[Analysis of DNA synthetic activity of aged epidermis]

The basal cells of old and young guinea pigs were separated by use of density gradient centrifugation. DNA contents of basal cells were measured on the smear specimens prepared by Feulgen's stainings. DNA synthetic activities of old guinea pigs and those of young guinea pigs were almost the same. These date suggested that there was no specific relationship between the DNA synthetic activity and aging of epidermis.