Inhibition of dietary fat-promoted development of (pre)neoplastic lesions in exocrine pancreas of rats and hamsters by supplemental vitamins A, C and E.

The effects of vitamins A, C and E on the development of putative preneoplastic foci in exocrine pancreas were investigated in azaserine-treated rats and N-nitrosobis(2-oxoproypy)amine-treated hamsters. The animals were fed a semipurified diet high in saturated fat (20% lard) either or not supplemented with vitamin A, vitamin C or vitamin E. A separate group maintained on a diet low in saturated fat (5% lard) was incorporated as extra controls. The animals were given their diets 12 days after the last treatment with carcinogen. At 4 months postinitiation, the pancreata were quantitatively examined for both the number and size of early, putative preneoplastic lesions and the presence of neoplastic lesions. Rats as well as hamsters maintained on 5% lard exhibited a significantly lower number of putative preneoplastic pancreatic lesions than animals fed a diet containing 20% lard. Growth of acidophilic but not of basophilic foci was inhibited in rats of the high vitamin A and C group, whereas vitamin E exerted an inhibitory effect on growth of basophilic but not of acidophilic foci. In hamsters maintained on a diet high in vitamins A or C, the number of early ductular lesions was significantly decreased, whereas the number of (micro)carcinomas was increased. Vitamin E did not have any modulating effect on development of ductal lesions in hamster pancreas.