Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Urinary levels of immunoreactive (IR) human NH2-terminal (hNT) of pro-opiomelanocortin were measured in 43 patients with various cell types of lung cancer (19 squamous cells, 12 oat cells, 2 large cells, and 10 adenocarcinoma), 32 patients with benign lung disease, two patients after hypophysectomy, and in 23 healthy volunteers. Lung cancer patients were divided into two subgroups according to the stage of the disease: 22 patients had "limited", and 21 patients "extensive" disease. Urinary and plasma levels were measured in 9 patients with lung cancer before and after radio- and chemotherapy or surgery. Urine samples were dialyzed and IR hNT material was extracted by Sep Pak C-18 cartridges using a propanol-2/TFA solvent system. The plasma and urinary IR hNT levels of the normal controls were 124 +/- 25 pg/ml and 47.8 +/- 14.5 pg/mg creatinine, respectively. The plasma levels of IR hNT were elevated (greater than mean + 2SD) in 65% of our patients with histologically proven lung cancer (422 +/- 775, mean +/- SD, pg/ml). The highest incidence of an elevated plasma level of IR hNT was found in oat cell carcinoma (83%). Elevated plasma IR hNT occurred in 66% of the patients with benign pulmonary disease (246 +/- 141 pg/ml, N.S.). In cancer patients with "limited" disease we found levels of 226 +/- 143 pg/ml and in patients with "extensive" disease 627 +/- 1074 pg/ml (N.S.). The urinary IR hNT level in lung cancer patients was 186 +/- 337 pg/mg creatinine and 81% of our patients had elevated levels.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Urinary levels of immunoreactive NH2-terminal of pro-opiomelanocortin in patients with malignant pulmonary disease. 253 37

alpha-Melanotropin (alpha-melanocyte-stimulating hormone, alpha-MSH) is a tridecapeptide, Ac-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH2. The minimal sequence of alpha-MSH required for agonism in the lizard (Anolis carolinensis) skin bioassay was determined to be Ac-His-Phe-Arg-Trp-NH2 (Ac-alpha-MSH6-9-NH2). Smaller fragments of this sequence (Ac-alpha-MSH6-8-NH2, Ac-alpha-MSH6-7-NH2, Ac-alpha-MSH7-9-NH2, and Ac-alpha-MSH7-8-NH2) were devoid of melanotropic activity. The tetrapeptide, Ac-alpha-MSH7-10-NH2, was also inactive, thus again demonstrating the importance of His at position 6 for minimal activity. The important potentiating amino acids were found to be Met-4, Lys-11, and Pro-12, since Ac-alpha-MSH4-10-NH2 was about 100 times more potent than Ac-alpha-MSH5-10-NH2, and Ac-[Nle4]-alpha-MSH4-11-NH2 was about 40 times more potent than Ac-alpha-MSH4-10-NH2 or Ac-[Nle4]-alpha-MSH4-10-NH2. Ac-alpha-MSH4-12-NH2 and Ac-[Nle4]-alpha-MSH4-12-NH2 were equipotent and about six times more potent than alpha-MSH. Since [Nle4]-alpha-MSH and Ac-[Nle4]-alpha-MSH4-13-NH2 were both equipotent but about sixfold less active than Ac-[Nle4]-alpha-MSH4-12-NH2, it is clear that valine at position 13 does not contribute to the potency of alpha-MSH, except possibly in a negative way. The minimal message sequence for equipotency to alpha-MSH appears to be Ac-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-NH2, since the analog, Ac-[Nle4]-alpha-MSH4-11-NH2, was as active as the native hormone. Ser-1, Tyr-2, Ser-3, Glu-5, and Val-13 are not important for melanotropic potency since Ac-alpha-MSH4-12-NH2 was more potent than alpha-MSH, and Ac-alpha-MSH5-10-NH2 and Ac-alpha-MSH6-10-NH2 were equipotent, being about 4,000 times less active than alpha-MSH.
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PMID:Alpha-melanotropin: the minimal active sequence in the lizard skin bioassay. 253 78

