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)

Chromogranin was demonstrated by immunohistochemistry in the cytoplasm of human beta-thyrotropin, human beta-follicle-stimulating hormone-, human beta-luteinizing hormone-, and human alpha-subunit-containing cells of the non tumorous human adenohypophyses. Some surgically removed human beta-thyrotropin-, human beta-follicle-stimulating hormone-, human beta-luteinzing hormone-, and human alpha-subunit-producing pituitary adenomas, as well as some null cell-adenomas, exhibited chromogranin immunoreactivity, whereas adenomas storing human growth hormone, human prolactin, or corticotropin were negative. Chromogranin immunopositivity was variable in extent and intensity; not every glycoprotein-producing cell could be immunostained in the nontumorous adenohypophysis and the majority of chromogranin-containing adenomas showed only focal positivity. No explanation can be offered for this variability. The demonstration of chromogranin by the avidin-biotin-peroxidase technique may be helpful in the immunohistochemical characterization of some glycoprotein hormone-producing pituitary adenomas, as well as null-cell adenomas of the human pituitary.
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PMID:Immunohistochemical localization of chromogranin in human hypophyses and pituitary adenomas. 298 72

Pro-opiomelanocortin (adrenocorticotropin/endorphin prohormone) is processed to yield active hormones by cleavages at paired basic amino acid residues. In this study, an enzyme that specifically cleaves at the paired basic residues of this prohormone has been purified from bovine pituitary intermediate lobe secretory vesicles, the intracellular processing site of proopiomelanocortin. This enzyme, named pro-opiomelanocortin converting enzyme, has been characterized as a glycoprotein of Mr approximately 70,000. It has an apparent isoelectric point between 3.5 and 4.0. The pH optimum of the pro-opiomelanocortin converting enzyme is between 4 and 5, but the enzyme is highly active at the intravesicular pH of 5.1-5.6. The enzyme specifically cleaved the Lys-Arg pairs of pro-opiomelanocortin to yield Mr = to 21,000-23,000 ACTH, beta-lipotropin, Mr 13,000 and 4,500 ACTH, beta-endorphin, and a Mr = 16,000 NH2-terminal glycopeptide, the products synthesized by the pituitary intermediate lobe in situ. NH2- and COOH-terminal analysis of the products indicated that the pro-opiomelanocortin converting enzyme cleaves the peptide bond either between the Lys and Arg or on the carboxyl side of the Arg at Lys-Arg pairs of pro-opiomelanocortin. The intracellular localization, pH optimum, and cleavage specificity of the enzyme suggest that it may function as a pro-opiomelanocortin processing enzyme in the pituitary intermediate lobe in vivo.
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PMID:Purification and characterization of a paired basic residue-specific pro-opiomelanocortin converting enzyme from bovine pituitary intermediate lobe secretory vesicles. 298 47

AtT20 cells, a line of murine pituitary tumour cells that secrete adrenocorticotropic hormone (ACTH), have been infected with the coronavirus mouse hepatitis virus strain A59 (MHV-A59). Between 5% and 10% of AtT20 cells are susceptible to the infection. Unlike infections of fibroblastic sac- and 17Cl 1 cells, the infection of AtT20 cells does not lead to cell fusion, despite the production of the fusogenic E2 viral spike glycoprotein. Within infected AtT20 cells the second viral envelope glycoprotein, E1, is located in a perinuclear region; at least until very late in the infection it fails to accumulate to detectable levels in the rough endoplasmic reticulum (RER). By contrast to infection of sac- and 17Cl 1 cells, where the RER is a major site of assembly of progeny virions, in AtT20 cells budding of progeny virions is restricted to the Golgi cisternae, which eventually vesiculate, and peri-Golgi smooth membraned vesicles. Apparently, therefore, the intracellular compartments into which wild-type MHV-A59 buds are determined not by the virus but by the host cells. MHV-A59 infected cultures of AtT20 cells can be serially passaged without loss of the infection or increase in the proportion of infected cells; they become persistently infected carrier cultures. The progeny virus from serially passaged, infected AtT20 cells is apparently wild-type. It infects sac- cells and induces them to form syncitia. Within the sac- syncitia the viral E1 glycoprotein accumulates in the RER and many virions assemble there.
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PMID:Infection of AtT20 murine pituitary tumour cells by mouse hepatitis virus strain A59: virus budding is restricted to the Golgi region. 299 76

