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)

This study was designed to examine the effects of i.p.-injected alpha-melanocyte stimulating hormone (MSH) on murine neutrophil migration into subcutaneously implanted sponges in response to IL-1-alpha, TNF-alpha, and C5a. The results show that as little as 0.1 ml of 5 x 10(-7) M MSH injected i.p. significantly blocked the accumulation of neutrophils in sponges in response to IL-1. This action of MSH was dose dependent, reversible, and was maximally effective if MSH was given at the same time as the injection of IL-1. This effect of MSH was not restricted to IL-1-induced neutrophil emigration, because MSH also antagonized the accumulation of neutrophils in response to both TNF and C5a. The proopiomelanocortin-derived peptide ACTH which contains the MSH sequence also significantly reduced neutrophil accumulation in response to IL-1, although less effectively than MSH. Similar studies with beta-endorphin showed that it had no effect on neutrophil accumulation in this system. The direct injection of MSH, beta-endorphin and ACTH into sponges or i.p. did not stimulate a neutrophil emigration and eliminated the possibility that MSH or ACTH suppressed the neutrophil influx in response to IL-1, TNF, or C5a by competing for circulating neutrophils. The action of MSH on IL-1, TNF, and C5a-induced neutrophil emigration suggests that this peptide may be an important regulator of the inflammatory response.
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PMID:Modulation of IL-1, tumor necrosis factor, and C5a-mediated murine neutrophil migration by alpha-melanocyte-stimulating hormone. 253 58

Endogenous opioid peptides derive from three precursors: proenkephalin A, maturing into enkephalins, proenkephalin B, maturing into dynorphins, and proopiomelanocortin, maturing into beta-endorphin and non-opioid fragments. All these opioid peptides can be detected by immunocytochemical methods in many neurons intrinsic to the gut and in cerebral and medullary neurons. The involvement of opioid peptides in the control of intestinal motility is demonstrated by experiments using injection of exogenous peptides or analogues, administration of antagonists or inhibition of their in vivo degradation. However, the pattern of action of opioids on intestinal motility is complex, since stimulant and inhibitory effects may occur via the different mu, delta and kappa opioid receptors, on muscle cells or on nerves and at central or peripheral sites. On the whole, opioid peptides should be considered as important neurotransmitters. Their main function on gut motility seems to be the regulation of other stimulant and inhibitory neurons inputting to the muscle cells of the gut.
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PMID:[Role of opioid peptides in intestinal motility]. 253 71

Forskolin, an activator of adenylate cyclase, stimulates adrenocorticotropin (ACTH) release and increases proopiomelanocortin mRNA levels in anterior pituitary cells by enhancing cyclic AMP (cAMP)-dependent protein kinase activity. The phorbol ester phorbol 12-myristate 13-acetate (PMA) evokes these same responses from anterior pituitary cells by activating protein kinase C. Both protein kinases most likely induce their cellular effects by catalyzing the phosphorylation of specific proteins. To elucidate the mechanisms by which cAMP-dependent protein kinase and protein kinase C promote ACTH secretion and synthesis, the phosphoproteins regulated by forskolin and PMA were identified in the cell line AtT-20, which consists of a homogeneous population of corticotrophs. Phosphoproteins were analyzed in different subcellular fractions by two-dimensional polyacrylamide gel electrophoresis and autoradiography. Forskolin increased phosphate incorporation into two proteins in the cytoplasmic fraction of 24 kilodaltons (kd) (pI 6.8) and 40 kd (pI 5.8), two proteins in the plasma membrane fraction of 32 kd (pI 8.3) and 60 kd (pI 8), and one protein in the nuclear fraction of 20 kd (pI 8.7). Insertion of the inhibitor of cAMP-dependent protein kinase into the AtT-20 cells, using a liposome technique, blocked the rise in phosphate incorporation induced by forskolin. PMA also stimulated phosphate incorporation into proteins in AtT-20 cells. PMA increased the phosphorylation of three cytoplasmic proteins of 25 kd (pI 7.6), 40 kd (pI 5.8), and 40 kd (pI 8.1) as well as two membrane proteins of 32 kd (pI 8.3) and 60 kd (pI 8) and one nuclear protein of 20 kd (pI 6.3).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Protein phosphorylation induced by phorbol esters and cyclic AMP in anterior pituitary cells: possible role in adrenocorticotropin release and synthesis. 253 66

