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, when added at the same time as the mitogenic lectin concanavalin A to mouse BALB/c spleen lymphocytes, inhibits cell proliferation. The suppressive effect of beta-endorphin is not exercised through a cAMP-dependent mechanism and is also observed when splenic lymphocytes are stimulated with phytohemagglutinin (4 micrograms/ml), anti-CD3 monoclonal antibody, or the Ca2+ ionophore A23187 (250 nM) and phorbol 12-myristate 13-acetate (1 ng/ml). The inhibitory effect of beta-endorphin on lymphocyte proliferation is dose and time dependent: when beta-endorphin is added 20 h after Con A stimulation no suppression of lymphocyte proliferation is observed. beta-Endorphin inhibits, in a dose-dependent manner, the release of interleukin-2 in concanavalin A-stimulated splenic lymphocytes, measured 24 h after stimulation. beta-Endorphin also controls the appearance of interleukin-2 receptors in the plasma membrane, but does not regulate the expression of the c-myc protooncogene. These data indicate that beta-endorphin inhibits lymphocyte activation signal transmission, downstream the generation of the second messengers Ca2+ and diacylglycerol and the expression of the protooncogene c-myc, by blocking interleukin-2 release and interleukin-2 receptors expression. Once the cells are in the G1 stage, beta-endorphin is no longer able to block lymphocyte proliferation.
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PMID:Beta-endorphin inhibits interleukin-2 release and expression of interleukin-2 receptors in concanavalin A-stimulated splenic lymphocytes. 147 86

Beta-endorphin (BE) and cholecystokinin (CCK) were measured in fresh PBMC isolated from human subjects and rats. The BE and CCK PBMC contents increased significantly with age both in human and rat models. Moreover, polyclonal stimulation induced a significant decrease of BE but not CCK contents in mononuclear cells from human aged subjects. The time course of changes in BE and CCK concentrations observed in fresh and cultured cells from subjects of different ages did not directly correlate to the time course of age-associated impairment of lectin-induced lymphocyte proliferative response and interleukin-2 synthesis. In fact, the lymphocyte functional defects were significantly observed only in the 71-99 year age group, whereas the neuropeptide changes were already evident in the 31-50 age group. Since BE has been shown to participate in the modulation of the immune system, the age-related modifications of PBMC BE could play a role in the immunodepression observed during aging.
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PMID:Age-related changes of beta-endorphin and cholecystokinin in human and rat mononuclear cells. 181 22

Delta-opiate receptors have been solubilized with the non-ionic bile salt detergent digitonin from NG108-15 cell membranes and reconstituted into lipid vesicles. Specific opiate binding was restored to soluble receptor preparations after supplementation with a brain lipid extract, and dilution below the effective detergent concentration. Saturable and specific opiate binding was measured for both membrane and vesicle preparations; dissociation constants (Kd) obtained from saturation isotherms of [3H]bremazocine binding were 1.3 and 4.2 nM, respectively. Relative affinity (IC50) values of ligand binding measured for subtype-selective agonists confirmed that a delta-opiate binding site interaction was recovered in vesicle preparations. Changes in agonist binding affinity noted for these experiments were explained by dissociation of the GTP-binding protein Gi from the receptor in detergent. The recovery of solubilized opiate receptors was nearly quantitative, and strictly dependent upon the total brain lipid preparation used in the reconstitution. Ligand binding was incompletely recovered after substituting pure, vesicle-forming phospholipid preparations. [3H]Bremazocine binding was also reconstituted after lectin affinity chromatography of solubilized receptor preparations, using conditions which likely effect the removal of endogenous lipid cofactors. A photoaffinity cross-linking methodology was employed to verify recovery of the delta-opiate receptor after its solubilization from membranes and reconstitution. Two membrane-associated proteins (50 and 70 kDa) were covalently tagged with an azido analog of beta-endorphin(Leu5) in cell membranes and subsequently identified by immunoblotting with antisera directed against this opioid. Labeling of the 50-kDa polypeptide was prevented by coincubating assay samples with a relative excess of (D-Pen2,5)enkephalin. This opioid binding polypeptide was also present in solubilized/reconstituted receptor preparations.
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PMID:Reconstitution of solubilized delta-opiate receptor binding sites in lipid vesicles. 216 3