Pro-opiomelanocortin (POMC) is a glycoprotein precursor for a number of neuropeptides and peptide hormones. The functional significance of the glycosylation of POMC has never been established. Using the antibiotic tunicamycin to block glycosylation of the prohormone in the mouse pars intermedia, we have compared processing of non-glycosylated prohormone with that of glycosylated prohormone in pulse-chase experiments. The peptides produced from non-glycosylated prohormone were shown to be correct cleavage products. Therefore it was concluded that, with the possible exception of peptides from the N-terminal region of the prohormone, the carbohydrate on POMC plays no role in directing cleavage or in protecting the prohormone from random proteolysis. Tunicamycin treatment retarded N-terminal acetylation of melanotrophin but had no apparent effect on acetylation of beta-endorphin. The mouse pars intermedia synthesizes two forms of POMC which differ in their degree of glycosylation. Our results indicated that, during secretion, the melanotrophs make no distinction between peptides derived from the two prohormones.
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PMID:The functional significance of glycosylation of pro-opiomelanocortin in melanotrophs of the mouse pituitary gland. 299 83

The cytoplasmic secretory granules of corticotrophs in the anterior pituitary are basophil in trichrome stains and periodic acid-Schiff positive in the histochemical stain for glycoprotein due to their content of the glycosylated 16 000 N-terminal fragment of the precursor protein proopiomelanocorticotrophin (POC). The granules show a positive immunocytochemical reaction to antibodies raised against ACTH, beta-endorphin and N-terminal fragments of POC. A small subset of corticotrophs contains immunoreactive alpha MSH in addition. Immunocytochemistry shows the corticotrophs to constitute about 15-20% of the anterior pituitary cells arranged both singly and in clumps. They are distributed in the median wedge and anteriorly, laterally and posteriorly adjacent to the pars nervosa which is often 'invaded' by corticotroph basophils. The alpha MSH subset is prominent in the rudimentary intermediate lobe and is scattered anteriorly in the pituitary of the human fetus. Crooke cell hyalinization is associated with pathologically maintained hypercortisolaemia and with glucosteroid therapy. The hyalinization is demonstrated in ultrastructure to be due to massive accumulation of intermediate cytoplasmic filaments 7-8 nm in diameter that are normally present in only small number. The change is associated with a varying degree of loss of secretory granules. In untreated Addison's disease there is a marked increase in the number of corticotrophs, many of which are arranged in distended alveoli to form micronodules. The vast majority of cases of pituitary-dependent Cushing's disease and all cases of Nelson's syndrome are associated with a basophil or chromophobe adenoma. These give a positive immunocytochemical reaction with anti-ACTH, beta-endorphin and N-terminal POC. In ultrastructure the cells of the chromophobe adenomas are seen to contain sparse secretory granules that are usually smaller than those in the chromophil adenomas. There are only very few reports of pituitary-dependent Cushing's disease found to be due to immunocytochemically confirmed corticotroph hyperplasia with or without a corticotroph adenoma. A few cases have been described in which the adenoma cells show Crooke's hyalinization, associated in one example with secretion of a big ACTH found more typically in ectopic ACTH-secreting tumours. A group of cases due to corticotroph adenoma has been reported whose excessive ACTH secretion is reduced by treatment with the dopamine agonist bromocriptine, in which it is suggested that the tumour cells arise from a subset of corticotrophs of pars intermedia origin.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Histopathology of the pituitary. 300 76

