RESUMO
8-Methoxypsoralen (8-MOP), 3-carbethoxypsoralen (3-CP), and 5-methoxypsoralen (5-MOP), with and without ultraviolet A (UVA), were compared as inducers of epidermal ornithine decarboxylase (ODC) and modulators of epidermal DNA synthesis in vivo in female Skh:hairless-1 albino mice. Both 8- and 5-MOP plus UVA induced epidermal ODC. Peak ODC activity was induced 24 hours after treatment, and ODC activity was still elevated at 48 hours. These same treatments also suppressed epidermal DNA synthesis 4 hours after treatment, as measured by tritiated thymidine incorporation. The psoralen 3-CP, which lacks the DNA monoadducts, failed to induce epidermal ODC either alone or with UVA and stimulated rather than suppressed incorporation of the tritiated thymidine.
