In vivo Na+- and Cl minus-independent transport across the skin of Rana esculenta.

The relationship between the trans-epithelial Na+ and Cl minus absorptions from dilute external solutions and the H+ and base excretions were studied in Rana esculenta in vivo. The following results relate to transport from Na2SO4 solutions: 1) The Na+ absorbed is exchanged against endogenous H+. 2) Diamox injection (1.10-4 M-kg-1) simultaneously inhibits both Na+ absorption and H+ excretion. 3) The addition of amiloride to the external medium (final concn: 5-10-5 M) inhibits Na+ absorption and H+ excretion. Measurements of chloride movements from choline chloride solutions give the following results: 1) The chloride absorbed is exchanged against a base, probably HCO3-. 2) Diamox injection (1-10-4 M-kg-1)inhibits the net fluxes of both ions. When transport is measured in NaCl solutions, it is impossible to measure the HCO3-excreted when H+ is also being excreted (HCO3- plus H+ in equilibrium CO2 plus H2O). In these solutions, therefore, only the action of Diamox on the sodium and chloride fluxes was followed and was found to have similar effects on these fluxes as those described for choline chloride and sodium sulphate solutions. The results are discussed in relation to other studies on the action of inhibitors on sodium and chloride transport in the in vitro skin.