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

Beta-Leu5-endorphin, a relative of "normal" beta-endorphin in which leucine is substituted for methionine at position 5 of the latter, has previously been found in high concentrations in the dialysate of schizophrenics. Its removal from plasma by means of hemodialysis has been claimed to relive the symptoms of schizophrenia. Using a highly sensitive radioimmunoassay of equal sensitivity to beta-endorphin and beta-leu5-endorphin, we have compared the plasma immunoreactivity of three schizophrenic patients befofe and after performance of their first session of membrane hemoperfusion. As compared to normal subjects, plasma beta-endorphin-like immunoreactivity was not greatly elevated in the schizophrenic patients before hemoperfusion.However, instead of the expected decrease, a consistent increase in the plasma levels of immunoreactive beta-endorphin was detected after hemoperfusion. In vitro experiments in which two different membranes and hemodialysis as well as hemoperfusion were used, revealed that synthetic beta-leu5-endorphin (and beta-endorphin) from human plasma was not cleared with any of these methods. This finding is inconsistent with the hypothesis that the claimed therapeutic effects of hemodialysis in schizophrenics are due to the removal of a beta-endorphin-like material from the plasma. Consequently, it seems to be unprobable that high concentrations of beta-leu5-endorphin occur in the dialysate or ultrafiltrate of schizophrenics.
 ...
PMID:Endorphins in schizophrenia: hemodialysis/hemoperfusion are ineffective in clearing beta-Leu5-endorphin and beta-endorphin from human plasma. 53 84

1. Heart tissues of several rodent species including the rat, gerbil (Meriones unguiculatus), hamster (Mesocricetus auratus) and guinea pig (Cavia porcellus) were extracted with an acetone-water-HCl mixture. An acid acetone powder was obtained by adding a copious volume of acetone to the extract. 2. Rat heart acid acetone powder was subjected to ion exchange chromatography on CM-cellulose. Gerbil heart acid acetone powder was subjected to salt fractionation, gel filtration on Sephadex G-10 and then ion exchange chromatography on CM-cellulose. Hamster and guinea pig heart acid acetone powders were subjected to gel filtration on Sephadex G-25. 3. The fractions were assayed for the ability to stimulate corticosterone production in isolated rat adrenal decapsular (zona fasciculata, zona reticularis and medulla) cells, to displace D-ala2-D-leu5-(tyrosyl-3,5-3H) enkephalin from binding to rat brain membranes, and to inhibit 125I-human beta-endorphin from binding to its antibodies. 4. The widespread occurrence of beta-endorphin-like immunoreactivity among the rat heart CM-cellulose fractions may reflect different species of beta-endorphin. The fraction with the highest beta-endorphin-like immunoreactivity and opiate receptor binding activity was strongly adsorbed on CM-cellulose. 5. In hamster and guinea pig hearts, beta-endorphin-like immunoreactivity and opiate receptor binding activity were distributed among high molecular weight and low molecular weight fractions. 6. In gerbil hearts, opiate receptor binding activity was present in fractions unretarded on Sephadex G-10 (i.e. with a molecular weight greater than 700) as well as in the retarded fractions (i.e. with a molecular weight smaller than 700).(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Beta-endorphin-like and adrenocorticotropin-like materials in heart tissues of the rat, gerbil, hamster and guinea pig. 197 55

Snake (Ptyas mucosa) pituitaries were heated, extracted with an acidic medium, and the extract subsequently chromatographed on carboxymethyl cellulose (CMC). Fractions were assayed for their abilities to displace D-ala2-D-leu5-[tyrosyl, 3,53H] enkephalin from binding to rat brain membranes and 125I-beta-endorphin from binding to its antibody, and to stimulate corticosterone production by isolated rat adrenal cells. The fraction unadsorbed on CMC (having the least basic character) had the lowest opiate receptor binding activity and beta-endorphin-like immunoreactivity. The highest steroidogenic activity, opiate receptor binding activity and beta-endorphin-like immunoreactivity were concentrated in a strongly adsorbed fraction. Snake pituitaries were also extracted with Tris-HCl buffer (pH 7.8). The extract from the second procedure was subsequently chromatographed on ConA-Sepharose, ultrafiltered and dialyzed to obtain a nonglycopeptide fraction with a molecular weight between 1,000 and 10,000. This fraction also exhibited steroidogenic and opiate receptor binding activities.
 ...
PMID:beta-Endorphin-like and adrenocorticotropin-like hormones in the pituitary of the snake Ptyas mucosa. 216 96

