Glutathione S-transferase in the midgut tissue of gypsy moth (Lymantria dispar) caterpillars exposed to dietary cadmium

• After chronic and acute ingestion of cadmium GST activity remained unchanged.
• GST activity of individual genotypes (egg masses) showed great plasticity.
• Midgut GST cannot be considered the first defense line after exposure to cadmium.

Activity of glutathione S-transferase (GST) in midgut of gypsy moth caterpillars exposed to 10 and 30 μg Cd/g dry food was examined. Based on the enzyme reaction through conjugation with glutathione, overall activity remained unaltered after acute and chronic treatment. No-observed-effect-concentration (10 μg Cd/g dry food) significantly increased activity only after 3-day recovery following cadmium administration. Almost all comparisons of the indices of phenotypic plasticity revealed statistically significant differences. Despite the facts that GST has important role in xenobiotic biotransformation, our results indicate that this enzyme in insect midgut does not represent the key factor in cadmium detoxification.