Dilantin-calcium interaction and active Na transport in frog skin

The effects of diphenylhydantoin (DPH) and calcium were simultaneously studied on solute transport in frog skin. In the presence of external Ca, DPH elicited a significant increase in active Na transport; in its absence, DPH had no significant effect on active transport. DPH increased passive permeability, but this action was independent of Ca. It appears that the increase in active transport elicited by DPH is due to a specific interaction with Ca at the transport site.