UNIPROT:P01189 - FACTA Search

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Query: UNIPROT:P01189 (beta-endorphin)
21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The aim of this study was to determine the ability of corticotropin-releasing hormone (CRH), lysine vasopressin (LVP), oxytocin (OT), and angiotensin II (AII) to stimulate adrenocorticotropin (ACTH) secretion from porcine anterior pituitary (AP) cells in vitro and to evaluate the role of protein kinase C (PKC) in the interaction between CRH and LVP. In this study, porcine AP cells were enzymatically and mechanically dispersed, cultured (150,000 cells/well) for 4 d, and then challenged with doses of various neuropeptides for 3 hr. CRH (10(-7)-10(-10) M) was the most potent of the peptides tested in stimulating ACTH release from porcine AP cells. In fact, none of the other peptides consistently affected ACTH concentrations relative to basal levels. However, LVP potentiated CRH action, even though by itself, it failed to stimulate ACTH production. Neither OT or AII potentiated CRH-stimulated ACTH release from porcine AP cells. To determine whether the inter-action between CRH and LVP was regulated partially by the protein Kinase C (PKC) pathway, we challenged AP cells in a 30-min incubation with 10(-7) M staurosporine (ST), a treatment predicted to decrease PKC activity. Then, cells were washed and challenged with 10(-9) M LVP, 10(-9) M CRH, and 10(-9) M CRH + LVP. Treatment with ST decreased (P < 0.05) CRH + LVP-stimulated ACTH release. To further demonstrate an interaction between protein kinase A (PKA) and PKC transduction pathways in the observed synergism between CRH and LVP to enhance ACTH secretion, we also challenged AP cells with 10(-7) M phorbol 12, 13-myristate acetate (PMA) and 5 microM forskolin (FOR) for 3 hr. This treatment was predicted to enhance PKA and PKC activities, respectively, and thereby enhance ACTH concentrations. Challenging cells with FOR + PMA enhanced (P < 0.001) ACTH release above basal concentrations, but more important, it increased (P < 0.001) ACTH concentration above that elicited by either drug given alone. Taken together, our in vitro studies support the conclusion that CRH is the principal regulator of ACTH secretion in the pig. In contrast to the results in most other species evaluated, vasopressin alone did not affect ACTH release. However, LVP can enhance the effectiveness of CRH in releasing ACTH, and this enhancement appears to rely, at least in part, on the activation of the PKC signal transduction pathway.
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PMID:Effects of corticotropin-releasing hormone, lysine vasopressin, oxytocin, and angiotensin II on adrenocorticotropin secretion from porcine anterior pituitary cells. 873 67

The effects of various neuropeptides on human plasma cells were studied. Of the various neuropeptides tested, vasoactive intestinal peptide (VIP) enhanced Ig production and growth in human plasma cell lines, IM-9 and AF-10, and in plasma cells generated in vivo (four out of four patients with plasma cell leukemia) and in vitro. In contrast, other neuropeptides (neuropeptide Y, somatostatin, substance P, peptide YY, neurokinin A, calcitonin gene-related peptide, chole-cystokinin octapeptide, and beta-endorphin) were ineffective. Moreover, VIP-induced enhancement was specifically blocked by VIP receptor antagonist. Among the various cytokines, IL-6, GH, and insulin-like growth factor I (IGF-I) also enhanced Ig production and thymidine uptake in plasma cells. However, VIP-induced enhancement was not mediated by IL-6, GH, or IGF-I because antibodies to these cytokines failed to block VIP-induced enhancement. Phorbol 12,13 dibutyrate enhanced Ig production and thymidine uptake in plasma cells, and the Phorbol 12,13 dibutyrate-induced enhancement was blocked by H7 (a protein kinase C inhibitor) but not by H8 (a protein kinase A inhibitor). Similarly, VIP-induced enhancement was blocked by H7 but not by H8. Collectively, VIP enhances plasma cell responses via mechanisms that may involve protein kinase C.
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PMID:Vasoactive intestinal peptide enhances immunoglobulin production and growth in human plasma cells via mechanisms that may involve protein kinase C. 876 69

