Tryptophan metabolite excretion by the American cockroach.

Abstrac t -1 . Three fluorescing materials have been discovered in excreta from the American cockroach, Periplaneta americana (L.), and found to increase in concentration as dietary nitrogen increases. 2. These compounds have been identified as kynurenic, xanthurenic and 8-hydroxyquinaldic acids. 3. Feeding cockroaches antibiotic eliminates 8-hydroxyquinaldic acid production, presumably by inhibiting gut microbial dehydroxylation of xanthurenic acid. 4. Excreta from wild-type and lavender-eye mutants contains aU three metabolites, while that from pearl-eye mutants contains none of them. 5. Xanthurenic and 8-hydroxquinaldic acids may contribute to cockroach gut tumor formation.