Homeostasis between lipid peroxidation and antioxidant enzyme activities in healthy human aging.
In healthy people the plasma malondialdehyde increases with age, however there is a simultaneous rise in the activities of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase in red blood cells, although both enzymes show a biphasic behaviour, that is, reaching the lowest values at 40-50 years of age to rise remarkably later on. No significant changes were found in the case of glutathione peroxidase but the age-dependent behaviour is similar to the other enzymes mentioned above. The activity of glutathione reductase shows a clear increase depending on age, up to middle age, with or without flavin adenine dinucleotide. We conclude that the increase in the activities of the anti-oxidant enzymes of the red blood cells during aging, could be interpreted as a positive feedback mechanism in response to rising lipid peroxidation. Consequently, from the point of view of the parameters used the homeostasis between the production of free radicals and anti-oxidant systems seems to be maintained in the common, normal aging pattern.
Instituto Universitario de Investigación Gerontológica y Metabólica, Universidad Autonoma, Servicio de Endocrinología y Nutrición, Hospital de la Princesa, Madrid, España.
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MA
Rodriguez-Martinez
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Ruiz-Torres
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood / Q000378:metabolism*; D000975:Antioxidants / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism; D005246:Feedback; D005260:Female; D005609:Free Radicals; D005954:Glucosephosphate Dehydrogenase / Q000097:blood; D005979:Glutathione Peroxidase / Q000097:blood; D005980:Glutathione Reductase / Q000097:blood; D006706:Homeostasis; D006801:Humans; D015227:Lipid Peroxidation; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D010734:Phosphogluconate Dehydrogenase / Q000097:blood
D000975:Antioxidants; D005609:Free Radicals; D008315:Malondialdehyde; D010734:Phosphogluconate Dehydrogenase; D005954:Glucosephosphate Dehydrogenase; D005979:Glutathione Peroxidase; D005980:Glutathione Reductase