Abstract
The serum concentrations of Cu, Zn-superoxide dismutase (SOD) in 32 patients with primary diabetes were determined by Sandwich Enzyme Immunoassay (EIA) for application to clinical diagnosis. Furthermore, comparison was made between the biological activity by conventional negative assay and the immunological activity by EIA. Serum Cu, Zn-SOD in the diabetics showed a significantly high level of 64±45ng/ml compared with 33±9ng/ml in the controls (p<0.001). The immunological values of Cu, Zn-SOD in the diabetics tended to increase in patients with a prolonged duration of the disease, with insulin-dependent diabetes, with a high triglyceride level and with obesity. The increase was significantly high especially in patients with a high hemoglobin Al level (p<0.05). However, no correlation was noted between the serum Cu, Zn-SOD level and the blood sugar level in the glucose tolerance test.
In the group with microangiopathy, on the other hand, serum Cu, Zn-SOD was markedly elevated in all cases and demonstrated the highest value of 103±52ng/ml especially in those with nephropathy, which was a significant increase compared to those without nephropathy (p<0.01). The immunological and biological activities were well correlated on the whole.
The above results suggested that the Cu, Zn-SOD level determined by immunological assay is closely related to the pathological conditions of diabetes, reflecting the relative or absolute deficiency of insulin and that Cu, Zn-SOD plays a physiological defensive role as a scavenger of active oxygen against tissue injuries due to primary diabetes and its complications.