Examination of the cardiovascular effects produced by peripheral administration of peptide sequences derived from adrenocorticotropic hormone (ACTH) led to the discovery of the pressor, cardioaccelerator, and natriuretic actions of intravenous (iv) ACTH-(4-10). Based on pharmacological studies in rats with alpha- and beta-adrenergic receptor antagonists, the cardiovascular effects of this peptide appeared to be mediated by the release of catecholamines. A peptide sequence analogous to ACTH-(4-10), gamma-melanocyte-stimulating hormone (gamma-MSH), possesses greater than 100-fold more cardiovascular activity and 1,000-fold more natriuretic activity than ACTH-(4-10). The pressor effect of iv gamma-MSH peptides appears to be dependent on the maintenance of preganglionic sympathetic drive, with no significant contribution of circulating vasopressin or angiotensin II. However, the presence of central vasopressinergic, and perhaps angiotensinergic, pathways appears to be crucial for expression of the full pressor effect of circulating gamma-MSH. Further evidence for the potential importance of the central nervous system (CNS) in these cardiovascular effects was obtained from central lesion experiments and a comparison of intracarotid vs. intrajugular infusions. Structure-activity studies suggested that the cardiovascular effects of ACTH-(4-10) or gamma-MSH are dependent on an Arg-hydrophobic amino acid sequence, located at or near their COOH-terminal. A similar requirement for biological activity is found in molluscan cardioexcitatory peptides, and the molluscan peptides have cardiovascular effects in rats, which resemble ACTH-(4-10) or gamma-MSH. This suggests that peptides of the gamma-MSH family are the pharmacological analogues, and perhaps the physiological homologues, of a cardioexcitatory family of peptides found in molluscs and birds. Elevated circulating levels of peptides derived from the NH2-terminal of pro-opiomelanocortin (POMC) have been found in psychological stress, cardiovascular distress, and hemorrhage. Increases in central sympathetic drive are common to all of these states. gamma-MSH peptides have been localized to POMC neurons in the arcuate nucleus and nucleus commissuralis of the rat. Projections from the latter nucleus innervate hindbrain vasomotor centers. Intraventricular administration of gamma-MSH produces prolonged elevation of mean arterial pressure. gamma-MSH peptides may provide a link between humoral and neurogenic mechanisms in cardiovascular regulation and could potentially be important neurotransmitters for central control of the cardiovascular system.
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PMID:ACTH-(4-10) through gamma-MSH: evidence for a new class of central autonomic nervous system-regulating peptides. 255 43

Utilizing results from previous structure-activity relationships and theoretical studies of alpha-melanotropin (alpha-MSH, Ac-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH2) and its related superpotent analogues, Ac-[Nle4,D-Phe7]-alpha-MSH and Ac-[Cys4,Cys10]-alpha-MSH, we have designed a new class of alpha-MSH4-13 and alpha-MSH4-10 cyclic lactam fragment analogues of alpha-melanotropin. The cyclic peptides have the following general structures: Ac-[Nle4,Xxx5,D-Phe7,Yyy10,Gly11]-alpha-MSH4-13- NH2 and Ac-[Nle4,Xxx5,D-Phe7,Yyy10]-alpha-MSH4-10-NH2, where Xxx = Glu or Asp and Yyy = Lys, Orn, Dab, or Dpr. Formation of the lactam bridge between the side-chain groups Xxx and Yyy was performed either in solution or on a solid-phase support. Seven cyclic peptides were prepared and bioassayed for their melanotropic potency by using standard frog (Rana pipiens) and lizard (Anolis carolinensis) skin bioassays. Relative to alpha-MSH (relative potency = 1), the potencies of the cyclic peptides in the lizard skin bioassay were as follows: alpha-MSH (1); Ac-[Nle4,Glu5,D-Phe7,Lys10,Gly11]-alpha-MSH4-13- NH2 (6); Ac-[Nle4,Asp5,D-Phe7,Lys10,Gly11]-alpha-MSH4-13- NH2 (100); Ac-[Nle4,Glu5,D-Phe7,Lys10]-alpha-MSH4-10-NH2 (9); Ac-[Nle4,Asp5,D-Phe7,Lys10]-alpha-MSH4-10-NH2 (90); Ac-[Nle4,Asp5,D-Phe7,Orn10]-alpha-MSH4-10-NH2 (20); Ac-[Nle4,Asp5,D-Phe7,Dab10]-alpha-MSH4-10-NH2 (5); Ac-[Nle4,Asp5,D-Phe7,Dpr10]-alpha-MSH4-10-NH2 (5). Similar results were obtained in the frog skin bioassay, but the analogues were much less potent. Cyclic melanotropins with 23-membered rings exhibited 100-fold higher melanotropic potency than alpha-MSH with selectivity for the lizard melanocyte receptors over the frog melanocyte receptors. Increasing or decreasing the ring size of these cyclic melanotropins from 23 diminishes the biological potency of the resulting cyclic peptide. The 23- and 24-membered ring analogues showed prolonged (residual) biological activities in both biological assays, but the smaller ring systems (20, 21, 22) did not. These results provide new insights into the structural and conformational requirements of alpha-MSH and its analogues at two different types of pigment cell (melanocyte) receptors.
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PMID:Potent and prolonged acting cyclic lactam analogues of alpha-melanotropin: design based on molecular dynamics. 255 12

