EXPRESSION OF HYDROGEN-PEROXIDE AND GLUTATHIONE METABOLIZING ENZYMES IN HUMAN SKIN FIBROBLASTS DERIVED FROM DONORS OF DIFFERENT AGES

We have examined the activities and mRNA abundance of two hydrogen per oxide metabolizing enzymes (glutathione peroxidase and catalase), glut athione concentration, and the activities of several enzymes that infl uence glutathione concentration, including glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G-6-PD), and gamma-glutamylcystein e synthetase (gamma-GCS), in 29 skin fibroblast lines derived from don ors ranging in age from 14 gestational weeks to 94 years of age. H2O2 metabolizing enzyme activities and mRNA abundances were greater in ski n fibroblast cultures established from postnatal donors than in fetall y derived cultures. There were no significant differences in either of these parameters in cell lines established from postnatal donors of d ifferent ages. Total glutathione concentration decreased with age, but GR activity appeared to be unaffected by age. In order to estimate th e ability of the cultures to produce NADPH (an important component of cellular redox status and a cofactor for GR), we determined glucose-6- phosphate dehydrogenase activity and mRNA abundance. We were unable to directly measure gamma-GCS activity or mRNA abundance in any of the s kin lines or in fetal lung fibroblasts; however, we were able to indir ectly demonstrate the presence of this enzyme by stimulating fetal lun g fibroblasts with H2O2 following treatment with L-buthionine-S,R-sulf oximine (BSO), an inhibitor of gamma-GCS activity. These results show that some, but not all, age-associated differences in antioxidant defe nse levels are maintained in a culture environment and are consistent with the hypothesis that developmental stages of life are associated w ith lower antioxidant defense levels than are present in postnatal pha ses of life. (C) 1996 Wiley-Liss, Inc.