Effect of exposure to carbon disulfide on tryptophan metabolism and the tissue vitamin B6 contents of rats.

Female Wistar rats were exposed to 100 ppm or 600 ppm carbon disulfide for 6 hours a day, 5 days a week for 12 weeks. During the exposure period, their urinary excretion of 4-pyridoxic acid was determined. The urinary excretions of xanthurenic acid and kynurenic acid after tryptophan loading were also determined. At the end of the exposure period, the rats were sacrificed and the levels of the five major forms of vitamin B6, pyridoxine, pyridoxal, pyridoxamine, pyridoxal phosphate and pyridoxamine phosphate, in the liver, kidneys and brain were determined by HPLC fluorometry. During the exposure the urinary excretions of xanthurenic acid and kynurenic acid after i.p. administration of tryptophan increased significantly in both experimental groups. However, urinary excretion of 4-pyridoxic acid decreased only slightly in the group exposed to carbon disulfide at 600 ppm and did not decrease in the group exposed to 100 ppm carbon disulfide. Furthermore, no significant changes were observed in the contents of vitamins B6 in any tissues examined. These results indicate that carbon disulfide does not cause vitamin B6 deficiency and thus that the disorders of tryptophan metabolism induced by carbon disulfide intoxication are not due to vitamin B6 deficiency.