Synopsis

A highly active antidandruff agent, zinc pyrithione was investigated on human skin cells (JTC-17) to test the hypothesis that like selenium sulfide, it may also have an antimetabolic action on epidermis, acting on dandruff by reducing increased epidermal turnover. It has been found from the uptake of 3H-thymidine into cells that zinc pyrithione added at levels of 0.25-1.0/xg/ml is effective in suppressing reversibly the DNA synthesis of human skin cells in vitro without a comparable inhibitory effect on RNA and protein synthesis, asshown by the respective uptakes of 3H-uridine and 3H-leucine. Its homologues, sodium pyrithione and omadine disulfide, at levels of 0.25-1.0/xg/ml also exhibit a similar eversible inhibition of DNA synthesis. On long term culture of human skin cells 15-27 % growth inhibition was observed with 0.2 /xg/ml of zinc pyrithione. Analysis using synchronized cells revealed that zinc pyrithione can act on all periods of DNA synthesis to suppress it.These findings upport the idea that zinc pyrithione may have an antidandruff effect by its antimetabolic action to the skin, rather than its antiyeast action