Effects of the diuretics, triamterene and mersalyl on active sodium transport mechanisms in isolated frog skin.

1. Triamterene reduces the rate coefficients for sodium movement into the transporting system of the isolated frog skin. The isotopically measured ;active sodium transport pool' is also reduced.2. Mersalyl reduces the rate coefficient for sodium and the calculated sodium flux from the transporting system to the inner bathing solution. The ;active sodium transport pool' is increased by this diuretic.3. The action of triamterene closely resembles that of amiloride and both reduce the entry of sodium into the system. In contrast, mersalyl limits the exit of sodium ions from the skin.