Action of aldosterone on frog skin in the presence and absence of in vitro molting effects.

The molting which occurs in frog skin following exposure to high concentrations of aldosterone interferes with the interpretation of physiological measurements. Exposure of skins from frogs maintained in standard smooth tanks to 5 - 10(-7) M aldosterone caused within a few hours erratic responses in short-circuit current Io and conductance K followed by sustained stimulation of Io and K; 10(-8) M aldosterone caused only stimulation of Io and K. Storage of frogs in "rojgh tanks" eliminated in vitro molting on exposure to 5 - 10(-7) M aldosterone. IO and K were then superimposable for 3 h, after which Io increased far more rapidly than K. These results are consistent with an early effect on permeability of the active pathway and later effects on metabolism, either a direct effect on the pump or enhanced interaction between transport and metabolism.