Synthesis and Metabolism of Tritium-Labeled DL-Kynurenine. ∗

Abstract

Summary

1. DL-kynurenine was labeled with tritium by the Wilzbach procedure. 2. Intraperitoneal injection of tritium-labeled DL-kynurenine into rats was followed by the excretion of labeled quinolinic acid and N¹-methylnicotinamide in the urine. The evidence is definite that kynurenine can serve as a precursor of quinolinic acid and N¹-methylnicotinamide. 3. During 24 hours after injection of 1 mg of labeled DL-kynurenine, 6.86% was excreted as unchanged labeled kynurenine.