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 intermediate lobe of the pituitary gland synthesizes the multifactorial precursor molecule pro-opiomelanocortin (POMC), from which, through a process of post-translational enzymatic processing, beta-endorphin-(1-31) (beta E) and a variety of N alpha-acetylated and C-terminally shortened forms of this peptide are generated. Using an in vitro superfusion system, the release of these endorphins from intact rat neurointermediate lobes (NILs) was investigated under basal and isoproterenol (ISO) stimulated conditions. Superfusion of NILs with the beta-adrenergic agonist ISO (30 min pulse) resulted in a rapid, sustained and concentration-dependent stimulation of the release of beta E-like immunoreactivity (beta E-IR) over basal as determined with an antiserum directed against the C-terminus of the beta E- (1-31) sequence (10(-6) M: + 145%; 10(-7) M: + 73%; 10(-8) m: + 41%). The release of N(alpha)-acetylated-endorphin-like immunoreactivity (AcE-IR) was stimulated to a similar extent. These effects of ISO were antagonized by the competitive alpha-adrenoceptor antagonist propranolol in a concentration-dependent manner, indicating the involvement of alpha-adrenoceptors. The beta-related peptides released from the NILs under basal and ISO-stimulated conditions were further characterized, based on their retention times in a reversed-phase HPLC system and their reactivity with specific antisera recognizing respectively the midportion of beta E, the N-terminus of acetylated endorphins, the C-terminus of tau-endorphin (beta E-(1-17); tau E), or the C-terminus of alpha-endorphin (beta E-(1-16); alpha E). In HPLC fractionated superfusates 10 peaks were resolved that reacted with the midportion beta E antiserum. In superfusates collected under basal conditions, three major peaks possessed chromatographical and immunological characteristics of Ac beta E-(1-26), Ac beta E- (1-27) Ac beta E-(1-31). In addition, a prominent peak was found eluting around the retention time of beta E-(1-31), that contained both acetylated and non-acetylated material. Six smaller peaks were observed, with the characteristics of beta E-(1-26) and beta E-(1-27) (these peptides were not resolved with the HPLC system used), Ac tau E, tau E, Aa alpha E, and des-tyrosine-alpha E (DT alpha E), respectively. In superfusates collected during superfusion of NILs with ISO (10(-6) M) all peaks were increased. However, those eluting as beta E-(1-31), beta E-(1-26)/beta E-(1-27), Ac beta E-(1-26) and Ac tau E appeared to be preferentially stimulated.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Isoproterenol-stimulated release of beta-endorphin and related peptides from the rat pituitary neurointermediate lobe in vitro: evidence for preferential release of certain molecular forms of beta-endorphin. 228 Aug 22

We have investigated the ontogeny of immunoreactive beta-endorphin (i-beta E) in the testes of rats from 5 to 150 days of age. i-beta E was measured by RIA in acid extracts of decapsulated testes and characterized by gel filtration chromatography. Significant age-related differences in both the levels and type of i-beta E were observed. Total levels of i-beta E in the testes were very low and barely detectable from 5-20 days of age, but rose sharply in parallel with testes weights from 20-60 days of age; thereafter, no significant changes in i-beta E were found through 150 days of age. Concentrations of i-beta E, expressed in pmol/g testis, fell precipitously between days 5 and 10 and remained relatively constant from 10-150 days. Most of the i-beta E at 5 and 15 days chromatographed like authentic beta-endorphin. However, with the onset of puberty (30-35 days) and during sexual maturation, much of the total i-beta E chromatographed like its' precursor beta-lipotropin (beta LPH). Hypophysectomy decreased the weight and total i-beta E levels of the testes to the same extent without altering the concentrations of i-beta E or the chromatographic pattern of i-beta E. These results indicate that beta E-like and beta LPH-like peptides are present in the rat testis and that age-related changes in both the levels and type of i-beta E correlate with various structural and functional aspects of testicular development.
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PMID:The ontogeny of immunoreactive beta-endorphin and beta-lipotropin in the rat testis. 252 84

A specific and quantitative method for the determination of rat beta-endorphin by the combination of HPLC and RIA was developed. Rabbit antiserum against camel beta-endorphin (c beta-E) was raised and used for RIA at the final concentration of 1:10000. The quantitative range estimated from the displacement curve was 0.1-2.0 ng. Cross-reactivities with Met-Enk, Leu-Enk, alpha-MSH, alpha-endorphin, ACTH and human beta-E were less than 0.1, less than 0.1, less than 0.1, less than 0.1, 2 and 100%, respectively. These peptides were separated from each other by reversed phase HPLC with UV254 nm detection, and the minimum detectable dose of c beta-E was found to be 1 microgram. beta-E-like immunoreactivity (beta-ELIR) in the HPLC effluent was determined by RIA. The HPLC-RIA chromatogram of authentic c beta-E exhibited a single peak which coincided with the peak of c beta-E detected by UV, and 80% of the injected c beta-E (1-100 ng) was detected in the c beta-E fraction. The HPLC-RIA chromatogram of rat pituitary, hypothalamus, cerebrospinal fluid and plasma revealed the presence of 1-3 peaks, one of which was observed at the position of c beta-E. The HPLC elution of rat pituitary resolved the material into two peaks of biological activity, one of which coincided with the peak of beta-ELIR at the position of c beta-E. The HPLC-RIA chromatogram of the c beta-E fraction from pituitary obtained by gel-chromatography exhibited three peaks, one of which coincided with c beta-E. These results suggest that beta-ELIR in the c beta-E fraction of the HPLC elution may reflect rat beta-E accurately.
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PMID:[A specific and quantitative determination of rat beta-endorphin. Combination of HPLC and RIA]. 609 34

