[The effect of antidiuretic hormone and catecholamines on transepithelial sodium transport]

Experiments were conducted on the isolated frog skin; it was shown that the activating action of pituitrin on the transepithelial transport of sodium decreased, and that of adrenaline increased with reduction of the concentration of this ion in the incubation medium. Strophanthine K, an inhibitor of (Na-+--K-+) -activated ATP-ase, prevented the activating effect of adrenaline on sodium transport, and in the medium with a low concentration of this ion--it only partially inhibited its actibating effect. A conclusion was drawn that the mechanisms of ADH and catecholamine activation of sodium transport by frog skin were not identical, although they had some common links. It is supposed that (Na-+--K-+)-activated ATP-ase was directly involved in the action mechanism of catecholamines on the system of active sodium transport in frog skin.