Glutathione peroxidase (EC1.11.1.9), glutathione-S-transferase (EC2.5.1.13), superoxide dismutase (EC1.15.1.1) and catalase (EC1.11.1.6) activities in tissues of ducklings deprived of vitamin E and selenium

1. Vitamin E and selenium deficiencies were produced in the Pekin duckling (Anser cinerens) and were characterized by the development of lesions after 14 d in gizzard, intestine, heart and skeletal muscle.2. The activities of glutathione peroxidase (EC1.11.1.9), using hydrogen peroxide and cumene hydroperoxide as substrates, glutathione-S-transferase (EC2.5.1.13), superoxide dismutase (EC1.15.1.1) and catalase (EC1.11.1.6) were measured in homogenate supernatant fractions of liver, heart, intestine, gizzard and skeletal muscle of deficient ducklings and of control birds given vitamin E or Se or both.3. Glutathione peroxidase activities were dramatically lower in tissues of Se-deficient ducklings, and this was unaffected by vitamin E. No adaptive changes were seen in the activity of the other enzymes, even after 21 d when the deficiency was severe.4. It appeared likely that the variability of the enzyme activities, other than glutathione peroxidase, in the different tissues studied might explain differences among the tissues in susceptibility to peroxidative damage.