Studies on the Mercapturic Acid Synthesis in Animals X. Glutathione in Relation to Growth of Rats on a Low Casein Diet Which Contained Bromobenzene and Naphthalene*

In Paper VIII of this series (1) we reported that in contrast to I-cystine and dl-methionine gluttihione does not augment the synthesis of mercapturic acids in the rat. Data were also obtained to indicate that the cysteine and the acetyl group of the mercapturic acids were not derived necessarily from glutathione (1). These results offered no evidence that cystine or cysteine is liberated from glutathione during metabolism in the rat. Dyer and du Vigneaud (2) reported results which indicated the possibility that cystine or cysteine may be liberated from glutathione during metabolism, inasmuch as cystine-deficient rats resumed growing when glutathione was administered to them either orally or sub cutem. We felt, therefore, that the ingestion of naphthalene and bromobenzene might possibly modify the normal metabolism of glutathione in the rat in such a way as to prevent the liberation from it of cystine or cysteine. Should this be true, it would then account perhaps for the inefficiency of glutathione in augmenting the synthesis of mercapturic acids in the rat. On the other hand, the demonstration that glutathione, when added to a diet which contained bromobenzene or naphthalene, promptly overcomes the deficiency in rats induced by these hydrocarbons would strongly suggest that the metabolic behavior of glutathione in the rat is not altered by the presence