Decreased glutathione transferase activities in zinc-deficient rats.

Weanling rats fed a zinc-deficient diet for 56 days exhibit a decrease in the total activities of glutathione transferases with 1-chloro-2,4-dinitrobenzene (CDNB) as substrate in the liver, esophagus and stomach. The level of acid-soluble sulfhydryl group, on the other hand, is decreased in the liver, but elevated in the esophagus and kidney. Deficient rats fed a zinc-replenished diet for just 7 days have a fully restored glutathione transferase activity in all tissues except the liver. In view of our earlier findings that the carcinogenic effects of nitrosamines are enhanced in zinc-deficient rats, the results that the dietary zinc deficiency reduces the activity of a 'chemical carcinogen-detoxifying enzyme system' are of more than routine interest.