UNIPROT:P01189 - FACTA Search

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Query: UNIPROT:P01189 (beta-endorphin)
21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Superfusion of rat hypothalamic slices with 10(-4) M N-methyl-D-aspartic acid (NMDA) resulted in increased release of alpha-melanocyte-stimulating hormone (alpha-MSH). Peptide release was blocked by 10(-6) M NG-nitro-L-arginine methyl ester (L-NAME) a specific competitive inhibitor of nitric oxide synthase but not by the inactive enantiomer D-NAME at 10(-6) M. The inhibition by L-NAME was reversed by the addition of 10(-5) mM L-arginine, an excess of enzyme substrate. Release of nitric oxide products into tissue superfusates was stimulated by a 50 mM concentration of potassium ions and by 10(-4) M NMDA. Potassium-stimulated release was blocked by L-NAME. Basal, potassium-stimulated and NMDA-stimulated release of nitric oxide products were significantly inhibited by the NMDA-receptor antagonist D(-)-2-amino-5-phosphopentanoic acid (AP5) at 10(-4) M and by the NMDA-channel blocker ketamine at 10(-4) M. We conclude that nitric oxide mediates the stimulatory action of glutamic acid on the release of alpha-MSH from the rat hypothalamus.
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PMID:N-methyl-D-aspartate (NMDA) stimulates release of alpha-MSH from the rat hypothalamus through release of nitric oxide. 788 30

During the postnatal period from day 2 to day 10 of life, basal and stress-induced adrenocorticotropic hormone (ACTH) and corticosterone releases are low as compared with adults. This period has been called the 'stress-hyporesponsive period', and its mechanisms are yet undetermined. In this study, we have tested the effects of substances excitatory to neuronal activity on the hypothalamic-pituitary-adrenal (HPA) axis. In 7-day-old rats, administration of the excitatory amino acid (EAA) agonists N-methyl-D,L-aspartic acid (NMA), quisqualic acid, and kainic acid (KA) induced a large increase in plasma ACTH and corticosterone concentrations. All three EAA induced a rapid and potent stimulation of ACTH release within 30 min, the effect on corticosterone secretion being weaker. KA was the more potent EAA, followed by NMA and quisqualic acid. The effect of NMA on the HPA axis was inhibited by pretreatment with a competitive antagonist to N-methyl-D-aspartic acid receptors, D,L-2-amino-5-phosphonovaleric acid. We next sought to determine which level of the HPA axis was affected by EAA administration. Several EAA (glutamic acid, N-methyl-D-aspartic acid, and KA from 10(-5) to 10(-2) M) had no stimulating action on ACTH release from 7-day-old anterior pituitary glands incubated in vitro. In vivo, the stimulating effect of NMA and KA on in vivo ACTH release was blocked after passive immunization with an anti-corticotropin-releasing hormone antiserum, but not after injection of an anti-arginine vasopressin antiserum.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of excitatory amino acid on the hypothalamo-pituitary-adrenal axis in the rat during the stress-hyporesponsive period. 809 78

Effects of melatonin on hypothalamic neurotransmitters in male mice were studied. Exogenous melatonin administered intraperitoneally significantly increased (p < 0.05) hypothalamic concentrations of aspartic acid and gamma-aminobutyric acid by over 29 and 50% respectively. Conversely, hypothalamic beta-endorphin concentration was significantly decreased (p < 0.05) 30 min after melatonin administration with doses between 5- and 100 micrograms/kg. Similarly, melatonin, at a concentration of 100 micrograms/kg, decreased (p < 0.05) the serotonin level in mouse hypothalamus by 46%. Melatonin, however, did not affect the concentration of hypothalamic glutamic acid over a dose range of 0.5-300 micrograms melatonin/kg. Our findings suggested that actions of pineal melatonin in animals such as inhibition on serum corticosterone levels might be mediated by the potentiation of activities of hypothalamic neurons containing gamma-aminobutyric acid and aspartic acid or by the inhibition of the beta-endorphin and serotonin hypothalamic neurons. The neurons containing glutamic acid in the hypothalamus were, however, not influenced by melatonin. Our results are in line with the suggestion that melatonin actions on adrenal corticosterone release or other endocrine secretions may be mediated by way of its actions on hypothalamic neurotransmitter activities.
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PMID:Effects of melatonin on hypothalamic gamma-aminobutyric acid, aspartic acid, glutamic acid, beta-endorphin and serotonin levels in male mice. 872 Jun 89

