EFFECTS OF DIETARY RETINYL PALMITATE OR 13-CIS-RETINOIC ACID ON THE PROMOTION OF TUMORS IN MOUSE SKIN

  • 15 February 1987
    • journal article
    • research article
    • Vol. 47  (4) , 967-970
Abstract
The present study was designed to determine the effects of dietary 13-cis-retinoic acid and retinyl palmitate on mouse skin tumor promotion by 12-O-tetradecanoylphorbol-13-acetate (TPA). Female CD-1 mice were initiated with 150 nmol of 7,12-dimethylbenz(.alpha.)anthracene and promoted twice weekly with 8 nmol of TPA. Diets supplemented with retinyl palmitate to yield 60,000 or 200,000 IU or 700,000 for 5 wk followed by 350,000 IU per kg of diet (700,000/350,000) fed to mice during tumor promotion resulted in 9%, 37%, and 65% inhibition of the papilloma yield, respectively, at 21 wk of promotion. Although topical applications of 13-cis-retinoic acid have been almost as effective as retinoic acid in preventing the appearance of mouse skin tumors, dietary 13-cis-retinoic acid at 200,000 or 700,000 IU per kg of diet resulted in no reduction in papilloma yield but did result in a dose-dependent decrease in the tumor burden (weight of tumors per mouse). Therefore, dietary retinyl palmitate yielded a dose-dependent inhibition of the number and weight of tumors promoted by TPA, whereas dietary 13-cis-retinoic acid resulted in a decrease in weight but not in number of tumors promoted by TPA.