METABOLIC AND FUNCTIONAL-CHANGES IN LYMPHOCYTES AND MACROPHAGES AS INDUCED BY AGING

Key enzyme activities of glycolysis, pentose-phosphate pathway, Krebs cycle, and glutaminolysis were measured in lymphocytes and macrophages of 3- and 15-month-old rats from the control, thioglycollate-injected , and Walker 256 tumor-implanted groups. The percentage of phagocytosi s, phagocytic index, and production of H2O2 in macrophages and the rat es of [2-C-14]-thymidine and [5-H-3]-uridine incorporation in cultured lymphocytes were also determined. The results indicate that the perce ntage of phagocytosis was not affected but the phagocytic index increa sed by twofold as a consequence of ageing, whereas the production of H 2O2 reduced. The rates of both [2-C-14]-thymidine and [5-H-3]-uridine incorporation in lymphocytes from aged rats were lower as compared to those of mature animals in the three groups. Taken as a whole, the res ults of enzyme activities suggest that ageing may reduce the capacity for glucose utilization in lymphocytes and macrophages under the three conditions. Lymphocyte and macrophage glutamine metabolism was not ma rkedly affected by ageing. Therefore, an impaired glucose metabolism d uring ageing may be one important mechanism for the alteration in lymp hocyte proliferation and macrophage phagocytosis observed and also for the modification of the response to inflammatory and tumor challenges .