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 neurointermediate lobes of dark adapted toads, Xenopus laevis, were incubated for 30 min in [3H]arginine, [3H]arginine plus [14C]glucosamine, or [3H]glucosamine and then chased for various time periods ranging from 1--3 h. The labeled polypeptides synthesized and secreted by the lobes were analyzed by acid-urea polyacrylamide gel electrophoresis. A glycosylated ACTH-endorphin precursor (32,000 mol wt) was synthesized during the pulse and identified by immunoprecipitation by ACTH-(11--24) antiserum. During the chase, this precursor was processed to various glycopeptides and peptides, including ACTH, beta-lipotropin, and alpha-MSH, which were subsequently secreted into the medium. An immunoprecipitable ACTH-related glycoprotein (approximately 150,000 mol wt) and other nonimmunoprecipitable glycoproteins (approximately 80,000--100,000 mol wt) were also synthesized and secreted by the neurointermediate lobe. The secretion of these glycoproteins and peptides was inhibited by dopamine. The significance of glycosylation of the precursor for the biosynthesis, processing, and secretion of the ACTH, beta-lipotropin-, and MSH-related peptides was examined by using a specific inhibitor of glycosylation, tunicamycin. Tunicamycin treatment did not affect the synthesis of the 32,000 mol wt ACTH-endorphin precursor but did prevent its glycosylation. The absence of carbohydrate on the precursor resulted in its rapid intracellular degradation. Precursors that escaped degradation were processed incompletely, leading to the formation and secretion of an unglycosylated intermediate and various other abnormal peptides. The data indicate that glycosylation of the ACTH-endorphin precursor may not be involved in the processes of intracellular transport, packaging, and secretion per se but, rather, may provide specific conformational stability to the precursor as a signal for directed limited proteolysis.
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PMID:The role of the carbohydrate in the stabilization, processing, and packaging of the glycosylated adrenocorticotropin-endorphin common precursor in toad pituitaries. 22 74

We have studied the effects of theophylline treatment on pigmentation characteristics and growth of two B16 melanoma cell lines, HFH-18 and P/140. Cell counts of control and theophylline-treated cultures confirmed that the drug inhibits cell growth. Light and electron microscope cytochemistry with the L-dopa reaction indicated that the two cell lines differ in their ability to transfer Golgi-associated tyrosinase to developing premelanosomes. The results of these experiments, considered with results of electrophoretic analyses and activity measurements by the Pomerantz method, also provide evidence that increased tyrosinase synthesis occurs in response to theophylline treatment. In addition, results indicate that theophylline induces changes in the rate of synthetic or degradative posttranslational modification of tyrosinase. Measurements of intracellular cyclic AMP levels by radioimmunoassay in control cultures and in theophylline- and alpha-MSH-treated cultures were made. Although the hormone induced spectacular increases in cyclic AMP levels, theophylline produced no detectable change. These results indicate that theophylline differs from alpha-MSH because theophylline-induced changes in pigmentation may not require the participation of intracellular cyclic AMP.
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PMID:Tyrosinase maturation and pigment expression in B16 melanoma: relation to theophylline treatment and intracellular cyclic AMP. 22 87

Melanophores from tadpoles of Xenopus laevis (Daudin) were isolated by digestion of tail fins with acetyltrypsin and collagenase and maintained in primary culture for 6 weeks up to 3 months. Within 36 to 72 h the melanophores develop one to eight dendritic processes per cell; secondary and tertiary branchings of the processes were frequently observed. The melanophores in primary culture disperse under the influence of alpha-MSH or cyclic AMP; upon rinsing out these substances the cells aggregate. In darkness, about 40% of the cells disperse their pigment, whereas under illumination the pigment of the melanophores aggregates. To date, attempts to initiate cell division in melanophores have not been successful.
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PMID:Morphological and physiological aspects of melanophores in primary culture from tadpoles of Xenopus laevis. 22 62

Differences in foetal and adult adrenal function may be due to qualitative as well as quantitative changes in the pituitary corticotrophic stimulus. Pituitary glands from adult and foetal sheep were freshly dissected and stored at -70 degrees C until extracted at pH 1.5. The extracts were subjected to chromatography on Sephadex G-100 superfine and fractions were assayed by multiple radioimmunoassays directed against the NH2- and CO2H-terminal sequences of ACTH and lipotrophin (LPH). Peaks corresponding to beta-melanocyte-stimulating hormone (beta-MSH), beta-LHP, gamma-LPH, beta-endorphin and ACTH were identified, with little or no evidence for the presence of alpha-MSH and corticotrophin-like intermediate lobe peptide. Three peaks of large molecular weight material, A. B and C, were identified and their relative proportions shown to be considerably greater in the foetus than in the adult. The immunoassay profile of peaks A and B suggested that they were 'stem hormones' which could give rise to a family of biologically active peptides. Since the 'family tree' which they engender varies according to the stage of development, it is proposed that the changes in the 'trophic family' may explain the different adrenal responses of the foetal and adult sheep.
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PMID:Adrenocorticotrophin-related peptides in adult and foetal sheep pituitary glands. 22 29

