Dietary modification of UV-induced epidermal ornithine decarboxylase.

The effect of several dietary antioxidant supplements upon ultraviolet light-induced ornithine decarboxylase activity was determined. Hairless mice received diets supplemented with either butylated hydroxytoluene, disulfiram, phenobarbital, glutathione (reduced), or a special antioxidant mixture for 2 weeks before irradiation with FS-20 fluorescent sun lamps. Epidermal ornithine decarboxylase activity, the induction of which is thought to be a necessary component of skin tumor promotion, was determined at designated post-irradiation periods. Significant inhibition of ornithine decarboxylase induction was found in epidermis from animals receiving diets containing butylated hydroxytoluene, the antioxidant mixture, or disulfiram whereas no significant effects were noted in animals receiving reduced glutathione or phenobarbital. Butylated hydroxytoluene, at physiological concentrations, had no effect upon ornithine decarboxylase activity when added directly to the reaction mixture. Nor did this compound, when provided in the diet of animals, evoke a notable effect upon 12-0-tetra-decanoylphorbol-13-acetate induced ornithine decarboxylase. The latter finding suggests that dietary butylated hydroxytoluene inhibition of ultraviolet light-induced ornithine decarboxylase is a response related directly to the degree of irradation insult rather than a general effect upon the processes associated with carcinogenic promotion.