As shown in Figure 5, the basal aortic superoxide anion production was significantly increased in either glucose-fed rats (P < 0.01) or glucose-fed rats also treated with corn oil (P < 0.05). Oral treatment with argan oil prevented this increase in glucose-fed rats, so that the basal superoxide anion production did not significantly differ from that in control rats (Fig. 5). As shown in Figure 6, the 5-wk glucose feeding, with or without corn oil, significantly elevated (P < 0.01) NADPH oxidase activity in aorta tissue. Chronic treatment with argan oil prevented an increase in NADPH oxidase activity in glucose-fed rats so that the aortic NADPH oxidase activity did not significantly differ from that in control rats (Fig. 6). Treatment with DPI, a selective inhibitor of NADPH oxidase, blunted all changes in the activity of the aortic NADPH oxidase in the four groups of rats (Fig. 6).