Effects of zinc deficiency of pre-existing cadmium-metallothionein in the pancreas

Abstract

Although the injection of cadmium salts increases the metallothionein (MT) concentration in a number of organs, including pancreas, the induced synthesis of pancreatic metallothionein was specifically decreased in zinc difeciency. The fate of C-induced metallothionein and the change in tissue distribution of Zn and Cd were studied with the onset of Zn deficiency. Rats were rapidly injected with CdCl 2 to induce MT synthesis, and were subsequently made Zn deficient. The lability of the pancreatic zn pool, as compared with that of liver and kidney, was demonstrated. During Zn deficiency, there eas little change in Cd concentration or MT level in either liver or kidney. When Zn dificiency led to a decrease in pre-existing pancreatic MT, Cd was not elimited from the pancreas, but was transferred to a high molecular weight fraction. On the basis of these results we suggest that the presence of Cd-Zn-MT has little effect on the eventual pancreatic Zn and MT contents, during subsequent Zn deficiency.