Abstract
The influence of age and sex on epidermal metabolism and histology was studied in mice (NMRI). Within a few weeks postpartum, thymidine triphosphate incorporation into DNA and amino acid incorporation into epidermal protein decreased. Differences between tail epidermis and other skin regions (back, abdomen, ear) were found. Sex dependent differences could not be demonstrated. A circadian rhythm of the studied epidermal metabolic processes was shown (artificial 12L: 12D light/dark cycle). Maximum incorporation of thymidine triphosphate and of amino acids was found at the end of the light period at 1800 h, while a minimum incorporation was demonstrated at the end of the dark period. Considering described biological variations, the mouse tail assay seems to be suited to study influences of drugs in epidermal metabolism and histology.