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)

The in vitro and in vivo effects of naloxone (NAL) and endogenous opioids namely methionine and leucine enkephalins (MET-ENK, LEU-ENK) and beta-endorphin (BETA-END) on the brain and lung angiotensin converting enzyme (ACE) activities were investigated. All three peptides dose -dependently inhibited ACE activity in vitro except 10(-5) M concentration of BETA-END which increased the lung ACE activity. NAL which intensified the in vitro inhibitory effect of the used opioids showed an antagonistic effect on the in vivo suppressive effect of BETA-END on both brain and lung ACE activities whereas it had neither antagonistic nor synergistic effect on the in vivo inhibiting effect of MET-ENK and LEU-ENK on the lung ACE activity. The results were consistent with those obtained by using morphine and NAL. As a result the possible contributory action of the excessively released endogenous opioids to overcome shock via their inhibiting effect on ACE was discussed.
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PMID:The in vitro and in vivo effects of enkephalins and beta-endorphin on ACE activity in mice. 301 70

The present study demonstrates the presence of the endogenous opioid peptides, beta-endorphin (beta-EP) and methionine-enkephalin (MET-ENK), and of ACTH in cell homogenates and interstitial fluid from sternal biopsy of leukemic children. The peptides were identified by chromatography and radioimmunoassay. In leukemic children with lymphoblastic cells present in the sternal sample, concentrations of immunoreactive (ir) beta-EP in the cell homogenate, but not in the fluid, were significantly higher than in leukemic children with normal bone marrow. In contrast, ir MET-ENK and ir ACTH did not differ between the two study groups either in the cell homogenate or in the fluid. These data suggest the presence of a complex system of opioid peptides in the cells and interstitial fluid of bone marrow of leukemic children with the highest concentrations of ir beta-EP appearing in samples collected during the active phase of the disease, and may suggest a possible role of opioid peptides as immunomodulatory substances.
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PMID:Changes in immunoreactive beta-endorphin, methionine-enkephalin and ACTH in bone marrow cells and fluid from leukemic children. 302 64

The peptides met- and leu-enkephalin were identified in the telencephalon, rombencephalon, diencephalon and hypophysis of Ambystoma mexicanum brain by radioimmunoassay procedure. The met-enkephalin was the predominant peptide present in the axolotl brain in contrast with leu-enkephalin, except in the hypophysis where the ratio MET/LEU was 2.2/l. The clear differences in the concentration between enkephalins through a submammalian brain species as Ambystoma genus and the possibility that leu-enkephalin is derived exclusively from a precursor like prodynorphin offers an excellent model for the opioids biosynthetic processes.
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PMID:IR-Met and IR-Leu enkephalin content in the axolotl brain (Ambystoma mexicanum). 341 59

Discrete, bilateral, radiofrequency destruction of the supra-optic nucleus resulted in a parallel fall in levels of immunoreactive (ir) dynorphin (DYN), ir-alpha-neo-endorphin (alpha-NE) and ir-vasopressin (VP) in the hypothalamus, neurointermediate lobe (NIL) of the pituitary and septum of rats, whereas in the medulla/pons, midbrain and anterior lobe (AL), levels of theses peptides were not significantly changed. The content of ir-beta-endorphin (beta-endorphin (beta-EP) was, in contrast, elevated in the hypothalamus and unchanged in the NIL and AL, while that of ir-met-enkephalin (ME) was modified in neither the hypothalamus nor medulla/pons. As evaluated in lesioned and sham rats, collectively, hypothalamic levels of ir-DYN, ir-alpha-NE and ir-vP were positively correlated with their counterparts in the NIL but not, with the exception of ir-VP, with those in the AL. Ir-beta-E did not show these relationships. Within the NIL and in the hypothalamus, levels of ir-DYN, ir-alpha-NE and ir-VP were positively correlated with each other and independent of those of ir-beta-EP and ir-ME. In the ALK and other brain tissues, however, only those of ir-DYN and ir-alpha-NE were positively and significantly correlated in contrast to ir-VP. Further, across all structures, although the ratio of levels of ir-alpha-NE to ir-DYN was quite constant, that of ir-VP to ir-DYN varied enormously. These data indicate that: (1) the supra-optic nucleus may contribute to NIL, hypothalamic and septal but not to AL, midbrain or medulla/pons pools of ir-VP, ir-DYN and ir-alpha-NE, and that it interacts with those of ir-beta-EP in the hypothalamus. (2) in the NIL and hypothalamus, ir-DYN, ir-alpha-NE and ir-VP are, as compared to ir-beta-EP and ir-ME, closely interrelated. (3) AL pools of DYN and ir-alpha-NE are closely coupled but, in contrast to NIL pools, not related to ir-VP and independent of the hypothalamus. (4) Extrahypothalamic brain pools of ir-DYN and ir-alpha-NE may be not related to ir-VP. The possible existence of ir-DYN and ir-alpha-NE independently or ir-vP in the AL and extrahypothalamic nervous tissue is discussed.
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PMID:Contribution of the supra-optic nucleus to brain and pituitary pools of immunoreactive vasopressin and particular opioid peptides, and the interrelationships between these, in the rat. 613 73