Several experiments were conducted to examine the effects of intracranial injection of opioid peptides and antagonists on learning and memory in the chick. Pretraining injection of [leu5]enkephalin and the selective delta receptor agonist [D-Pen2,L-Pen5]enkephalin (DPLPE) into the intermediate medial hyperstriatum ventrale (IMHV) produced impairment. ICI 174,864, a delta-selective antagonist, reversed the impairment produced by either [leu5]enkephalin or DPLE, results indicating that delta receptors may play a role in learning in the chick and suggesting that the impairment produced by [leu5]enkephalin is mediated through delta opioid receptors. beta-endorphin produced a naloxone-reversible impairment in performance, which suggests that this impairment is mediated by opioid receptors. Bilateral injection of beta-endorphin into the IMHV produced impairment, as did unilateral injection into the right, but not left, IMHV. Only bilateral injections into IMHV of [leu5]enkephalin were effective. These results suggest that the effects of beta-endorphin are centrally mediated whereas the effects of [leu5]enkephalin may be localized to other brain regions or are peripherally mediated. These initial results suggest that opioids are associated with learning and memory in the chick.
 ...
PMID:Influence of opioid peptides on learning and memory processes in the chick. 253 40

The binding of three tritiated opioid agonists--dihydromorphine, D-ala2-D-leu5-enkephalin and ethylketocyclazocine--was subjected to competition by unlabeled beta-endorphin, dynorphin-(1-13), and various fragments of these peptides, and the results analyzed by a computer program that we developed in an earlier study [11]. Peptides in both groups bound with highest affinity to sites 1 and 3 in our 4-site model, corresponding to the mu and delta sites of conventional classifications, with the dynorphin peptides also interacting with site 2, the kappa site. These results are discussed in relationship to the possible biological roles of these peptides as analgesics or as modulators of analgesia.
 ...
PMID:Computer analysis of the effect of beta-endorphin and dynorphin and related compounds on opioid binding to mouse brain membrane. 256 53

The action of enkephalin-analogues (D-ala2-D-leu5-enkephalin and D-ala2-D-met-enkephalin) and morphine, iontophoretically applied, was tested on rat cortical neurons intracellularly recorded "in vivo". Inhibition of cellular excitability of 60% of the tested cells followed the iontophoretic administration of opioid peptides. 50% of the inhibited cells were also hyperpolarized. The amplitude of membrane hyperpolarization was related to the value of the membrane potential. In 13 out of the 30 inhibited cells the change in membrane input resistance was measured; the input resistance was decreased by 30%. In 8 cells, hyperpolarized by the opioid peptides, the depolarizing postsynaptic potentials, evoked by cortical stimulation, were also reduced in amplitude. Naloxone, iontophoretically applied, reversed and/or prevented the peptide responses. On the same neurons, morphine induced a bursting pattern of spiking activity and increased the membrane input resistance: this action was naloxone-insensitive. The reported results suggest that opioid peptides and morphine activate, respectively, naloxone-sensitive and naloxone-insensitive mechanisms on the same cortical neurons, leading to different and, in some respect, opposite effects on the neuronal activity.
 ...
PMID:Met- and leu-enkephalins inhibit rat cortical neurons intracellularly recorded in vivo while morphine excites them: evidence for naloxone-sensitive and naloxone-insensitive effects. 279 77

Purified T lymphocytes have a specific binding site for naloxone, the opiate antagonist. The KD for the site was 50.6 +/- 2.4 nM, while the Hill coefficient (n) was 1.67 +/- 0.16, indicating a degree of positive cooperativity of ligand binding. The bound naloxone was partially displaceable by various opiate agonists including morphine (56%), beta-endorphin (61%), met5- and leu5-enkephalin (40% each), [D-ala2, D-leu5]-enkephalin (78%) and [D-ala2, D-leu5]-enkephalinamide (66%). Virtually all of the binding capacity was recovered in the particulate membrane fraction after sonic lysis of the cells. There was great interindividual variability in Bmax between samples, suggesting a possible mechanistic basis for the variability in drug action seen between different individuals.
 ...
PMID:Binding of naloxone to human T lymphocytes. 282 15

