Cadmium influence on the rat liver.

Influence of cadmium on the intestinal and hepatic tissue of rat was studied in acute injection and oral as well as subchronic and chronic oral experiments with the purpose of better understanding of the penetration mechanisms of cadmium into these tissues. Acute single oral dose of CdCl2 32.5 mg.kg-1 inhibited in vitro the respiration of intestinal scrapings (44%) and in liver slices (25.7%). In combined oral doses of 32.5 mg.kg-1 + 162.5 mg.kg-1 inhibition in the intestine increased with exposure time, while in the liver it decreased. Amount of presumable metallothionein in the liver was approximately ten times higher than that in the intestine. Respiration was measured by a Clark electrode. Binding of cadmium to metallothionein was determined by column chromatography and spectrophotometry. Physiological findings are in agreement with morphological ones. In cases when, following an acute single oral dose, a 50% change was detected in the absorptive jejunal zone, a 10% change was observed in the liver parenchyma. In the case of combined oral dose of 60-70% of absorptive villi zone is damaged by cadmium, which penetrates by passive diffusion into lamina propria and by blood to the liver, where it acts toxically in 30%. Active transport of cadmium after chronic application is preserved. Correlation of physiological and morphological findings was evident.