The role of N-sulfation in the N-hydroxy-2-acetylaminofluorene-mediated outgrowth of diethylnitrosamine-initiated hepatocytes to γ-glutamyltranspeptidase-positive foci in male rat liver

The ability of N-hydroxy-2-acetylaminofluorene (N-OH-AAF) to promote the appearance of gamma-glutamyltranspeptidase-positive (GGT+) foci initiated by diethylnitrosamine (DEN) was studied in a slightly modified Solt and Farber protocol. This protocol consisted of the following treatments: initiation with a single dose of DEN followed by selection/promotion with several non-necrogenic doses of N-OH-AAF and partial hepatectomy. Treatment with N-OH-AAF resulted in a 25-fold increase of the liver volume occupied by GGT+ cells as compared to controls. The role of N-sulfation of N-OH-AAF in the GGT+ foci-selecting activity of N-OH-AAF was studied using the sulfotransferase inhibitor pentachlorophenol (PCP). Inhibition of the N-sulfation pathway with PCP during selection with N-OH-AAF resulted in a greater than 80% decrease in the volume occupied by GGT+ cells, without effects on the number of GGT+ foci generated with this protocol. Also, PCP reduced the number of so called oval and bile duct cells generated by the N-OH-AAF/partial hepatectomy treatment. It is concluded that N-sulfation of N-OH-AAF is responsible for the N-OH-AAF-mediated outgrowth of DEN-initiated hepatocytes to preneoplastic GGT+ foci.