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)

Neurotensin (NT), administered intracisternally to mice, produced significant dose-dependent antinociception in three analgesic tests: tail immersion, hot-plate and acetic acid writhing. Naloxone (1-5 mg/kg), an opiate antagonist administered i.p. 20 min before NT administration, did not significantly alter NT-induced antinociception in any of these tests; naloxone did significantly reverse beta-endorphin-induced antinociception. However, centrally and peripherally administered thyrotropin-releasing hormone antagonized NT-induced (but not beta-endorphin-induced) antinociception. Equimolar doses of another tripeptide (Pro-Leu-Gly-NH2; melanostatin) did not alter the effects of NT. The data obtained in this study confirm NT-induced antinociception, provide further evidence that NT does not activate naloxone-sensitive opiate receptors and demonstrate that this brain effect of NT is antagonized by thyrotropin-releasing hormone. These findings therefore support the hypothesis that NT and thyrotropin-releasing hormone are functional antagonists in the central nervous system.
 ...
PMID:Neurotensin-induced antinociception in mice: antagonism by thyrotropin-releasing hormone. 611 61

A possible contribution of brain beta-endorphin and somatostatin to the epileptogenicity established by amygdaloid kindling was investigated in rats. Fourteen male rats were chronically implanted with electrodes placed bilaterally into the amygdala. The rats received 1 sec of electrical stimulation to the left amygdala each day. Generalized seizures were observed on average 10 days after initiation of kindling and the electrical stimulation was continued up to twenty-one days. Two months after the completion of the kindling procedure, each kindled and control rat was killed by microwave irradiation and the brains were dissected on ice into thirteen subregions. Each region was homogenized and centrifuged twice in 0.1 N acetic acid. The supernatant extracts were decanted and stored at - 20 degrees C until assay. Immunoreactive beta-endorphin and somatostatin were measured by radioimmunoassays. There were no significant differences in brain beta-endorphin contents between the two groups. In kindled rats, immunoreactive somatostatin was increased significantly in amygdala, sensorimotor, piriform, and entorhinal cortex. The results suggest that changes in somatostatin may be associated with epileptic susceptibility induced by the electrical kindling procedure.
 ...
PMID:Changes of immunoreactive somatostatin and beta-endorphin content in rat brain after amygdaloid kindling. 613 22

The role of various bioactive peptides in the control of secretion of hypothalamic somatostatin into the hypophysial portal blood was examined in anesthetized rats. Hypophysial portal blood was withdrawn at a rate of 5.0 microliter/min into a chilled tube through a cannula placed over the stump of the pituitary stalk and segmented every 20 min by air bubbles. Immunoreactive somatostatin (IRS) in the plasma was extracted with acetic acid and acetone and quantified by RIA. Basal levels (mean +/- SE) of plasma IRS in the hypophysial portal blood were 646 +/- 36 and 317 +/- 44 pg/ml in urethane- and pentobarbital-anesthetized rats, respectively. Under urethane anesthesia, injection of synthetic neurotensin into the lateral ventricle at various doses in the range of 0.016--2 microgram/rat caused a significant and dose-related increase of plasma IRS levels in the hypophysial portal blood, and this effect of neurotensin was significantly (P less than 0.05) suppressed by pretreatment with diphenhydramine (1 mg/100 g BW, iv), a histamine receptor blocker. Enhancement of IRS release by neurotensin was also observed in pentobarbital-anesthetized rats. Intraventricular injection of substance P (10 microgram/rat), beta-endorphin (1 and 5 microgram/rat), or [Met5]enkephalin had no effect on the level of somatostatin in the hypophysial portal blood of urethane-anesthetized rats. These results suggest a release of hypothalamic somatostatin into the hypophysial portal blood in response to intraventricular administration of neurotensin, probably by a histaminergic mechanism.
 ...
PMID:Effect of intraventricular injection of neurotensin and other various bioactive peptides on plasma immunoreactive somatostatin levels in rat hypophysial portal blood. 616 24

