Inhibition of tumor promotion and hepatocellular growth by dietary restriction in mice

'To whom correspondence should be addressed The effects of dietary restriction on the growth of hepatic focal lesions in phenobarbital (PB) promoted mice were examined. Dietary restriction which can inhibit many age-related diseases in rodents including hepatic cancer also decreases cell proliferation and increases apoptosis in the liver. In contrast, PB, a non-genotoxic rodent hepatocarcin-ogen, enhances the growth of hepatic focal lesions in mice and rats by increasing cell proliferation and inhibiting apoptosis. The present study examined the impact of dietary restriction on PB-induced hepatic tumor promotion. Focal lesions were produced by diethylnitrosamine (DEN) treat-ment (35 mg DEN/kg body weight injections, twice per week for 8 weeks). After lesions were produced, mice were placed into one of the following four groups: NEH-0