Is the Tryptophan Load Test a Valid Index for a Chemically-Induced Vitamin B 6 Deficiency?

Abstract

Summary

Chronic administration of aminooxyacetic acid (AOAA) to rats after a tryptophan load resulted in an increase in xanthurenic acid and oxalic acid excretion and a decrease in pyridoxic acid excretion, thus suggesting a vitamin B₆ deficiency. Sub-convulsive doses of the drug resulted in a partial depletion of liver, but not brain, pyri-doxal phosphate and pyridoxamine phosphate. Thus, it would appear that increased xanthurenic acid excretion ofter a tryptophan load is a valid index for measuring a vitamin B₆ deficiency induced by chronic administration of aminooxyacetic acid.