However, the processing preference for the sequences of pairs of basic amino acids (as tested using the entire series of mutant cleavage sites; -LysArg- (native), -ArgArg-, -ArgLys-, -LysLys-, -HisArg-, -MetArg- at the ACTH/beta-lipotropin junction and -LysLys- (native), -LysArg-, -ArgArg-, -ArgLys- in beta-endorphin) was the same in both insulinoma and adrenal chromaffin cells, suggesting recognition and cleavage by similar enzymes in both cell types. The cell-specific processing of mPOMC may thus result from expression of a common core set of processing enzymes and factors unique to each cell type affecting the enzyme accessibility to precursor cleavage sites.
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PMID:Expression and processing of mouse proopiomelanocortin in bovine adrenal chromaffin cells. A model system to study tissue-specific prohormone processing. 185 97

We have combined gene cloning with an assay for prohormone biosynthesis and processing in Xenopus oocytes to identify the genes that encode mammalian prohormone processing enzymes. The coinjection of RNA encoding murine prohormone convertase 1 (mPC1), a mammalian endoprotease, along with proopiomelanocortin RNA into an oocyte results in the appropriate cleavage after paired basic residues in the proopiomelanocortin polyprotein necessary to generate corticotropin. The ability of mPC1 to generate corticotropin, along with the observation that mPC1 is specifically expressed in endocrine and neuronal cells, suggests that the mPC1 gene encodes the endopeptidase responsible for the pathway of proopiomelanocortin cleavage observed in the anterior pituitary.
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PMID:Isolation and functional expression of a mammalian prohormone processing enzyme, murine prohormone convertase 1. 186 7

Neurointermediate lobes (NILS) of the pituitary glands of adult male Sprague-Dawley rats were incubated in media in the presence of corticotropin-releasing factor (CRF), a stimulator of proopiomelanocortin (POMC) peptide release. Alpha-helical CRF, a peptide known to inhibit CRF induced POMC peptide release from the anterior pituitary, was incubated with NILS for a period of 90 min, to study its potential ability to modulate peptide release from the intermediate lobe. The alpha-helical peptide reduced beta-endorphin release from NILS, as measured by radioimmunoassay (RIA), when added for the entire incubation, or when added 30 min after start of the incubation period, with CRF present. Alpha-helical CRF alone reduced beta-endorphin release, as compared to control or CRF-treated lobes. Ultrastructural examination of intermediate lobes fixed at the end of incubations revealed a reduction in the numbers of Golgi-associated dense granules, an indicator of new peptide synthesis, in intermediate lobe tissue treated with alpha-helical CRF alone, both peptides together, or with CRF followed by alpha-helical peptide. The in vitro studies demonstrate the effectiveness of the antagonist peptide on intermediate lobe peptide secretion, thereby extending its effects to both POMC-secreting areas of the pituitary gland.
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PMID:Interaction of corticotropin-releasing factor (CRF) and alpha-helical CRF on rat neurointermediate lobes: in vitro studies. 189 31

The release of free [3H]arachidonic acid and its metabolites (AAM) from mouse embryo cortical neurones cultured in serum-free medium stimulated by beta-endorphin C-terminal dipeptide (glycl-L-glutamine, Gly-Gln) was investigated. Gly-Gln but not the related dipeptide, glycyl-glutamic acid, caused a 2-fold elevation of AAM release which was blocked in the absence of extracellular calcium, in the presence of 5 mM magnesium and by the phospholipase A2 (PLA2) inhibitor, mepacrine. Other proopiomelanocortin (POMC) peptides did not elicit AAM release. The response to Gly-Gln was unaffected by D-amino-2-phospho-5-valeric acid (AP5) and 7-chlorokynurenic acid (7-ClKY), antagonists respectively at the ligand and allosteric glycine binding sites of the NMDA glutamate receptor subtype. However, it was inhibited in a dose-dependent manner by antagonists at the phencyclidine (PCP) and sigma sites. The results suggest that Gly-Gln causes AAM release by activating PLA2 through the mediation of a PCP/sigma-like receptor.
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PMID:Beta-endorphin C-terminal peptide evokes arachidonic acid release from cortical neurones. 190 34