Interleukin 1 (IL1) is a macrophage-derived polypeptide which signals neurons in the preoptic-anterior hypothalamus to initiate fever and the acute-phase glycoprotein response. Recently, increases in cerebrospinal fluid and hypothalamic levels of beta-endorphin have been reported during endotoxin (LPS)- and IL1-induced fevers, suggesting that this opioid may participate in the modulation of IL1 effects in the CNS. In this study, we investigated whether purified (human) IL1 influences the specific binding of three prototypic opioid agonists (2-D-alanine-5-L-methionineamide, DAME; (-)-ethylketocyclazocine, EKC; dihydromorphine, DHM) and one antagonist (naloxone) to opioid receptor-enriched membrane preparations in cerebral cortex, hypothalamus, midbrain, pons, medulla, and cerebellum of guinea pig brain. IL1 reduced the binding of these ligands to their receptors during a 30-min incubation. The extent of IL1 inhibition of a given ligand for its binding sites varied according to the brain region; within some regions, the extent of this inhibition also varied with the four ligands tested. But in cortex the effect of IL1 on the specific binding of DHM is dose-dependent. Similar results were obtained with crude homologous IL1. S. enteritidis endotoxin, suspended in pyrogen-free saline at concentrations from 4 to 36 micrograms/ml, did not inhibit the binding of these opioid ligands to their receptors in any brain region. These results indicate that IL1 interacts with the opiate receptors in guinea pig brain. This interaction, moreover, is not limited to the hypothalamus alone, the primary site of the pyrogenic action of IL1, but also occurs in other brain regions.
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PMID:Interleukin 1 reduces opioid binding in guinea pig brain. 301 Feb 57

One hundred and forty human fetal pituitary glands were removed from fetuses at 7-40 weeks of gestation and studied by light microscopy and immunocytochemistry to localize adenohypophysial hormones. For immunocytology, the avidin-biotin-peroxidase complex technique was more sensitive and identified hormones in younger fetuses than did the immunoperoxidase method. Adrenocorticotrophin, beta-endorphin, and growth hormone were the first hormones detected; they were identified by intense cytoplasmic immunopositivity at 8 weeks of gestation. Between 10 and 20 weeks, many growth hormone containing cells were large and showed scattered, faint positivity; after 20 weeks, smaller cells with intense positivity predominated. alpha-Subunit of the glycoprotein hormones was identified at 9 weeks of development; beta-subunits of thyroid-stimulating hormone, follicle-stimulating hormone, and luteinizing hormone appeared by 12 weeks. Gonadotrophs differed in numbers related to fetal age and sex. From 15 to 25 weeks, glands of female fetuses contained more gonadotrophs than did those of males; after 25 weeks, there was no significant difference in total gonadotroph numbers. Throughout gestation, adenohypophyses of male fetuses had more luteinizing hormone containing cells than follicle-stimulating hormone containing cells; pituitaries of females had approximately the same numbers of follicle-stimulating hormone containing and luteinizing hormone containing cells. Prolactin was identified in few small cells at 12 weeks; at term, prolactin-containing cells were numerous, comparable to those seen in the hyperplasia of maternal glands in late gestation and during lactation. This comprehensive study indicates morphologic correlations with pituitary hormone extraction data and with the appearance of the various hormones in the fetal circulation.
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PMID:Human fetal adenohypophysis. Histologic and immunocytochemical analysis. 301 83

