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 ability of ACTH fragments and of an ACTH analogue [9-tryptophan(o-nitrophenylsulfenyl)] corticotropin-(1-24)-tetracosapeptide[Trp-(Nps)9 ACTH1-24] to stimulate adenylate cyclase in bovine adrenal cortex membranes and a crude membrane fraction from rat adrenals has been determined. Partial agonists like Trp (Nps)9 ACTH1-24 displayed intrinsic activity in the rat adrenal preparation only if tested in the presence of 5'-guanylylimidodiphosphate [Gpp(NH)p]. On the other hand, no addition of Gpp(NH)p was necessary to demonstrate intrinsic activity of Trp(Nps)9 ACTH1-24 for bovine adrenal cortex adenylate cyclase. A large decrease (15-fold) of the apparent Km values for ACTH1-24, ACTH1-23 and ACTH1-17 was observed with the rat adrenal preparation when Gpp(NH)p was added. The shift in apparent Km values for ACTH1-24 and ACTH1-23 for the bovine adrenal cortex adenylate cyclase system was small or insignificant when Gpp(NH)p was added. The observations suggest that the hormone receptor facilitates the action of guanylnucleotide sites in the membrane. When guanylnucleotide sites are occupied by Gpp(NH)p even weak interactions of the hormone receptor with e.g. partial agonists are propagated to the catalytic subunits of the adenylate cyclase complex resulting in enhanced activity. The differences in adenylate cyclase activation with hormone fragments or analogues and different target tissues may rather reflect the state of the coupling process involving guanylnucleotide binding sites of the isolated membrane fraction than differences in the receptor itself.
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PMID:Adrenal cortex adenylate cyclase. In vitro acitivity of ACTH fragments and analogues. 18 24

The purpose of this investigation was to elucidate the biological significance of lysine11 and of the tripeptide sequence =Lys-Pro-Val-NH2 for the biological activity of alpha-melanocyte-stimulating hormone. To this end the in vitro melanotropic activities of twenty-four synthetic peptides related to the hormone were determined. Extension or reduction of the length of the lysine11 side chain results in a marked decrease of the melanotropic potency of the respective analogue. The C-terminal tripeptide (11--13), the tetrapeptide (10--13), and the pentapeptide (9--13) were found to be hormonally active in the same order of magnitude as the central hexapeptide (5--10). The following conclusion was drawn: alpha-MSH possesses (in contrast to ACTH) two message sequences (active sites), (i)-Glu-His-Phe-Arg-Trp-, and (ii)-Gly-Lys-Pro-Val-NH2 which are capable of independently triggering the hormone receptor responsible for melanin dispersion. Thus, despite the close structural similarity of the two hormones, alpha-MSH and ACTH appear to react with their respective target cell receptors by quite different chemical mechanisms, implying different receptor structures.
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PMID:Hormone-receptor interactions. The message sequence of alpha-melanotropin: demonstration of two active sites. 21 33

The hippocampus appears to be an important modulator of the negative feedback effects of glucocorticoids on the hypothalamic-pituitary-adrenal axis. It is not known if hippocampal subfields CA1-4 or the dentate gyrus differentially alter gene expression of corticotropin-releasing hormone (CRH) in the paraventricular nucleus (PVN) of the hypothalamus. We, therefore, examined the effects of selective destruction of dentate gyrus granule cells, which send excitatory glutaminergic inputs to subfields CA4, CA3 and CA2, on CRH expression in the PVN. To determine the possible involvement of steroid receptors in the regulation of CRH expression, we examined the effects of intrahippocampal colchicine on gene expression of the mineralocorticoid (MR; type I) and glucocorticoid (GR; type II) receptors in hippocampal CA fields and dentate gyrus. Colchicine produced a selective loss of dentate gyrus granule cells without affecting pyramidal cells in CA1-4 as early as 1 day after injection; granule cells were completely destroyed after 3 days. CRH mRNA levels were reduced by 38-48% in the PVN 2-14 days after colchicine. MR mRNA levels were decreased in dorsal and ventral CA fields 1-7 days after colchicine. GR mRNA levels were relatively unchanged, showing a slight decrease only in dorsal CA fields on days 2-7. Unexpectedly, CRH was transiently expressed in dorsal and ventral CA fields 1-3 days after colchicine. In the same time period, mRNA levels of inositol 1,4,5-trisphosphate kinase were decreased, suggesting that increases in neural metabolic activity, indicated by this marker, are not responsible for the transient CRH effect. The results suggest that the dentate gyrus is important for maintenance of steroid hormone receptor mRNA levels in the hippocampus and CRH expression in the hypothalamic PVN, and that CRH gene expression is differentially regulated in the hypothalamus and hippocampus.
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PMID:Intrahippocampal colchicine alters hypothalamic corticotropin-releasing hormone and hippocampal steroid receptor mRNA in rat brain. 132 Feb 16