Aging of the female reproductive system results in a decline in estrous cyclicity which is due, in part, to alterations in hypothalamic function. Opioid peptides, especially the proopiomelanocortin (POMC)-derived neuropeptide, beta-endorphin, are thought to play a role in maintaining normal patterns of LH secretion. Previous studies have shown that the level of hypothalamic beta-endorphin and POMC messenger RNA (mRNA) decreases in old animals; however, it is unknown whether opioid peptides are involved in age-related reproductive decline. To determine whether POMC gene expression changes with age and is related to reproductive status, we assessed POMC mRNA levels by in situ hybridization histochemistry in the periarcuate region of young (3-4 months), middle-aged (10-12 months), and old (17-19 months) ovariectomized rats. Two methods of quantitation were used: 1) slides were apposed to x-ray film and POMC mRNA levels were quantitated over the entire periarcuate region, and 2) the same slides were dipped in emulsion and the level of POMC was quantitated in individual cells. POMC mRNA levels decreased 20-30% by the time animals were middle-aged, and no further decline was noted in the old animal groups. The decrease in POMC mRNA levels in the middle-aged and old animals occurred regardless of their reproductive status prior to ovariectomy. In addition, there was a 30-40% decline in the number of cells expressing POMC mRNA in middle-aged and old animals, suggesting an overall age-related decline in POMC gene expression in middle-aged and old animals independent of reproductive status.
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PMID:Age-related changes in proopiomelanocortin (POMC) gene expression in the periarcuate region of ovariectomized rats. 191 74

In the pars intermedia of the pituitary the prohormone proopiomelanocortin (POMC) is tissue-specifically processed to, among other peptides, alpha-melanotropin (alpha MSH). In the South African clawed toad Xenopus laevis this hormone mediates the process of background adaptation: release of alpha-MSH causes darkening of the animal, while inhibition of alpha-MSH release results in a pale toad. Elevated release of alpha-MSH coincides with a higher rate of POMC gene transcription. The present study aims to find possible transcriptional regulatory elements in the Xenopus POMC gene. For that purpose the complete nucleotide sequence of the POMC gene and its 5'- and 3'- flanking regions were determined and analyzed. The Xenopus POMC gene promoter contains several regions which may be regulatory DNA elements in view of their similarity with corresponding regions of mammalian POMC gene promoters. In the rat POMC gene promoter, many of these regions represent protein-binding sequences. Besides the promoter sequence and the protein-coding sequences, no other segments with significant identity between the Xenopus and human POMC genes were found. Intron A of the Xenopus POMC gene contains a simple sequence, (TATC)76, and a JH12 repetitive element, while the 3'-flanking region contains a repetitive-EcoRI-monomer-2 element. Comparison of the JH12 sequence of the POMC gene with JH12 sequences from other Xenopus genes revealed a 335-bp consensus sequence which is flanked by a 30-bp inverted repeat. This JH12 consensus sequence is significantly larger than the previously reported JH12 core region. Alignment of intron B of the Xenopus POMC gene with database sequences revealed a consensus sequence of a novel Xenopus repetitive element of 330 bp flanked by a nearly perfect inverted repeat, indicating that this element may be a transposon-like element.
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PMID:Structural analysis of the entire proopiomelanocortin gene of Xenopus laevis. 191 55

Opioid peptides, a group of transmitter substances with a high degree of phylogenic conservation, have many different functions, including a role in modulation of cells of the immune system. We have postulated the existence of such peptides in the parasite Schistosoma mansoni in view of their possible role in host-parasite interactions. In this report we show that beta-endorphin, which is a member of the opiate family and is derived from the proopiomelanocortin (POMC) precursor, is present in S. mansoni. Southern blots of cercarial genomic DNA, hybridized with two oligonucleotide probes complementary to highly conserved POMC sequences, showed a POMC-related gene in this trematode. Northern blot analysis of adult worm RNA indicated that this gene was actively transcribed. Significant amounts of beta-endorphin, adrenocorticotropin (ACTH), and alpha-melanocyte stimulating hormone (alpha-MSH) were detected in all developmental stages of the parasite by radioimmunoassays with the use of antisera to human peptides. By means of reverse-phase high-performance liquid chromatography (HPLC), we found that the parasite beta-endorphin-like material and the human opiate have a high degree of homology. These results appear to constitute the first demonstration of a POMC-related gene transcribed in an invertebrate.
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PMID:The helminth Schistosoma mansoni expresses a peptide similar to human beta-endorphin and possesses a proopiomelanocortin-related gene. 196 86


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