Epidermal Ornithine Decarboxylase, Polyamines, Cell Proliferation, and Tumor Promotion

Ornithine decarboxylase (ODC) level and the levels of its biosynthetic product, putrescine, are elevated in various proliferative cell systems. Furthermore, numerous studies have indicated that the polyamine biosynthetic enzymes ODC and S-adenosylmethionine decarboxylase (SAMD) are implicated in neoplastic growth.1-3In adult mouse epidermis, very high levels of induction of ODC may be obtained by application of certain phorbol esters,4,5and more recently it has been shown that irradiation of adult hairless mouse skin with ultraviolet energy (UVL) in the sunburn range will also induce similar high levels of ODC.6,7 A smaller increase of epidermal ODC activity was found in the epidermis of patients suffering from psoriasis by Russell et al.8Elevation of epidermal ODC level has also been found in the skin of rats subjected to hair plucking and in rats that were fed high-protein diets.9The purpose of this review, therefore, is to discuss