Behaviour of nucleolar organizer regions in the different Wistar rat liver lobes.

The area and number of silver-nucleolar organizer regions (Ag-NORs) in the hepatic lobes were determined in 3 male Wistar rats. There was a statistically significant increase in the percentage of Ag-NORs per nucleus in the right lateral and caudate lobe in relation to the left lateral and middle lobes. The area and number of Ag-NORs are greater in the caudate and right lateral lobes in relation to the left lateral and middle lobes. Since the Ag-NOR is a parameter which indicates hepatocytic protein synthesis, the different activity which corresponds to each lobe of the rat's liver makes it possible to assume that there is a functional heterogeneity which should be considered in the study of the hepatic regeneration according to the type of partial hepatectomy carried out.