Journal
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY
Volume 171, Issue -, Pages 31-35Publisher
ELSEVIER SCIENCE INC
DOI: 10.1016/j.cbpa.2014.02.007
Keywords
Hypoxia; Ischemia/reperfusion; Purine nucleoside phosphorylase; Purine salvage; Xanthine oxidase
Categories
Funding
- Consejo Nacional de Ciencia y Tecnologia [SEP-CONACYT 152784]
- Centro de Investigaciones Biologicas del Noroeste S.C. (CIBNOR) [PC0.10]
- Consejo Nacional de Ciencia y Tecnologia (CONACYT) [270373, 260513]
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Purine nucleoside phosphorylase (PNP) and xanthine oxidase (XO) are key enzymes involved in the purine salvage pathway. PNP metabolizes purine bases to synthetize purine nucleotides whereas XO catalyzes the oxidation of purines to uric acid. In humans, PNP activity is reported to be high in erythrocytes and XO activity to be low in plasma; however, XO activity increases after ischemic events. XO activity in plasma of northern elephant seals has been reported during prolonged fasting and rest and voluntary associated apneas. The objective of this study was to analyze circulating PNP and XO activities in marine mammals adapted to tolerate repeated cycles of ischemia/reperfusion associated with diving (bottlenose dolphin, northern elephant seal) in comparison with semiaquatic (river otter) and terrestrial mammals (human, pig). PNP activities in plasma and erythrocytes, as well as XO activity in plasma, from all species were quantified by spectrophotometry. No clear relationship in circulating PNP or XO activity could be established between marine, semiaquatic and terrestrial mammals. Erythrocytes from bottlenose dolphins and humans are highly permeable to nucleosides and glucose, intraerythrocyte PNP activity may be related to a release of purine nucleotides from the liver. High-energy costs will probably mean a higher ATP degradation rate in river otters, as compared to northern elephant seals or dolphins. Lower erythrocyte PNP activity and elevated plasma XO activity in northern elephant seal could be associated with fasting and/or sleep- and dive-associated apneas. (C) 2014 Elsevier Inc. All rights reserved.
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