526
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Michael LH, Seitz P, McMillin-Wood J, Chang D, Hazlewood C, Entman ML. Mitochondrial water in myocardial ischemia: investigation with nuclear magnetic resonance. Science 1980; 208:1267-9. [PMID: 6246584 DOI: 10.1126/science.6246584] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Nuclear magnetic resonance studies of mitochondria isolated from ischemic hearts after coronary vessel occlusion indicated a decrease in water proton relaxation times. This change coincided with a decrease in the hydration of the samples. It is suggested that in ischemia, changes in macromolecular hydration may be one of the first mechanisms to alter function in the mitochondria, which are vital to the energy-transducing process in heart muscle.
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527
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Amos DS, Brittleback A, Bromley S, Chang D, Forenan N, Hamilton-Fairley D, Joseph T, Leeder DS, Lambert H, Maloney C, Mott A, O'Donnell E, Prior A, Read R, Smithies M, Williams B. Medical students and the HJSC. West J Med 1980. [DOI: 10.1136/bmj.280.6214.650-c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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528
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Bowers CY, Momany F, Reynolds GA, Chang D, Hong A, Chang K. Structure-activity relationships of a synthetic pentapeptide that specifically releases growth hormone in vitro. Endocrinology 1980; 106:663-7. [PMID: 7353536 DOI: 10.1210/endo-106-3-663] [Citation(s) in RCA: 134] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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529
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Hintz RL, Liu F, Marshall LB, Chang D. Interaction of somatomedin-C with an antibody directed against the synthetic C-peptide region of insulin-like growth factor-I. J Clin Endocrinol Metab 1980; 50:405-7. [PMID: 6153391 DOI: 10.1210/jcem-50-2-405] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Insulin-like growth factor-I is a human plasma peptide with strong structural homology to human prosinsulin. This peptide has been classified as a somatomedin on the basis of its biological actions and growth hormone dependence. We have generated an antibody to the synthetic 12 amino acid C-peptide region of insulin-like growth factor-I and used it to compare three somatomedin preparations to insulin-like growth factor-I. We also compared these somatomedin preparations to insulin-like growth factor-I using the standard SM-C RIA. We conclude that insulin-like growth factor-I and somatomedin-C behave identically in these two RIA's and are very similar if not identical molecules.
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530
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Abstract
An attempt was made to establish the normal range of 27 different parameters in the serum of 45 healthy, purebred, New Zealand White rabbits (3-5 kg). The reproducibility of the results was acceptable. Sensitive isoenzyme patterns (LDH, CK) could change, however, significantly if different methods were used in the bleeding procedure. Isoenzyme patterns (LDH and CK) of rabbit sera were different from that of human sera. All obtained results were compared with earlier data sporadically published in literature on rabbits.
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531
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Pipoly GM, Nathans GR, Chang D, Deuel TF. Regulation of the interaction of purified human erythrocyte AMP deaminase and the human erythrocyte membrane. J Clin Invest 1979; 63:1066-76. [PMID: 36405 PMCID: PMC372050 DOI: 10.1172/jci109376] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The binding of purified human erythrocyte AMP deaminase to human erythrocyte membranes and the effect of binding on enzyme catalytic activity was investigated. AMP deaminase binds preferentially and specifically to the cytoplasmic surface of the erythrocyte membrane. The binding is saturable, reversible, and responsive to alterations of pH, of ionic strength, and of ATP and AMP concentrations. A limited number (approximately equal to 2.2 X 10(4) per erythrocyte) of apparently homogeneous high affinity (Ka approximately equal to 2.6 X 10(7) M-1) binding sites is present. The stability of purified and endogenously bound AMP deaminase is markedly improved by the interaction with the membrane, whereas the catalytic activity of AMP deaminase is sharply reduced. AMP deaminase displaces membrane bound glyceraldehyde 3-phosphate dehydrogenase in roughly a dose-response manner. No evidence for binding of AMP deaminase to spectrin or band 3 (the G3PD binding protein) was found in sucrose gradients, however. The interaction of AMP deaminase with the erythrocyte membrane may play an important role in the regulation of cellular adenine nucleotide metabolism.
