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 aim of this study is to elucidate the role of "beta-endorphin (beta-End) & beta-lipotropin (beta-LPH)" on the regulation of gonadotropin (Gn) secretion. We investigated the relationships between immunoreactive beta-End plus beta-LPH and Gn in peripheral plasma of normal menstruating women, 1) during periovulatory period, especially at the time of Gn surge, 2) at the estrogen induced Gn surge (positive feedback) and 3) at the time of hypoxic stress. Plasma concentrations of beta-End plus beta-LPH were measured as immunoreactive beta-End (i-beta-End) by RIA after extraction with Sep-Pak C18. First, we assessed pulsatile Gn secretions during periovulatory period in 19 normal women every 10 minutes for 4 hours, some women were at the time of Gn surge in its ascending limb, plateau of the peak, and descending limb of the surge. Meanwhile, circadian variations of plasma i-beta-End levels of these subjects were assessed at 4 hours' interval on the same day. In two subjects, on the day before the onset of LH surge, significantly low (p less than 0.05) basal and peak levels of i-beta-End were observed, although the basic patterns of circadian rhythm were preserved. Secondly, changes of plasma i-beta-End levels during estrogen (estradiol benzoate 1mg i.m.) induced positive feedback tests were evaluated in 16 normal women and 6 hypothalamic amenorrheic women by daily blood sampling. In normal subjects, small but significant increases (p less than 0.05) of plasma i-beta-End were observed when Gn showed initial decreases at 48 hours after injection. Subsequently at 72 hours, however, plasma i-beta-End decreased precipitously at the time of Gn surge. On the other hand, in hypothalamic amenorrheic women who were devoid of Gn surge, no significant changes of plasma i-beta-End levels were observed. The transient decreases of plasma i-beta-End just prior to the Gn surge support the idea that i-beta-End exerts tonic inhibition on the onset of Gn surge and the disappearance of its inhibition might trigger the positive Gn surge. And it was also suggested that release mechanisms of both i-beta-End and Gn are impaired in hypothalamic amenorrhea. Thirdly, in acute hypoxic stress experiment, 5 normal female volunteers were placed in hypobaric (500 mbar) condition in which oxygen supply is a half of atmosphere, simultaneous blood samplings of Gn, prolactin and i-beta-End were performed every 15 minutes for 3 hours.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[The role of "beta-endorphin & beta-lipotropin" on the gonadotropin regulation in the mechanism of human ovulation]. 296 70

Recently it was reported that beta-endorphin-like immunoreactivity (beta-ELI) was detectable not only in plasma, but also in erythrocytes. To assess the presence of beta-ELI in human erythrocytes and also to determine if erythrocyte-associated beta-ELI may be released into plasma in stress situations, beta-ELI concentrations in plasma and erythrocytes were measured in pairs in normal menstrual cyclic women, postmenopausal women and pregnant women during delivery. After separating from plasma, erythrocytes pellets were lysed by adding distilled water. Extraction of beta-ELI in plasma and RBC lysate was performed with a Sep-pack C18 cartridge (Waters Associates Inc.), and beta-ELI concentrations were measured with a New England Nuclear radioimmunoassay kit. The following results were obtained: 1) There certainly are two pools of beta-ELI; one in plasma, the other erythrocyte-associated. 2) During delivery beta-ELI concentrations in plasma showed a great change, but beta-ELI concentrations in erythrocytes remained almost unchanged. From these results it is unlikely that erythrocytes act as a peripheral reservoir of circulating beta-ELI.
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PMID:[Beta-endorphin-like immunoreactivity in peripheral blood, especially in erythrocytes during delivery]. 296 89