The role of antigen concentration on the immunosuppressive effect of adrenocorticotropin (ACTH) was tested in 6-week-old White Rock chickens that were immunized i.v. with 1 ml of heat-treated Salmonella pullorum at packed cell volume concentrations of .06 to .00015%, At 16 and 10 hr before the antigen (Ag) injection, the birds received either 4 IU . 100 g body wt-1 of ACTH i.m., or the gelatin (Gel) vehicle. Total, 2-mercaptoethanol sensitive (2-MES), and 2-mercaptoethanol resistant (2-MER) agglutinin antibody titers were determined. The ACTH significantly suppressed total agglutinin titers with the lower Ag concentrations (.0015 and .00015%) but not with the higher Ag concentrations. The ACTH significantly suppressed 2-MES titers only when Ag concentrations were low but suppressed 2-MER titers regardless of Ag concentration. The results indicated that there may be critical Ag concentrations capable of inducing maximal humoral antibody responses in moderate environments but which allow these responses to be suppressed by environments that stimulate increased pituitary-adrenal activity.
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PMID:Concentration of Salmonella pullorum antigen and the immunosuppressive effect of adrenocorticotropin in growing chickens. 630 89

In three experiments, 6- to 7-week-old chickens were exposed to one or two standard heating episodes and were injected immediately afterward with different concentrations of heat-killed Salmonella pullorum antigen (Ag) or phosphate-buffered saline. The standard heat episode consisted of three .5-hr exposures of 44 to 46 C with .5-hr periods of 22 C between exposures. Nonheated chickens were maintained at 22 C. When two heating episodes were used, there was a 12-hr interval between episodes. Sera from blood collected at 0 through 15 days postimmunization (PI) were titrated for total agglutinins and assayed for corticosteroids in all three experiments. Additionally, in Experiment 3, sera were titrated for 2-mercaptoethanol-resistant (2-MER) antibody. Total agglutinins were suppressed from 5 through 13 days PI by one heating episode in birds receiving lower doses of Ag but not in those receiving higher doses. When birds were exposed to two heat episodes, 12 hr apart, total agglutinin titers were suppressed in birds receiving the low Ag dose during the induction phase (4 to 5 days PI) only. During the declining phase (7 to 14 days PI), the effect was reversed, and titers were significantly lower in heated birds receiving the higher dosage. These results are similar to those previously obtained with ACTH (adrenocorticotropin). Determination of 2-MER antibody indicated that IgM was probably suppressed during the induction of the immune response but that IgG was suppressed during the declining phase of the response. Serum corticosteroid concentrations were significantly increased immediately after exposure to high temperature.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Interaction of high temperature and Salmonella pullorum antigen concentration on serum agglutinin and corticosteroid responses in white rock chickens. 653 35

Effects of alpha-melanocyte-stimulating hormone (alpha-MSH), beta-melanocyte-stimulating hormone (beta-MSH), beta-lipotropin (beta-LPH), and beta-endorphin (beta-EPH) at concentrations from 10(-9) M up to 10(-6) M on human adipose tissue lipoprotein lipase (LPL) were studied in a cell-free system. alpha-MSH and beta-MSH did not exert any effect on LPL; no degradation of these peptides in the incubation medium could be detected by HPLC analysis. beta-LPH and beta-EPH failed to alter enzyme activity. However, HPLC analysis revealed an unspecific rapid degradation of the peptides due to the activity of tissue proteases. Therefore, the protease inhibitors amastatin, antipain, APMSF, and TPCK were tested at concentrations of 10(-5), 10(-4), and 10(-3) M for their efficacy to inhibit degradation. None of the inhibitors was able to substantially reduce proteolysis of beta-LPH, as was the case with amastatin, APMSF, and TPCK for beta-EPH. However, antipain at 10(-4) M preserved at least 20% of the initial peptide concentration from proteolysis up to 150 min. Antipain caused a decrease in lipoprotein lipase activity (LPLA), which was dependent on concentration. The adverse effect of antipain at concentrations of 10(-4) M on LPL was completely abolished by beta-EPH at a concentration of 10(-6) M.
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PMID:Proopiomelanocorticotropin (POMC) peptides and lipoprotein lipase activity in vitro. 747 1

