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)

Isolated intermediate lobe cells from 40 rat pituitaries were incubated for 3 h with [35S]methionine + [3H]-phenylalanine, [35S]methionine, [3H]valine, and [3H]leucine. The cell extracts were purified by carboxymethyl-cellulose chromatography (CMC) and the fraction eluting with ovine adrenocorticotropic hormone (ACTH) was further purified either by another CMC under the same conditions or by high performance liquid chromatography (HPLC). Microsequencing of the product from the second CMC allowed the identification of a peptide containing methionine 4 and phenylalanine 7, as expected for the NH2 terminus of ACTH. Purification by HPLC of a similar peptide obtained from the three other incubations gave three main raoactive peaks which were further characterized by their migration rates on polyacrylamide gels, molecular weight, and microsequencing. Results indicated that intact ACTH (residues 1-39) is present in extracts of rat intermediate lobe, but in very small quantities (less than 1% of the beta-endorphin content). ACTH is probably broken down into smaller fragments, e.g. alpha-melanocyte-stimulating hormone (alpha-MSH) (ACTH, 1-13) and corticotropin-like intermediate lobe peptide (CLIP) (ACTH, 18-39). These studies also revealed with existence of a peptide having identical sequence with the (N-1) terminus of the ACTH/lipotropin (LPH) precursor.
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PMID:Biosynthesis and characterization of adrenocorticotropic hormone, alpha-melanocyte-stimulating hormone, and an NH2-terminal fragment of the adrenocorticotropic hormone/beta-lipotropin precursor from rat pars intermedia. 22 83

A major and several minor trichloroacetic acid (TCA) soluble, bioassayable melanotropic peptides, as well as bioreactive and immunoreactive alpha-MSH have been found in the hypothalamus, olfactory bulb and cerebral cortex of normal and hypophysectomized rats. By employing subcellular fractionation procedures it was demonstrated that alpha-MSH and the major TCA soluble melanotropic peptide (MMPB) were localized in synaptosomes and were released by hypoosmotic shock. The analysis of MMPB by electrophoretic and chromatographic procedures reveales that it is not ACTH4-10, ACTH1-10, ACTH1-24, NAcACTH1-10 or alpha-MSH. MMPB was found to cross-react with an antiserum specific for the Lys-Pro-Val NH2 sequence in alpha-MSH, indicating that this C-terminal sequence of alpha-MSH may be present in its structure. MMPB was also shown to differ electrophoretically from the two major TCA soluble melanotropic peptides found in the neurointermediate lobe of the pituitary. In view of their synaptosomal localizations MMPB and alpha-MSH may play a role in synaptic function in the nervous system.
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PMID:Melanotropic peptides: presence in brain of normal and hypophysectomized rats, and subcellularly localized in synaptosomes. 22 37

Three 3-hr incubations of pars intermedia cells from 40 rat pituitaries with [35S]methionine, [3H]lysine, and [3H]leucine sufficed for the identification and chemical characterization of biosynthesized beta-lipotropin, gamma-lipotropin, and beta-endorphin. From the molecular weight, migration on polyacrylamide gels, and sequence Met5, Lys9, Leu14,17, rat beta-endorphin was shown to be identical to its sheep homologue and no trace of Leu5 beta-endorphin could be detected. Rat beta-lipotropin differs from that of sheep in its elution properties on CM-cellulose, and its sequence shows Leu2,10,14, Lys20. Rat gamma-lipotropin shows the same NH2-terminal sequence as beta-lipotropin and is again different from its sheep homologue. The identification of rat beta-lipotropin was confirmed by its selective cleavage into beta-endorphin after trypsin digestion of the citraconylated peptide, a property not observed with rat gamma-lipotropin.
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PMID:In vitro biosynthesis and chemical characterization of beta-lipotropin, gamma-lipotropin, and beta-endorphin in rat pars intermedia. 27 17

The endogenous opioid peptide, beta-endorphin, induces nonconvulsive limbic epileptiform activity when administered intraventricularly to rats. Epileptiform activity is elicited by beta-endorphin in doses that are devoid of analgesic or behavioral signs. Equimolar intraventricular doses of morphine or of the enkephalin analog [DAIa2,Met5]enkephalin-NH2 fail to elicit this limbic epileptiform activity. These observations, together with the recent immunohistochemical localization of beta-endorphin to midline limbic structures, suggest that beta-endorphin may have an important role in the regulation of limbic excitability.
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PMID:beta-Endorphin induces nonconvulsive limbic seizures. 28 26

All the opiate-like peptides we tested (Met-enkephalin, (D-Ala2)-Met-enkephalin-NH2, beta-endorphin, (D-Ala2)-beta-endorphin, (D-Ala2)-alpha-endorphin, (D-Ala2)-gamma-endorphin) were capable of reducing distress vocalizations (DV's) in socially-isolated chicks when injected into the vicinity of the fourth ventricle in doses as low as 100 picomoles. All of these substances were at least as potent as equimolar doses of morphine sulfate. In general, DV's were a more sensitive measure of opiate-like peptide effects than reductions in body temperature. In a more limited study using peripheral injections, it was determined that (D-Ala2)-Met-enkephalin at doses of 400 nanomoles/kg, like morphine sulfate, was more effective in reducing DV's, than an equimolar dose of beta-endorphin. beta-endorphin was not as effective via a peripheral route as it was via central administration.
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PMID:Reduction of distress vocalization in chicks by opiate-like peptides. 31 90

