[Effect of vitamin A on the endogenous synthesis and system of N-nitrosodimethylamine detoxication in the rat liver].

The administration of N-nitrosodimethylamine (NDMA) and its endogenic synthesis from amidopyrine and sodium nitrite decreases in the liver the level of reduced glutathione, ascorbic acid, glutathione reductase and glutathione-S-transferase activities, the accumulation of oxidized glutathione as well as the damage of DNA. The gamma-glutamyltransferase activity, the marker of carcinogenesis, increased. The damaging action of NDMA under the influence of vitamin A deficiency increased, but the vitamin excess decreased the biochemical changes in the liver.