Effect of diabetes on the tissular Zn/Cu ratio

One of the parameters related to the development of coronary disease in dia betic patients is the tissular Zn/Cu ratio. We evaluated the levels of Zn a nd Cu, and the Zn/Cu ratio in insulin target tissues in diabetic and normog lucemic growing Wistar rats in order to determine the influence of diabetes and the disease evolution period. Diabetes was induced chemically by admin istration of streptozotocin. In order to determine the influence of the dur ation of diabetes on the Zn/Cu ratio, three time periods were studied: 7, 2 1 and 60 days. The animals were subsequently sacrified and the target tissu es (liver, adipose tissue, and skeletal muscle) were removed. Zn and Cu lev els were measured by AAS after wet mineralization. STZ-induced diabetes mod ified the tissular Zn and Cu content. There was a significant decrease (p<0 .01) in liver and adipose tissue, but not in skeletal muscle. The in adipos e tissue and skeletal muscle, but not in liver, effects were dependent on t he duration of diabetes. The Cu content was higher in the liver of diabetic rats (p<0.1) and lower in adipose tissue (p<0.1) and skeletal muscle (NS). Tissular Cu levels also were affected significantly by the duration of dia betes. The Zn/Cu ratio showed a generalized decrease, except in skeletal mu scle. This decrease was dependent on the presence of diabetes mellitus and the duration of the disease (p<0.01).