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 purpose of the present study was to further characterize the inhibition by prostaglandin E2 (PGE2) of adrenocorticotropin (ACTH) and beta-endorphin release from rat anterior pituitary fragments in vitro. Peptide hormone release was induced by vasopressin, which initiates secretion via cell surface receptors, or by secretagogues which can mimic various post-receptor mechanisms and the effect of PGE2 was examined. Concentration-response curves of the effect of vasopressin on the release of beta-endorphin-like (beta-End-IR) and ACTH-like immunoreactivity (ACTH-IR) were constructed in the absence or presence of a fixed concentration of PGE2. The concentration-response curve of vasopressin was shifted to the right about 8-fold by PGE2 (1 mumol/l) without altering the maximum effect. PGE2 (60 nmol/l-1 mumol/l) markedly reduced beta-End-IR release induced by 8-bromoadenosine-3',5'-cyclic-monophosphate (8Br-cAMP) (1 mmol/l). Omission of Ca2+ from the incubation medium did not prevent PGE2-induced inhibition of 8Br-cAMP-evoked secretion. 4 beta-Phorbol, 12 beta-myristate, 13 alpha-acetate (PMA) stimulated beta-End-IR and ACTH-IR release in a concentration-dependent manner. This effect was not blocked by indometacin or eicosatetraynoic acid. PG E2 (greater than 100 nmol/l) reduced PMA (100 nmol/l)-elicited secretion by about 50%. PG E2 (1 mumol/l) almost halved beta-End-IR release caused by K+ (30 mmol/l). After pre-incubation in Ca2+-free medium, re-introduction of Ca2+ (1.3 mmol/l) elicited beta-End-IR release. This response was abolished by PG E2 (1 mumol/l). The addition of Ba2+ (10 mmol/l) to a Ca2+-free medium markedly enhanced beta-End-IR release.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of prostaglandin E2 on ACTH and beta-endorphin release from rat adenohypophysis in vitro after secretagogues which can mimic various first or second messengers. 301 94

Opiate addiction and stress have been associated with altered immune responses. In this study, we evaluated the influence of morphine and the stress responsive opioid peptide beta-endorphin (beta-END) on O-2 and H2O2 production by cultured human peripheral blood mononuclear cells. Exposure of these cells during 48 hr of culture to morphine and beta-END at pharmacologically (10(-8) M) and physiologically (10(-12) M) relevant concentrations, respectively, markedly suppressed peripheral blood mononuclear cell O-2 and H2O2 release in response to the respiratory burst stimuli opsonized zymosan and phorbol myristate acetate. Both opioids also induced a minimal, but statistically significant, increase in resting O-2 and H2O2 generation. The modulatory effects of morphine and beta-END on peripheral blood mononuclear cell oxygen metabolism appeared to involve a classical opioid receptor, because opioid activity was blocked by naloxone and was not observed with N-acetylated-beta-END. Using purified lymphocyte and monocyte preparations, we determined that although opioids directly increase monocyte-resting oxygen metabolism, lymphocytes are the primary target cell in opioid-mediated suppression of monocyte respiratory burst activity. The release of a suppressive product from opioid-triggered lymphocytes was inhibited by cyclosporine. Based on the results of this study, we propose that opioid-mediated suppression of mononuclear phagocyte respiratory burst activity is another factor to be considered in the immunodeficiency of opiate addiction and stress.
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PMID:Opioid-mediated suppression of cultured peripheral blood mononuclear cell respiratory burst activity. 303 15

Immunoreactivity of human tissue mast cells (TMCs) was studied in one case of solitary mastocytoma of the skin, three cases of malignant mastocytosis, and in six lymph nodes with reactive intrasinusoidal increase of TMCs. Immunohistochemically, TMCs reacted positively to antisera against vimentin, common leukocyte antigen (CLA), lysozyme, alpha 1-antitrypsin (alpha 1-AT), and alpha 1-antichymotrypsin (alpha 1-ACT) and to a monoclonal antibody (KiB3) that detects preferentially B-lymphocytes. Additionally, strong positive reactions to polyclonal antisera against adrenocorticotropic hormone (ACTH) and human peptide histidine isoleucine (PHI) and weaker reactions to antisera against leu-enkephalin and met-enkephalin were observed; all other antisera tested yielded negative results. Positive stainings for vimentin, CLA, alpha 1-AT, alpha 1-ACT, and lysozyme further support the hypothesis that human TMCs may be related to the myeloid-monocytic system. The positive reactivity of TMCs to antisera against ACTH, PHI, leu-enkephalin, and met-enkephalin has not been reported previously. These findings suggest that TMCs are able to store and/or produce regulatory peptides in addition to many other well-known, granule-bound mediators.
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PMID:Immunoreactivity of normal and neoplastic human tissue mast cells. 312 43