LLC-PK1 cells were transfected with a cDNA encoding rabbit neutral endopeptidase (NEP; EC 3.4.24.11), an abundant enzyme of the kidney proximal brush border. Clones of cells expressing high levels of the protein were isolated. Selective biotinylation and radioimmunolabelling were used to determine that 85-95% of NEP was localized in the apical domain of filter-grown LLC-PK1 cells. Pulse-chase and selective biotinylation studies revealed that the majority (85%) of newly made NEP was directly targeted to the apical membrane. However, a soluble form of NEP was found to be secreted in approximately equal amounts from both sides of the monolayer when expressed in LLC-PK1 cells. Transfected pro-opiomelanocortin, a pituitary hormone precursor, was secreted almost exclusively into the basolateral medium, suggesting that the bulk flow is to the basolateral membrane. This behaviour contrasts with that observed in MDCK cells, where both the transmembrane and secreted forms of NEP are directly targeted to the apical membrane and where the secretion of pro-opiomelanocortin is unpolarized.
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PMID:Direct targeting of neutral endopeptidase (EC 3.4.24.11) to the apical cell surface of transfected LLC-PK1 cells and unpolarized secretion of its soluble form. 782 24

The subtilisin-like enzyme PC1 (also known as PC3) cleaves the neuropeptide precursor proopiomelanocortin at paired basic residues in transfection experiments, thus providing evidence for a critical role in precursor processing. While mRNA for this enzyme is highly enriched in neuroendocrine tissues, little is known about the tissue and subcellular distribution of the PC1 protein. This study used immunocytochemical techniques to investigate the anatomical distribution of PC1, both alone and compared to met-enkephalin (MET-enk), in AtT-20 pituicytes transfected with proenkephalin cDNA. A high density of PC1 immunostaining was observed in a small region adjacent to the nucleus and in the tips of the processes of these cells. Dual-staining immunocytochemistry of whole cells illustrated that both PC1 and MET-enk immunoreactivity were present in the tips, but PC1 was concentrated in a region adjacent to the nucleus while MET-enk punctate staining was dispersed throughout the soma. This codistribution was confirmed in semithin sections of dual-stained cells cut at 1-1.5 microns through the thickness of the cells. PC1 staining resembled that of TGN38, a marker for the trans-Golgi network. When PC1 immunocytochemistry was performed in cells that were pretreated with brefeldin A, a drug that redistributes the proximal Golgi compartments to the endoplasmic reticulum, there was a complete disruption of the defined locus of PC1 immunoreactivity. Taken together, our data indicate that (1) PC1 is concentrated in a region of the cell body resembling the trans-Golgi network and (2) both the enzyme and the processed peptide are transported to the tips of the processes.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Immunocytochemical localization of the neuropeptide-synthesizing enzyme PC1 in AtT-20 cells. 811 23

Neutral endopeptidase (EC 3.4.24.11, NEP) is a type-II integral membrane protein found in a wide variety of cell types. We previously produced a secreted form of the enzyme by deletion of the cytoplasmic and transmembrane domains and in-frame fusion of the cleavable signal peptide of pro-opiomelanocortin [Lemay, Waksman, Roques, Crine and Boileau (1989) J. Biol. Chem. 264, 15620-15623]. Here we have used this secreted form of NEP and fused to it the glycosylphosphatidylinositol (GPI)-anchor attachment signal of decay-accelerating factor to produce a GPI-anchored form. Expression of this chimeric form in Cos-1 cells resulted in cell-surface activity. This activity could be released from the cell surface by phosphatidylinositol-specific phospholipase C and radiolabelling studies showed that the protein could incorporate [3H]ethanolamine, indicating that the enzyme was GPI-anchored. The Km value, using [D-Ala2,Leu5]enkephalin as substrate, of GPI-anchored NEP (62 +/- 5 microM) was comparable with that of wild-type NEP (70 +/- 4 microM), as were the sensitivities to the inhibitors phosphoramidon and thiorphan. However, pulse-chase studies showed that the biosynthesis and cell-surface delivery of GPI-anchored NEP was delayed compared with that of the wild-type transmembrane form of NEP. These results suggest a lower rate of biosynthesis and/or cellular transport for GPI-anchored NEP compared with its transmembrane counterpart.
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PMID:Expression of an enzymically active glycosylphosphatidylinositol-anchored form of neutral endopeptidase (EC 3.4.24.11) in Cos-1 cells. 816 36


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