Preventive effect of zinc compounds, polaprezinc and zinc acetate against the onset of hepatitis in Long-Evans Cinnamon rat

It is known that Long-Evans Cinnamon (LEC) rats are characterized by the fu lminant hepatitis occurring as a result of an abnormal hepatic deposition o f Cu due to the lack of the Cu-transporter p-type ATPase. To prevent the he patitis, two Zn compounds, Zn acetate and polaprezinc were given orally to LEC rats aged 30 days. At 100 days after birth, the control group composed of LEC rats fed a basal diet (Cu, 17 ppm; Zn, 50 ppm; Fe, 150 ppm) exhibite d slight jaundice and showed high activities of serum enzymes related to he patic function. The groups fed the diet fortified(1000 ppm as Zn) with Zn a cetate or polaprezinc did not have jaundice. The hepatic Cu concentrations were 174 +/- 34 mu g/g and 156 +/- 23 mu g/g in the polaplezinc group and Z n acetate group, respectively. The control group showed 267 +/- 17 mu g Cu/ g and 298 +/- 62 mu g Fe/g in the liver. The Fe concentration was about 1.7 times the concentration in the two Zn groups. Hepatic free Cu and Fe conce ntrations were 2.6 +/- 0.3 and 21.4 +/- 5.8 mu g/g, 1.7 +/- 0.7 and 6.8 +/- 1.1 mu g/g, and 1.3 +/- 0.1 and 6.2 +/- 0.8 mu g/g in the control, polapre zinc and zinc acetate groups, respectively. Intestinal metallothionein (MT) concentrations were not increased significantly by the Zn diets. The two Z n compounds inhibit Cu absorption from the intestinal tract, resulting in a decrease of hepatic Cu deposition. The new Zn compound as well as Zn aceta te is categorized as a therapeutic drug for Cu poisoning, including Wilson' s disease.