Distribution and Metabolism of 14C-Tryptophan in Normal and Endotoxin-Poisoned Mice
AUTOR(ES)
Moon, Robert J.
RESUMO
dl-Tryptophan (benzene ring-14C) and its metabolites persist longer and in greater quantity in tissues of endotoxin-poisoned mice than in tissues of normal mice. Correspondingly less label is excreted in urine and feces and expired as 14CO2 in the poisoned animals. The distribution of label (1.1 × 106 dpm per microgram of tryptophan) was relatively constant whether it was administered alone or in combination with 20 mg of unlabeled l-tryptophan. Tryptophan must be metabolized through the tryptophan oxygenase pathway to be converted to carbon dioxide, but attempts to quantitatively correlate depressed tryptophan oxygenase activity with depressed carbon dioxide production were unsuccessful. It appears that neither tryptophan oxygenase nor substrate availability exclusively determine the quantity of tryptophan converted to 14CO2 except under highly selected conditions. The validity of an earlier suggestion that expired 14CO2 could be used to monitor in vivo tryptophan oxygenase activity is not supported by our data.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=422898Documentos Relacionados
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