par Doriaux, Myriam;May, Claude ;Thys, Olivier
Référence PASCAL. F 52, Biochimie, biophysique moléculaire, biologie moléculaire et cellulaire, 34, 2-3, page (197-204)
Publication Publié, 1979
Article révisé par les pairs
Résumé : Administration of the diazafluoranthen derivative AC-3579 induces in rat liver, the hypertrophy of the smooth endoplasmic reticulum (SER) and the formation of lamellate cytosomes. The cytochemical demonstration of one microsomal marker, glucose-6-phosphatase, was performed in treated liver cells in situ and was correlated to biochemical determinations performed in subcellular fractions isolated by differential and gradient centrifugation. While glucose-6-phosphatase is evenly distributed inside the liver lobule in the control, it presents a heterogeneous localization within the lobule of treated animals. The cytochemical reaction appears considerably decreased in the centrolobular regions, when compared to the perilobular ones. Ultrastructural examination of the centrolobular hepatocytes of treated animals shows that the cytochemical reaction products are irregularly dispersed within the anastomosed tubules of the hypertrophied SER. A discontinuous reaction is discerned in the cisternae of concentric whorled membranes. The specific activity of glucose-6-phosphatase in liver homogenate of treated rats was decreased by about 20% as compared to the controls. After 4 or 8 days AC-3579 treatment, no glucose-6-phosphatase reaction was detected in the lamellate cytosomes, neither in situ nor in their isolated form. The absence of this microsomal marker in the cytosomal membranes did not exclude their SER origin, since an intense hydrolytic degradation takes place inside the cytosomes as demonstrated by the high concentration of acid phosphatase revealed in these organelles after purification by gradient centrifugation.