Various classes of antidepressant drugs with distinct pharmacologic actions are differentially effective in the treatment of classic melancholic depression--characterized by pathological hyperarousal and atypical depression--associated with lethargy, hypersomnia, and hyperphagia. All antidepressant agents exert their therapeutic efficacy only after prolonged administration. In situ hybridization histochemistry was used to examine in rats the effects of short-term (2 weeks) and long-term (8 weeks) administration of 3 different classes of activating antidepressant drugs which tend to be preferentially effective in treating atypical depressions, on the expression of central nervous system genes thought to be dysregulated in major depression. Daily administration (5 mg/kg, i.p.) of the selective 5-hydroxytryptophan (5-HT) reuptake inhibitor fluoxetine, the selective alpha 2-adrenergic receptor antagonist idazoxan, and the nonspecific monoamine oxidase A and B inhibitor phenelzine increased tyrosine hydroxylase mRNA levels by 70-150% in the locus coeruleus after 2 weeks of drug and by 71-115% after 8 weeks. The 3 drugs decreased corticotropin-releasing hormone mRNA levels by 30-48% in the paraventricular nucleus of the hypothalamus. The decreases occurred at 8 weeks but not at 2 weeks. No consistent change in steroid hormone receptor mRNA levels was seen in the hippocampus with the 3 drugs, but fluoxetine and idazoxan increased the level of mineralocorticoid receptor (MR) and glucocorticoid receptor (GR) mRNA, respectively, after 8 weeks of drug administration. Proopiomelanocortin (POMC) mRNA levels in the anterior pituitary and plasma adrenocorticotropic-hormone (ACTH) levels were not altered after 2 or 8 weeks of drug treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The antidepressants fluoxetine, idazoxan and phenelzine alter corticotropin-releasing hormone and tyrosine hydroxylase mRNA levels in rat brain: therapeutic implications. 135 83

1. The darkening actions of MCH (melanin concentrating hormone), alpha-MSH and the synthetic analog [Nle4, D-Phe7]-alpha-MSH on the toad, Bufo ictericus ictericus, melanophores were studied regarding the role of calcium in the hormone receptor coupling, signal transduction and intracellular pigment translocation. 2. In the absence of external calcium, MCH and both melanotropins still elicit maximal skin darkening. 3. Verapamil, a calcium-channel blocker, completely abolishes the alpha-MSH-induced response and partially inhibits MCH-induced darkening, although the calcium carrier, ionophore A23187, was unable to promote any pigment translocation. 4. Since darkening responses promoted by cyclic nucleotides proceeded normally in the presence of verapamil and extracellular calcium was not necessary for melanotropin dispersing action, it is suggested that the blocking activity obtained with verapamil is probably due to an impairment of the Ca2+-dependent adenylate cyclase activity. 5. Reversal of melanotropin-induced darkening could be obtained with melatonin, in both normal and Ca2+-free Ringer, whereas MCH darkening is reversed by melatonin only in the absence of calcium. 6. The results seem to indicate that calcium is not required for hormone receptor binding and pigment migration, whereas it is specifically needed for signal transduction.
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PMID:alpha-MSH (melanocyte stimulating hormone) and MCH (melanin concentrating hormone) actions in Bufo ictericus ictericus melanophores. 288 67

Metastatic K-1735 murine melanoma cells are amelanotic in culture or in the subcutis of syngeneic mice. When injected into the internal carotid artery, these cells produce melanotic brain metastases. The production of melanin in tumor cells growing in the brain was directly correlated with induction of melanocyte-stimulating hormone receptor (MSH-R) steady-state mRNA transcripts. K-1735 cells isolated from brain lesions and implanted into the subcutis or grown in culture lose MSH-R transcripts and become amelanotic. In contrast to K-1735 cells, B16-BL6 melanoma cells constitutively produce melanin and express high levels of MSH-R mRNA regardless of the site of growth. Somatic cell hybrids between K-1735 and B16 cells produced melanin and expressed high levels of MSH-R mRNA transcripts, regardless of the site of growth, suggesting the dominance of the B16 phenotype. Treatment with alpha-MSH failed to upregulate MSH-R expression in cultured K-1735 cells or to maintain MSH-R expression in K-1735 cells isolated from brain metastases to be grown in culture. Responsiveness to alpha-MSH as determined by cell proliferation, melanin production, and intracellular accumulation of cyclic AMP directly correlated with MSH-R expression. These data demonstrate that a specific organ environment influences the phenotype of metastatic cells by regulation of specific genes that encode for cell surface receptors.
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PMID:Transcriptional induction of the melanocyte-stimulating hormone receptor in brain metastases of murine K-1735 melanoma. 780 24

