Selective expression of glutathione transferase isoenzymes in chemically induced preneoplastic rat hepatocyte nodules.

Isoenzymes of glutathione transferase were shown to occur at selectively altered levels in rat hepatocyte nodules produced by 2-acetylaminofluorene treatment. Changes were measured by different substrates, antibodies raised against purified glutathione transferases, and by purification of the major isoenzymes. Isoenzymes composed of subunits 1, 2 and 3, expressed in normal liver tissue, all occurred at increased concentrations in nodules, whereas the level of transferase 4-4 was decreased. The most conspicuous change was the appearance of glutathione transferase 7-7 (or transferase P), the concentration of which in negligible in normal liver.