Hepatic and renal metabolism of copper and zinc in the diabetic rat.

The influences of acute and chronic insulin-dependent diabetes on copper and zinc status of liver, kidney, and intestine were investigated in rats at 0-4 wk after streptozotocin (STZ) treatment. The concentration and the tissue contents of copper in liver and kidney were significantly elevated by 1 wk after STZ injection and increased thereafter, attaining levels two- and fivefold higher, respectively, than controls by 4 wk. Increased concentrations of zinc were also present in liver and kidney at 7 and 2 days after treatment, respectively, but zinc accumulated to a lesser degree than copper. In contrast, the concentration of copper and zinc in duodenum from control and all STZ-diabetic groups were similar. Increased and decreased quantities of copper and zinc were bound to metallothionein (MT) in liver and kidney, respectively, within 2 days after STZ injection. Thereafter, the quantities of both metals associated with MT increased with time in both tissues. Additional changes in zinc distribution in hepatic cytosol occurred prior to significant increases in the concentration of this metal in the tissue. The potential significance of altered trace metal metabolism during short-term changes in endocrine status and adverse effects of heavy metal accumulation during chronic hormonal imbalance are discussed.