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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Psychopharmacology 79 (1983), S. 79-81 
    ISSN: 1432-2072
    Keywords: Corticosteroid response to stress ; Tryptophan availability ; Amino acids ; 5HT synthesis ; Tryptophan ; Tyrosine ; Valine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Prior administration of valine to rats has been shown previously to prevent restraint stress-induced increases in brain tryptophan and 5HT turnover. The present study demonstrates that the accompanying attenuation of the corticosteroid response to this stress is substantially reversed by administration of tryptophan with the valine. Tyrosine is not effective in reversing this attenuation, and in fact itself attenuates the corticosteroid response to the stress when given alone. It is concluded that at least part of the corticosteroid response to restraint stress is mediated by an increase in serotonergic activity that is dependent on increased supply of the precursor, tryptophan, and that this can be antagonised by either of two amino acids which compete with tryptophan for access to the brain. Implications for stress-associated human disorders are discussed.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-072X
    Keywords: Phanerochaete chrysosporium ; Lignin model compounds ; Lignin metabolism ; β-aryl ether dimers ; β-ether cleavage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The white rot basidiomycete Phanerochaete chrysosporium metabolized 4-ethoxy-3-methoxyphenyl-glycerol-β-guaiacyl ether (V) in low nitrogen, stationary cultures under which conditions the ligninolytic enzyme system is expressed. 4-Ethoxy-3-methoxyphenylglycerol XIII, guaicol and 4-ethoxy-3-methoxybenzyl alcohol (II) were isolated as metabolic products. Exogenously added XIII was rapidly converted to 4-ethoxy-3-methoxybenzyl alcohol indicating that it is an intermediate in the metabolism of V. P. chrysosporium also metabolized 1-(4′-ethoxy-3′-methoxyphenyl)-2-(2″-methoxyphenoxy)-3-hydroxypropane VI. The degradation pathway for this dimer also included initial β-ether cleavage and α-hydroxylation of the diol product 1-(4′-ethoxy-3′-methoxyphenyl) 2,3 dihydroxypropane (XI) to yield the triol XIII which was cleaved at the α, β bond to yield 4-ethoxy-3-methoxybenzyl alcohol. Finally P. chrysosporium also cleaved the dimer 1-(4′-ethoxy-3′-methoxyphenyl)-2-(2″-methoxyphenoxy)-1-hydroxypropane (VIII) at the β-ether linkage yielding 1-(4′-ethoxy-3′-methoxyphenyl) 1,2 dihydroxypropane (IX) which was subsequently cleaved at the α, β bond to yield II. All of the results indicate that oxidative β-ether cleavage is an important initial reaction in the metabolism of β-aryl ether lignin substructure dimeric compounds. Metabolities were identified after comparison with chemically synthesized standards by gas liquid chromatography-mass spectrometry.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-072X
    Keywords: Phanerochaete chrysosporium ; Lignin model compounds ; β-aryl ether dimers ; Metabolism αβ cleavage ; Veratryl alcohol ; 4-ethoxy-3-methoxybenzyl alcohol ; Alkyl-phenyl cleavage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The white rot fungus Phanerochaete chrysosporium metabolized the lignin model compounds veratylglycerol-β-guaiacyl ether I and 4-ethoxy-3-methoxy-phenylglycerol-β-guaiacyl ether V in stationary culture under an atmosphere of 100% oxygen and under nitrogen limiting conditions. 2-(o-methoxyphenoxy)-ethanol VII was identified as a product of the metabolism of both substrates. Veratryl alcohol and 4-ethoxy-3-methoxybenzyl alcohol IV were identified as metabolites of I and V respectively. Metabolites were identified after comparison with chemically synthesized standards by mass spectrometry. These results indicate the existence of an enzyme system capable of directly cleaving the etherated dimers I and V at the α, β bond. The additional identification of 2-(o-methoxyphenoxy)-1,3 propanediol IX as a metabolic product indicates that cleavage of the alkyl-phenyl bond of these dimers or their metabolites also occurs.
    Type of Medium: Electronic Resource
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