ANTITUMOR ACTION OF DIETARY RESTRICTION IS LESION-DEPENDENT IN MALE FISCHER-344 RATS

The effects of dietary restriction (DR) on spontaneous oncogenesis in male Fischer 344 rats were analyzed. Previously reported analyses of s tudies carried out in our laboratory demonstrated that DR reduces the incidence and delays the onset, but not the progression, of leukemia i n male F344 rats. In this report, the influence of DR on pituitary tum ors, adrenal pheochromocytoma, pancreatic islet cell turners, and inte rstitial cell tumors of the testis was analyzed. DR reduced the relati ve incidence (relative onset rates) and delayed the onset of tire Sour tumors. DR also retarded the progression (duration from onset to deat h) of pituitary tumors and pheochromocytoma. DR has delayed the onset of all tumors of the male F344 rat so far analyzed, but its effect oil tumor progression appears to be lesion-dependent.