From neurointermediate lobe (NIL) extracts of two species of Cyprinidae, Carassius auratus and Cyprinus carpio, several peptides were separated by high-performance liquid chromatography (HPLC) on a C18 muBondapak column eluted with a methanol/acetic acid/triethylamine mixture. Monitoring all fractions by radioimmunoassay (RIA) with an antibody against melanocyte-stimulating hormone (MSH) C terminal gave positive reactions for fractions 7, 11-12, 15-16, 23-24, and 25-27. For further characterization, the elution positions of these peaks were compared to those of known synthetic reference substances. Peak 7 elutes in the same position as oxidized alpha MSH, whereas peak 15-16 matches the elution position of des-acetyl alpha MSH and 23-24 that of alpha MSH. The product from peak 26-27 has several characteristics of the diacetylated form of alpha MSH: its immunoreactivity in RIA, its sensitivity to weak bases and to HCl and its mass spectrum which is identical with that of mammalian diacetyl alpha MSH. In both species, the diacetylated form is predominant in the intracellular pool. This study establishes the coexistence of three different forms of alpha MSH, a des-acetylated, monoacetylated, and diacetylated in the cyprinid NIL extracts.
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PMID:Separation and partial characterization by high-performance liquid chromatography and radioimmunoassay of different forms of melanocyte-stimulating hormone from fish (Cyprinidae) neurointermediate lobes. 298 88

The presence of immunoreactive beta-endorphin (ir beta-E) in the endometrium was studied by immunoperoxidase staining of tissue sections at various stages of the menstrual cycle. Ir beta-E was found in the endometrium during the secretory phase of the cycle, from the fourth postovulatory day to the desquamating phase, but not in the proliferative phase or during the first three postovulatory days of the cycle. Ir beta-E was located in the cytoplasm of the epithelial cells of the glands. Samples of endometrium were homogenized, and peptides were extracted with Sep Pak C18 cartridge, followed by purification of ir beta-E by cation-exchange high-pressure liquid chromatography. In samples of secretory endometrium, a peak of ir beta-E was found with identical location of that of reference beta-E. The concentration of ir beta-E in the secretory endometrium varied from 5.0 to 12.6 pg/g of tissue. The appearance of ir beta-E in the endometrium during the secretory phase may have importance in the early events of reproduction.
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PMID:Immunoreactive beta-endorphin is demonstrable in the secretory but not in the proliferative endometrium. 315 66

Bovine posterior pituitaries were extracted with an acidic medium designed to maximize solubilization of peptides while precipitating high-molecular-weight protein. The supernatant was then extracted with C18 reversed-phase cartridges to generate a peptide-enriched fraction. Cartridge eluates were subjected to ion-exchange extraction, using a batch procedure which fractionated the peptides into basic, acidic, and neutral pools. Amino-terminal fragments of bovine pro-opiomelanocortin were found to be resolved into separate pools by this method. The 1 to 49 fragment was eluted in the acidic pool while the 1 to 77 fragment was eluted in the basic pool. The 1 to 77 fragment was purified by reversed-phase high-performance liquid chromatography. Amino acid analysis of the fragments, generated from trypsin and V8 protease digestion of the 1 to 77 fragment, permitted assignment of cystine bridges between residues 2 and 24 and between residues 8 and 20. Results from amino sugar analysis were consistent with the presence of an O-linked oligosaccharide at threonine45 and an N-linked oligosaccharide at asparagine65.
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PMID:Use of reversed-phase and ion-exchange batch extraction in the purification of bovine pituitary peptides. 403 Sep 47

Human semen contains large amounts of authentic beta-endorphin and other beta-endorphin immunoreactive peptides. To eliminate the non-specific effects of semen in the beta-endorphin RIA, the beta-endorphin immunoreactive peptides were extracted with octadecylsilane-C18 reverse phase beads. beta-Endorphin immunoreactivity was parallel to the RIA standard curve. Sephadex G-50 gel chromatography showed that 93% of the immunoreactive material coeluted with beta-endorphin. Reversed phase high pressure liquid chromatography of semen extract demonstrated several peaks of beta-endorphin immunoreactivity; one of these was coincident with synthetic h-beta-endorphin61-91.
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PMID:beta-Endorphin 61-91 and other beta-endorphin-immunoreactive peptides in human semen. 625 52

This is a report of the development, calibration, and validation of a series of techniques required to measure beta-endorphin (beta-END)-like immunoreactivity in human plasma, including sieve and affinity chromatography. The RIA, which uses the antibody Brenda, is very sensitive (IC50 = 5-15 fmol/tube at a final concentration of 1:40,000). The extraction process, which uses the Sep-Pak C18 cartridge (Waters Associates, Inc.), is simple and rapid and has a recovery rate of more than 90%. It extracts proopiomelanocortin, beta-lipotropin, and beta-END. Physiological validation was provided by the measurement of beta-END-like immunoreactivity in a pool of plasma of normal humans (2.25 fmol/ml plasma), two pregnant women at term (9.5 and 10.75 fmol/ml), and one patient with Nelson's disease (2 pmol/ml plasma).
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PMID:Human plasma beta-endorphin-like peptides: a rapid, high recovery extraction technique and validation of radioimmunoassay. 630 Jan 82

