ABILITY OF M-CHLOROPEROXYBENZOIC ACID TO INDUCE THE ORNITHINE DECARBOXYLASE MARKER OF SKIN TUMOR PROMOTION AND INHIBITION OF THIS RESPONSE BY GALLOTANNINS, OLIGOMERIC PROANTHOCYANIDINS, AND THEIR MONOMERIC UNITS IN MOUSE EPIDERMIS IN-VIVO

m-Chloroperoxybenzoic acid (CPBA) was tested for its ability to induce the ornithine decarboxylase (ODC) marker of skin tumor promotion. In contrast to benzoyl peroxide, dicumyl peroxide, and 2-butanol peroxide , 5 mg of CPBA applied twice at a 72-h interval induce ODC activity at least as much as 3 mu g of 12-O-tetradecanoylphorbol-13-acetate (TPA) . ODC induction peaks 36 h after a single CPBA treatment but is maxima l 5 h after two applications of CPBA at a 48-h interval. The ODC-induc ing activity of CPBA is dose dependent and sustained after chronic tre atment. In contrast to TPA, two CPBA treatments at 12-24 h intervals p roduce no refractory state against ODC induction. The mechanism of ODC induction by CPBA is iron dependent Various hydrolyzable tannins, con densed tannins (CTs) and their monomeric units remarkably inhibit the ODC response to multiple CPBA treatments. At 22 mg, gallic acid, Alepp o gall tannic acid (TA), catechin, and loblolly pine bark CT inhibit t he most CPBA-induced ODC activity. Aleppo gall TA is even effective wh en applied sever al hours before CPBA. The tumor-promoting activity of CPBA and its inhibition by plant tannins remain to be evaluated.