The regional distribution of Met-enkephalin, beta-endorphin and alpha- and gamma-type endorphins in rat brain was investigated. To that end, brains were dissected into anatomically defined areas. Acetic acid tissue extracts were fractionated using an HPLC system suitable for separation of endorphins and peptide concentrations were subsequently measured by specific radioimmunoassay systems. The distribution of Met-enkephalin and beta-endorphin through the brain was fairly uneven and in accordance with results obtained by others. The peptides alpha-endorphin, gamma-endorphin, des-Tyr-alpha-endorphin (DT alpha E) and des-Tyr-gamma-endorphin (DT gamma E) were detectable in almost all brain areas. Their distribution, however, appeared to be uneven. Hypothalamus and septum showed the highest levels of alpha- and gamma-type endorphins. These regions also contained high amounts of beta-endorphin, underscoring a precursor function of this peptide in the formation of alpha- and gamma-type fragments. In general, levels of alpha-endorphin were higher than those of des-Try-alpha-endorphin, whereas the opposite was found for gamma- and des-Tyr-gamma-endorphin.
 ...
PMID:Regional distribution of alpha- and gamma-type endorphins in rat brain. 617 96

Beta-Endorphin and ACTH immunoassays were employed to examine the concentrations, distributions, and character of those peptides in rat gastrointestinal tissues. Sections of the gastrointestinal tract were obtained from fasted and fed animals and were extracted in 5 N acetic acid containing proteolytic enzyme inhibitors. Aliquots immunoassayed for beta-enddorphin and ACTH revealed highest concentrations to be present in the small bowel, with stomach and colon containing little immunoreactivity. Tissues from fasted animals contained more immunoreactivity than did those from fed animals. Gel chromatography showed the presence of large molecular weight forms of beta-endorphin and ACTH in gut extracts. Concanavalin A affinity chromatography revealed that approximately 5% of gut immunoreactivity contained carbohydrate. Therefore, beta-enddorphin and ACTH immunoreactivities are present im the gut. The demonstration of large molecular weight and glycosylated forms of immunoreactivity suggests the presence of biosynthetic precursors of beta-endorphin and ACTH. The increase in immunoreactivity in response to fasting suggests that these peptides play a role in gut physiology.
 ...
PMID:Beta-endorphin and adrenocorticotropin in extrapituitary sites: gastrointestinal tract. 624 23

To begin to define the nature of the biosynthesis and processing of ACTH and beta-endorphin in the human, anterior pituitary tissue (fresh normal and adenomatous, and autopsy) was extracted in acetic acid in the presence of protease inhibitors and subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The gel slice eluates were assayed for ACTH and beta-endorphin immunoactivity. Human anterior pituitary tissue contained four major size classes of ACTH and three major size classes of beta-endorphin. We found that in all tissue sources examined there was a virtual absence of 13-15K ACTH, which is a major form in the rat and mouse. When comparing extracts obtained from fresh normal or adenomatous anterior pituitary tissue, we also found a drastic decrease in beta-lipotropin and beta-endorphin in extracts of autopsy human anterior pituitaries. These results suggest that the biosynthesis and processing of pituitary ACTH and beta-endorphin in the human may be different than in the mouse, and because of apparent postmortem proteolysis of beta-endorphin, human pituitary obtained at autopsy is probably not a good source of material for biochemical studies of pituitary tissue.
 ...
PMID:The distribution of forms of adrenocorticotropin and beta-endorphin in normal, tumorous, and autopsy human anterior pituiary tissue: virtual absence of 13K adrenocorticotropin. 624 41

Adult human hypothalamic tissue was analyzed for the presence of products generated by post-cleavage processing of ACTH 1-13. The displacement curve generated by immunoreactive alpha-melanocyte stimulating hormone (alpha-MSHi) in extracts (5 M acetic acid or acidified ethanol) of adult human hypothalamic tissue was parallel to the alpha-MSH radioimmunoassay standard curve, and alpha-MSHi eluted as a single peak on Sephadex G-10, G-25, and G-50 columns in a manner identical to that of synthetic alpha-MSH. The alpha-MSHi was clearly distinguishable in its mobility on Sephadex G-50 columns from such peptides as beta-MSH, luteinizing hormone releasing hormone, and ACTH. After high performance liquid chromatography of extracts of hypothalamic tissue from young as well as aged men and women, we found that the major peak of alpha-MSHi (75-95% of total alpha-MSHi) coeluted with desacetyl alpha-MSH (ACTH 1-13 amide) rather than alpha-MSH. We suggest that desacetyl alpha-MSH, rather than alpha-MSH, is the predominant alpha-MSHi in adult human brain tissue.
 ...
PMID:Characterization of immunoreactive alpha-melanocyte stimulating hormone (alpha-MSHi) in human brain tissue. 626 92

