Abnormal Tryptophan Metabolites in Human Pregnancy and their Relation To Deranged Vitamin B 6 Metabolism

Summary

Following ingestion of 10 g Dl-tryptophan, normal subjects excrete kynurenine, kynurenic acid and occasionally N_a-acetyl kynurenine. In pregnancy many additional metabolites, including 3-hydroxy-kynurenine, occur in the urine. The abnormal tryptophan metabolite excretion pattern in these women is strikingly similar to the one described in vit. B₆ deficient rats. Administration of pyridoxine suppresses to a large degree the excretion of the abnormal substances.