The amygdala, particularly the central amygdaloid nucleus, is important for the expression of adrenocorticotropin and corticosterone responses during stress. The aim of the present study was to determine if the central amygdaloid nucleus directly innervated the hypothalamic paraventricular nucleus. To accomplish this aim, the Phaseolus vulgaris leucoagglutinin lectin anterograde tracing method was used. Injections of the tracer into the medial central amygdaloid nucleus resulted in axonal and terminal labeling within the medial and lateral parvocellular parts of the caudal paraventricular nucleus. A dense patch of labeling was observed within the lateral wing of the lateral part of the parvocellular paraventricular nucleus. Only a few labeled axons were observed within the paraventricular nucleus of animals that had lectin injections localized to the lateral part of the central nucleus. Tracer injections localized to the medial amygdaloid nucleus resulted in axonal and terminal labeling primarily within the anterior parvocellular and periventricular regions of the paraventricular hypothalamic nucleus. Sparse to moderate axonal and terminal labeling was observed within the magnocellular parts of the paraventricular nucleus in animals that had injections of tracer into either the medial central nucleus or the medial nucleus. No labeling was observed within the paraventricular nucleus of animals that had injections of lectin within other amygdaloid nuclei or adjacent regions of the striatum. The results demonstrated a topographically organized projection from the amygdala to the hypothalamic paraventricular nucleus. The central nucleus mainly innervates the caudal lateral and medial parvocellular paraventricular nucleus. The medial nucleus innervates the rostral parvocellular parts of the paraventricular nucleus. These pathways could form the anatomical substrates of amygdaloid modulation of neuroendocrine responses to stressors.
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PMID:Direct projections from the central amygdaloid nucleus to the hypothalamic paraventricular nucleus: possible role in stress-induced adrenocorticotropin release. 255 78

We examined the cultured mouse melanoma cell line B16 (clone F1) and its wheat germ agglutinin-resistant variant Wa4 that suffers from abnormal protein glycosylation (a high fucose:sialic acid ratio in glycoproteins). In both cell lines the adenylate cyclase system was endowed with a functional guanine nucleotide binding protein Gs and was efficiently coupled to alpha-MSH receptors. In the B16 cell line F1 studied we also observed an efficient stimulation of adenylate cyclase activity by helodermin, VIP and the VIP analogue [acetyl-His1]VIP, and also by PGE1. In membranes from the lectin-resistant variant Wa4, the stimulations by VIP-like peptides and by PGE1 were reduced by 60% and 50%, respectively, while the stimulation by alpha-MSH remained normal. As other components of the adenylate cyclase system (Gs site, catalytical unit) appeared unchanged in the Wa4 variant, we conclude that impaired glycosylation essentially affected the number of both VIP-like peptide receptors and PGE1 receptors.
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PMID:Decreased adenylate cyclase activation by helodermin and PGE1 in the lectin-resistant variant Wa4 of the mouse melanoma cell line B16. 255 62

Lectin binding sites of adrenocorticotropic hormone (ACTH) secretory granules of human pituitary adenomas and of nonadenomatous pituitary tissue adjacent to adenomas were studied by postembedding immunocytochemical doublestaining on ultrathin sections followed by electron microscopy. The specific hormones produced by the secretory granules were identified by labeling one side of the section with anti-human pituitary hormone antibodies conjugated to gold particles. Simultaneously, the other side was labeled with horseradish peroxidase-lectin to reveal lectin binding sites. Specimens were obtained from four human ACTH-producing pituitary adenomas and from nonadenomatous pituitary tissue surrounding three other adenomas. The four ACTH-producing adenomas showed either weak or negative reactions with concanavalin A, whereas the nonadenomatous ACTH-producing pituitary cells reacted strongly with concanavalin A. Moreover, ACTH secretory granules were significantly larger in the nonadenomatous cells than in adenoma cells. Differences in biochemical structure and ultrastructure between nonadenomatous (normal) pituitary cells and adenoma cells secreting the same specific hormones were demonstrated, and the clinical implications of the results were discussed.
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PMID:Differences in glycoconjugates of adrenocorticotropic hormone-secretory granules between nonadenomatous pituitary cells and adenoma cells as detected by double labeling. 284 95

Electron-immunocytochemical staining with lectin (concanavalin A: Con A) binding sites analysis was applied to study secretory granules of human pituitary adenomas and surrounding normal pituitary tissue using post-embedded serial ultrathin sections. Twelve cases of human pituitary adenoma and three specimens of normal pituitary tissue surrounding adenomas were studied: the cases were operated on between 1982 and 1984. The tumors consisted of four prolactin (PRL)-, six growth hormone (GH)-, and two adrenocorticotropic hormone (ACTH)-producing adenomas. In parallel with the detection of Con A binding sites of secretory granules, their secreting hormones were characterized electron-microscopically with the immunocytochemical horseradish peroxidase (HRP) labeling using the avidin-biotin technique. The two cases of ACTH-producing adenomas showed either weak or negative reactions with Con A on secretory granules, while normal ACTH-producing pituitary cells showed strong reactions with Con A on every secretory granule observed. Large secretory granules of PRL- or GH-producing cells showed negative reactions with Con A both in the pituitary adenoma and normal pituitary, while some small granulated or sparsely granulated adenoma cells also showed strong reactions with Con A. The complexity of human pituitary adenomas is illustrated as well as the difference in biochemical structure of normal pituitary cells and pituitary adenoma cells secreting the same specific hormone.
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PMID:Difference of lectin binding sites of secretory granules between normal pituitary and adenoma cells. 299 Jan 44

