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)

A novel pituitary protein, 7B2, of approximately 180 amino acids has been suggested to colocalise with LH in the pituitary gonadotropes. Increased secretion of LH is known to occur in functionless pituitary tumours. We have therefore measured 7B2 immunoreactive equivalents in the 24-h medium of explant pituitary cultures prepared from 17 functionless, 20 somatotropic, 16 PRL secreting and 8 corticotropic adenomas. A synthetic fragment corresponding to amino acids 23-39 of 7B2 was used to raise antisera (rabbits), prepare radiolabel (chloramine T iodination) and also serve as the assay standard. 7B2-immunoreactive equivalents in the medium from the functionless tumours was 517 +/- 149 pmol/l, significantly higher than that of the somatotropic tumours (248 +/- 90 pmol/l, P less than 0.05), prolactinomas (108 +/- 37 pmol/l, P less than 0.001) and corticotropin producing adenomas (107 +/- 77 pmol/l, P less than 0.001) (one-way analysis of variance). Gel permeation chromatography of medium obtained from functionless tumours revealed two immunoreactive 7B2 peaks one eluting at a coefficient of 0.28 corresponding to that of normal human pituitary extract and another eluting at a coefficient of 0.59. Gel chromatography profiles of medium obtained from somatotropic tumours contained similar immunoreactive 7B2 peaks (elution coefficient 0.28 and 0.57). These findings demonstrate that 7B2-like material is secreted by pituitary adenomas in explant culture with the highest level from functionless tumour cultures.
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PMID:7B2, a new protein secreted by human functionless pituitary tumours, in vitro. 340 Apr 5

Immunoreactive alpha-, beta- and gamma-endorphins and beta-lipotropin--C-terminal peptide fragments of pro-opiomelanocortin (POMC)--were discovered and measured by RIA in the bovine adrenal medulla and cortex. These peptides were also discovered in perfusates of the adrenal gland. POMC proper and some intermediate forms of its processing not differing in electrophoretic mobility from the respective molecular forms of hypophyseal POMC were identified in the medulla and cortex of the adrenals by the immunoblotting technique with the use of antiserum to beta-lipoprotein. It is concluded that POMC gene is expressed in the adrenal medulla and cortex and that as a result of POMC processing a noticeable amount of its peptide fragments is formed and secreted in adrenal cells. The authors thus suggest the presence of existence of the pituitary-unrelated mechanisms of adrenal function control with participation of POMC peptides synthesized in the adrenals.
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PMID:[Identification of pro-opiomelanocortin and the secretion of its peptide fragments in the adrenals of the bull]. 402 67

To assess the effect of chronic hypersecretion of corticotropin (ACTH) and other peptides derived from proopiomelanocortin , and of cortisol, on plasma adrenal androgen concentration, plasma dehydroepiandrosterone sulphate (DHEA-S), dehydroepiandrosterone (DHEA), androstenedione (delta 4 A), and cortisol were measured in 14 children and adolescents with Cushing's disease, a 9-year-old boy with an ectopic ACTH-producing tumour, and a group of normal, age-related individuals. The plasma DHEA-S concentration was normal for chronological age in 9 of 12 patients and for bone age in 7 of 10 patients. The plasma DHEA level was normal for chronological age in 12 of 14 patients and for bone age in 8 of 10 patients. In contrast, the concentration of plasma delta 4 A was raised for chronological age in 6 of 13 patients and for bone age in 7 of 10 patients. All patients had raised plasma cortisol levels in the afternoon and other laboratory and clinical signs of hypercortisolism. In the boy with an ectopic ACTH-producing tumour, plasma DHEA-S was moderately raised, plasma DHEA was normal, and plasma delta 4 A was very high. This patient's plasma ACTH levels ranged from 1340 to 1520 pg/ml and the cortisol levels from 51 to 95 micrograms/dl. The findings suggest that a factor other than ACTH is also required for adrenal androgen secretion. Since the other proopiomelanocortin -related peptides--ie, the N-terminal peptide (1-76), beta-endorphin (beta-EP), beta-lipotropin (beta-LPH), and gamma-lipotropin (gamma-LPH)--are raised in the plasma of patients with Cushing's disease, one of these is unlikely to be that putative factor.
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PMID:Dissociation between plasma adrenal androgens and cortisol in Cushing's disease and ectopic ACTH-producing tumour: relation to adrenarche. 614 33

