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 outer cortex of the human thymus contains a one- to two-cell-thick layer that is immunoreactive with antisera against beta-endorphin, (Leu)- and (Met)-enkephalin, bombesin, and substance P. The epithelial nature of these immunostained cells is revealed by immunoelectron microscopic studies showing the presence of desmosomal junctions. The presence of peptide-containing cells in the outer cortex, where the most immature and recently immigrated thymocytes are found, emphasizes the role of neuropeptides in regulating the microenvironment for T cell development.
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PMID:Neuropeptide-immunoreactive cells in human thymus. 170 21

The effects of single and repeated doses of met-enkephalin (Met-E) on the ultrastructure and TSH-like immunoreactivity (IR) of pituitary TSH-producing cells, and TSH plasma levels in male rats and the influence of pretreatment with a dopamine antagonist, haloperidol, on these, were evaluated. Both acute and repeated Met-E administration produced changes in TSH cells consisting of: an increase in TSH-like IR, enlargement and dilation of RER and Golgi apparatus, size-increase of secretory granules, and the presence of a variable number of cytoplasmic vacuoles. The ultrastructural changes were more evident in the chronically treated animals, whereas no differences were found in IR-intensity between both Met-E treated groups. Haloperidol alone modifies neither ultrastructure nor TSH-like IR of TSH producing cells, but it prevented the Met-E produced changes. On the other hand, Met-E treatment resulted in a decrease of TSH plasma levels, but being significant only in the acutely injected animals. No variations were produced by haloperidol alone, but it prevented the decrease of TSH plasma levels stimulated by Met-E. Our results suggest that Met-E plays a role in the release of TSH, and that dopamine is implicated in this process. The possible mechanisms through which Met-E influences TSH secretion are discussed.
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PMID:Study of the rat TSH-producing cells after met-enkephalin treatment: effects of dopamine antagonists. 176 27

Evidence for the presence of an enkephalinergic system in the ganglia of the pond snail, Lymnaea stagnalis, has been obtained with 3 experimental approaches. Scatchard analysis with [3H]etorphine reveals a monophasic high-affinity opiate binding site (Kd 2.3 nM) which is naloxone-sensitive. Immunocytochemical localization of Met- and Leu-enkephalin-like substances as well as alpha-MSH- and ACTH-like materials was demonstrated within specific populations of neurons. Substances with Met- and Leu-enkephalin and Met-enkephalin sulfoxide RIA reactivities were detected also in HPLC fractions corresponding to the retention times of authentic enkephalin standards. Together, the results provide strong evidence for the presence of enkephalinergic mechanisms in the nervous system of Lymnaea stagnalis. Additionally, the report provides indirect evidence for the existence of a macromolecular opioid precursor. This enkephalinergic system shows striking similarities to opioid mechanisms found in vertebrates and bespeaks a common evolutionary origin.
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PMID:Evidence for an enkephalinergic system in the nervous system of the pond snail, Lymnaea stagnalis. 196 5

Effects of the glucocorticoid milieu on the basal and ether stress-induced prolactin (PRL) release and on the immunostaining for hypothalamic vasoactive intestinal peptide (VIP), beta-endorphin (beta-EP), dynorphin-A (DYN-A) and methionine-enkephalin (Met-ENK), were examined in separate groups of male rats. After colchicine treatment in intact rats, VIP-containing cell bodies were observed only in the suprachiasmatic nucleus (SCN). Adrenalectomy (ADX), performed 7 days previously, resulted in the additional appearance of VIP-immunoreactive neurons in the parvocellular subdivision of the paraventricular nucleus (PVN), as well as in significantly higher basal and stressed PRL levels than intact values. Treatment of intact rats with a high dose (500 micrograms/kg body weight (s.c.) daily for 7 days) of dexamethasone (DEX), but not with a low dose (50 micrograms/kg) of DEX, significantly reduced both the basal and stressed PRL release. Administration of either the low or high dose of DEX to ADX rats prevented the appearance of the PVN-VIP neurons. In addition, the ADX-induced high basal and stressed PRL levels were restored to intact values by the low dose of DEX, and completely suppressed by the high dose of DEX. The staining of SCN-VIP-, beta-EP-, DYN-A or Met-ENK neurons was not affected by any treatment employed in this study. These results suggest that the appearance of PVN-VIP immunostaining in ADX rats may, at least in part, be responsible for the enhanced PRL secretion observed in this group. However, SCN-VIP-, beta-EP-, DYN-A- or Met-ENK neurons do not seem to play a pivotal role in the glucocorticoid regulation of PRL secretion.
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PMID:The immunostaining for the hypothalamic vasoactive intestinal peptide, but not for beta-endorphin, dynorphin-A or methionine-enkephalin, is affected by the glucocorticoid milieu in the rat: correlation with the prolactin secretion. 197 81