Using polymerase chain reaction amplification of commercially available DNA templates, we have mapped the human corticotropin-c releasing hormone receptor gene (CRHR) to the long arm of chromosome 17 (17q12-qter).
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PMID:Human corticotropin-releasing hormone receptor gene (CRHR) is located on the long arm of chromosome 17 (17q12-qter). 783 24

Studies on neuroendocrine hormone receptor have been hampered by low numbers and concentrations of receptors found within and outside the neuroendocrine system. The complementary peptide approach is particularly useful for dealing with this problem and has been used to characterize lymphoid receptors for arginine vasopressin (AVP), corticotropin (ACTH), substance P, and opioid peptides. A nonapeptide derived by reading of the complementary DNA strand of the bovine AVP gene in the 3' to 5' direction specifically blocks the AVP helper signal for interferon-gamma production by mouse T lymphocytes. Antibodies to 3'-5' AVP-binding peptide bound to cells, and the binding was inhibited by excess AVP. Thus, binding of anti-3'-5'AVP-binding peptide antibodies to the AVP receptor was specific. The complementary peptide approach has also been used to produce antibodies specific for the ACTH receptor complex. Complementary peptides to ACTH derived by reading in either the 5' to 3' or 3' to 5' direction were able to bind to ACTH. Monospecific antibodies to the ACTH (1-24) complementary peptide caused an ACTH-like steroidogenic response of cultured mouse adrenal cells, presumably by binding to the ACTH receptor, and binding was specifically inhibited by ACTH. The ACTH receptor complex from solubilized adrenal cells was shown to consist of four subunits with M(r) 83,000, 64,000, 52,000, and 22,000. The 83,000 and 52,000 M(r) subunits are disulfide linked and noncovalently associated with the other subunits, with binding of labeled ACTH localized to the 83,000 M(r) subunit. Similarly, a complementary peptide was shown to bind directly to substance P in a saturable and dose-dependent manner.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Complementary peptides as probes to explore neuropeptide receptors on lymphocytes. 787 40

Molecular cloning experiments have led to the identification and characterization of a family of five receptors for the melanocortin (melanotropic and adrenocorticotropic) peptides. The first two members of the family cloned were the well-characterized melanocyte-stimulating hormone receptor (MSH-R) and adrenocorticotropin receptor (ACTH-R). The three new melanocortin receptors have been termed the MC3-R, MC4-R, and MC5-R, according to the order of their discovery, and little is known at this point concerning their function. Agouti and extension are two genetic loci known to control the amounts of eumelanin (brown-black) and phaeomelanin (yellow-red) pigments. Chromosomal mapping demonstrated that the MSH-R, now termed MCI-R, mapped to extension. Extension was shown to encode the MCI-R, and mutations in the MCI-R are responsible for the different pigmentation phenotypes caused by this locus. Functional variants of the MCI-R, originally characterized in the mouse, have now also been identified in the guinea pig and cow. Dominant constitutive mutants of the MCI-R are responsible for causing dark black coat colors while recessive alleles result in yellow or red coat colors. Agouti, a secreted 108 amino acid peptide produced within the hair follicle, acts on follicular melanocytes to inhibit alpha-MSH-induced eumelanin production. Experiments demonstrate that agouti is a high-affinity antagonist, acting at the MCI-R to block alpha-MSH stimulation of adenylyl cyclase, the effector through which alpha-MSH induces eumelanin synthesis. The MCI-R is thus a unique bifunctionally controlled receptor, activated by alpha-MSH and antagonized by agouti, both contributing to the variability seen in mammalian coat colors. The variable tan and black coat color patterns seen in the German Shepherd, for example, can now be understood on the molecular level as the interaction of a number of extension and agouti alleles encoding variably functioning receptors and a differentially expressed antagonist of the receptor, respectively.
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PMID:The melanocortin receptors: agonists, antagonists, and the hormonal control of pigmentation. 870 Oct 84

Hypothalamic corticotropin releasing hormone (CRH) controls the release of adrenocorticotrophic hormone (ACTH) from the pituitary and, and therefore has a major role in the activation of the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis function has been shown to be impaired in the neonatal period as well as in aging. Since corticotropin-releasing hormone receptor (CRHr) plays a crucial role in the regulation of HPA axis, using in situ hybridization histochemistry we have analyzed the rat pituitary for the presence of CRHr mRNA in the neonatal period and during aging. The results show an increase in CRHr mRNA in 3-day-old rats, with a progressive increase within the first month. In the aging rat, we observed a down-regulation of the CRHr mRNA localized in the anterior pituitary, gland viceversa, an increased signal in the intermediate lobe. Our findings demonstrate age-related changes in the expression of the CRHr mRNA in the pituitary, with a differential regulation in the anterior and intermediate lobes of aging rats.
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PMID:Age-related changes in the expression of corticotropin-releasing hormone receptor mRNA in the rat pituitary. 873 49


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