Effects of an oral glucose challenge on free radicals/antioxidants balancein an older population with type II diabetes

Background. Our goal was to assess the effect of chronic vs acute hyperglyc emia on free radicals (FR)/antioxidants balance in serum and leukocytes in an older (>65 years old) population with type II diabetes mellitus (DM). Methods. Case-control study comparing older male patients with type TI DM w ith normal controls. FRs and antioxidants were measured at baseline and 120 min after an oral 100-g glucose lend. Results, Baseline measurements showed an increased level of oxidized glutat hione (GSSG) (p = .01) in the serum of diabetic subjects. Similar findings were observed at the intracellular level in the same group for GSSG (p = .0 004), total glutathione (GSH + GSSG) (p = .0001) (GSH is reduced glutathion e), decreased GSH/GSSG ratio (p = .0001), and ascorbic acid (p = .008). Mon ocytes from diabetic subjects produced larger amounts of nitric oxide (NO) in vitro (p = .03). After the oral glucose challenge, between-group compari sons demonstrated similar findings at the intracellular level for increased oxidized glutathione (p = .0001), GSH + GSSG (p = .0001), decreased GSH/GS SG (p = .0001), ascorbic acid(p = .02), and increased NO ( p = .02) For the diabetic subjects. Within-group comparisons showed a significant drop of a scorbic acid in the control and the diabetic groups (p < .01), an increased level of GSSG in the diabetic group (p < .01), a decreased GSH/GSSG ratio (p < .05), and decreased production of NO by monocytes after in vitro stimu lation in the control group (p < .05). Conclusions. Our results suggest that type II diabetes in an older populati on is associated with increased basal oxidative stress. Hyperglycemic chall enge is associated with an accentuation of this phenomenon as measured in t he leukocytes.