Two analogues of alpha-MSH (Ac-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH2), Ac-[Nle4, Asp5, D-Phe7, Lys10]alpha-MSH4-10NH2 and Ac-[Nle4, Asp5, D-Phe7, Lys10] alpha-MSH4-10-NH2, were synthesized, and the melanotropic activities of the peptides were compared in several bioassays. Potencies were determined in the in vitro frog and lizard skin bioassays and in the S91 melanoma cell tyrosinase assay. Both analogues were equipotent or more potent than alpha-MSH in all bioassays, and the activities of the analogues were prolonged compared to alpha-MSH. The two analogues were very resistant to inactivation by purified proteolytic enzymes (alpha-chymotrypsin, trypsin, and pepsin). The two peptides could be topically applied and transdermally delivered across the skin of mice in vivo, resulting in a shift from pheomelanogenesis to eumelanogenesis within follicular melanocytes. The cyclic analogue exhibited greater potency, prolonged activity, and stability against enzyme inactivation than did the linear peptide. The significance of the findings for the further design of melanotropin analogues is discussed, as in the possible relevance of these melanotropin analogues for use in biomedical studies.
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PMID:Linear and cyclic alpha-melanotropin [4-10]-fragment analogues that exhibit superpotency and residual activity. 255 3

Novel D-amino acid modified, hexapeptide inhibitors of alpha-melanocyte-stimulating hormone (Ac-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH2, alpha-MSH) are described. The discovery of the alpha-MSH inhibitory activity of a known somatotropin (growth hormone) secretagogue, H-His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 ([His1, Lys6-]GHRP, I), and its chemical similarity to the alpha-MSH6-11 sequence provided the impetus to investigate the structure-activity relationships of MSH-GHRP hybrid analogues. In this study we compared the melanotropic activity of a series of peptides of the generic formula H-His-Xaa-Yaa-Trp-D-Phe-Lys-NH2 (H-[Xaa7, Yaa8, D-Phe10] alpha-MSH6-11-NH2) on the R. pipiens (frog) and A. carolinensis (lizard) skin in vitro bioassays. In summary, D-Phe7-Ala8 substitution (II) in the heptapeptide template yielded an MSH-like agonist of moderately low potency (EC50 ca. 10(-6) M) relative to alpha-MSH; D-Ala7-Ala8 substitution (III) abolished agonist or antagonist activity. alpha-MSH inhibition was effected by MSH-GHRP analogues having D-Trp7-Ala8, D-Arg7-Ala8, D-Trp7-Arg8 or Phe7-Arg8 substitutions. The D-Trp7-Ala8 and Phe7-Arg8 modified derivatives (I and VI) selectively inhibited alpha-MSH on the R. pipiens assay (pA2 = 4.7 and 5.8, respectively), as they did not possess antagonist (or agonist) activities on the A. carolinensis assay. In contrast, the D-Arg7-Ala8 and D-Trp7-Arg8 modified derivatives (IV and V) inhibited alpha-MSH on both the R. pipiens and A. carolinensis assays (pA2 values ranging 5.0-6.0).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Discovery and structure-activity relationships of novel alpha-melanocyte-stimulating hormone inhibitors. 256 82

Recent studies have shown that inhibitory feedback mechanisms regulate the release of the endogenous opioid peptides beta-endorphin (acting predominantly at mu opioid receptors in the brain), dynorphin (a kappa opioid receptor ligand) and [Met]enkephalin (a delta opioid receptor ligand) from the rat hypothalamus. By using specific antagonists of the various opioid receptor types, it is shown that the release of these peptides from hypothalamic slices in vitro is not only controlled by homologous (auto)-receptors, but that cross-regulation between the three neuronal opioid receptor types also occurs; thus, the delta receptor antagonist N,N-diallyl-Tyr-Aib-Aib-Phe-Leu increases the release of all three peptides, the mu receptor antagonist D-tetrahydroisoquinoline-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2 increases that of beta-endorphin and dynorphin, and the kappa receptor antagonist nor-binaltorphimine increases that of dynorphin; all these effects occur in the presence of tetrodotoxin, indicating a presynaptic site of action. We propose the term "allelo-receptors" to describe this particular form of neuronal regulation in which an endogenous ligand, acting via its own specific receptor, also regulates the release of related peptides which activate different classes of opioid receptors.
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PMID:Presynaptic auto- and allelo-receptor regulation of hypothalamic opioid peptide release. 257 Mar 78

