INHIBITION OF ESTROGEN-INDUCED RENAL-CARCINOMA IN SYRIAN-HAMSTERS BY VITAMIN-C

Abstract

The ability of vitamin C to inhibit induction of renal carcinoma by estrogens was tested in male Syrian hamsters in vivo. The animals received estrogen (estradiol or diethylstilbestrol) implants s.c. Hamsters which were continuously given vitamin C, administered in the drinking water for estradiol-treated or in the food for diethylstilbestrol-treated animals, were observed to develop renal carcinoma with a significxantly lower incidence (10 of 33 animals with estradiol implants; 14 of 29 animals with diethylstilbestrol implants) than animals which did not receive vitamin C supplementation (16 of 23 animals with estradiol implants, 11 of 13 animals with diethystilbestrol implants). Administration of vitamin C to estradiol-treated hamsters for only the first 3 mo. of the carcinogenesis expeirment had no effect on tumor incidence, but vitamin C in drinking water for the last 3 mo. also lowered incidence. Vitamin C supplementation did not significantly alter the absorption of estrogen from the implant; it did not change the estrogenic effect on the hamsters, nor did it significantly influence estrogen-dependent H-301 [kidney] tumor cell growth. The results were taken as evidence for a mechansim of tumor induction via oxidation of estrogens to reactive metabolites capable of inducing kidney tumors.