[Relationship between nitric oxide and oxygen free radicals in different duration of diabetes in rat kidney]

To study the relationship between nitric oxide(NO) and oxygen free radicals in rat kidney of diabetes mellitus(DM), the authors examined the changes of renal tissue NO level and nitric oxide synthase(NOS) activity, lipid peroxidation(LPO) level and superoxide dismutase(SOD), peroxidase(POD) and catalase (CAT) activities in streptozotocin(STZ)-induced diabetic rats and normal controls(NC) at the 2nd, 8th- and 16th-week. The results showed that renal-tissue NO level and NOS activity were increased at the 2nd week, but decreased at the 8th- and 16th-week; LPO levels were significantly elevated in all DM groups than those in NC groups. SOD, POD and CAT activities decreased significantly in the 8th and 16th week DM groups compared with those in NC groups. The results suggest that NO level in kidney of STZ-induced diabetic rats dynamically change with the disease course of development. This change may be related with the change of anti-oxidation in kidney which high glucose induces.