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Query: UNIPROT:P01189 (
beta-endorphin
)
21,003
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Tartrate-resistant acid phosphatase (TRAcP) is a reliable cytochemical marker for the diagnosis of hairy cell leukemia (HCL). The enzyme has been the subject of much biochemical investigation yet its function in the hairy cells (HC) is still unknown. Two TRAcPs have been purified from HCL spleen tissues by a series of chromatographic separations. The two enzymes, provisionally called peak 1 and peak 2, had specific activities of greater than 600 U/mg and 800 U/mg respectively when p-nitrophenyl phosphate (p-NPP) was used as substrate and had Km values in the range of 1 to 5 mM p-
NPP
. The two TRAcPs had the same substrate specificities and inhibitor sensitivities, therefore could be isoforms of the same enzyme. Their pH optima were between 5 and 6 for all substrates tested including the phosphotyrosine-containing peptide, Raytide, which was still hydrolyzed efficiently at neutral pH. Neither phosphoserine nor phosphoserine-containing casein were hydrolyzed by either enzyme. The TRAcPs of HC may thus be capable of functioning as protein-
tyrosine
phosphatases (PTP). High activity of a PTP could regulate the activities of protein-
tyrosine
kinases and thereby influence the growth and differentiation of the hairy cells.
...
PMID:Protein-tyrosine phosphatase activity of hairy cell tartrate-resistant acid phosphatase. 156 56
Dopamine (DA) neurons participate in tonic inhibition of prolactin (PRL), whereas
beta-endorphin
(beta-End) and serotonin (5-HT) neurons appear to be important stimulatory links for nocturnal PRL surges that occur throughout the first half of pregnancy in the rat. The purpose of this study was to determine how these neuronal components might be organized within the pathway controlling PRL release during gestation. Maximal stimulation of DA receptors with the agonist bromocriptine mesylate (Bromo) completely blocked the PRL response to beta-End (100 ng/microliters/min for 15 min) given intracerebroventricularly (i.c.v.) on day 8 of pregnancy. DA receptor blockade, produced by implanting a 25 mg pellet of haloperidol (Hal) on day 7 of pregnancy, resulted in PRL levels of 500-600 ng/ml by the following morning. beta-End i.c.v. or 250 mg/ml/kg BW of the DA synthesis inhibitor, alpha-methyl-p-
tyrosine
(alpha-MPT), given during the intersurge period, were equally effective in significantly increasing PRL (p less than 0.01) above pretreatment levels. beta-End and alpha-MPT evoked similar increases in rats pretreated with Hal, suggesting the stimulatory effect of beta-End on nocturnal PRL surges may primarily be due to DA inhibition. The next objective was to determine how beta-End and 5-HT might interact to stimulate the nocturnal surge. Day 8 pregnant rats were infused continuously with the opioid receptor blocker, naloxone hydrochloride (Nal), at a rate of 2.0 mg/10 min from 1000-1300 h. The PRL response to an injection of 20 mg/kg BW 5-hydroxytryptophan (5-HTP) at 1200 h was greatly attenuated, compared to controls infused with saline instead of Nal. This suggests that 5-HT stimulates PRL, at least in part, by an action at opioid receptors. Distilled H2O or 10 mg/kg BW of the selective S2 receptor blocker, ketanserin tartrate (Ket), was given intraperitoneally (i.p.) during the intersurge period on day 8 of pregnancy. All animals demonstrated an identical response to beta-End given 2 hours later, regardless of the type of pretreatment. It appears that beta-End does not stimulate PRL by way of an S2 receptor. Although beta-End induced a significant increase in PRL on day 16 of pregnancy, the response was attenuated by more than 60% compared to the response on day 8 of pregnancy. This attenuation may involve placental lactogens, shown to be secreted during this time and to inhibit PRL secretion.(ABSTRACT TRUNCATED AT 400 WORDS)
...
