Partial purification of the epidermal G2 chalone based on an in vivo assay system

The epidermal G2 chalone was partially purified from hairless mouse skin extracts by means of chromatography and ultrafiltration and tested in vivo on hairless mouse epidermis. The active component had a molecular weight of less than 10,000 daltons. It significantly but had no effect on epidermal cells at the G1/S transition. Extracts from mouse spleen or skeletal muscle treated in the same way as the skin extracts had no inhibitory effect on epidermal G2 cells.