The effects of forskolin or phorbol-13-myristate (PMA) injected intrathecally (i.t.) or intracerebroventricularly (i.c.v.) on the inhibition of the tail-flick and hotplate responses induced by morphine or beta-endorphin administered i.c.v. were studied. Animals pretreated with forskolin (20 micrograms) i.t. for 10 min had an attenuated inhibition of the tail-flick response induced by i.c.v. administered morphine (2 micrograms) or beta-endorphin (1 microgram). However, i.t. pretreatment with PMA (100 ng) was not effective in reducing the inhibition of the tail-flick response induced by morphine or beta-endorphin administered i.c.v. In addition, i.t. pretreatment with either forskolin or PMA did not affect the inhibition of the hotplate response induced by morphine or beta-endorphin administered i.c.v. Forskolin pretreatment i.c.v. for 10 min attenuated the inhibition of the tail-flick and hotplate responses induced by i.c.v. administered morphine or beta-endorphin. However, i.c.v. pretreatment with PMA was not effective in reducing the inhibition of the tail-flick or hotplate responses induced by morphine or beta-endorphin administered i.c.v. Our results suggest that activation of adenylate cyclase located at both spinal and supraspinal sites appears to be involved in antagonizing antinociception induced by morphine and beta-endorphin administered supraspinally. However, spinal or supraspinal protein kinase C may not be involved in antagonizing antinociception induced by morphine or beta-endorphin administered supraspinally.
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PMID:Differential effects of forskolin and phorbol-13-myristate injected intrathecally or intracerebroventricularly on antinociception induced by morphine or beta-endorphin administered intracerebroventricularly in the mouse. 877 60

Although both angiotensin II (Ang II) and potassium ion (K+) induce marked elevations of cytosolic free calcium concentration, [Ca2+]c, in adrenal zona glomerulosa cells-an effect which is thought to trigger aldosterone synthesis-Ang II is also known to reduce the sustained [Ca2+]c rise induced by K+. We have examined whether this effect of Ang II on the calcium messenger system is reflected at the level of the final biological response, aldosterone synthesis. In superfused isolated rat glomerulosa cells, K+ (8 mM) induced a sustained, 60-fold increase in aldosterone production. In contrast, the maximal response to Ang II (10 nM) amounted to only 10 times the basal production. When added subsequent to K+ stimulation, Ang II provoked an immediate and dramatic drop in aldosterone synthesis, to levels obtained with Ang II alone. Under conditions of maximal K+ stimulation, this effect depended upon Ang II concentration, while the well-known synergistic effect was observed with submaximal concentrations of both agonists. The inhibitory effect of Ang II could be reproduced with dioctanoylglycerol, a selective activator of protein kinase C. By contrast, the aldosterone response to adrenocorticotropic hormone (ACTH) was not affected by Ang II. At submaximal concentrations of ACTH, the steroidogenic effect of Ang II was even additive to that of ACTH. Thus, we have shown that, under conditions of maximal stimulation, Ang II exerts a profound inhibition of steroidogenesis in K(+)-stimulated rat adrenal glomerulosa cells. This counter-regulatory mechanism may ensure adequate levels of aldosterone production in vivo.
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PMID:Demonstration of an angiotensin II-induced negative feedback effect on aldosterone synthesis in isolated rat adrenal zona glomerulosa cells. 879 59

Melanoma cells express receptors for melanocyte-stimulating hormone (MSH) in variable abundance. CGP 41251, a derivative of staurosporine with an increased selectivity for protein kinase C (PKC) inhibition, was found to modulate MSH receptors in human D10 and HBL cells and in the mouse B16 cell line. Up-regulation was observed in D10 and B16 cells at a concentration of 290 nM and 190 nM, respectively. In HBL cells, however, the PKC inhibitor induced a pronounced MSH receptor down-regulation with an EC50 of only 32 nM. In D10 and HBL cells, alpha-MSH and CGP 41251 synergistically regulated MSH receptors whereas these agents had an antagonistic effect in B16 cells. PKC stimulation by short-term treatment with phorbol ester had an opposite effect on MSH receptors as compared to CGP 41251. In B16 cells, CGP 41251 at a concentration of 100 nM increased the sensitivity to MSH-induced melanogenesis. The staurosporine derivative inhibited proliferation of HBL, B16, and D10 cells at EC50s of 180 nM, 190 nM, and 520 nM, respectively. Furthermore, CGP 41251 increased the dendricity of the cells. In a concentration range between 300 nM and 1 mu M, CGP 41251 induced a sharp increase of the mean cell diameter from 16 mu m to 19 mu m. Thus, the effects of the selective PKC inhibitor on MSH receptors are induced at lower concentrations than needed for the inhibition of proliferation or for the change in cell morphology. These results suggest that the number of MSH receptors expressed on the surface of cultured melanoma cells correlates with the level of constitutive PKC activity in individual cell lines.
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PMID:A selective protein kinase C inhibitor (CGP 41251) positively and negatively modulates melanoma cell MSH receptors. 890 45