Nitric oxide synthase (NOS)-containing neurons are found in many loci throughout the central nervous system, which include the cerebral cortex, the cerebellum, the hippocampus, and the hypothalamus. NO plays a very important role in control of neuronal activity in all of these areas by diffusing into neurons where it activates soluble guanylate cyclase (sGC) leading to generation of cyclic guanosine monophosphate (cGMP) and cyclooxygenase 1 leading to generation of prostaglandins. Both of these active agents are involved in mediating the actions of NO, the first gaseous transmitter. In the cerebellum, NO is extremely important and it is also thought to mediate long-term potentiation in the hippocampus. Various stresses and corticoids have been shown in monkeys and also in rodents to cause neuronal cell death. This may be via the stimulation of glutamic acid release, which by N-methyl-D-aspartate (NMDA) receptors causes release of NO, which can lead to neuronal cell death. In the hypothalamus,. NO stimulates corticotropin-releasing hormone (CRH), prolactin releasing factor, growth hormone-releasing hormone (GHRH), and somatostatin, lutenizing hormone-releasing hormone (LHRH), but not follicle stimulating hormone-releasing factor (FSHRF) release. In situations of increased release of NO in the hypothalamus, it could cause neuronal cell death. Following bacterial or viral infections, toxic products of the ineffective agents, such as bacterial lipopolysaccharide (LPS), circulate to the brain, where they induce interleukin-1 and iNOS mRNA and synthesis. After several hours delay, massive quantities of NO are released. Induction of iNOS occurs in the choroid plexus, meninges, in circumventricular organs, and in large numbers of iNOS neurons in the arcuate and paraventricular nuclei. The large amounts of NO released by iNOS may well produce death not only of neurons but also glial. Repeated bouts of systemic infection even without direct neural involvement could result in induction of iNOS in the central nervous system and lead to large fall out of neurons in hippocampus to impair memory, hypothalamus to decrease fever, and neuroendocrine response to infection, and could play a role in the pathogenesis of degenerative neuronal diseases of aging, such as Alzheimers. The largest induction of iNOS occurs in the anterior pituitary and pineal glands. The damage to the pituitary could also impair responses to stress and infection, and the release of NO during infection could be responsible for the degenerative changes in the pineal and diminished release of melatonin, an antioxident, and consequently, an antiaging hormone, that occur with age.
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PMID:The nitric oxide hypothesis of brain aging. 931 47

A degenerate primer, specific for the opioid core sequence YGGFM, was used to clone and sequence proopiomelanocortin (POMC) cDNAs from the brain of the African lungfish, Protopterus annectens, and from the brain of the western spadefoot toad, Spea multiplicatus. In addition, the opioid-specific primer was used to clone and sequence a 3'RACE product corresponding to a portion of the open reading frame of S. multiplicatus proenkephalin. For both species, cDNA was made from a single brain and a degenerate opioid-specific primer provided a reliable probe for detecting opioid-related cDNAs. The African lungfish POMC cDNA was 1,168 nucleotides in length, and contained regions that are similar to tetrapod POMCs and fish POMCs. The African lungfish POMC encodes a tetrapod-like gamma-MSH sequence that is flanked by sets of paired basic amino acid proteolytic cleavage sites. The gamma-MSH region in ray-finned fish POMCs either has degenerate cleavage sites or is totally absent in some species. However, the African lungfish gamma-MSH sequence does contain a deletion which has not been observed in tetrapod gamma-MSH sequences. The beta-endorphin region of lungfish POMC has the di-amino acid sequence tryptophan-aspartic acid in the N-terminal region and an additional glutamic acid residue in the C-terminal region of beta-endorphin - features found in fish beta-endorphin, but not tetrapod beta-endorphins. The western spadefoot toad POMC was 1,186 nucleotides in length, and exhibited an organizational scheme typical for tetrapod POMCs. However, the toad POMC did lack a paired basic amino acid proteolytic cleavage site N-terminal to the beta-MSH sequence. Thus, like rat POMC, it is doubtful that beta-MSH is an end product in either the toad brain or intermediate pituitary. At the amino acid level, the toad POMC had 76% sequence identity with Xenopus laevis POMC and 68% sequence identity with Rana ribidunda POMC. The use of these POMC sequences to assess phylogenetic relationships within anuran amphibians will be discussed. With respect to the fragment of S. multiplicatus proenkephalin cDNA, two metenkephalin sequences and the metenkephalin-RF sequence were found encoded in this fragment. As seen for X. laevis and R. ridibunda proenkephalin, a leuenkephalin sequence was not detected in the C-terminal region of the S. multiplicatus proenkephalin. The absence of a leuenkephalin sequence may be a common feature of anuran amphibian proenkephalins.
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PMID:Cloning of proopiomelanocortin from the brain of the african lungfish, Protopterus annectens, and the brain of the western spadefoot toad, Spea multiplicatus. 1042 92