Recent studies have shown that both proopiomelanocortin (POMC)-derived peptides and a range of POMC gene transcripts are present in the testis. Previous immunocytochemical studies have reported immunoreactive (ir)-beta-endorphin (EP) and ir-ACTH to be localized in the Leydig cells, and ir-NacEP in spermatogonia and primary spermatocytes. In the present study, we have further examined the hypothesis that testicular Leydig cells are the principal site of synthesis of these peptides, by determining the effects of the administration of the cytotoxic drug ethane dimethane sulphonate (EDS) which selectively destroys the Leydig cells of the testis. As expected, serum testosterone levels fell and serum FSH/LH levels increased within 3 days of EDS administration, returning to normal levels 4-8 weeks later. In contrast, the testicular content of POMC-derived peptides and POMC mRNA levels in these animals was not significantly altered throughout the experimental period. In addition, POMC mRNA was not detected in a purified Leydig cell preparation derived from adult male rats, and POMC-derived peptides were also undetectable in the media of a similar preparation following cell culture. These data suggest that in the adult the predominant site of rat POMC gene expression is in testicular interstitial cells other than Leydig cells.
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PMID:Effect of ethane dimethane sulphonate on proopiomelanocortin (POMC) mRNA and POMC-derived peptides in the rat testis. 255 Feb 99

The possible role of protein kinase C (PKC) in the cyclic AMP-dependent mechanism of action of corticotropin-releasing factor (CRF) on proopiomelanocortin cells of anterior and intermediate pituitary glands was examined after pretreatment of cells in culture with the PKC inhibitor retinal or the phorbol ester PMA, which depletes cell stores of the kinase. We found that these drugs not only abolished ACTH response to PMA and vasopressin, which both activate PKC, but unexpectably also dampened by 80-90% the stimulatory effect of CRF. Cell treatment with retinal failed to prevent CRF-induced accumulation of cyclic AMP. Retinal and PMA pretreatments of intermediate pituitary cells likewise inhibited alpha-MSH secretion stimulated by CRF. These data provide evidence to suggest that the mechanism of action of CRF on pituitary cells involves both cyclic AMP and PKC messenger systems.
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PMID:Indirect evidence that protein kinase C plays a critical role in signal transduction of both vasopressin and corticotropin-releasing factor on pituitary cells in culture. 255 Dec 65

Activation of the hypothalamic-pituitary-adrenal axis (HPAA) by single-dose ethanol administration, which achieved moderately high blood ethanol levels, was explored in naive rats in order to determine the mechanism of ethanol's activation of the stress axis. Adult male rats received a single dose (3.2 g/kg body weight-1 of a 12% solution of ethanol in physiological saline. The plasma concentration of immunoreactive (ir) adrenocorticotropic hormone (ACTH), beta-endorphin (BE) and corticosterone (CS) was determined by radioimmunoassay, whereas, plasma concentrations of epinephrine (E) and norepinephrine (NE) were quantified following reverse-phase liquid chromatographic separation and amperometric detection. Ethanol induced maximal plasma ACTH levels within minutes, which declined toward basal levels by 60 min, whereas, plasma concentration of CS rose rapidly and remained elevated at 60 min. Plasma ACTH and CS levels in saline-treated control animals did not vary significantly at any time point. Consistent with co-release of ACTH from corticotrophs, the plasma concentration of ir-BE increased 5-fold at 15 min and declined towards basal levels at 60 min after-ethanol challenge. Plasma E increased 10- to 20-fold as compared to saline controls or preinjection levels and returned to preinjection levels by 90 min, in a manner similar to ethanol-induced changes in proopiomelanocortin-derived peptides and CS. Removal of the adrenal medulla and thus the source of E prior to ethanol administration, did not attenuate activation of the HPAA. Passive immunoneutralization of arginine vasopressin (AVP), using a high-titer AVP antiserum and a protocol which was found to block ether-induced ACTH secretion by 40% in adult male rats, failed to even partially block ethanol-induced ACTH or CS secretion. The results of this study indicate that neither adrenal medulla-derived E nor AVP are significant regulators or coregulators of corticotroph secretions following a moderately high, single-dose, intragastric administration of ethanol.
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PMID:Single-dose ethanol administration activates the hypothalamic-pituitary-adrenal axis: exploration of the mechanism of action. 255 77