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532
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Lai CY, Cancedda F, Chang D. Primary structure of cholera toxin subunit A1: isolation, partial sequences and alignment of the BrCN fragments. FEBS Lett 1979; 100:85-9. [PMID: 437113 DOI: 10.1016/0014-5793(79)81136-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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533
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Uyeno ET, Chang D, Folkers K. Substance P found to lower body temperature and aggression. Biochem Biophys Res Commun 1979; 86:837-42. [PMID: 106854 DOI: 10.1016/0006-291x(79)91788-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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534
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Bliznakov EG, Wan YP, Chang D, Folkers K. Partial reactivation of impaired immune competence in aged mice by synthetic thymus factors. Biochem Biophys Res Commun 1978; 80:631-6. [PMID: 629796 DOI: 10.1016/0006-291x(78)91615-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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535
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Rosell S, Rökaeus A, Chang D, Folkers K. Indirect vascular actions of (Gln4)-neurotensin in canine adipose tissue. ACTA PHYSIOLOGICA SCANDINAVICA 1978; 102:143-7. [PMID: 626094 DOI: 10.1111/j.1748-1716.1978.tb06057.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The vasoconstrictor action of the tridecapeptide (Gln4)-neurotensin has been studied in subcutaneous adipose tissue in the inquinal region of anesthetized dogs. Close intra-arterial infusion of (Gln4)-neurotensin, 30--120 pmol X kg-1 b.wt. X min-1, elicited similar vasoconstrictions in the adipose tissue on the infusion side and on the contralateral side. This suggests that (Gln4)-neurotensin must enter the general circulation before it can elicit vasoconstriction. Removal of parts of the gastrointestinal tract did not change the vasoconstrictor response. Thus, there is no indication of release of vasoactive substances from the gastrointestinal tract by (Gln4)-neurotensin. Infusion into the portal vein elicited the same vasoconstriction in adipose tissue as the same dose administered i.v. It is suggested that the vasoconstrictor action in adipose tissue is not caused by (Gln4)-neurotensin per se. Instead, vasoactive substance(s) may be formed from (Gln4)-neurotensin.
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536
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537
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Fisher GH, Chang D, Howard G, Folkers K. Synthesis of 31- and 35-amino acid carboxyl terminal fragments of the beta subunit of the human chorionic gonadotropin. J Org Chem 1977; 42:3341-3. [PMID: 903853 DOI: 10.1021/jo00441a004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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538
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Anderson WR, Frick W, Daves GD, Barofsky DF, Yamaguchi I, Chang D, Folkers K, Rosell S. Mass spectra of underivatized peptide amides related to substance P. Biochem Biophys Res Commun 1977; 78:372-6. [PMID: 907687 DOI: 10.1016/0006-291x(77)91264-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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539
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Rökaeus A, Burcher E, Chang D, Folkers K, Rosell S. Actions of neurotensin and (Gln4)-neurotensin on isolated tissues. ACTA PHARMACOLOGICA ET TOXICOLOGICA 1977; 41:141-7. [PMID: 579053 DOI: 10.1111/j.1600-0773.1977.tb02134.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The actions of neurotensin and (Gln4)-neurotensin have been investigated on a number of isolated tissues. They were ineffective in contracting the guinea pig vas deferens, the rabbit aortic strip or the frog rectus abdominis muscle in concentrations up to 0.24 micron. Neurotensin and (Gln4)-neurotensin relaxed the rat duodenum at fairly high concentrations (24 nM). The guinea pig ileum contracted in response to increasing doses, although the maximum response were only one half that caused by histamine. Tachyphylaxis was observed at dose intervals of less than 12 minutes, but this tachyphylaxis did not inhibit responses to acetylcholine, histamine, 5-HT or to DMPP, suggesting that the neurotensins may act at specific receptor sites. They contracted the rat fundus strip at concentrations of 0.24 nM and higher. The neurotensins and 5-HT were approximately equipotent on this tissue, although the maximum responses was about 80% of that to 5-HT. The contractions of the rat fundus strip could not be blocked by atropine, hexamethonium, methysergide, morphine or by 7-OH-THC. These data indicate that neurotensin and (Gln4)-neurotensin are equipotent as far as smooth muscle stimulating activity is concerned. Of those organs tested, the rat fundus strip seems to be the most suitable one for studies concerning structure-activity relationships.