Sensitivity in the 10-100 pg range for enkephalins, beta-endorphin, tyrosine (T), 12 tyrosylglycine (T-G) and tyrosylglycylglycine (T-G-G) was attained by using a high-performance liquid chromatographic (HPLC) method with electrochemical detection which is at least 100 times more sensitive than HPLC with UV detection. The chromatographic conditions on a reversed-phase C18 silica column were 50 mM sodium phosphate buffer (pH 2.1) (A) in acetonitrile-methanol (1:1) (B), isocratic mixture, flow-rate 0.6-1 ml/min, UV detection at 205 nm, electrochemical oxidation potential + 1.25 V. The separation of T, T-G and T-G-G was obtained by using 10% B while the separation of the pentapeptide, enkephalins required 40% B. Separation of enkephalins from beta-endorphin was attained at a shorter retention times did not exceed 15 min. This method can be used to determine tissue levels and pharmacodynamics of enkephalins and beta-endorphin. A highly specific measurement of the different enzymes involved in the metabolism of enkephalin has been achieved.
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PMID:Analysis of enkephalins, beta-endorphins and small peptides in their sequences by highly sensitive high-performance liquid chromatography with electrochemical detection: implications in opioid peptide metabolism. 631 25

Chromatographic procedures are described here for the resolution of beta-endorphin and its related peptides at picomolar concentration. Initially gel filtration is carried out on Sephadex G75 in 50% acetic acid, providing peptides with the approximate molecular size of beta-endorphin. The group of beta-endorphin-related peptides is resolved by ion-exchange chromatography on the pyridinium form of sulfopropyl Sephadex C25 in the presence of 50% acetic acid. The addition of 125I-labeled marker peptides prior to chromatography allows the recovery of each peptide to be calculated and provides a guide for identifying the elution positions of the endogenous peptides. Additional resolution can be obtained by high-pressure liquid chromatography (HPLC) of the sulfoxide forms of the peptides on muBondapak C18 under acidic conditions. The advantages and disadvantages of ion-exchange chromatography and high-pressure liquid chromatography are discussed for the purification of small amounts of basic, hydrophobic peptides.
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PMID:Chromatography of peptides related to beta-endorphin. 632 12

This study was designed to assess practically the suitability of different C18 reversed-phase radially compressed polythene cartridges (Radial-Pak, Waters Assoc.) in two types of radial-compression systems, for the separation and analysis of various neuropeptides at both high (less than 5 micrograms) and low (greater than 100 pg) levels in biological extracts and to compare them with well established techniques using stainless-steel columns. A solvent system fully compatible with both radially compressed and steel columns is described. The completely volatile mobile phase (acetonitrile gradient containing trifluoroacetic acid) allows ultraviolet detection below 215 nm, gives good resolution and is readily compatible with the further radioimmunoassay and bioassay of collected fractions. The efficiency of radially compressed 5 and 10 microns "capped" and "non-capped" C18 silica supports and slurry-packed steel columns has been assessed by: (1) separation and recovery of a complex standard mixture of neuropeptides; (2) separation and subsequent identification of degradation products formed during the incubation of neurotensin with rat cortical synaptosomes; (3) analysis of alpha-melanotropin and corticotropin-(18-39) in tissue culture media containing varying amounts of foetal calf serum; and (4) characterization of corticotropin-like immunoreactivity in human cerebrospinal fluid. The Z-module fitted with the capped 10-microns irregular C18 silica cartridge gave better resolution than with the mu Bondapak steel column but the selective retention was similar. The back-pressures in the Z-module are much reduced (approximately 13 bar at 1 ml/min); therefore, flow-rates may be increased and analysis times greatly reduced. In order to obtain good resolution with the RCM-100 module which uses a non-capped stationary phase, a salt must be added (e.g. 15 mM sodium chloride) to the mobile phase to reduce polar interactions between the peptide and the free silanol groups on the stationary phase. This makes the solvent non-volatile and therefore less useful.
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PMID:High-performance liquid chromatography of neuropeptides using radially compressed polythene cartridges. 632 86


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