Morphine and the synthetic opioid met-enkephalin analog [D-Ala2, MePhe4, Met(0)5ol] enkephalin (FK 33-824) injected intraperitoneally to rats at doses of 5-20 and 0.5-2 mg/kg respectively showed a protective effect on gastric lesion induced by cold-restraint stress. This protective effect was abolished by pretreatment with indomethacin. This suggests a role for prostaglandins in the protection, induced by opioids of the gastric mucosa against the development of stress-induced ulcers.
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PMID:Effect of indomethacin on opioid-induced gastric protection in cold-restrained stress. 199 88

Met- and leu-enkephalin contents in midbrain (including hypothalamus) and striatum of rats were determined by radioimmunoassay after bestatin (racemate) injection (200 g, i.c.v.). It was found that bestatin administration influenced the midbrain met-enkephalin content, values and directions of the changes observed being dependent upon the time after the injection. The data obtained confirm the participation of aminopeptidase in enkephalin inactivation and present evidence for the possibility of regional variations of enkephalin catabolism pathways in the brain.
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PMID:[The effect of the aminopeptidase inhibitor bestatin on the enkephalin level in the rat brain]. 208 25

Most peptide hormones and neurotransmitters are synthesized as larger precursor proteins, which are post-translationally processed to mature bioactive products. An early event in prohormone maturation is endoproteolytic cleavage, occurring usually at pairs of basic amino acids (e.g. Lys-Arg). Since many of the characteristics of a prohormone endoprotease are unknown, distinguishing these enzymes from other cellular proteases in vitro has been difficult. In this report, the substrate specificity of a model prohormone processing system, the insulinoma cell line Rin m5F, was characterized in vivo to establish a set of criteria by which putative proinsulin endoproteases may be assessed. To determine the role of composition of the paired basic amino acid site in directing cleavage, a series of mutant prohormones containing altered cleavage sites was constructed and expressed in Rin m5F cells. Proopiomelanocortin (POMC) was used as a substrate since this prohormone was previously shown to be processed by these cells. To control for positional effects, all four permutations of lysine and arginine (Lys-Arg, Arg-Arg, Arg-Lys, and Lys-Lys) were introduced at both the efficiently processed cleavage site separating the ACTH and beta-lipotropin (beta-LPH) domains of POMC and at the inefficiently processed site in the beta-endorphin sequence near the COOH-terminus of the precursor. His-Arg and Met-Arg sites were also introduced at the ACTH/beta-LPH junction to assess the requirement for paired lysines and arginines. Identification of POMC-derived peptides demonstrated efficient processing of Lys-Arg and inefficient processing of Lys-Lys and Arg-Lys sites at both positions in the prohormone. The Arg-Arg sequence, however, was processed in a position-dependent manner, being efficiently cleaved between ACTH and beta-LPH but only about 50% processed within beta-endorphin. His-Arg was not cleaved in Rin m5F cells, although surprisingly Met-Arg was partially processed. These results indicate a strict preference of the insulinoma prohormone endoprotease(s) for paired basic amino acids ending in arginine, but that processing efficiency of some sequences may be modulated by location within the precursor molecule.
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PMID:An in vivo characterization of the cleavage site specificity of the insulin cell prohormone processing enzymes. 216 Apr 59

