Effect of partial hepatectomy on the response of rat liver to aflatoxin B1

The effect of partial hepatectomy (PH) on aflatoxin B1 (AFB1) action in rat liver has been examined using adult male Fischer 344 rats. The elevated levels of hepatic DNA synthesis, present 26 hr after PH (> 15 times the control level) and 33 hr after PH, are rapidly inhibited by i.p. administration of AFB1. The percentage inhibitions are greater than those observed using intact or sham-operated animals. However, it was possible to demonstrate elevation of DNA synthesis in PH rats treated with AFB1. Rats 2 hr after being treated with AFB1 (0.075 mg/kg) at 24 and 31 hr after PH exhibited levels of DNA synthesis 380 to 400% of those present in sham-operated uninjected controls. After 62 weeks, the livers of the PH rats treated with AFB1 displayed no hepatocellular carcinoma. There was present, however, an increased incidence of lesions believed to be preneoplastic. The differences between the long-term effects of AFB1 and other hepatocarcinogens on the livers of PH rats are discussed in terms of their relative capacities and modes of action in inhibiting DNA synthesis.