The erythrocyte membrane in essential hypertension characterization of the temperature dependence of lithium efflux

Rachel Levy, Avinoam Livne

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Erythrocytes of most patients with essential hypertension are distinguished by a typical pattern of temperature-dependence of Li efflux. In the present study we have attempted to characterize this unique temperature response. Measurements of Li efflux into Na medium and Lii-Nao countertransport were conducted simultaneously at finely spaced temperature intervals with increments of 1 to 2°C in the range of 10-40°C. The Arrhenius plots for the efflux in Na medium and for Lii-Nao countertransport in erythrocytes of both normotensives and hypertensives were biphasic with slopes representing apparent energies of activation of about 28 and 8 kcal/mol below and above the 'break', respectively. However, the 'break' in the Arrhenius plot appeared at distinctly different temperatures: 30°C for normotensives and 20°C for hypertensives. The Li efflux was resolved into N-ethylmaleimide-sensitive and -insensitive components. The sensitive component exhibited a typical biphasic temperature response, with the characteristic 'break': at 30°C for normotensives and at 20°C for hypertensives. In contrast, the N-ethylmaleimide-insensitive component was alike in normotensives and hypertensives. It is concluded that: (a) the unique temperature dependence of Li efflux in erythrocytes of hypertensives results from a localized modification in the membrane; (b) the N-ethylmaleimide-sensitive component represents a protein moiety which distinguishes between the erythrocyte membrane of normotensives and hypertensives; (c) the expression of the temperature dependence as judged by the sharp transition in slope (within 1 to 2°C), apparently reflects the cooperative involvement of membrane lipids, associated with the Li efflux system.

Original languageEnglish
Pages (from-to)41-48
Number of pages8
JournalBiochimica et Biophysica Acta - Biomembranes
Volume769
Issue number1
DOIs
StatePublished - 11 Jan 1984

Keywords

  • (Erythrocyte membrane)
  • Hypertension
  • Li transport
  • Temperature dependence

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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