Extracts of human term placenta were fractionated by Sephadex G-75 gel filtration and assayed for immunoreactive ACTH. Both high and low molecular weight protein fractions were detected to be immunologically reactive toward anti-human ACTH (1--39 alpha) antibody. For the extraction of low molecular weight ACTH from human term placenta (pl. -ACTH), a glacial acetic acid-acetone mixture was employed, while a pH 3.0-HCl solution was used for high molecular weight immunoreactive ACTH. The high molecular weight immunoreactive ACTH fraction (F-I), co-eluted with horse hemoglobin from a Sephadex G-75.column in 0.1M acetic acid, was essentially devoid of low molecular weight materials as revealed by polyacrylamide gel disc electrophoresis at pHs 9.5 and 4.3. Tryptic digestion of F-1 at pH 8.1 and 37 degrees C for 4 hr with E/S of 1/100, followed by fractionation with a Sephadex G-75, resulted in the formation of lower molecular weight fragments. One fragment was eluted at the same position as that of porcine ACTH with a recovery of 86% of immunoreactivity of F-I. Another fragment which was eluted last exhibited positive beta-endorphin receptor binding activity. These results suggest the presence of a common precursor protein to ACTH and beta-endorphin in human term placenta.
 ...
PMID:[Studies on immunoreactive ACTH from human term placenta. (I) Detection of a high molecular weight-immunoreactive ACTH in term placenta (author's transl)]. 626 17

The thiolcarboxyl peptide [17-thiolglycine]-beta-endorphin-(1-17) (I) was synthesized by the solid-phase method. Reaction of peptide I with citraconic anhydride gave citraconyl-[Lys(Cit9,GlyS17]-beta-endorphin-(1-17) (Ia). Peptide Ia was coupled to another synthetic peptide, [Lys(Cit)19,24,28,29]-beta-endorphin-(18-31), by reaction with silver nitrate--N-hydroxysuccinimide in water. All citraconyl groups were removed in aqueous acetic acid, and [Gly17]-beta-endorphin was isolated in 30-40% yield. The synthetic analog had 10% analgesic potency and 59% opiate--receptor binding activity when compared with human beta-endorphin.
 ...
PMID:New segment-coupling method for peptide synthesis in aqueous solution: application to synthesis of human [Gly17]-beta-endorphin. 627 Jun 58

Five corticotropin-producing tumours were examined for peptides related to the corticotropin-beta-lipotropin precursor. Two were basophil pituitary adenomas and three were bronchial carcinoids. The cells of the two pituitary adenomas stained with antisera against beta-endorphin and against pro-gamma-melanotropin, the NH2-terminal fragment of the corticotropin-beta-lipotropin precursor, but not with antisera against alpha-melanotropin or beta-lipotropin. The corticotropin-storing tumor cells of the bronchial carcinoids stained with antisera against beta-endorphin, beta-lipotropin or pro-gamma-melanotropin. Only one of the three bronchial carcinoids contained cells reacting with the antiserum against alpha-melanotropin. Although the two types of corticotropin-storing tumours (pituitary adenoma and bronchial carcinoid) differed with respect to beta-lipotropin content, the over-all picture indicates that the proteolytic processing of the corticotropin precursor proceeds along similar lines in tumour cells and in pituitary corticotrophs. An acetic acid extract of one of the bronchial tumours was subjected to gel chromatography and immunochemical analysis of material related to pro-gamma-melanotropin. The immunoreactive material displayed a considerable size heterogeneity, with the predominant components having a molecular weight larger than that of authentic pro-gamma-melanotropin.
 ...
PMID:Evidence for the presence of pro-gamma-melanotropin, the NH2-terminal fragment of the corticotropin-beta-lipotropin precursor, in corticotropin-producing tumours. 627 99


<< Previous 1 2 3 4 5 6 7 8 Next >>