Behavior of nucleolar organizer regions in the different hepatic lobes after end-to-side portacaval shunt in the rat.

: Protein synthesis activity in the hepatic lobes in control and end-to-side portacaval shunt rats was studied by assaying one of the argyrophilic components (Ag-NOR) of the hepatocytic nucleolus. The differences found in the area and number of Ag-NOR for each nucleus and in the percentage of Ag-NOR area to nucleus area in each hepatic lobe in control rats as well as in the end-to-side portacaval shunt rats suggest that there are interlobular differences in the control rats related to this parameter that are indicative of protein synthesis and cell proliferation. Furthermore, the changes that occur in these parameters after the deprivation of portal flow produced by an end-to-side portacaval shunt make it possible to hypothesize on the existence of a hepatic lobular functional heterogeneity in the rat liver.