[Activity of the glutathione redox system in human erythrocytes at various ages]

Abstract

Human erythrocytes were separated into three groups according to their density and age by centrifugation in a continuous Percoll gradient. The specific activities of glucose-6-phosphate dehydrogenase, catalase, glutathione peroxidase, glutathione reductases as well as the glutathione and selenium content were highest in the youngest cell and uniformly decreased by about 20-30% in the eldest group. The age-dependence of superoxide dismutase was much more pronounced. The malondialdehyde content taken as an estimate for lipid peroxidation showed an inverse age dependence and increased by 35% in the eldest cell population. Red blood cells from 10 anemic patients exhibited less glutathione and also less malondialdehyde, while GSH-peroxidase and GSSG-reductase contents were higher. The parameters showed similar age profiles as in healthy subjects. The findings support the concept of lipid peroxidation as one of the causal events in red cell aging, but do not allow to deduce the involvement of a single enzyme related to the glutathione redox cycle in this process.