Spironolactone. An aldosterone agonist in the stimulation of H+ secretion by turtle urinary bladder.

In the isolated turtle bladder, spironolactone inhibits sodium transport in the presence of aldosterone or endogenous mineralocorticoid hormone. In contrast to this antagonism for the stimulation of sodium transport by aldosterone, the stimulation of hydrogen ion secretion by aldosterone is not inhibited by spironolactone. In hormone-depleted bladders, spironolactone stimulates hydrogen ion secretion. The extent of stimulation is similar to that of aldosterone. Spironolactone functions as an agonist for aldosterone for the stimulation of urinary acidification.