Hypoxemic and ischemic tolerance in emperor penguins

Citation:
Zenteno-Savin, T, Leger JS, Ponganis PJ.  2010.  Hypoxemic and ischemic tolerance in emperor penguins. Comparative Biochemistry and Physiology C-Toxicology & Pharmacology. 152:18-23.

Date Published:

Jun

Keywords:

antioxidant enzymes, asphyxial hypoxia, Catalase, cerebral tolerance, dive-associated ischemia/reperfusion, emperor penguin, Glutathione peroxidase, Glutathione-S-transferase, harbor seal, human skeletal-muscle, Hypoxemia, Ischemia, liver, muscle, nonshivering thermogenesis, oxidative stress, oxygen species, proton conductance, reactive, ringed seal, tissues

Abstract:

Oxygen store depletion and a diving bradycardia in emperor penguins (Aptenodytes forsteri) expose tissues to critical levels of hypoxemia and ischemia. To assess the prevention of re-perfusion injury and reactive oxygen species (ROS) damage in emperor penguins, superoxide radical production, lipid peroxidation (thiobarbituric acid reactive substances (TBARS)), and antioxidant enzyme activity profiles in biopsy samples from muscle and liver were determined and compared to those in the chicken and 8 species of flighted marine birds (non-divers and plunge divers). In muscle of emperor penguins, superoxide production and TBARS levels were not distinctly different from those in the other species; among the antioxidant enzymes, catalase (CAT) and glutathione-S-transferase (GST) activities were significantly elevated above all species. In the liver of emperor penguins, TBARS levels were not significantly different from other species; only CAT activity was significantly elevated, although GST and glutathione peroxidase (GPX) activities were 2-3 times higher than those in other species. The potential for ROS formation and lipid peroxidation is not reduced in the pectoral muscle or liver of the emperor penguin. Scavenging of hydrogen peroxide by CAT and the conjugation of glutathione with reactive intermediates and peroxides by GST and GPX appear to be important in the prevention of ROS damage and re-perfusion injury in these birds. (C) 2010 Elsevier Inc. All rights reserved.

Notes:

n/a

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DOI:

10.1016/j.cbpc.2010.02.007