PMID:Mechanisms for the stimulatory effects of opioidergic and serotonergic input signals on prolactin in pregnant rats. 157 43
The possible existence of a feedback control by endogenous opioids of the spinal release of
met-enkephalin
-like material was assessed in vivo, in halothane-anesthetized rats whose intrathecal space was continuously perfused with an artificial cerebrospinal fluid supplemented with various opioid-related drugs. Both the intrathecal perfusion of the mu agonist D-Ala2-D-MePhe4-Gly-ol5-enkephalin (DAGO) (10 microM) and the delta agonist
Tyr
-D-Thr-Gly-Phe-Leu-Thr (DTLET) (10 microM) produced a significant inhibition of the spinal outflow of
met-enkephalin
-like material. The effect of DAGO, but not that of DTLET, could be prevented by naloxone (10 microM), and, conversely, the effect of DLTET, but not that of DAGO, was no longer observed in the presence of naltrindole (10 microM). Therefore naloxone and naltrindole acted as potent and selective mu and delta antagonists, respectively, when perfused at 10 microM in the intrathecal space of halothane-anesthetized rats. As expected from the lack of a tonic opioid control of spinal enkephalinergic neurones, neither naloxone nor naltrindole alone affected the spontaneous outflow of
met-enkephalin
-like material. However, naltrindole, but not naloxone, markedly increased the spinal overflow of
met-enkephalin
-like material due to intrathecal administration of either porcine calcitonin (10 microM) or the peptidase inhibitors thiorphan (10 microM) plus bestatin (20 microM). These data suggest that delta, but not mu, receptors are involved in a phasic opioid inhibitory control of the release of
met-enkephalin
-like material in the rat spinal cord.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Feedback inhibition of met-enkephalin release from the rat spinal cord in vivo. 160 25
Adrenocorticotropic (ACTH) and melanocyte stimulating (MSH) hormones have been demonstrated in the same cells in the cephalic half of the pars distalis of the chicken pituitary glands in three ways: (I) immunohistochemistry, (II) radioimmunoassay (RIA) using both anti-human or porcine ACTH and synthetic
alpha-MSH
antibodies, and (III) isolation and purification, followed by the determination of amino acid compositions of both hormones. The contents of ACTH and
alpha-MSH
are estimated by RIA to be 1600 and 10 ng/gland, respectively. ACTH missed 1 (des-Phe39-ACTH) or 2 residues (des-Glu38, Phe39-ACTH) from the C-terminal portion was also isolated. The recoveries of these ACTHs are differed from preparation to preparation. The complete amino acid sequence of chicken ACTH (39 residues) has been determined as NH2-Ser-
Tyr
-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-Gly-Arg-Lys-Arg- Arg- Pro-Ile-Lys-Val-
Tyr
-Pro-Asn-Gly-Val-Asp-Glu-Glu-Ser-Ala-Glu-Ser-
Tyr
-Pro- Met-Glu-Phe-OH Strikingly the amino acid sequence of chicken ACTH shows a closer resemblance to that from an amphibian, Xenopus (3 residue substitution) than that from another bird, the ostrich (7 residue substitution) or the turkey (at least 9 residue substitution).
...
PMID:Characterization of chicken ACTH and alpha-MSH: the primary sequence of chicken ACTH is more similar to Xenopus ACTH than to other avian ACTH. 165 32
Three different monoiodinated radioligands of
alpha-MSH
(
alpha-melanocyte-stimulating hormone
) were compared in a binding assay with human D10 melanoma cells: [
Tyr
(125I)2]-
alpha-MSH
, [
Tyr
(125I)2,NIe4]-
alpha-MSH
, and [
Tyr
(125I)2,NIe4,D-Phe7]-
alpha-MSH
. They were prepared either by the classical chloramine T method or by the Enzymobead method. A simple and rapid purification scheme was developed consisting of a primary separation on reversed-phase C18 silica cartridges immediately after the iodination, followed by HPLC purification before each binding experiment. Biological testing of the three radioligands showed that they all retained high melanotropic activity in the B16 melanin assay and the Anolis melanophore assay. However, in human D10 melanoma cells, [
Tyr
(125I)2,NIe4]-
alpha-MSH
led to a high degree of non-specific binding to the cells which could not be displaced by excess
alpha-MSH
and only partially by [NIe4]-
alpha-MSH
. The [
Tyr
(125I)2,NIe4,D-Phe7]-
alpha-MSH
tracer gave similar results but with a much lower proportion of non-specific binding. On the other hand, [
Tyr
(125I)2]-
alpha-MSH
proved to be an excellent radioligand whose non-specific binding to the D10 cells was not higher than 20% of the total binding.
...
PMID:Biologically active monoiodinated alpha-MSH derivatives for receptor binding studies using human melanoma cells. 165 37
Bremazocine, a benzomorphan, has been reported to have kappa, mu and epsilon opioid receptor binding activities. The present studies were then designed to determine what types of opioid receptors and neurotransmitters were involved in inhibiting the tail-flick response induced by bremazocine in male ICR mice. U50, 488H, a prototypic kappa agonist, was used for comparison. Bremazocine, at doses from 0.1 to 1 microgram given i.c.v., dose-dependently inhibited the tail-flick response. The paw-licking hot plate response, even at high doses of bremazocine, was not completely inhibited. The inhibition of the tail-flick response induced by bremazocine (1 microgram) given i.c.v. was blocked by i.c.v. coadministration of
beta-endorphin
-(1-27) (3 and 6 micrograms), an epsilon opioid receptor antagonist and norbinaltorphimine (4 micrograms), a kappa opioid receptor antagonist. On the other hand, the inhibition induced by i.c.v. U50,488H (40 micrograms) was blocked by i.c.v. norbinaltorphimine, but not
beta-endorphin
-(1-27). D-Phe-Cys-
Tyr
-D-Try-Orn-Thr-Pen-Thr-NH2 (CTOP; 0.5 microgram) and beta-funaltrexamine (beta-FNA; 2.5 micrograms), selective mu opioid receptor antagonists, and ICI 174,864 (10 micrograms), a delta-opioid receptor antagonist, which blocked the effects induced by DAMGO (16 ng) and DPDPE (20 micrograms), respectively, did not block inhibition of the tail-flick response induced by bremazocine (1 microgram) given i.c.v. The inhibition of the tail-flick response induced by i.t. administration of bremazocine (1 microgram) was blocked by i.t. coadministration of norbinaltorphimine but not CTOP, ICI 174,864, or
beta-endorphin
-(1-27).(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Involvement of epsilon and kappa opioid receptors in inhibition of the tail-flick response induced by bremazocine in the mouse. 165 27
Endothelin 3 (ET3) is a member of the novel vasoconstrictive peptide family, identified in the porcine central nervous system. The effect of ET3 on the hypothalamic-pituitary-adrenal axis in male rats was examined in vivo and in vitro. Intravenous bolus injection of 1000pmol/kg of ET3 in free moving rats caused significant increases in plasma ACTH and corticosterone levels, almost equivalent to those of 100pmol/kg of rat
corticotropin
-releasing hormone (rCRH). Since an iv bolus injection of ET3 1000pmol/kg did not cause significant changes in the blood pressure of anesthetized rats or the locomotor activity of free moving rats, it seems unlikely that ET3 1000pmol/kg acted as a nonspecific stressor. When ET3 (10(-11) greater than 10(-7)M) was added to cultured anterior pituitary cells, neither direct stimulation of ACTH release nor potentiation of rCRH action was noted. Although it has been shown that ET3 administered systemically probably does not cross the brain-blood-barrier, circulating ET3 may reach the brain tissues through regions lacking the tight barrier, circumventricular structures. The next studies included pretreatment of antagonists or blockers of ACTH stimulating hormones to elucidate the mechanisms of ET3 induced ACTH release. The action of ET3 was virtually abolished by pretreatment of CRH-antagonist alpha helical CRH (150 micrograms/rat icv). But pretreatment of catecholamine-blocker alpha methyl-
tyrosine
(100mg/kg iv), arginine vasopressin-antagonist dP-thy(Me)AVP (50 micrograms/rat iv) and prostaglandin-blocker indomethacin (3mg/rat iv) did not inhibit the action of ET3. The results indicate that ET3 may play the role of a neuropeptide and that the stimulation of the CRH-neurons is mainly responsible for activation of ACTH and corticosterone release.
...
