The Effect of Deoxycorticosterone-glucoside on the Sodium Transport in Frog Skin

　1）The effect of mineralocorticoids on the active sodium transport was studied through the short-circuited isolated frog skin, according to Ussing's method．The short-circuitcurrent was electrically measured and simultaneously the sodium flux was determined，using ²²Na as tracer．

　2）Deoxycorticosterone-glucoside（DCG）increases the active transport potential, E_Na，suggesting the direct action of mineralocorticoid on Na-pump．

　3）When applied to the medium bathing the corium surface at the concentration ranging from 1 to 10μg/ml, DCG definitely enhances the short-circuit current, which is believed equivalent to the actively transported sodium netflux．

　4）DCG, which is added into the inside（corium side）solution, stimulates the current more effectively than when added to the outside（epidermal side）solution．Accordingly it is supposed that either there may exist some diffusion barrier in ep dermis which inhibits the passage of DCG into the skin, or Na-pump may be located near corium in frog skin．

　5）DCG increases the sodium influx and decreases outflux and thus an increased netflux appears．This apparently paradoxical dual action of DCG upon the sodium influx and outflux through frog skin, can readily be explained mathematically as the result of increased netflux across the skin．

　6）The action of progtsterone was not unequivocally demonstrated, while corticosterone and hydrocortisone invariably increased the short-circuit current though not so strongly as DCG does in the same concentration．