Effect of amiloride on sodium transport of frog skin

Summary The effect of Amiloride on intracellular sodium content of the isolated frog skin was investigated. The maximal effect on intracellular exchangeable sodium concentration (–10 meq/kg cell water) was found at concentrations of Amiloride in the incubation solution between 0.3 and 1.0×10^–4 M/l, and at an incubation time of 6–15 min. Since total intracellular sodium concentration is also reduced by approximately 10 meq/kg cell water, it follows that the intracellular non-exchangeable sodium concentration was not affected by Amiloride. Water content, extracellular volume, and intracellular potassium concentration remained constant. The short circuit current reached a new steady state within a few seconds after addition of Amiloride. It is concluded that Amiloride affects a sodium transport pool, which contains about 10% of the exchangeable intracellular sodium.Supported by the Deutsche Forschungsgemeinschaft.