Serial sections from epoxy resin-embedded rat anterior pituitaries were sequentially immunostained for endorphin, [Met]enkephalin, and growth hormone, respectively. We found that [Met]enkephalin immunoreactivity was confined to the growth hormone producing cells. Corticotropin/endorphin cells in the anterior pituitary from both normal and adrenalectomized rats did not contain any [Met]enkephalin immunoreactivity. When anterior pituitary cells were maintained in monolayer culture for 10 days, [Met]enkephalin immunoreactivity was still located in the growth hormone-producing cells although the staining was weaker than in the somatotrophs in pituitary tissue fixed immediately after death of the animals. This suggested that somatotrophs synthesize [Met]enkephalin. However, this cannot be proved conclusively until biosynthesis experiments have been performed. The following conclusions were drawn from these findings. (i) Anterior pituitary [Met]enkephalin is not an extraction artifact derived from beta-endorphin with which it shares the NH2-terminal pentapeptide sequence. (ii) In the anterior pituitary, beta-endorphin is not the precursor to [Met]enkephalin. [Met]Enkephalin in somatotrophs may be of brain origin and in the somatotrophs may be bound to intracellllar receptors as has been shown for luteotropin releasing hormone in gonadotropic cells.
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PMID:Pituitary somatotrophs contain [Met]enkephalin-like immunoreactivity. 36 11

Rats were given four daily, interperitoneal injections (80 micrograms/kg) of Met-enkephalin, (D-Ala2)-Met-enkephalin-NH2, beta-endorphin, (D-Ala2)-beta-endorphin or the diluent (0.9% NaCl acidified to, 0.01 M with acetic acid). Animals were subsequently tested for food and water inake and activity. Met-enkephalin injections did not affect any of the measures but its (D-Ala2) analog reduced food intake and some of the activity measures in a complicated way. beta-Endorphin injections did not affect food or water intake; in familiar situations these animals were less active while novel situations seemed to potentiate activity. The (D-Ala2) analog reduced wheel running over 24 hours.
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PMID:Systemic administration of Met-enkephalin, (D-Ala2)-Met-enkephalin, beta-endorphin, and (D-Ala2)-beta-endorphin: effects on eating, drinking and activity measures in rats. 52 99

The release of melanocyte-stimulating hormone (MSH) into the medium during incubation and the pituitary tissue content of MSH were measured separately using pituitary glands collected from rats at various stages of the oestrous cycle. The MSH was measured by a biological assay using a synthetic alpha-MSH as standard. The release of MSH was maximal during thepro-oestrous phase and MSH content of the pituitary gland was highest during dioestrus. The influences of the tripeptide Pro-Leu-Gly-NH2, which inhibits MSH secretion in vivo, and of progesterone on the release of MSH in vitro were studied with tissue collected at various phases of the oestrous cycle. Pro-Leu-Gly-NH2 was effective in inhibiting MSH release both at pro-oestrus and oestrus but not at dioestrus. Progesterone overcame this inhibition.
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PMID:Differences in the release of melanocyte-stimulating hormone in vitro by rat pituitary glands collected at various times during the oestrous cycle. 56 39

A number of questions remain unsettled about the release of melanocyte-stimulating hormone (MSH) and about its function. Even though relatively few investigators are studying this area, some generalities have emerged during the last 10 years. It now seems that release of MSH from the pituitary is inhibited by a substance present in the hypothalamus. The structure of this physiologic inhibitor of MSH release may still not be considered an established entity but there is evidence for additional mechanisms capable of exerting a fine control on the release of MSH. Contrary to some opinions, the release of MSH does not always occur together with the release of ACTH, and the release of the two hormones can be dissociated in several laboratory and clinical situations. In addition, many studies have shown that the pituitary peptide, MSH, exerts behavioral and electroencephalographic effects in both the rat and man. The hypothalamic peptide Pro-Leu-Gly-NH2 (MIF-I) also has direct effects on the central nervous system that may include alleviation of the symptoms of Parkinson's disease.
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PMID:Some questions related to melanocyte-stimulating hormone. 96 14

Melanin was measured in various parts of the rat brain by a spectrophotofluorometric assay. This method could detect natural, Sepia melanin as well as melanin synthesized from L-DOPA. Contrary to published expectations of other investigators, measurable amounts of melanin were found in the brain of albino as well as pigmented rats. The highest concentrations of melanin occurred in the pons-medulla and midbrain, but all regions within the blood-brain barrier contained greater concentrations than samples from many other tissues in the body. No significant change in the melanin content was found after various endocrine manipulations such as removal of the pituitary, pineal, adrenals, thyroid, testes, or ovaries, exposure to constant illumination or darkness, and daily injection for 5 weeks of alpha-MSH, Pro-Leu-Gly-NH2 (MIF-I) or melatonin. As expected, retinal tissue from black-hooded rats contained extremely high levels of melanin whereas that from albino rats contained no melanin. It is thought that the presence of melanin in the brain of albino and pigmented rats may have a function which is still unknown.
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PMID:Melanin in the rat brain. 102 Dec 12


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