title: Purine nucleoside phosphorylase and xanthine oxidase activities in erythrocytes and plasma from marine, semiaquatic and terrestrial mammals.
abstract: 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.
authors: Centro de Investigaciones Biológicas del Noroeste, S.C., Programa de Planeación Ambiental y Conservación, Instituto Politécnico Nacional 195, Playa Palo de Santa Rita Sur, La Paz, Baja California Sur, C.P. 23096, Mexico. Electronic address: rlopez@cibnor.mx.
authors: Roberto I
authors: RI
authors: López-Cruz
authors: Centro de Investigaciones Biológicas del Noroeste, S.C., Programa de Planeación Ambiental y Conservación, Instituto Politécnico Nacional 195, Playa Palo de Santa Rita Sur, La Paz, Baja California Sur, C.P. 23096, Mexico. Electronic address: mbarjau@cibnor.mx.
authors: Myrna Barjau
authors: MB
authors: Pérez-Milicua
authors: Sonoma State University, Department of Biology, 1801 E. Cotati Ave., Rohnert Park, CA 94928, USA. Electronic address: crocker@sonoma.edu.
authors: Daniel E
authors: DE
authors: Crocker
authors: Centro de Investigaciones Biológicas del Noroeste, S.C., Programa de Planeación Ambiental y Conservación, Instituto Politécnico Nacional 195, Playa Palo de Santa Rita Sur, La Paz, Baja California Sur, C.P. 23096, Mexico; Hospital General de Zona No.1. Instituto Mexicano del Seguro Social, La Paz, Baja California Sur, Mexico. Electronic address: r.gaxiolar@gmail.com.
authors: Ramón
authors: R
authors: Gaxiola-Robles
authors: Cabo Dolphins, Paseo de la Marina 7A, Cabo San Lucas, Baja California Sur, C.P. 23410, Mexico. Electronic address: jbernal@cabodolphins.com.
authors: Jaime A
authors: JA
authors: Bernal-Vertiz
authors: Acuario de Veracruz A.C., Departamento de Mamíferos Acuáticos, Aves y Reptiles, Veracruz, Veracruz, Mexico. Electronic address: alejandro_delarosat@hotmail.com.
authors: Alejandro
authors: A
authors: de la Rosa
authors: Institute for Environmental Medicine, Perelman School of Medicine, University of Pennsylvania, 1 John Morgan Building, 3620 Hamilton Walk, Philadelphia, PA 19104, USA. Electronic address: joseva@mail.med.upenn.edu.
authors: José P
authors: JP
authors: Vázquez-Medina
authors: Centro de Investigaciones Biológicas del Noroeste, S.C., Programa de Planeación Ambiental y Conservación, Instituto Politécnico Nacional 195, Playa Palo de Santa Rita Sur, La Paz, Baja California Sur, C.P. 23096, Mexico. Electronic address: tzenteno04@cibnor.mx.
authors: Tania
authors: T
authors: Zenteno-Savín
mesh_terms: D000328:Adult; D000818:Animals; D059001:Aquatic Organisms / Q000378:metabolism*; D004912:Erythrocytes / Q000201:enzymology*; D005260:Female; D006801:Humans; D008297:Male; D008322:Mammals / Q000097:blood / Q000378:metabolism*; D011683:Purine-Nucleoside Phosphorylase / Q000097:blood*; D014969:Xanthine Oxidase / Q000097:blood*
chemical_list: D014969:Xanthine Oxidase; D011683:Purine-Nucleoside Phosphorylase
keywords: Hypoxia; Ischemia/reperfusion; Purine nucleoside phosphorylase; Purine salvage; Xanthine oxidase