Changes of Metallothionein, Copper, Zinc, and Zinc-dependent Enzymes Induced by Immobilization Stress

In order to study the effects of stress on copper (Cu), zinc (Zn), Zn- related enzymes, and metallothionein (MT) in liver, we used the immobilization procedure as an experimental model of stress. Acute immobilization stress caused changes of Zn, Cu, and MT concentrations in rat liver. The Zn level in total liver homogenates increased for 39% (p < 0.00011). This increase originated from the Zn concentration in nuclear fraction, suggesting a higher content of Zn-dependent enzymes and large molecular weight proteins. The stress induced increase of alkaline phosphatase (ALP), which is Zn- related metalloenzyme, closely followed the changes in the Zn concentration in liver. However, the activity of another Zn-dependent enzyme, 5\u27-nucleotidase (5\u27-NT), was lower after acute stress. The total Cu concentration was about twice higher in the stressed group in comparison with the control group, but no redistribution of Cu within hepatocytes was found. MT concentration was measured in the mitochondrial-lysosomal fraction of liver homogenates. It was found that acute immobilization stress caused about a 100% increase in the MT concentration in liver