RESUMEN
Wistar male rats weighing 230-250 g were given 10 mg aminopyrine and 10 mg sodium nitrite daily, by gavage, for 20 days. The histological changes in the liver are of the cirrhotic type. The ultrastructural changes are dependent on the hepatocyte position in the hepatic structural changes are dependent on the hepatocyte position in the hepatic lobule. Thus, in the perilobular area one finds hepatocytes with an increased volume and hypertrophic nuclei and nucleoli, mitochondriae swollen with dispersed cristae, decrease of the number of free ribosomes, glycogen depletion, GER decrease and SER development. In the centrolobular area, the most injured, there are necrotic changes with numerous cytolysosomal formations. The histoenzymological results show a decrease of LDH, SDH, CyOx, GtDH, StDH, ATP-ase and G6P activities. The activity of Ac.P on the contrary, is greater in the intoxicated rats, which correlates with the above-mentioned necrobiosis processes.