ABSTRACT
The effect of tamoxifen on the liver of adult rats was studied by histological, histochemical and ultrastructural studies. Twenty five adult rats, of both sexes, were used in this study. The animals were divided into two groups: The first group [5 animals] was used as a control group and the second group [20 animals] received tamoxifen tablets [40 mg/kg body weight] daily for 3 months. Histological results revealed severe hydropic degeneration in the centrilobular and midzonal areas of the hepatic lobules, cellular infiltration and mild dilatation of some blood sinusoids. The histochemical results revealed marked decrease of succinic dehydrogenase enzyme activity, marked increase of both alkaline and acid phosphatase enzymes activity and marked decrease of DNA contents of the liver cells. Ultrastructural studies revealed some ultrastructural degenerative changes of the cytoplasmic organelles including proliferation of smooth endoplasmic reticulum, fragmentation of rough endoplasmic reticulum and degeneration of the mitochondrial matrix. The present study suggested that careful assessment of the risk of chronic tamoxifen administration on the liver function tests should be considered in the prophylactic use of the drug