Using the unlabelled antibody method at the light microscope level, and the immunogold method at the electron microscope level, the distribution of the different adenohypophysial cells was demonstrated in the teleost Poecilia latipinna, by means of antisera to both teleostean and mammalian pituitary hormones and their subunits. Anti-salmon prolactin, but not anti-rat or -ovine prolactin, gave a specific staining of the acidophils of the rostral pars distalis (RPD), while anti-trout growth hormone (GH), but not anti-rat GH, stained similar but always separate cells in the proximal pars distalis (PPD). Antisera to the whole molecules of mammalian glycoprotein hormones stained the entire population of basophils in the PPD, but separate populations of gonadotrophs and thyrotrophs could be discriminated using anti-salmon gonadotrophin and anti-human thyrotrophin beta subunit. Antisera to ACTH (1-24) and (11-24) sequences, as well as beta-endorphin and met-enkephalin, stained the lead haematoxylin-positive cells of the RPD and pars intermedia (PI), whereas anti-alpha-MSH stained only the PI cells. Ultrastructural examination showed that these immunoreactivities were present in the same secretory granules, and were always greater in pale granules rather than electron dense granules. In the RPD, blebs of ACTH-immunoreactive cytoplasm were found to protrude through the gaps in the basement membrane into the neurohypophysis. The second "PAS-positive" cell type of the PI showed a strong cross-reaction with anti-salmon gonadotrophin, suggesting that it may produce a glycoprotein chemically related to the gonadotrophin(s).
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PMID:Immunocytochemical demonstration of pituitary cell types in the teleost Poecilia latipinna, by light and electron microscopy. 302 62

The neuropeptides arginine vasopressin and oxytocin are generated from their prohormones in the hypothalamoneurohypophysial system by enzymatic cleavages at paired basic residues (i.e. Lys-Arg). This study describes the purification of an enzyme from bovine neural lobe secretory vesicles, the putative site of this processing, which is capable of cleaving several prohormones at paired basic residues. The enzyme is a glycoprotein of Mr approximately 70,000 and has an acidic pH maximum. It processes the heterologous precursors pro-opiomelanocortin and insulin at paired basic residues in a manner similar to a pro-opiomelanocortin-converting enzyme derived from bovine intermediate lobe secretory vesicles which has been described previously. In addition, the neural lobe-derived converting enzyme cleaves the human vasopressin prohormone in vitro to yield arginine vasopressin-Gly10-Lys11-Arg12 as the major vasopressin cleavage product. This indicates that the enzymatic cleavage in the vasopressin precursor occurred primarily on the carboxyl side of the arginine in the pair of Lys-Arg basic residues separating the vasopressin peptide from the neurophysin moiety in the precursor. The properties of the neural and intermediate lobe-derived enzymes are virtually identical, raising the possibility that a family of similar enzymes may be responsible for cleaving a number of prohormones at paired basic residues in different tissues.
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PMID:Purification and characterization of a paired basic residue-specific prohormone-converting enzyme from bovine pituitary neural lobe secretory vesicles. 302 39

The immunocytochemical technology in our laboratory has evolved in response to specific needs for more efficient, refined stains for each antigen. The rationale for the application of each of the immunocytochemical techniques used today is described, and detailed methods are given. In the early 1970s, it was determined that the peroxidase-antiperoxidase complex (PAP) stain provided the most sensitive means of detection of adrenocorticotropin (ACTH) at the electron microscope level even in tissues prepared with conventional fixation and embedding techniques that are considered rather harsh for the maintenance of antigenicity. Application of the same PAP complex technique to the larger glycoprotein antigens, like follicle-stimulating hormone (FSH), however, proved far more difficult; and the problem was resolved partially when more gentle fixation-embedding protocols were applied. The production of an efficient, reliable stain for FSH was achieved only with the avidin-biotin peroxidase complex (ABC) stains were applied in the early 1980s. This technique also allowed more efficient reactions for all the antigens, and morphometric data could thereby be collected more rapidly. Thus, we concluded that the light microscope immunoperoxidase techniques were excellent for the morphometric analysis of pituitary cell types in both pre-embedding and postembedding stains. However, the need for a more refined stain for its quantification at the electron microscope level on individual organelles led to the development of the colloidal gold stain in 1983-1984. This technique, which is new to our laboratory, is also described and illustrated in this report. Also included is a description of our studies of the effect of fixation and embedding processes on hormone antigenicity and techniques used to control background and nonspecific reactions. It is hoped that the novice will find the description of the rationale for the evolution of technology in our laboratory useful in making choices for his or her own immunocytochemical stains.
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PMID:Immunocytochemical studies of pituitary hormones with PAP, ABC, and immunogold techniques: evolution of technology to best fit the antigen. 308 66


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