Incubation of rat adrenal glomerulosa cells with low concentrations (up to 50 nM) of the protein kinase (PKC) inhibitor staurosporine (ST) inhibited aldosterone (ALDO) and cyclic AMP (cAMP) production stimulated by adrenocorticotropic hormone (ACTH) and cholera toxin. Only higher concentrations (1.6 microM) of staurosporine inhibited dibutyryl-cAMP- and forskolin-induced stimulation of aldosterone production. cAMP levels were increased only with low concentrations of the PKC inhibitor. This latter increase was avoided by treatment with a maximal concentration of isobutylmethylxanthine (MIX). Our results suggest that: (1) second messengers other than cAMP are involved in ACTH action; (2) staurosporine inhibits different kinases involved in ACTH action in a dose-dependent manner; (3) the protein kinase inhibited by high concentrations of staurosporine appears to be the cAMP-dependent kinase, PKA; and (4) the protein kinase inhibited by low concentrations of staurosporine remains to be identified. This latter species is suggested as being involved in mediating ACTH-induced activation of Gs.
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PMID:Effects of staurosporine on ACTH-mediated stimulation of aldosterone production. 891 88

We studied the effect of the adenylate cyclase activator forskolin, of protein kinase C-activating phorbol esters and of prolonged preganglionic input activation on the inhibitory response of the perfused superior cervical ganglion of the cat to exogenous met-enkephalin (Met-ENK). Met-ENK inhibited, in a concentration-dependent manner, the postganglionic compound action potential evoked by cervical sympathetic trunk stimulation. The inhibition was reversible, was blocked by naloxone as well as by pertussis toxin and showed no homologous desensitization in the concentration range 0.01-10 microM. Pretreatment of the ganglion with 4 beta-phorbol 12,13-dibutyrate or 4 beta-phorbol 12,13-diacetate depressed the Met-ENK response for several hours, while pretreatment with forskolin had no effect. This action of phorbol esters was prevented by the protein kinase inhibitor H-7 but not by the calmodulin antagonist W-7 or the protein kinase A inhibitor HA 1004 and was calcium-dependent. Recovery of the response from the depression produced by phorbol esters was not affected by a protein synthesis inhibitor. A 40 Hz 20 min stimulus train to the cervical sympathetic trunk mimicked the effect of phorbol esters, depressing for several hours the inhibition produced by Met-ENK. Stimulus trains of duration shorter than 5 min or frequency lower than 5 Hz were ineffective. This effect of prolonged preganglionic stimulation occurred even when the stimulus train was delivered during complete block of nicotinic and muscarinic ganglionic transmission but was lost when the stimulus train was delivered during perfusion with calcium-free Krebs. The protein kinase inhibitor H-7 prevented the depression of the Met-ENK response by the train, while W-7 and HA 1004 had no effect. These findings suggest that, in the superior cervical ganglion of the cat, a kinase, activated by phorbol esters and inhibited by H-7, exerts a long-term control of the ganglion cell responsiveness to opiate receptor activation. A similar mechanism can be synaptically activated by a non-cholinergic transmitter, released by the preganglionic axons during prolonged, high frequency, activity.
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PMID:Long-term depression of a sympathetic ganglionic response to opioids by prolonged synaptic activity and by phorbol esters. 896 46

