Parenteral zinc and tissue metallothionein in normal and diabetic rats

The effect of parenteral zinc on tissue metallothionein (MT) was studied in normal and streptozotocin-induced diabetic rats. The accumulation of Zn-MT in liver and pancreas of normal and diabetic rats following the administration (ip) of various amounts of zinc was not different. Renal Zn-MT was higher in the diabetic group, and this was not changed by zinc injection. Although diabetic rats, relative to normal, possessed a markedly higher concentration of Cu-MT in kidney initially, this difference decreased considerably after zinc injection. The ratio of Cu-MT to cytosolic Cu in kidney was not affected by parenteral zinc and was highest in diabetic rats. Zinc injection markedly reduced food intake, water consumption, and urine output in both normal and diabetic rats. Blood glucose of diabetic rats also decreased 24 h after zinc administration. Our results indicate that relative to normal, MT and zinc metabolism are different in kidney, and to some extent liver, but not different in the pancreas of the chemically induced diabetic rat.