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540
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Frick W, Chang D, Folkers K, Daves GD. Critical experimental parameters in gas chromatographic-mass spectrometric analysis of oligopeptide hydrolysates at the picomole level. Anal Chem 1977; 49:1241-5. [PMID: 883654 DOI: 10.1021/ac50016a045] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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541
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Andersson S, Rosell S, Hjelmquist U, Chang D, Folkers K. Inhibition of gastric and intestinal motor activity in dogs by (Gln4) neurotensin. ACTA PHYSIOLOGICA SCANDINAVICA 1977; 100:231-5. [PMID: 888712 DOI: 10.1111/j.1748-1716.1977.tb05941.x] [Citation(s) in RCA: 107] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The action of (Gln4)-neurotensin was studied on the spontaneous motor activity in isolated canine fundic, antral and intestinal pouches. All pouches had been prepared more than 6 months prior to the experiments. Spontaneous motor activity was recorded for at least 1 h before the Gln4)-neurotensin was infused i.v. for 30 min in doses ranging between 6.3 and 100 ng X kg-1 X min-1. In the vagally denervated fundic pouches (Gln4)-neurotensin inhibted motor activity in doses above 25 ng X kg-1 X min-1. The vagally innervated antral pouches were more sentitive than the vagally denervated fundic pouches to the action of (Gln4)-neurotensin. Thus motor inhibition was induced by doses as low as 6.3 ng X kg-1 X min-1. The effect of (Gln4)-neurotensin on motor activity in intestinal pouches was inconsistent. Inhibition was seen in 1 out of 7 expts. The present results show that the gastric motor activity is the most sensitive function to (Gln4)-neurotensin so far studied.
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542
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Frick W, Daves GD, Barofsky DF, Barofsky E, Fisher GH, Chang D, Folkers K. Sample derivatization and structure analysis by field desorption mass spectrometry. Peptide methylation-methanolysis. BIOMEDICAL MASS SPECTROMETRY 1977; 4:152-4. [PMID: 890074 DOI: 10.1002/bms.1200040306] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Analysis by field desorption mass spectrometry of reaction product mixtures produced by treatment of peptides with methanol and hydrogen chloride augments significantly structural data derived by direct field desorption mass spectrometry analysis of the peptides. Analyses of data obtained by three peptides, beta-Ala-HisOH, p-Glu-Ser-GlyOH and Glu-Ser-Gly-AspOH are used for illustration. Data from field desorption mass spectrometry of peptide methylation-methanolysis product mixtures are used to (a) distinguish [M]+- from [M + H]+ in peptide field desorption mass spectrometry spectra, (b) ascertain the number of carboxyl groups present in a peptide, (c) identify a pyro-glutamyl N-terminus and (d) derive peptide sequence information. Definitive assignments of ion relationships are facilitated by use of methanol and deuteromethanol in paired experiments.
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543
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Goldstein AL, Low TL, McAdoo M, McClure J, Thurman GB, Rossio J, Lai CY, Chang D, Wang SS, Harvey C, Ramel AH, Meienhofer J. Thymosin alpha1: isolation and sequence analysis of an immunologically active thymic polypeptide. Proc Natl Acad Sci U S A 1977; 74:725-9. [PMID: 265536 PMCID: PMC392366 DOI: 10.1073/pnas.74.2.725] [Citation(s) in RCA: 220] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The amino acid sequence of a biologically active polypeptide isolated from calf thymus, termed thymosin alpha1, has been determined. Thymosin alpha1 is a heat stable, highly acidic molecule composed of 28 amino acid residues. This peptide is one of several present in thymosin fraction 5 that may participate in the regulation, differentiation and function of thymus-dependent lymphocytes (T cells). A nomenclature for the family of polypeptides present in thymosin fraction 5 is suggested.
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544
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Lai CY, Mendez E, Chang D, Wang M. Primary structure of cholera toxin B-subunit. Biochem Biophys Res Commun 1977; 74:215-22. [PMID: 836280 DOI: 10.1016/0006-291x(77)91396-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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545
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Rosell S, Burcher E, Chang D, Folkers K. Cardiovascular and metabolic actions of neurotensin and (Gln4)-Neurotensin. ACTA PHYSIOLOGICA SCANDINAVICA 1976; 98:484-91. [PMID: 998299 DOI: 10.1111/j.1748-1716.1976.tb10340.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The actions of the tridecapeptides neurotensin and (Gln4)-neurotensin have been studied on the heart and on the blood flow in subcutaneous adipose tissue, skin and small intestine of anesthetized dogs. In addition, their possible actions have been investigated on blood glucose concentration and lipolysis in subcutaneous adipose tissue. The two peptides were found to be approximately equipotent. Intravenous infusion of 20-120 ng X kg-1 X min-1 produced slight hypotension, an initial vasodilatation in the small intestine and a delayed vasoconstriction in denervated subcutaneous adipose tissue and to a lesser extent in the skin and small intestine. At this infusion rate, neurotensin and (Gln4)-neurotensin did not elicit vasodilatation in the skin or adipose tissue and had no effect on heart rate. The delayed vasoconstriction in adipose tissue was not inhibited by local alpha-receptor blockade. Both neurotensin and (Gln4)-neurotensin increased glucose concentration in the upper dose range. No effects on lipolysis were observed, either in vivo or in vitro. These experiments show that neurotensin and (Gln4)-neurotensin have both vasodilator and vasoconstrictor actions in the peripheral vasculature but seem to be without cardiac actions. They also increase blood glucose concentration. It remains to be shown whether these actions are direct or whether some are indirectly mediated.
