[Morphologic changes in the liver of rats treated with monensin]

Monensin, a carboxylic ionophore, collapse Na+ gradient across biological membranes, increases intracellular pH and affects many processes involved in transport, posttranslational modification and secretion of proteins, moreover endocytosis and degradation in lysosomes. Concerning the liver, the action of monensin in vitro or in perfused liver, showed an altered secretion of protein and altered transport of VLDL; in bile-fistula rats, monensin caused a decrease of bile flow, altered protein profile and bile acids secretion. Because the effects of monensin seem to be complicated, in this note it has been studied the action of monensin on the morphology of liver cells to have a picture not only of the parenchymal cells, but also of the sinusoidal cells, which cooperation with the general liver functions become increasingly evident. The results obtained after staining of liver biopsies with Sudan Black, Sudan III and Sudan IV showed that monensin induces a diffuse cholestasis and islands of hepatocytes in steatosis, in agreement with the data in literature. Cells lining the sinusoid with phagocytic activity and that might be identified with fat-storing cells, showed an increase of their lipid droplets that might be attributed to vitamin A.