D-alpha tocopheryl succinate (vitamin E succinate), which is known to induce differentiation and growth inhibition in murine B-16 melanoma cells, reduced basal and melanocyte-stimulating hormone (MSH)-stimulated adenylate cyclase (AC) activity in vitro. Vitamin E succinate treatment also reduced sodium fluoride- and forskoline-stimulated AC activity of melanoma cells in vitro. Treatment of cells with vitamin E succinate (6 micrograms/ml] for a period of 24 hours was sufficient to reduce MSH-stimulated AC activity. Other forms of vitamin E, such as d1-alpha tocopheryl nicotinate, d1-alpha tocopheryl acetate, and d1-alpha tocopherol, which did not affect growth or morphology of melanoma cells, were relatively less effective in altering basal and MSH-stimulated AC activity. Retinoic acid, which inhibited the growth of B-16 melanoma cells, also reduced basal and MSH-, NaF-, and forskolin-stimulated AC activity in vitro. Prostaglandin A2, which inhibited growth and altered morphology, did not change basal or MSH-stimulated AC activity. These results show that one of the mechanisms of action of vitamin E succinate and retinoic acid on melanoma cells may involve reduction of basal and MSH-sensitive AC activity, and this vitamin effect is not necessarily related to growth inhibition.
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PMID:Alpha tocopheryl succinate inhibits melanocyte-stimulating hormone (MSH)-sensitive adenylate cyclase activity in melanoma cells. 369 13

The role of protein kinase C in melanosome dispersion was examined using the melanophores of the lizard Anolis carolinensis and an in-vitro rate method of bioassay. The phorbol ester 12-O-tetradecanoyl-phorbol-13-acetate (TPA), which directly activates protein kinase C, was able to potentiate the melanophore response to alpha-MSH in a dose-dependent manner. Similarly, the stimulatory response to forskolin, which activates the adenylate cyclase catalytic subunit, was also potentiated by TPA. The response of the melanophore to cyclic AMP, however, remained unaltered by any dose of TPA. We thus propose that the potentiation of alpha-MSH potency by TPA is through an interaction of protein kinase C with adenylate cyclase and, more specifically, that this interaction may be at the level of the linkage of the nucleotide regulatory subunit Ns with the catalytic moiety C of adenylate cyclase.
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PMID:Role of protein kinase C in the pigment cell of the lizard (Anolis carolinensis). 381 40

SJL/J mice which developed a high incidence of spontaneous reticulum cell neoplasms, developed a low rate incidence (20-25%) of myeloid leukemia (ML) after X-irradiation. The possible effect of adrenal steroid imbalance to radiation-induced ML in SJL/J mice was tested. Intact and thymectomized animals were exposed to a single dose of 300 r whole body irradiation and treated with either hydrocortisone acetate, prednisone, metyrapone and adrenocorticotropin as coleukemogenic agents. Hydrocortisone and prednisone exerted a marked coleukemogenic effect, increasing the ML incidence to a similar rate of about 50-70%, at a mean latent period of 300 days. Prominent leukemic infiltration were observed in the bone marrow, spleen, lymph nodes and liver of the leukemic animals. Results of cytological and histological studies, including cytochemistry and ultrastructure, were all consistent with the diagnosis of acute myeloid leukemia (AML). Since AML is the type of human secondary leukemia which appears increasingly in patients treated with alkylating drugs and/or irradiation and corticosteroids for Hodgkin's disease or other neoplastic diseases, the experimental model of AML induced in SJL/J mice could be used for elucidation of mechanisms of leukemogenesis in secondary leukemia.
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PMID:High incidence of acute myeloid leukemia in SJL/J mice after X-irradiation and corticosteroids. 386 24

We have studied the effect of L-prolyl-L-leucyglycinamide (PLG) on the release of melanocyte-stimulating hormone (MSH) from the rat pituitary gland both in vitro and in vivo. Superfusion of neurointermediate lobes with medium containing PLG or PLG-acetate (dose range 1-1000 ng/ml) did not affect the spontaneous release of MSH as determined by radioimmunoassay or by bioassay. Also during static incubations of rat hemipituitaries, PLG (6.6-50 ng/ml) was without effect on alpha-MSH release. Administration of PLG (1-250 ng iv) to intact male and female rats and rats being lesions in the medio-basal hypothalamus did not induce a fall in serum alpha-MSH levels. It is concluded that PLG does not affect the release of alpha-MSH from the rat intermediate lobe. It is unlikely therefore that PLG mediates the inhibitory influence of the CNS on MSH release.
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PMID:The failure of L-prolyl-L-leucylglycinamide to inhibit the release of alpha-melanocyte-stimulating hormone in the rat. 610 29