The staphylococcal exfoliative toxins (ETs) A and B (ETA and ETB) are 27-kDa exotoxins produced by certain strains of Staphylococcus aureus and are the causative agents of staphylococcal scalded-skin syndrome. The crystal structures of the ETs strongly indicate that the proteins are members of the serine protease family of enzymes, although protease activity until now has not yet been conclusively demonstrated. Here, we show that the peptide beta-melanocyte-stimulating hormone (beta-MSH) is cleaved by ETA and that both ETA and ETB are capable of cleaving alpha-MSH. Both toxins exhibit cleavage at specific glutamic acid residues in MSH peptides. Moreover, biologically inactive mutants of ETA were incapable of cleaving beta-MSH.
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PMID:Staphylococcal exfoliative toxins cleave alpha- and beta-melanocyte-stimulating hormones. 1072 46

Numerous studies have shown that the administration of a glutamate receptor agonist or a high dose of glutamate stimulates pituitary hormone secretion in animals. However, only a single human study has reported that an oral load of glutamic acid induced the secretion of prolactin and probably adrenocorticotropic hormone (ACTH) (but not other pituitary hormones). Because of glutamate's use in foods as monosodium glutamate (MSG), a flavoring agent, and the limited amount of human data, we studied the effect of a large oral dose of MSG in humans on the secretion of prolactin and other pituitary hormones. Fasting male subjects bearing venous catheters received on separate days each of the following four treatments: a vehicle, MSG (12.7 g), a high protein meal (a physiologic stimulus of prolactin secretion) by mouth, or an intravenous infusion of thyrotropin-releasing hormone (TRH, a pharmacologic stimulus of prolactin secretion). Plasma hormone responses were quantitated by RIA at 20-min intervals for 4 h. The protein meal induced a modest increase and TRH infusion a substantial increase in plasma prolactin, whereas MSG ingestion did not. MSG ingestion also did not raise the plasma concentrations of any of the other pituitary hormones measured (luteinizing hormone, follicle-stimulating hormone, thyroid-stimulating hormone, growth hormone) or of cortisol. Ingestion of MSG raised plasma glutamate concentrations 11-fold; the protein meal did not raise plasma glutamate. The results demonstrate that MSG ingestion in humans does not modify anterior pituitary hormone secretion. One implication is that diet-derived glutamate may not penetrate into hypothalamic regions controlling anterior pituitary function.
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PMID:Pituitary hormone secretion in normal male humans: acute responses to a large, oral dose of monosodium glutamate. 1073 81