The effects of pretreatment with a protein kinase C activator, phorbol 12,13-dibutyrate, on antinociception induced by i.c.v.-administered mu-opioid receptor agonist (D-Ala2, NMePhe4, Gly(ol)5) enkephalin (DAMGO) or morphine and epsilon-opioid receptor agonist beta-endorphin were studied in male ICR mice. The tail-flick responses were used for antinociceptive tests. I.c.v. pretreatment with phorbol 12,13-dibutyrate (50 pmol) for 30 or 60 but not 10 min attenuated antinociception induced by i.c.v.-administered DAMGO. I.c.v. pretreatment with phorbol 12,13-dibutyrate (10 and 50 pmol) for 60 min caused a dose-dependent attenuation of DAMGO (19.5 pmol)- or morphine (6.0 nmol)-induced antinociception. The dose-response curve for DAMGO-induced antinociception was shifted to the right by 7.3-fold by i.c.v. pretreatment with phorbol 12,13-dibutyrate (50 pmol) for 60 min. However, the i.c.v.-administered beta-endorphin-induced antinociception was not affected by the same pretreatment with phorbol 12,13-dibutyrate. The attenuation of i.c.v.-administered DAMGO- and morphine-induced antinociception by phorbol 12,13-dibutyrate was reversed by concomitant i.c.v. pretreatment with a selective protein kinase C inhibitor calphostin C. These results suggest that activation of protein kinase C by phorbol 12,13-dibutyrate leads to the desensitization of mu-, but not epsilon-opioid receptor-mediated antinociception. These findings also provide additional evidence for differential intracellular modulation on antinociceptive action of mu- and epsilon-opioid receptor agonists.
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PMID:Pretreatment with protein kinase C activator phorbol 12,13-dibutyrate attenuates the antinociception induced by mu- but not epsilon-opioid receptor agonist in the mouse. 897 79

1. The synthesis and secretion of aldosterone in the adrenal zona glomerulosa in physiologic conditions is controlled by adrenocorticotropin (ACTH), angiotensin II (AII), and extracellular (K+). 2. ACTH effects on aldosterone output are explained by cyclic AMP-(cAMP)- and Ca(2+)-dependent mechanisms. 3. All effects on aldosterone secretion are initiated by an increase in Ca2+ influx through hormone-operated Ca2+ channels and G-protein- and phospholipase C-(PLC) dependent hydrolysis of phosphoinositides leading to the generation of inositol 1,4,5 trisphosphate (IP3) and DAG that induce intracellular Ca2+ release and PKC activation, respectively. 4. ACTH increases DAG formation with marginal or undetectable IP3 generation. The effect of ACTH on DAG levels is discussed. 5. The requirement of external Ca2+ in PLC activation and aldosterone secretion also is discussed.
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PMID:Recent progress in understanding aldosterone secretion. 918 96

Although arginine-vasopressin (AVP) is reported to produce greater ACTH biosynthetic and secretary responses than does corticotropin-releasing hormone (CRH) in sheep anterior pituitary cells, neither factor appears to increase pro-opiomelanocortin (POMC) mRNA levels, as does CRH in the cells of some other species. Since only a fraction of cells that express POMC mRNA may be able to respond to AVP, the aim of this study was to further delineate the regulation of POMC mRNA in ovine anterior pituitary corticotrophs, as a whole and in functional subpopulations of corticotrophs. We measured the effects of AVP, CRH or activation of protein kinase C by phorbol myristate acetate (PMA) in cultured cells. We compared responses in intact populations with those of cultures from which CRH-target cells were pharmacologically eliminated. Dissociated adult ovine anterior pituitary cells were cultured overnight, treated with either vehicle (intact) or a CRH-toxin conjugate that specifically eliminates CRH-target cells (CRH-target-depleted), washed, returned to culture and subsequently challenged with vehicle, AVP (100 nM), CRH (10 nM) or PMA (1 microM) for 5 h. The media were assayed for ACTH by RIA and the cells for POMC mRNA by Northern blot analysis. In intact populations, AVP and CRH increased ACTH secretion from 6.5 +/- 1.2 to 216 +/- 22 and 81 +/- 14 ng/well respectively, but only AVP caused an increase in steady-state POMC mRNA levels (+48 +/- 10%). Direct activation of protein kinase C with PMA mimicked the effect of AVP on ACTH secretion (318 +/- 16 ng/well), but did not alter POMC mRNA levels. In CRH-target-depleted populations, control ACTH secretion (11 +/- 3 ng/well) and POMC mRNA (+69 +/- 7%) were elevated, compared with intact populations. AVP (55 +/- 8 ng/well) and PMA (120 +/- 17 ng/ well), but not CRH, increased ACTH secretion; POMC mRNA was not significantly elevated by any of the treatments. Taken together, these data provide further support for the notion of dissociation between secretion of ACTH and expression of POMC mRNA, and demonstrate that AVP increases steady-state POMC mRNA levels in ovine anterior pituitary cells. The data are also consistent with the concept that complex interactions, possibly including those between cells, influence ACTH secretion and steady-state POMC mRNA levels.
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PMID:Effects of vasopressin and elimination of corticotropin-releasing hormone-target cells on pro-opiomelanocortin mRNA levels and adrenocorticotropin secretion in ovine anterior pituitary cells. 924 48

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