Effect of copper or insulin in diabetic copper-deficient rats.

The effects of copper and insulin on lipogenesis and glucose tolerance were studied using diabetic, copper-deficient rats. Diabetes was induced by intraperitoneal injection of 50 mg streptozotocin/kg body weight to rats fed a sucrose-copper deficient diet for 7 weeks. Five days later the rats were injected intraperitoneally with [14C]glucose with either saline, insulin, copper, or copper plus insulin. The disappearance of serum [14C]glucose at 30, 60, and 120 min postinjection and the incorporation of [14C]glucose into lipid of epididymal fat 2 hr after administration were determined. The combined effect of copper and insulin significantly decreased peak blood glucose at 30 min and increased the incorporation of [14C]glucose into lipid in the epididymal fat pad when compared to either copper or insulin alone. The enhancement of glucose utilization may be due to a formation of a more stable complex which will increase insulin binding and/or decrease its degradation.