Opioid receptors reportedly exist on neuronal tissue of central and peripheral origin as well as on cells of the immune system. Previously, an opioid receptor has been purified from the neuroblastoma x glioma hybrid cell line, NG108-15 cells. In an effort to compare these results with opioid receptors isolated from primary neuronal tissue, we employed a methodology based on the molecular recognition theory to develop a monoclonal antibody which was used to isolate and biochemically characterize murine brain opioid receptors. We herein report the purification of an opioid receptor from mouse brain with a molecular weight of 65,000 daltons (range was 62-70 kD under reducing conditions) using a monoclonal antibody to an (the) opioid receptor. In situ labeling experiments with the delta-class selective opioid receptor affinity ligand, cis-(+)-3-methylfentanylisothiocyanate (SUPERFIT) of brain membrane confirmed these observations. Moreover, SUPERFIT, when coupled to the binding site, could block the recognition of the receptor by the monoclonal antibody. However, the selective, mu-class opioid receptor affinity reagent, 2-(p-ethoxybenzyl)-1-N,N-diethylaminoethyl-5-isothiocyanatobenz imidazole was ineffective at masking the binding site from recognition by the monoclonal antibody. Likewise, opioid-like receptors were purified from murine leukocytes which migrated at a molecular weight of 58,000 daltons under nonreducing conditions and 70,000 daltons under reducing conditions. In addition, immunoaffinity-purified receptor is shown to specifically bind the delta-class-selective opioid ligand, cis-(+)-3-methylfentanylisothiocyanate as well as the endogenous opioid peptides, beta-endorphin and [Met]-enkephalin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Anti-opioid receptor antibody recognition of a binding site on brain and leukocyte opioid receptors. 216 12

In adult healthy beagle dogs, plasma concentrations of ACTH, cortisol, alpha-MSH, GH, prolactin and arginine vasopressin (AVP) were measured after i.v. administration of [D-Ala2,N-Me-Phe4,Met-(O)5-ol]-enkephalin (DAMME) at doses of 0.1, 0.5, 1, 5 and 10 micrograms/kg body weight. Significant dose-dependent increases occurred for ACTH, cortisol and GH at dose rates of 0.5, 1, 5 and 10 micrograms/kg body weight. Increments in plasma concentrations of prolactin were significant only at 5 and 10 micrograms DAMME/kg, and there was no significant effect on plasma concentrations of alpha-MSH and AVP. Prior i.v. administration of the opiate antagonist naloxone (0.1 mg/kg) attenuated the DAMME (10 micrograms/kg)-stimulated release of ACTH and cortisol. The results demonstrate that the [Met]-enkephalin analogue DAMME stimulates the release of ACTH, cortisol, GH and prolactin in dogs, and that this stimulation is, at least in part, mediated by mu-opioid receptors. The observations for ACTH and cortisol are different from those in man, where DAMME lowers their basal concentrations.
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PMID:Effects of a [Met]-enkephalin analogue ( [D-Ala2,N-Me-Phe4,Met-(O)5-ol]-enkephalin) on canine pituitary function. 217 54

For chemical affinity labeling of the melanotropin receptor several alpha-MSH fragments containing phenylalanine mustard were synthesized in solution. Tested in the frog skin bioassay the derivatives roughly preserved the biological activity of the corresponding natural sequences. Alkylating peptides with prolonged biological activity containing phenylalanine mustard in place of arginine, phenylalanine or methionine are inhibitors of alpha melanotropin, suggesting an irreversible binding to reactive nucleophiles on the part of the MSH receptor, where the Met-Glu-His-Phe-Arg sequence is attached.
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PMID:Synthesis of alpha-MSH fragments containing phenylalanine mustard for receptor studies. 217 34


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