Detection of ornithine decarboxylase gene expression in 12-O-tetradecanoylphorbol-13-acetate-treated mouse skin using in situ hybridization.

The localization of ornithine decarboxylase gene expression in mouse skin by tumour promoter, 12-O-tetradecanoylphorbol-13-acetate, was investigated using in situ hybridization. After 4 h of treatment with tumour promoter, the grains representing ornithine decarboxylase mRNA increased remarkably in number in the epidermis, especially in the follicular region. When the cells containing more than 5 grains were counted as positive, the number of positive cells increased by about 52-fold in the follicular epidermis, by about 19-fold in the interfollicular epidermis and by 4-fold in the dermis, as compared with controls. These results indicate that the epidermal cells are mainly responsible for the activation of ornithine decarboxylase by 12-O-tetradecanoylphorbol-13-acetate.