The galactose-binding lectin from the Chinese herb Trichosanthes kirilowii (Tianhuafen) stimulated the incorporation of D-[3-3H]glucose into lipids in isolated rat epididymal adipocytes. The lectin, however, did not inhibit lipolysis induced by either epinephrine or corticotropin in these adipocytes. Similarly, it did not suppress corticotropin-induced lipolysis in isolated hamster adipocytes. At a dose that did not stimulate lipolysis on its own, the lectin slightly potentiated the lipolytic effects of corticotropin and epinephrine. These findings are discussed in relation to previous observations on other galactose-binding lectins.
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PMID:Effect of Trichosanthes kirilowii lectin on lipolysis and lipogenesis in isolated rat and hamster adipocytes. 300 62

Considerable evidence indicates the existence of multiple types of opioid receptors. The three major types have been named mu, delta and kappa. The earlier evidence was based on pharmacological as well as membrane binding experiments. This paper will emphasize more recent studies using solubilized opioid binding sites. Several laboratories, including our own, have succeeded in separating kappa receptors from other types. A similar separation of mu from delta receptors has not yet been achieved. By crosslinking experiments with 125I- human beta-endorphin we have been able to provide strong evidence for differences in molecular size between the major binding components of mu (65K) and delta (53K) receptors. It is not yet established whether the difference resides in the protein or carbohydrate portion of these glycoproteins. These results suggest that the three major types of opioid receptors represent distinct molecular entities. An active opioid binding protein solubilized from bovine striatal membranes has been purified to apparent homogeneity. The major purification steps involve affinity chromatography and lectin chromatography on immobilized wheat germ agglutinin. The purified material gave a single band of molecular weight 65K Da on SDS-PAGE. Its specific activity for opioid binding was ca. 13,000 pmol/mg protein and its properties are those of a component of the mu receptor.
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PMID:Subunit structure and purification of opioid receptors. 304 Sep 75

Calmodulin, a ubiquitous Ca2+-binding regulatory protein, is phosphorylated exclusively on tyrosine-99 in an insulin-dependent manner by wheat germ lectin-purified preparations of insulin receptors from rat adipocyte plasma membranes. Calmodulin is phosphorylated in the presence of polylysine, histone Hf2b, and protamine sulfate, but not in the absence of these cofactors or in the presence of other basic compounds known to interact with calmodulin, such as mellitin, myelin basic protein, chlorpromazine, trifluoperazine, substance P, glucagon, polyarginine, mastoparin, beta-endorphin, spermine, spermidine, and putrescine. The incorporation of 32P into calmodulin, expressed in terms of moles of phosphate per moles of calmodulin and assayed at calmodulin concentrations of 1.2 and 0.06 microM, is 0.023 + 0.002 and 0.046 + 0.006, respectively. This low stoichiometry is likely due to the relative impurity of the receptor preparation, as similar studies not shown here, using highly purified human insulin receptors, yield a stoichiometry of 1 mol phosphate/mol calmodulin. The time course of phosphorylation is characterized by a short initial lag phase of approximately 5 min, a rapid linear rate from approximately 5 to 40 min, with a steady state of 32P incorporation being approached at approximately 60 min. The K0.5 for ATP is 104 + 18 microM. Phosphorylated calmodulin is partially purified by HPLC on a C4 column using a trifluoroacetic acid/acetonitrile gradient solvent system. Phosphoamino acid analysis and limited thrombin digestion were used to determine that the site of insulin-induced phosphorylation of calmodulin is exclusively on tyrosine-99 regardless of the basic protein cofactor used. Phosphorylated calmodulin does not exhibit the characteristic Ca2+ shift normally observed with calmodulin in electrophoretic gels, an observation that is consistent with this modification affecting the biological activity of the molecule. Thus, the tyrosine phosphorylation of calmodulin represents a potentially important post-translational modification altering calmodulin's ability to regulate a variety of enzymes involved in growth, differentiation, and metabolic regulation.
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PMID:The in vitro phosphorylation of calmodulin by the insulin receptor tyrosine kinase. 341 47


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