Several lines of evidence suggest that the endogenous opioid peptides endorphins may play a role in the defensive response of the organism to stress. The present paper summarizes these findings as well as evidence linking endorphins to the anterior pituitary polypeptide hormone adrenocorticotropin (ACTH). Evidence is presented that endorphins may function as trophic hormones in peripheral target organs such as the adrenal medulla and the pancreas. As such they may be part of the physiological mechanisms that mediate adrenaline and glucagon release in response to stress. Endorphins (enkephalins) are also suggested to play a role in the control of the pituitary gland during stress. In such capacity they may act as hormone-releasing or inhibiting factors. Finally, endorphins appear to play a role in the behavioral concomitants of stress. In such capacity endorphins are suggested to function as modulators of neural systems that mediate the elaboration and expression of the reactive/affective components of stress. Speculations on the mode of interaction between endorphins and ACTH in the global response to stress are discussed.
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PMID:The role of endorphins in stress: evidence and speculations. 625 Jan 4

Radioimmunoassay developed to measure N-terminal peptide of pro-opiomelanocortin isolated from porcine pituitaries was used to measure changes in the concentration of immunoreactive material in rat plasma. The N-terminal peptide immunoreactive material decreased in plasma after hypophysectomy of both female and male rats below the level of detectability and substantially increased after adrenalectomy as compared to normal control rats. The same changes were observed when beta-endorphin and ACTH like immunoreactive material was measured. The primary culture of rat anterior pituitary cells released ACTH and N-terminal peptide-like immunoreactive material into the incubation medium. The results seem to indicate that the N-terminal immunoreactive material is a secretory product produced by the pituitary gland.
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PMID:Concomitant changes of ACTH, beta-endorphin and N-terminal portion of pro-opiomelanocortin in rats. 628 83

N-terminal peptide of pro-opiomelanocortin (N-POMC) was measured in the human amniotic fluid. At the gestational age of 16 to 20 weeks, the radioimmunoassay with three different antibodies demonstrated the respective values of 2.39 +/- 0.78, 4.69 +/- 2.27, and 5.92 +/- 2.66 ng/ml. These values are approximately 10 times higher than the measurements in the plasma of women at the corresponding gestational period. The amniotic fluid collected during the delivery had significantly lower concentrations of N-POMC than the amniotic fluid at 16 to 20 weeks' gestation. However, the plasma values of N-POMC had increased approximately three times when measured at delivery and compared with the plasma values at 16 to 20 weeks' gestation. Adrenocorticotropic hormone, measured simultaneously with N-POMC in some of the samples, showed changes similar to those in N-POMC. The N-POMC immunoreactivity from the amniotic fluid has the same retention time on reversed-phase high-performance liquid chromatographic separation as the peptide purified from the human pituitary gland, thus indicating the identity of both peptides.
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PMID:N-terminal peptide of pro-opiomelanocortin in human amniotic fluid. 630 97

The primary mechanism of activation of intracellular prohormones seems to involve proteolytic cleavage at sequences of consecutive basic residues. Thus, all the known biologically active peptides derived from the prohormone of corticotropin and beta-endorphin appear to be excised initially by enzymes with this specificity. The C-terminal peptide, beta-endorphin (1-31), is generated by cleavage at a lysyl arginine sequence and an additional cleavage can give rise to the related peptides, beta-endorphin (1-27) and beta-endorphin (1-26). These derivatives of beta-endorphin are released by an endopeptidase that appears to catalyse cleavage on the carboxyl side of paired lysine residues, followed by the action of a carboxypeptidase B-like enzyme (Fig. 1). The beta-endorphin fragments, beta-endorphin (1-27) and beta-endorphin (1-26), have been isolated from porcine and bovine pituitary but the C-terminal dipeptide, glycyl glutamine, has not been reported previously. Here we describe the isolation of glycyl glutamine from porcine pituitary and present evidence for its presence in sheep brain stem. When applied ionophoretically to brain stem neurones in the rat, the dipeptide exhibited an inhibitory action on cell firing.
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PMID:Glycyl glutamine, an inhibitory neuropeptide derived from beta-endorphin. 631 48

