Antioxidant enzymes in ringed seal tissues: potential protection against dive-associated ischemia/reperfusion.
Diving seals experience heart rate reduction and preferential distribution of the oxygenated blood flow to the heart and brain, widespread peripheral vasoconstriction, and selective ischemia in the most hypoxia-tolerant tissues. The first breath after the dive restores the oxygenated blood flow to all tissues and raises the potential for the production of reactive oxygen species (ROS). We hypothesized that in order to counteract the damaging effects of ROS and to tolerate repetitive cycles of ischemia/reperfusion associated with diving, ringed seal (Phoca hispida) tissues have elevated activities of antioxidant enzymes. Activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) were measured by spectrophotometric techniques in heart, kidney, liver, lung, and muscle extracts of ringed seals and domestic pigs (Sus scrofa). The results suggest that in ringed seal heart SOD, GPx and GST activities are an efficient protective mechanism for counteracting ROS production and its deleterious effects. Apparently CAT activity in seal liver and GPx activity in seal muscle participate in the removal of hydroperoxides, while seal lung appears to be protected from oxidative damage by SOD and GPx activities.
Vázquez-Medina
José Pablo
JP
Departamento de Biología Marina. Universidad Autónoma de Baja California Sur, La Paz, Baja California Sur, México.
Zenteno-Savín
Tania
T
Programa de Planeación Ambiental y Conservación, Centro de Investigaciones Biológicas del Noroeste, S.C., Mar Bermejo 195, Playa Palo Santa Rita, La Paz, Baja California Sur, CP 23090-México. Electronic address: tzenteno04@cibnor.mx.
Elsner
Robert
R
Institute of Marine Science. University of Alaska Fairbanks, Fairbanks, AK, U.S.A.
D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D004242:Diving / Q000502:physiology*; D005260:Female; D005979:Glutathione Peroxidase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D008168:Lung / Q000201:enzymology; D008297:Male; D009132:Muscles / Q000201:enzymology; D009206:Myocardium / Q000201:enzymology; D018384:Oxidative Stress; D046049:Phoca / Q000502:physiology*; D015427:Reperfusion Injury / Q000517:prevention & control*; D013482:Superoxide Dismutase / Q000378:metabolism
D000975:Antioxidants; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase