A study of urinary tryptophan metabolites in relation to the phenylalanine content of semi-synthetic diets in a patient with phenylketonuria.
The influence of different phenylalanine (Phe) levels in semi-synthetic diets on the urinary excretion of tryptophan (Try) metabolites was studied in one untreated phenylketonuric (PKU) patient. Low dietary Phe decreased the excretion of indoleacetic acid, indolelactic acid, indican and Try but did not increase 5-hydroxyindoleacetic acid. Under the low Phe diet, the excretion of N-acetyltryptophan, kynurenic and xanthurenic acid are greatly increased in the urine after a Try load. The possible significance of the extensive acetylation of Try and Phe is discussed in relation to the low blood levels of Try and PKU and to the phenomenon of decreasing blood Phe levels in PKU.
D000328:Adult; D004032:Diet; D006801:Humans; D008297:Male; D010649:Phenylalanine / Q000378:metabolism*; D010661:Phenylketonurias / Q000097:blood / Q000652:urine*; D014364:Tryptophan / Q000652:urine*
D010649:Phenylalanine; D014364:Tryptophan