Sensitive and specific radioimmunoassays for gamma- and beta-endorphin-like peptides (gamma E and beta E) were used to examine the distribution and relationship of these peptides in the pituitary and in microdissected nuclear brain areas of the male rat. In the pituitary, the highest amounts of gamma E and beta E were found in the neurointermediate region of the gland. On a molar basis, gamma E-like immunoreactivity was found to exist as a relatively constant proportion of beta E-like peptides throughout the pituitary. In the brain, while beta E-like peptides were detected in many brain areas, gamma E-like peptides were detected in only a limited number of sites. In most of these areas, the molar ratio of gamma E to beta E-like peptides closely approximated that found in the pituitary. However, in the ventromedial nucleus of the hypothalamus and nucleus accumbens a higher proportion of gamma E to beta E was measured. These results suggest preferential formation of gamma E or related peptides in certain areas of the brain may occur.
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PMID:Regional distribution of gamma- and beta-endorphin-like peptides in the pituitary and brain of the rat. 616 71

Gamma-endorphin (gamma E) and related peptides were localized in the brain of the rat, and compared to the distribution of beta-endorphin related peptides. gamma E-like immunoreactivity (gamma E-LI) was shown to exist only in brain regions known to receive innervation from POMC neurons but not in their pericaria in the arcuate nucleus. Nuclei of the hypothalamus and ventral forebrain contained the major concentration of gamma E-LI and extracts from these regions were purified and subjected to HPLC in order to identify gamma E-related peptides. gamma E, des-tyrosine1 gamma E, des-enkephalin-gamma E, and alpha-N acetyl gamma E co-elutable peptides as well as various unidentified forms were evident. This study provides evidence of the endogenous presence of pharmacologically active gamma E-related peptides in brain regions where they have been postulated to modulate dopaminergic transmission.
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PMID:Localization and identification of gamma-endorphin and beta-endorphin-like peptides in the hypothalamus and ventral forebrain of the rat. 619 7

In the current study we tested the hypothesis that human plasma beta-endorphin (beta E) is derived from at least two subpopulations of beta E-releasing cells: one sensitive to glucocorticoids as well as to dopamine (DA; regulated analogously to the corticotrophs of the rat pituitary), and one insensitive to glucocorticoids but sensitive to DA (regulated analogously to the melanotrophs of the rat pituitary). To test this hypothesis, human plasma levels of ACTH, cortisol, and beta E-like immunoreactivity were measured at baseline and after haloperidol treatment (0.05 mg/kg, i.v.) in two experimental groups, one pretreated with dexamethasone (1.5 mg) and one pretreated with placebo. Plasma PRL levels were also measured in both groups as an indicator of DA receptor blockade. Dexamethasone partially suppressed both baseline and haloperidol-stimulated levels of human plasma beta E-like immunoreactivity, whereas it completely suppressed both basal and haloperidol-stimulated levels of ACTH and cortisol and had no statistically significant effect on either basal or haloperidol-stimulated PRL levels. These data support a negative feedback effect of glucocorticoids on one DA-sensitive cell population that releases both ACTH and beta E (corticotroph like), but not on a second cell population that releases beta E but not ACTH.
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PMID:Evidence for two differentially regulated populations of peripheral beta-endorphin-releasing cells in humans. 840 51

The responsiveness of the POMC system to exogenous stimuli and the diurnal and seasonal rhythmicity of ACTH and beta-endorphin (beta E) in plasma were studied in outdoor-reared domestic ganders. Plasma levels of ACTH- and beta E-like immunoreactivities were determined by direct and specific radioimmunoassays. In the first series of experiments immunoreactive (ir) ACTH and beta E were measured in the plasma of male domestic geese after 5 min of ether stress and after administration of 2 micrograms/kg lipopolysaccharide (LPS). Both ir-ACTH and ir-beta E levels increased 5 and 10 min after ether inhalation, but the increase in the ir-beta E concentration was only half that of the ir-ACTH. The plasma ir-ACTH levels were elevated after 60 and 120 min but not after 90 min of LPS administration: ir-beta E levels were unchanged at all time points. In a second series of experiments blood samples were taken on 30 March. 16 June, 4 August, and 27 October. On these days diurnal samplings were performed at 02:00, 06:00, 10:00, 14:00, 18:00, and 22:00 h. A two-way analysis of variance showed significant diurnal and seasonal changes for both hormones and significant interaction between the diurnal and seasonal levels. The highest daily mean values of the plasma ir-ACTH and ir-beta E concentrations were measured in June. The maximum of the ir-ACTH level was at 10:00 h in March and August, but at 22:00 h in June and October. The changes in ir-beta E concentrations paralleled those of ir-ACTH, but the changes did not reach statistical significance in every case.
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PMID:Characteristics of the proopiomelanocortin system in the outdoor-bred domestic gander. II. Seasonal and circadian rhythmicity; effect of ether stress and lipopolysaccharide administration. 944 22