ANTIOXIDANT DEFENSES IN MARINE FISH .1. TELEOSTS

1. A variety of tissues from six marine teleost fishes of diverse ecop hysiological characteristics was assayed for superoxide dismutase, cat alase, and glutathione peroxidase activities. 2. Blood (3-37 nmol g-1 Hb), liver, heart, red muscles, ovaries and capillaries from the choro id and gas-bladder retia displayed higher superoxide dismutase (2-8 nm ol g-1 wet tissue) contents as compared with other tissues. 3. Catalas e was present at high levels in blood (c. 300-1000 pmol g-1 Hb) and li ver (c. 100 to 250 pmol g-1 wet tissue), at moderate levels in heart, spleen, kidney and in choroid and gas-bladder retia (30-40 pmol g-1 we t tissue), and at low levels in the other tissues. Glutathione peroxid ase content was relatively low (1-30 pmol g-1 wet tissue) in the tissu es and structures examined excepting blood. 4. The content of antioxid ant enzymes of blood, liver, heart and red muscle seem to be correlate d to the fish swimming and metabolic activities.