PMID:[Endothelin 3 (ET3) stimulates the hypothalamic-pituitary-adrenal axis mainly by corticotropin-releasing-hormone (CRH)]. 166 69
Intermediate pituitaries of the reptile, Anolis carolinensis, were separately pulse labeled with [3H]Trp and [3H]
Tyr
. The major form of
alpha-MSH
was purified by immunoprecipitation and isolated by reverse phase HPLC. Tryptic peptide analysis indicated that the [3H]Trp-labeled C-terminal fragment of Anolis
alpha-MSH
had the same retention time as mammalian ACTH(9-13) amide; however, the [3H]
Tyr
-labeled N-terminal fragment did not coelute with either mammalian ACTH(1-8) or N-acetyl-ACTH(1-8). Purification of
alpha-MSH
from 76 Anolis intermediate pituitaries confirmed that a sequence change had occurred in the N-terminal region of Anolis
alpha-MSH
. The tissues were acid extracted and purified by Sephadex G-25 chromatography and reverse phase HPLC to yield 4.5 micrograms of purified Anolis
alpha-MSH
for amino acid composition analysis and automated Edman degradation sequence analysis. The major form of Anolis
alpha-MSH
is nonacetylated and has the following novel primary sequence: Ser-
Tyr
-Ala-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro(Val-amide). The presence of Val-amide was verified by immunological analysis, tryptic peptide analysis and amino acid composition analysis.
...
PMID:Detection of a novel sequence change in the major form of alpha-MSH isolated from the intermediate pituitary of the reptile, Anolis carolinensis. 166 89
The effect on blood pressure and heart rate of central administration of dynorphin A(1-13) and of beta-, gamma-, and alpha-endorphin related peptides was studied in urethane-anesthetized rats. Intracerebroventricular (i.c.v., 0.1-10 micrograms) administration of
beta-endorphin
resulted in a dose-dependent, naltrexone-reversible hypotension and bradycardia. N-terminally modified fragments of
beta-endorphin
did not reduce blood pressure and heart rate. On the other hand, a dose of 10 micrograms of
beta-endorphin
(1-27), which lacks the four C-terminal amino acid residues of
beta-endorphin
, induced a fall in blood pressure and had a biphasic effect on heart rate. These responses, however, were resistant to pretreatment with naltrexone. None of the fragments of
beta-endorphin
smaller than
beta-endorphin
(1-27) affected blood pressure when administered i.c.v. in a dose of 10 micrograms. A small transient bradycardia was observed after i.c.v. administration of 10 micrograms of
beta-endorphin
(1-26), alpha, and
gamma-endorphin
. The naltrexone-reversible bradycardic response of alpha- and
gamma-endorphin
was not present in des-
tyrosine
- and des-enkephalin-alpha- and
gamma-endorphin
and also not in alpha-endorphin(10-16) and
gamma-endorphin
(10-17). Upon i.c.v. administration (0.1-50 micrograms) a dose-dependent, naltrexone-reversible decrease in blood pressure and heart rate was induced by dynorphin A(1-13). The present data indicate a hypotensive influence of
beta-endorphin
,
beta-endorphin
(1-27), and dynorphin A(1-13), whereas other fragments of
beta-endorphin
had little or no effect on the cardiovascular parameters investigated.
...
PMID:Effects of dynorphin A(1-13) and of fragments of beta-endorphin on blood pressure and heart rate of anesthetized rats. 167 37
In the presence of physiological cations (in Krebs-4-(2-hydroxyethyl)-1- piperazineethanesulfonic acid buffer) at 37 degrees C the Ki value's of
beta-endorphin
for mu- and delta-opioid receptor binding sites in rat neocortical membranes, labeled with [3H][D-Ala2,MePhe4,Gly- ol5]enkephalin (DAMGO) and [3H][D-Ala2-D-Leu5]enkephalin (in the presence of unlabeled DAMGO), respectively, amounted to about 9 and 22 nM. Surprisingly, a very different selectivity pattern for the endogenous opioid peptide was found when the affinity of
beta-endorphin
for functional presynaptic opioid receptors was examined. Thus,
beta-endorphin
strongly inhibited the electrically evoked release of [3H]NE from rat neocortical slices with an IC50 value of about 0.5 nM, whereas [14C] acetylcholine release from neostriatal slices was inhibited with an IC50 value of about 100 nM. On the other hand, the electrically evoked release of [3H]dopamine from striatal slices was not affected by
beta-endorphin
. The inhibitory effects of DAMGO and
beta-endorphin
on [3H]NE release from neocortical slices were equally well antagonized by naloxone. Moreover, 10 nM of the highly selective mu-opioid receptor antagonist D-Phe-Cys-
Tyr
-D-Trp-Arg-Thr-Pen- Thr-NH2 antagonized competitively the inhibitory effect of
beta-endorphin
on [3H]NE release.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Beta-endorphin: a highly selective endogenous opioid agonist for presynaptic mu opioid receptors. 167 39
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