Fate and the biochemical effects of 2,4,6-trinitrotoluene exposure to tiger salamanders (Ambystoma tigrinum)

Biotransformation, metabolic enzyme profiles, and the glutathione antioxida nt system in tiger salamanders (Ambystoma tigrinum) from a 14-day exposure to 2,4,6-trinitrotoluene (TNT) in situ were examined, Concentrations of par ent compound and metabolites were measured in skin, kidney, and liver tissu e. In addition, cytochrome P450 (p450) and cytochrome b5 content and their dependent isozyme activities, ethoxyresorufin O-dealkylation, pentoxyresoru fin O-dealkylation, and the glutathione antioxidant system in the skin, liv er, lung, kidneys, and blood were evaluated. Considerable differences were found in relative concentrations of TNT and its metabolites in the skin, re lative to the liver and kidney. Trace amounts of TNT were detected only in the skin and liver of exposed animals while one of the secondary reduction metabolites, 2,6-diaminonitrotoluene, was found only in liver and kidney. D ifferences in the metabolite concentrations between systemic organs (liver, kidneys) and the skin suggest that the skin may be important in the primar y reduction of TNT. In addition, measurable levels of these basal enzyme in dicators were detected; yet of those evaluated only hepatic p450 content wa s affected by TNT exposure. The qualitative and quantitative differences in TNT and its metabolites in tissues suggest the fate and metabolism of the TNT in salamanders. Furthermore, results indicate that tiger salamanders po ssess considerable levels of xenobiotic metabolizing and antioxidant enzyme s in these tissues but are not sensitive indicators of TNT exposure. (C) 20 00 Academic Press.