DIETARY-PROTEIN INTERVENTION DURING THE POSTDOSING PHASE OF AFLATOXIN BETA-1-INDUCED HEPATIC PRENEOPLASTIC LESION DEVELOPMENT

Abstract

The effects of high and low dietary protein intervention on the growth and development of hepatic preneoplastic lesions were examined. Inbred male F344 rats fed a semipurified (AIN-76) 20% casein diet were given doses orally of aflatoxin B1 (10 doses, each 250 .mu.g/kg). One week after the last dose, animals were fed diets containing either 5 or 20% casein. Animals fed a 5% diet throughout the 12 wk postdosing period had a marked reduction in development of .gamma.-glutamyltransferase-positive foci. Animals fed a 20% casein diet throughout the same period had the highest response. Groups fed the 5% casein diet for half of the postdosing period and 20% for the other half had intermediate responses. The high response observed in animals fed a high-protein diet apparently can be inhibited by the postinitiation intervention of a low-protein diet. Likewise, the low response observed in the animals fed a low-protein diet was increased by the introduction of a high-protein diet late in the experiment.