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 argyroph ilic components (Ag-NOR) of the hepatocytic nucleolus. The differences found in the area and number of Ag-NOR for each nucleus and in the pe rcentage of Ag-NOR area to nucleus area in each hepatic lobe in contro l rats as well as in the end-to-side portacaval shunt rats suggest tha t there are interlobular differences in the control rats related to th is parameter that are indicative of protein synthesis and cell prolife ration. Furthermore, the changes that occur in these parameters after the deprivation of portal flow produced by an end-to-side portacaval s hunt make it possible to hypothesize on the existence of a hepatic lob ular functional heterogeneity in the rat liver.