The fetal pituitary gland secretes beta-endorphin in blood in response to delivery. However, other forms of endorphin have recently been observed in the fetal pituitary, such as N-acetyl-beta-endorphin, which is devoid of opiate activity, and a desacetylated form of alpha-melanocyte-stimulating hormone. Both endorphins originate in the pituitary intermediate lobe. The sensitivity of this lobe to labor stress was assessed by the evaluation of beta-endorphin, N-acetyl-beta-endorphin, melanocyte-stimulating hormone, and desacetylated alpha-melanocyte-stimulating hormone in maternal plasma and cord blood in 11 cases of vaginal delivery and 10 cases of elective cesarean section without labor. Plasma peptide levels were determined by specific radioimmunoassays after extraction on Sep-Pak C-18 cartridges and high-performance liquid chromatography fractionation. Cord blood samples of infants delivered vaginally showed higher beta-endorphin (8.5 +/- 1.6 pmol/L, mean +/- SE) and desacetylated alpha-melanocyte-stimulating hormone (13.6 +/- 3.2 pmol/L) levels than those delivered by elective cesarean section (3.7 +/- 0.8 and 4.2 +/- 1.1 pmol/L, for beta-endorphin and desacetylated alpha-melanocyte-stimulating hormone, respectively). N-acetyl-beta-endorphin and alpha-melanocyte-stimulating hormone levels do not differ in relation to the mode of delivery. In maternal circulation beta-endorphin levels were higher in those delivered vaginally (5.2 pm 1) than in women who had cesarean sections (2.5 +/- 0.5 pmol/L), whereas no changes were found for the other peptides. In vaginal deliveries, the level of desacetylated alpha-melanocyte-stimulating hormone was higher in cord blood (13.6 +/- 3.2 pmol/L) than in maternal plasma (6.5 +/- 3 pmol/L); there were no significant differences with regard to the other peptides. Fetal and maternal levels of all the peptides were similar in cases of cesarean section. We conclude that parturition activates proopiomelanocortin peptide release from both the anterior and the intermediate pituitary lobe and that the fetus secretes the appropriate beta-endorphin molecule, that is, the peptide able to bind opiate receptors. Concomitant secretion of desacetylated alpha-melanocyte-stimulating hormone may occur with adrenal androgen activation at birth.
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PMID:Fetal intermediate lobe is stimulated by parturition. 255 31

Since the intracellular messengers of various proopiomelanocortin-derived peptides remain ambiguous at best, we have investigated the possible involvement of phosphoinositide metabolism in aldosterone secretion evoked by alpha-MSH, beta-LPH, as well as ACTH in rat and calf adrenal glomerulosa cells. We have also examined the cAMP responses in the adrenal glomerulosa cells to alpha-MSH comparing it with those of ACTH. Our results showed that neither alpha-MSH, beta-LPH, nor ACTH increased inositol triphosphate (IP3) or other inositol phosphates in adrenal glomerulosa cells while increasing aldosterone secretion from the same cells. Angiotensin II, known to cause hydrolysis of the phosphoinositides, increased IP3 in these adrenal cells in a dose-dependent manner. Both ACTH and alpha-MSH raised the cAMP levels in the calf adrenal glomerulosa cells, although the magnitude of the increase of cAMP in response to ACTH was greater. These findings suggest that IP3 as a mediator of alpha-MSH- and beta-LPH-induced aldosterone secretion is not likely and other mediator(s) may be involved.
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PMID:Proopiomelanocortin-derived peptides, phosphoinositides, cAMP, and aldosterone secretion. 255 49

