DECREASE IN FREE-RADICAL PRODUCTION WITH AGE IN RAT PERITONEAL-MACROPHAGES

The respiratory-burst reaction has been studied in rat peritoneal macr ophages of different ages (3, 12 and 24 months) using phorbol 12-myris tate 13-acetate (PMA) to stimulate NADPH oxidase. Production of O-2(-) and H2O2 decreased with age (about 50 and 75% respectively); however, no difference in NAPH oxidase activity was found. NO . production was also reduced with age (40%). Furthermore, a progressive and significa nt decrease in the pentose phosphate flux was detected as a function o f age in control and PMA-stimulated macrophages. The NADPH/NADP(+) rat io decreased with age in control and PMA-stimulated macrophages. Gluco se uptake was lower in middle-aged (12 months) and old (24 months) ani mals but no differences were found between these groups.