title: Could Na,K-ATPase play a role in potassium leakage from irradiated erythrocytes?
abstract: BACKGROUND
  In developing countries, the access to red blood cell (RBC) irradiators is restricted. Thus, it is a common practice in blood banks to stock irradiated RBC units until they expire. The aim of this work is to elucidate the involvement of Na,K-ATPase in potassium leakage from prophylactically irradiated RBCs.
  
  
  METHODS
  Whole blood was collected from healthy donors, and blood concentrates were irradiated with 25Gy of γ-radiation within 24h of collection. At days 3, 5, 7, 9, 11, 14 and 28 post-irradiation, fractions were removed and centrifuged and Na,K-ATPase activity from ghost membranes was determined.
  
  
  RESULTS
  The inhibition of Na,K-ATPase activity in RBCs reached 12.6% by day 7 of storage and up to 50% by day 14 of storage. The addition of vitamin C prevented the irradiation-induced loss of Na,K-ATPase activity. The irradiation of RBCs provoked an increase in potassium plasma levels and a decrease in sodium plasma levels. The incubation of RBCs with ouabain did not change the sodium or potassium levels in the plasma, and the addition of vitamin C only partially prevented a decrease in sodium levels caused by irradiation.
  
  
  CONCLUSIONS
  Because the inhibition of Na,K-ATPase by ouabain did not cause potassium accumulation in the plasma, we conclude that the irradiation-induced inhibition of the pump is not a key factor driving this effect.
authors.affiliation: Laboratório de Bioquímica Celular, Faculdade de Bioquímica, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindu, São João del Rei, Brazil.
authors.forename: Grazielle Aparecida S
authors.initials: GA
authors.lastname: Maia
authors.affiliation: Laboratório de Bioquímica Celular, Faculdade de Bioquímica, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindu, São João del Rei, Brazil.
authors.forename: Vanessa Faria
authors.initials: VF
authors.lastname: Cortes
authors.affiliation: Laboratório de Biologia Celular e Mutagênese, Faculdade de Bioquímica, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindu, São João del Rei, Brazil.
authors.forename: Rosy Iara Maciel de A
authors.initials: RI
authors.lastname: Ribeiro
authors.affiliation: Laboratório de Estrutura e Regulação de Proteínas e ATPases (LERPA), Programa de Biologia Estrutural, CCS, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Julio Alberto
authors.initials: JA
authors.lastname: Mignaco
authors.affiliation: Laboratório de Bioquímica Celular, Faculdade de Bioquímica, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindu, São João del Rei, Brazil.
authors.forename: Hérica
authors.initials: H
authors.lastname: de Lima Santos
authors.affiliation: Laboratório de Estrutura e Regulação de Proteínas e ATPases (LERPA), Programa de Biologia Estrutural, CCS, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. Electronic address: cfontes@bioqmed.ufrj.br.
authors.forename: Carlos Frederico Leite
authors.initials: CF
authors.lastname: Fontes
authors.affiliation: Laboratório de Bioquímica Celular, Faculdade de Bioquímica, Universidade Federal de São João del Rei, Campus Centro-Oeste Dona Lindu, São João del Rei, Brazil. Electronic address: leaugust@yahoo.com.br.
authors.forename: Leandro A
authors.initials: LA
authors.lastname: Barbosa
mesh_terms: D004791:Enzyme Inhibitors / Q000494:pharmacology; D004912:Erythrocytes / Q000378:metabolism* / Q000528:radiation effects*; D006801:Humans; D011188:Potassium / Q000097:blood*; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013048:Specimen Handling / Q000379:methods*
chemical_list: D004791:Enzyme Inhibitors; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium
keywords: Gamma irradiation; Na,K-ATPase; RBC storage