We have investigated the presence of ACTH, alpha-MSH and beta-endorphin, three peptides which derive from the multifunctional precursor protein proopiomelanocortin (POMC) in the brain of the rainbow trout Salmo gairdneri. Using both the indirect immunofluorescence and peroxidase-antiperoxidase techniques, a discrete group of positive cells was identified in the hypothalamus, within the anterior part of the nucleus lateralis tuberis. alpha-MSH-containing neurons represented the most abundant immunoreactive subpopulation. Coexistence of alpha-MSH, ACTH and beta-endorphin was observed in the lateral part of the nucleus. ACTH- and beta-endorphin-containing cells were mainly distributed in the rostral and caudal regions of the nucleus. In the medial portion of the nucleus lateralis tuberis, numerous cells were only stained for alpha-MSH. Moderate to dense plexuses of immunoreactive fibers were observed in the ventral thalamus and the floor of the hypothalamus. Some of these fibers projected towards the pituitary. The concentrations of ACTH, alpha-MSH and beta-endorphin-like immunoreactivities were measured in microdissected brain regions by means of specific radioimmunoassays. Diencephalon, mesencephalon and medulla oblongata extracts gave dilution curves which were parallel to standard curves. The highest concentrations of POMC-derived peptides were found in the diencephalon (alpha-MSH: 4.28 +/- 0.43 ng/mg prot.; ACTH: 1.08 +/- 0.09 ng/mg prot.; beta-endorphin: 1.02 +/- 0.1 ng/mg prot.), while lower concentrations were detected in the mesencephalon, medulla oblongata and telencephalon. The present results demonstrate that various peptides derived from POMC coexist within the same cell bodies of the fish hypothalamus. Taken together, these data suggest that expression and processing of POMC in the fish brain is similar to that occurring in pituitary melanotrophs.
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PMID:Proopiomelanocortin (POMC)-related peptides in the brain of the rainbow trout, Salmo gairdneri. 256 Jan 77

We examined effects of sodium valproate, a gamma amino butyric acid (GABA)-transaminase inhibitor, on the secretion of immunoreactive (IR)-ACTH and IR-beta-endorphin/LPH from cultured rat anterior pituitary cells to determine whether sodium valproate has a direct action on the secretion of ACTH and its related peptides from the cultured rat anterior pituitary gland. During the 3 h incubation, the basal secretion of IR-ACTH and IR-beta-endorphin/LPH decreased to 50.8% and 58.3%, respectively, of the control concentration after adding 10(-7) M sodium valproate into the incubation media and to 67.7% and 69.3%, respectively, of the control levels with 10(-8) M sodium valproate. However, sodium valproate at a concentration of 10(-6) M or 10(-9) M did not affect the basal concentration of IR-ACTH and IR-beta-endorphin/LPH. Sodium valproate at a concentration of 10(-7) M significantly attenuated the stimulated release of IR-ACTH and IR-beta-endorphin/LPH by 10(-9) or 10(-10) M of ovine corticotrophin releasing factor. These results indicate that sodium valproate could directly effect rat anterior pituitary cells to suppress both basal and stimulated release of proopiomelanocortin derived peptides and this supports the hypothesis that sodium valproate has a direct effect at the pituitary corticotroph in reducing plasma ACTH.
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PMID:Effect of sodium valproate on the secretion of proopiomelanocortin derived peptides from cultured rat anterior pituitary cells. 256 Dec 74


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