Effect of psoralen-induced photodermatitis on tryptophan metabolism in guinea pigs.

Tryptophan metabolism after load test, along the kynurenine pathway was studied in guinea pigs, before and during the psoralen-induced photodermatitis. This skin injury, during the acute phase, causes a large increase in urinary excretion of total metabolites and a significant increase of liver tryptophan pyrrolase.