Ten peptides related to melanocyto-stimulating hormone (MSH) have been identified in an acid acetone extract of the chum salmon pituitary. All these peptides are related to the alpha-MSH and beta-MSH families, but no peptide related to gamma-MSH has been found. This result is in accordance with the finding that the gamma-MSH segment is deleted from the N-terminal peptide of salmon pro-opiocortin (NPP I). Based on the structures of newly isolated peptides, the maturation process of MSH is discussed. The major components of salmon MSH were tested for biological activities. In the lipolytic assay with rabbit fat cells, alpha-MSH I and alpha-MSH II were equipotent, but beta-MSH I and NPP I exhibited very low or no activity. On the other hand, the des-acetyl-alpha-MSH I was found to be four times as potent as alpha-MSH I in this assay. The steroidogenic activities of alpha-MSH I and N-des-acetyl-alpha-MSH I were approximately 0.05% of the potency of ovine ACTH. All other peptides exhibited less than 0.01% potency. Salmon alpha-MSHs were found to be somewhat more potent melanophore-stimulating agents than the beta-MSHs.
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PMID:Chemical and biological characterization of salmon melanocyte-stimulating hormones. 632 92

An in vivo labeling technique was utilized to demonstrate the in situ biosynthesis of pro-opiomelanocortin (POMC)-, beta-endorphin- and alpha-melanotropin (MSH)-like molecular species in rat brain. Unrestrained adult female rats were bilaterally cannulated in the hypothalamic arcuate nuclear region; [35S]methionine was infused either over a 15-min period with sacrifice 2 hr subsequently, or at a constant rate for 6 hr prior to sacrifice. Sequential immune-affinity chromatography and several chromatographic and electrophoretic techniques were employed to detect and characterize POMC-related material in the hypothalamic arcuate nuclear region, preoptic area, and median eminence. Four molecular species containing both corticotropin (ACTH) and beta-endorphin antigenic determinants within the same molecules were detected in the arcuate nuclear region and preoptic area. Two forms were similar to rat pituitary POMC with respect to apparent molecular weight (35,000 and 31,500) and [35S]methionine-containing tryptic fragments (one methionine each in N-terminal glycopeptide, ACTH, and beta-endorphin sequences of rat POMC). The other two forms (apparent Mr of 21,000 and 19,000) contained only the labeled tryptic fragments characteristic of ACTH and beta-endorphin. The detection of the latter forms suggests that POMC in brain, unlike its post-translational processing in rat pituitary, undergoes primary cleavage between the N-terminal peptide and the ACTH sequence. Peptides physicochemically indistinguishable from authentic beta-endorphin and des-acetyl alpha-MSH were detected in approximately equimolar amounts in all three brain regions. The ratio of POMC-like material to the alpha-MSH- and beta-endorphin-sized peptides was highest in the arcuate nuclear region, suggesting that POMC-like proteins are synthesized in the arcuate nuclear region and are processed into the smaller molecular species during axonal transport.
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PMID:Demonstration of in vivo synthesis of pro-opiomelanocortin-, beta-endorphin-, and alpha-melanotropin-like species in the adult rat brain. 632 9

The N-terminal peptide of salmon proopiocortin has been isolated and the primary structure including two disulfide bonds elucidated. The peptide consisted of 76 amino acid residues, which is 27 residues shorter than the bovine and human peptides. The N-terminal 44 residues of the teleost peptide exhibited significant sequence homology to those of the mammalian peptides. The salmon peptide, however, is lacking in the counterpart of gamma-MSH which is located between residues 51 and 64 in the mammalian peptides.
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PMID:Gamma-melanotropin is not present in an N-terminal peptide of salmon proopiocortin. 734 16


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