The minimal sequence of alpha-MSH required for full agonism on fish (Synbranchus marmoratus) melanocytes was determined to be Ac-alpha-MSH5-10-NH2 since Ac-alpha-MSH6-10-NH2 and Ac-alpha-MSH6-9-NH2 were inactive. The N-terminal tripeptide sequence, Ser-Tyr-Ser, lacked any contribution to potency since the 4-13 (Ac-[Nle4]-alpha-MSH4-13-NH2) sequence was equipotent to alpha-MSH. The important potentiating amino acids were found to be Met at position 4 of the amino terminus and Val at position 13 of the carboxy terminus of the hormone, since Ac-alpha-MSH4-10-NH2 was about 100 times more potent than the Ac-alpha-MSH5-10-NH2 sequence, and Ac-[Nle4]-alpha-MSH4-13-NH2 was about 10 times more active than Ac-[Nle4]-alpha-MSH4-12-NH2. The minimal sequence for equipotency to alpha-MSH was demonstrated to be Ac-[Nle4]-alpha-MSH4-13-NH2. [Nle4, D-Phe7]-alpha-MSH was about 10 times more active than alpha-MSH. Unexpectingly, several conformationally restricted cyclic melanotropins were either partial agonists ([Cys4, Cys10]-alpha-MSH) or totally inactive (Ac[Cys4, Cys10]-alpha-MSH4-10-NH2) on fish melanocytes. These results point out some rather remarkable differences between S. marmoratus and tetrapod melanophores relative to structural requirements for MSH receptor recognition and signal transduction.
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PMID:Melanotropin structure-activity studies on melanocytes of the teleost fish, Synbranchus marmoratus. 271 25

A novel neuropeptide which stimulates adenylate cyclase in rat anterior pituitary cell cultures was isolated from ovine hypothalamic tissues. Its amino acid sequence was revealed as: His-Ser-Asp-Gly-Ile-Phe-Thr-Asp-Ser-Tyr-Ser-Arg-Tyr-Arg-Lys-Gln- Met-Ala- Val-Lys-Lys-Tyr-Leu-Ala-Ala-Val-Leu-Gly-Lys-Arg-Tyr-Lys-Gln-Arg-Val-Lys-Asn-Lys - NH2. The N-terminal sequence shows 68% homology with vasoactive intestinal polypeptide (VIP) but its adenylate cyclase stimulating activity was at least 1000 times greater than that of VIP. It increased release of growth hormone (GH), prolactin (PRL), corticotropin (ACTH) and luteinizing hormone (LH) from superfused rat pituitary cells at as small a dose as 10(-10)M (GH, PRL, ACTH) or 10(-9)M (LH). Whether these hypophysiotropic effects are the primary actions of the peptide or what physiological action in the pituitary is linked with the stimulation of adenylate cyclase by this peptide remains to be determined.
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PMID:Isolation of a novel 38 residue-hypothalamic polypeptide which stimulates adenylate cyclase in pituitary cells. 280 20

The effects of shortening the ACTH molecule from either end of the peptide chain on adrenal glycolysis and steroidogenesis were examined in mouse adrenal cell suspensions. Shortening the (1-24) sequence to (1-17), (1-16) and (1-14), thereby interfering with the basic tetrapeptide (15-18) assigned to the address message, progressively reduced both glycolytic and steroidogenic potencies by four, six and ten orders of magnitude respectively, without impairing the capacity for maximal excitation. The glycolytic potency of the (1-18) sequence, which was amidated at the C-terminal, equalled that of ACTH (1-24), but the steroidogenic potency was reduced by an order of magnitude. The (1-13) sequence of alpha-MSH, which contains substitutions at both terminals, had glycolytic and steroidogenic potencies intermediate between those of ACTH(1-16) and ACTH(1-17). Deletion of Ser1,Tyr2 from ACTH(1-18)-NH2 reduced both potencies by an order of magnitude. ACTH(11-24) and (7-38) were inactive or inhibitory. The capacity for excitation was further examined by comparing responses to peptide fragments (1-4), (1-10), (1-13), (4-10), (4-11), (5-10), (5-14), (7-13) and (11-24) at a concentration of 1 mmol/l. All fragments, excepting (1-4), (5-10) and (11-24) were active. The activities of fragments (5-14) and (7-13), as opposed to (5-10), suggest that the requirements for methionine in position 4 may be replaced by the (11-13) tripeptide.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:ACTH and adrenal aerobic glycolysis. II: Effects of aminoterminal peptide fragments on lactic acid and steroid production by mouse adrenocortical cells. 282 35


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