UV-induced changes in urinary polyamine excretion in the mouse.

Exposure of hairless mice to the light of a germicidal lamp (254 nm) under conditions which are known to induce epidermal DNA synthesis, cell proliferation, and polyamine metabolism produced a marked increase of polyamine excretion in the urine which lasted for many days. The increase was about the same for free and acetylated polyamines. Although the ratio of N1-acetylspermidine/N8-acetylspermidine increased somewhat in the urine of animals exposed to UV, the increase was not significant enough to be useful as a marker of enhanced cell proliferation. A single topical dose of alpha-difluoromethylornithine, a selective inhibitor or ornithine decarboxylase, prevented the UV-induced increase of polyamine excretion in agreement with its effect on UV-induced epidermal polyamine turnover.