In this work, we characterized the active site in the alpha-melanotropin hormone (alpha-MSH) sequence responsible for the enhancement of cAMP production in incubated striatal slices by using different alpha-MSH fragments. We also analyzed the effects of the co-incubation of the SCH23390, a dopaminergic D(1) antagonist, with the MSH fragments, to study the involvement of the D(1) receptor on this induction. A rise was observed in the levels of cAMP after addition of the 6 microM fragments MSH((1-10)), and 0.6 and 6 microM MSH((5-13)); however, the values were lower than those induced by 6 microM alpha-MSH. On the contrary, the addition of MSH((9-13)), MSH((7-11)), or MSH((6-9)) did not affect the cAMP content. The presence of 10 microM SCH23390 blocked the effect of the fragments on cAMP production. We conclude that the biologic activity of alpha-MSH, as observed through the levels of cAMP, declines when the length of its polypeptide chain is shortened, and that the presence of glutamic acid in the molecule, as well as the core sequence, are of importance for fragments' activity.
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PMID:Structure-activity studies of alpha-melanotropin fragments on cAMP production in striatal slices. 1095

Polyelectrolyte multilayer films made of poly (L-lysine) (PLL) and poly (L-glutamic acid) (PGA) have been functionalized by covalent binding of a synthetic analogue of the anti-inflammatory peptide, alpha-melanocyte-stimulating hormone (alpha-MSH) to PGA to create biologically active coatings for tracheal prostheses. The morphology and in vivo stability of the films were investigated by atomic force microscopy and confocal laser scanning microscopy, respectively. For the in vivo evaluation, 87 rats were implanted and examined for a period superior to 3 months. Histological analysis, performed 1 month after implantation, showed a fibroblast colonization of the periprosthetic side and a respiratory epithelium type on the endoluminal side of the implant for all the polyelectrolyte coatings tested. However, for prostheses modified by PGA ending multilayer films, a more regular and less obstructive cell layer was observed on the endoluminal side compared to those modified by PLL ending films. Systemic anti-inflammatory IL-10 production was only detected in rats implanted with prostheses functionalized by alpha-MSH, demonstrating, in vivo, the anti-inflammatory activity of the embedded peptide into multilayer architectures.
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PMID:Polyelectrolyte multilayers functionalized by a synthetic analogue of an anti-inflammatory peptide, alpha-MSH, for coating a tracheal prosthesis. 1558 65

To date proopiomelanocortin (POMC), the precursor protein for melanotropin (MSH), adrenocorticotropin (ACTH), lipotropins (LPH), and beta-endorphin (beta-END) in the pituitary gland, has been studied extensively over a wide spectrum of vertebrate classes. A paucity of information exists, however, with regard to POMC in the avian class, where to date POMC from only one species, the domestic chicken, appears to have been fully characterized. In the present study, we report the use of three clones of cDNA to provide the complete nucleotide sequence of ostrich prePOMC cDNA, consisting of 1072 bp (excluding the poly(A) tail). The deduced amino acid sequence of 253 amino acid residues includes the N-terminal signal peptide of 17 amino acid residues. The predicted amino acid sequence in the overall arrangement of its domains, conforms to that found in other tetrapods. Sequence domains for gamma-MSH, ACTH, alpha-MSH, gamma-LPH, beta-MSH, and beta-END are located at positions 74-85, 134-172, 134-146, 175-220, 203-220, and 223-253, respectively, in ostrich prePOMC, but some of them may not be released in the ostrich pituitary gland, despite the presence of nine potential processing sites consisting of 2-4 dibasic amino acids each. Substitution of glutamic acid for a dibasic amino acid at position 202 in ostrich prePOMC could prevent release of beta-MSH. To date the release of pro-gamma-MSH, beta-LPH, ACTH, gamma-LPH, and beta-END have been confirmed by direct isolation and characterization from ostrich pituitary extracts. In the present study, we have also identified ACTH, gamma-LPH and beta-END in a single frozen ostrich pituitary slice by means of MALDI-TOF mass spectrometry. When compared to a wide range of vertebrate prePOMC molecules, ostrich prePOMC revealed a high level of amino acid sequence identity (77%) with chicken prePOMC, which is the only other avian sequence available. As with other vertebrate classes, considerable intraclass differences were also evident between chicken and ostrich prePOMCs, which belong to different avian orders. Identity of ostrich prePOMC with non-avian tetrapod counterparts is only moderate (53-56%), whereas lower identities (20-49%) are evident over a range of fish prePOMCs.
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PMID:Molecular cloning and characterization of preproopiomelanocortin (prePOMC) cDNA from the ostrich (Struthio camelus). 1645 26

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