Hormone-induced pigment translocation studies were conducted at both the light and electron microscopic levels on cultured dermal iridophores from the Mexican leaf frog, Pachymedusa dacnicolor. Two distinct types of dermal iridophores were characterized which differed in (1) their in vivo locations, (2) their overall morphologies in vitro, (3) their responses to alpha-MSH, ACTH, c-AMP or theophylline, (4) their physical alterations of light, and (5) certain ultrastructural features. One iridophore (Type I) was found to be physiologically responsive to the above hormones or agents by a reversible retraction of cellular processes and a thickening of the cell body, an event which is inhibited by cytochalasin B. The other iridophore (Type II) appeared to be unresponsive. Type I iridophores contain cube-like pigmentary organelles, refractosomes, while Type II iridophores contain larger, bar-shaped refractosomes. In addition, both iridophore types contain 60 and 100 A microfilaments as well as microtubules. By in large, micorfilaments were found within microvilli, beneath and parallel to the plasma membrane and in the perinuclear region. Occasionally, bundles of 100 A microfilaments were found between layers of refractosomes in Type I iridophores. These results are discussed in relation to hormone-induced changes in cell shape.
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PMID:Hormone-induced pigment translocations in amphibian dermal iridophores, in vitro: changes in cell shape. 22 36

In man, discrete neurons of the infundibular (arcuate) nucleus contain compounds that can be stained with anti-endorphin (alpha and beta), anti-ACTH, anti-MSH (alpha and beta) and anti-beta-LPH immune sera (I.S.). In the fetus, certain neurons stain with anti-beta-endorphin or anti((17--39)ACTH starting from the 11th week of fetal life. At the ultrastructural level, these neurons contain elementary granules that are immunoreactive with anti-beta-endorphin. In the adult, neurons immunoreactive with anti-beta-endorphin are found in the infundibular nucleus. Their axonal fibers terminate around blood vessels in the neurovascular zone and in the pituitary stalk, or establish contacts with non-immunoreactive perikarya of the infundibular nucleus. These neurons can be stained with anti(17--39)ACTH and anti-beta-endorphin I.S. The most reactive are also stained moderately with anti-alpha-MSH, anti-beta-MSH, anti-beta-LPH, anti-alpha-endorphin, or anti(1--24)ACTH I.S. These results indicate that, in man, compound(s) identical with or immunologically related to endorphins, beta-LPH, ACTH and MSH are secreted by certain hypothalamic neurons. These agents probably originate from a common precursor molecula similar to the so-called pro-opiocortin.
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PMID:Infundibular neurons of the human hypothalamus simultaneously reactive with antisera against endorphins, ACTH, MSH and beta-LPH. 22 33

Specific radioimmunoassays (RIAs) for ACTH, beta-endorphin, alpha-MSH and beta-MSH were used to identify the immunoreactive components released during incubation of rat anterior pituitary cells in primary culture. Such measurements were performed after separation of the incubation media by chromatography on Sephadex G-50 or G-75. The ACTH-RIA measured approximately equal amounts of 13 and 4.5K ACTH while equal proportions of components migrating at the position of beta-LPH and beta-endorphin were measured in the beta-endorphin RIA system. Immunoreactive components migrating at the position of gamma-LPH and alpha-MSH were measured in the beta-MSH and alpha-MSH RIA systems, resp. 3 purified corticotropin-releasing fractions (CRF) prepared from porcine hypothalami and increasing concentrations of N6,O2'-dibutyryl cyclic AMP and theophylline led to parallel release of ACTH, beta-endorphin, beta-MSH and alpha-MSH immunoreactivities while preincubation with dexamethasone led to a 30-60% inhibition of the release of all peptides. The present data show that the release of ACTH, beta-LPH, beta-endorphin, gamma-LPH and alpha-MSH-like immunoeactivities occurs in parallel in anterior pituitary cells in culture both under basal and acute stimulatory or inhibitory conditions of release.
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PMID:Parallel release of ACTH, beta-endorphin, alpha-MSH and beta-MSH-like immunoreactivities in rat anterior pituitary cells in culture. 22 47

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

In rat hypothalamus intraventricularly injected with colchicine, the same neurons of the ventral region are stained with I.S. against alpha and beta-endorphin, (1-24) and (17-39) ACTH, alpha and beta-MSH, and beta-LPH. They are distinct from those producing LH-RH, somatostatin, neurophysin, and dopamine. These results suggest that the same neurons elaborate peptides identical with or immunologically related to endorphins, ACTH, alpha-MSH and beta-LPH, probably issued from a common precursor.
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PMID:[Immunocytologic analysis, in rat hypothalamus, of neurons producing peptides related to endorphin, ACTH, MSH and beta-LPH. Comparison with other peptidergic and monoaminergic neurons]. 23 Aug 87

In rat brains intraventricularly injected with colchicine, the same discrete neurons of the arcuate and ventromedial nuclei can be stained with antisera against alpha- and beta-endorphins, (1-24)ACTH, (17-39)ACTH, alpha- and beta-MSH, and beta-LPH, as demonstrated by comparative studies in consecutive serial sections. These neurons are strongly reactive with anti-(17-39)ACTH, anti-beta-endorphin, anti-alpha-MSH and anti-beta-MSH, and more faintly stained with anti-alpha-endorphin, anti-beta-LPH and anti-(1-24)ACTH. Exceptionally, neurons reactive with anti-(17-39)ACTH and anti-beta-endorphin are poorly stained or completely negative with anti-alpha-MSH and anti-beta-MSH. Immunoreactive fibers end in the lateral median eminence and in the arcuate nucleus proper, or form ascending pathways along the third ventricle. Comparative studies with other antisera or with the Falck and Hillarp technique show that these neurons differ from the elements producing LH-RH, somatostatin, neurophysin, oxytocin, vasopressin and dopamine. These results suggest that the same neurons of the rat hypothalamus synthesize several neuropeptides identical with or immunologically related to endorphins, ACTH, alpha-MSH and beta-LPH, probably arising from a common precursor molecule similar to that found in the corticotropic cells of the pituitary. These neuropeptides of a common cellular and molecular origin might be involved in basic processes of the central nervous system as neurotramsmitters or neuromodulators.
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PMID:Neurons of the rat hypothalamus reactive with antisera against endorphins, ACTH, MSH and beta-LPH. 23 Sep 4


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