The regional distribution of Met-enkephalin, beta-endorphin and alpha- and gamma-type endorphins in rat brain was investigated. To that end, brains were dissected into anatomically defined areas. Acetic acid tissue extracts were fractionated using an HPLC system suitable for separation of endorphins and peptide concentrations were subsequently measured by specific radioimmunoassay systems. The distribution of Met-enkephalin and beta-endorphin through the brain was fairly uneven and in accordance with results obtained by others. The peptides alpha-endorphin, gamma-endorphin, des-Tyr-alpha-endorphin (DT alpha E) and des-Tyr-gamma-endorphin (DT gamma E) were detectable in almost all brain areas. Their distribution, however, appeared to be uneven. Hypothalamus and septum showed the highest levels of alpha- and gamma-type endorphins. These regions also contained high amounts of beta-endorphin, underscoring a precursor function of this peptide in the formation of alpha- and gamma-type fragments. In general, levels of alpha-endorphin were higher than those of des-Try-alpha-endorphin, whereas the opposite was found for gamma- and des-Tyr-gamma-endorphin.
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PMID:Regional distribution of alpha- and gamma-type endorphins in rat brain. 617 96

Thyropin binding to high affinity receptors on human and porcine membranes was studied at pH 7.4, 37 degrees C, in 10 mM Tris-HCl, 150 mM NaCl, 0.1% albumin. By preincubating the membranes in high salt concentration before binding studies, the number of high affinity receptors could be increased 4- to 8-fold. The salt-induced exposure of high affinity TSH receptors was pH- and temperature-dependent and was maximal at pH 5.0, 37 degrees C in the presence of 1 M (NH4)2SO4. Other salts tested, including NaCl, HN4Cl, and Na2SO4, were also able to increase high affinity THS binding. The receptors exposed by salt were indistinguishable from those present on the membranes before such treatment. They had an affinity constant of 0.5 to 1 X 10(10 M-1, and a high TSH specificity with no inhibition of 125I-TSH binding in the presence of a thousandfold excess of gamma-globulin, thyroglobulin, corticotropin, cholera toxin, and gangliosides. Thyrotropin binding to low affinity TSH binding sites (affinity constant 1 to 3 X 10(7) M-1) measured at pH 6.0, 4 degrees C in 10 mM Tris/acetate, 0.1% albumin was unaltered by pre-exposure of membranes to high salt concentrations. These receptors had low TSH specificity and binding was inhibited by gamma-globulin, thyroglobulin, cholera toxin, and gangliosides. The salt-induced selective exposure of high affinity receptors with unaltered number of low affinity sites is further support for the existence of two separate TSH binding sites on thyroid membranes.
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PMID:Salt-induced exposure of high affinity thyrotropin receptors on human and porcine thyroid membranes. 625 Oct 45

Retinoic acid was found to be a potent stimulant of pigmentation in human Hs939 melanoma cells. Exposure to 1 microM retinoic acid for longer than four days caused both a decrease in the rate of cell proliferation and a concomitant increase in melanogenesis. These effects of retinoic acid progressed lin-early in a time-dependent and a dose-dependent fashion such that at the end of a seven-day treatment cell growth was inhibited by approximately 65%, and both melanin content and tyrosinase activity increased more than three-fold over the control. Interpolation of the dose-response curves indicated that 3 nM retinoic acid would cause half-maximal melanogenesis stimulation. No elevation in the level of cyclic adenosine 3':5'-monophosphate could be detected in the melanoma cells following various periods of exposure to retinoic acid, and the cells were unresponsive to alpha-melanocyte-stimulating hormone. In the presence of the tyrosinase inhibitor phenylthiocarbamate, retinoic acid was capable of inhibiting cell proliferation without enhancing melanin synthesis. The tumor promoter phorbol myristate acetate did not affect either the proliferation or the differentiation of the Hs939 melanoma cells. However, the enhancement of melanogenesis by 1 microM retinoic acid was inhibited by 66% in the presence of 0.1 microM phorbol myristate acetate. The tumor promoter did not reverse the growth-inhibitory effect of retinoic acid. Phorbol, a non-tumor promoter, was effective. Other retinoids, such as 13-cis-retinoic acid, retinyl acetate, nd the trimethylmethoxyphenyl analog of retinoic acid, also inhibited the proliferation and enhanced melanin production in the Hs939 cells. In contrast, retinyl palmitate, the phenyl analog of retinoic acid, and the pyridyl analog of retinoic acid were ineffective.
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PMID:Stimulation of melanogenesis in a human melanoma cell line by retinoids. 625 61


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