Effects of opioid peptides on immunoreactive corticotropin-releasing factor (I-CRF) release from the rat hypothalamus were examined using a rat hypothalamic perifusion system and a rat CRF RIA in vitro. beta-Endorphin (0.3 - 30 nM), dynorphin (0.3 - 30 nM) and FK 33-824 (1 - 10 microM) suppressed basal I-CRF release in a dose-dependent fashion. At 2.2 nM concentrations of these peptides, mean percent inhibition was 56% for beta-endorphin; less than 5% for alpha-endorphin; 44% for dynorphin; 23% for leucine-enkephalin; 6% for methionine-enkephalin; less than 5% for FK 33-824; and less than 5% for D-ala2, D-leu5-enkephalin. The inhibitory effects of beta-endorphin and enkephalins were completely blocked by naloxone, but those of dynorphin were only partially blocked. These results suggest that opioid peptides act through opioid receptors and inhibit I-CRF release from the hypothalamus under our conditions. Therefore, endogenious opioid peptides may have a physiological role in the CRF-releasing mechanism of the hypothalamus.
 ...
PMID:Effects of opioid peptides on immunoreactive corticotropin-releasing factor release from the rat hypothalamus in vitro. 287 96

The pituitaries of vitellogenic sockeye salmon (Oncorhynchus nerka) were extracted with a mixture of acetone, water, and hydrochloric acid. The precipitate which formed upon the addition of a copious volume of acetone to the extract, designated acid acetone powder, was subjected to salt fractionation and desalting, followed by ion-exchange chromatography on CM-cellulose. An unadsorbed fraction (S-1) and four adsorbed fractions (S-2, S-3, S-4 and S-5) were obtained. Adrenocorticotropic activity was detected in the fractions by their ability to stimulate isolated rat adrenal decapsular cells to produce corticosterone and by their immunoreactivities in an adrenocorticotropin-specific radioimmunoassay. The steroidogenic activities of all fractions, except S-4, were blocked by corticotropin inhibiting peptide. Opiate activity was detected in the fractions by their ability to inhibit the binding of either [3H]naloxone or (D-ala2, D-leu5)-[3H]enkephalin to rat brain membranes. There was a discrepancy in the potencies of the five fractions in the two opiate radioreceptor assays, indicating the presence of opiate peptides with different affinities of binding to the micron- and delta-opiate receptors of the rat brain. There was a separation between adrenocorticotropic and opiate receptor binding activities, suggesting that the activities were due to separate molecular entities.
 ...
PMID:Adrenocorticotropin- and opiate-like hormones from pituitaries of the sockeye salmon Oncorhynchus nerka. 303 49

A rat X mouse hybridoma line producing a monoclonal antibody against leu5 enkephalin has been obtained. The monoclonal antibody belongs to the IgG2b class and has an affinity constant of 8.0 X 10(8) M-1 at 4 degrees C. This antibody exhibits approximately 40% cross-reactivity with 1-6 dynorphin but very weak cross-reactivities with met5 enkephalin (1.4%), 1-13 dynorphin (1.3%) and beta-endorphin (0.0045%). The detailed study, by competitive assay, of the interaction between this antibody and various enkephalin derivatives shows that the carboxy-terminal part of the molecule and, particularly, the leu side chain constitutes the immunodominant group. Nevertheless, the tyrosyl residue also contribute considerably to the binding, probably via a peculiar conformation effect, although we can not exclude the tyrosyl residue acting as a secondary contact residue. This monoclonal antibody has been used in a radioimmunoassay to determine leu5 enkephalin like immunoreactive material present in rat brain and hypothalamus.
 ...
PMID:Production and characterization of a rat monoclonal antibody against leu5 enkephalin. 370 76


1 2 Next >>