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546
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Folkers K, Chang D, Humphries J, Carraway R, Leeman SE, Bowers CY. Synthesis and activities of neurotensin, and its acid and amide analogs: possible natural occurrence of [Gln4]-neurotensin. Proc Natl Acad Sci U S A 1976; 73:3833-7. [PMID: 1069268 PMCID: PMC431229 DOI: 10.1073/pnas.73.11.3833] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
It was considered, a priori, that the isolation of the tridecapeptide, neurotensin, might have inadvertently sllowed the hydrolysis of either the [Gln4]- or the [Leu13-NH2]-moieties. Neurotensin and its three acid and amide analogs, i.e., [Gln4]-neurotensin, neurotensin-NH2, and [Gln4]-neurotensin-NH2 were synthesized. Neurotensin and [Gln4]-neurotensin were indistinguishable by the hypotensive assay, hyperglycemic assay, contraction of the ileum, and radioimmunoassay. Neurotensin-NH2 and [Gln4]-neurotensin-NH2 showed less than 1% of these neurotensin activities. Present information does not elucidate whether the glutamic acid residue in position 4 of neurotensin in situ is present as Glu4 or as Gln4. At high levels, neurotensin released the luteinizing hormone, follicle stimulating hormone, and thyrotropin; [Gln4]-neurotensin-NH2 released thyrotropin, and [Gln4]-neurotensin released luteinizing hormone and follicle stimulating hormone, but these activities do not appear biologically significant.
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547
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Andersson S, Chang D, Folkers K, Rosell S. Inhibition of gastric acid secretion in dogs by neurotensin. Life Sci 1976; 19:367-70. [PMID: 957875 DOI: 10.1016/0024-3205(76)90040-0] [Citation(s) in RCA: 110] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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548
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Magnusson T, Carlsson A, Fisher GH, Chang D, Folkers K. Effect of synthetic substance P on monoaminergic mechanisms in brain. J Neural Transm (Vienna) 1976; 38:89-93. [PMID: 5576 DOI: 10.1007/bf01262967] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Synthetic substance P has been discovered to stimulate significantly the formation of dopa in the limbic, striatum, hemisphere and diencephalon regions of the brain and the lower brain stem. There was no effect upon 5-hydroxytryptophan formation or on tryptophan or tyrosine levels. After inhibition of monoamine synthesis by N'-(DL-SERYL)-N2-(2, 3, 4-trihydroxybenzyl)hydrazine, substance P significantly accelerated the disappearance of dopamine, noradrenaline and 5-hydroxytryptamine. Substance P appears to stimulate monoaminergic neurons in the brain and to serve as an excitatory transmitter in nerve terminals impinging upon dopaminergic cell bodies. A similar stimulation of noradrenaline and 5-hydroxytryptamine indicate a similar transmitter role for noradrenergic and serotonergic neurons. These data strengthen questions about the possible clinical influence of substance P in disease states involving monoaminergic mechanisms including Parkinsonism and schizophrenia.
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549
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Abstract
The toxin of Vibrio cholerae was separated into two subunits by gel filtration on Sephadex G-75 in 5% formic acid. The subunits were designated A and B. Amino acid analysis indicated that subunit B corresponded to choleragenoid. Renatured subunit B was found to be antigenically identical to the whole molecule, whereas renatured subunit A was not. On reduction and S-carboxymethylation with [2-14C] iodoacetate in 8 m urea, subunit A separated into two polypeptides of unequal sizes, A1 and A2, with equal amounts of radioactivity. Subunit B, on the other hand, remained a single molecular species. Molecular weights of the polypeptides A1, A2, and B were estimated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate-urea buffer, in conjunction with amino acid analysis, to be 20,000, 7,500, and 9,500 daltons, respectively. The carboxyl terminal sequence of subunit B was found to be -Met-Ala-Asn. After treatment of toxin with cyanogen bromide, the peptide Ala-Asn could be isolated and quantitated. From this data the number of B polypeptides in a molecule of toxin was estimated as six.
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550
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Chang D, Greibrokk T, Knudsen R, Howard G, Humphries J, Folkers K, Bowers CY. Differentiation of factor C-LHIH and the synthetic contraceptive polypeptide, H-Thr-Pro-Arg-Lys-OH. Biochem Biophys Res Commun 1975; 65:1208-13. [PMID: 1052422 DOI: 10.1016/s0006-291x(75)80358-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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