Abstract
Summary
DL-tryptophan-7a-C14 was administered intraperitoneally to adult rats at a level of 0.715 mg/kg of body weight. In some experiments loads of L-tryptophan, kynu-renine, hydroxyanthranilic acid or quinolinic acid (equivalent on a molar basis to 2 g of L-tryptophan in a 70 kg man) were given 30 minutes prior to the labeled tryptophan. Rats given a tracer dose of DL-tryptophan-7a-C14 excreted 18-20% of the C14 as C14O2 and 7.2-7.6% in the urine in the first 12 hours. The injection of a load of L-tryptophan 30 minutes prior to the DL-tryptophan- 7a-C14 caused an increase in C14O2 to 33.6% of the dose and the urinary C14 level increased to 9.1%. The injection of 0.14 mM/kg of 3-hydroxyanthra-nilic acid 30 minutes prior to administration of the labeled tryptophan caused a depression of the C14O2 excretion to 8.8% and increased the urinary C14 level to 23.6%. Autoradio-graphs of chromatograms of the urines and C14 analyses of more than 8 of the known tryptophan metabolites isolated from the urines showed that the major share of activity present in the urine from rats receiving the 3-hydroxyanthranilic acid load was present in an unidentified component.
We wish to acknowledge the technical assistance of Margaret Kowitz.
Get full access to this article
View all access options for this article.