STIMULATION OF ACTIVE SODIUM TRANSPORT ACROSS THE ISOLATED TOAD BLADDER AFTER INJECTION OF ALDOSTERONE TO THE ANIMAL12

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Abstract
Active sodium transport by the isolated urinary bladder of Bufo marinus was studied by means of the short-circuit current technique of Ussing and Zcrahn. Sodium transport by this preparation was found to be greater when toads had been maintained in distilled water rather than in saline. This increase was associated with a higher concentration of circulating aldosterone. This hormone was shown to be produced by toad adrenal tissue. Injection of aldosterone d, 1 21-monoacetate to the animals the day prior to sacrifice resulted in a stimulation of sodium transport by the isolated bladder, whether the toads had been kept in saline or in distilled water. But after administration of aldosterone for 5 days, the activity of sodium transport was the same, regardless of environment. The effect of habitat or aldosterone injections on active sodium transport by the isolated toad bladder did not influence the responsiveness of the preparation to the stimulation of sodium transport by vasopressin. Bladder tissue water, sodium, potassium and chloride concentrations did not vary significantly despite large changes in sodium transport. Administration of aldosterone to toads produced changes in plasma potassium, urine sodium and potassium concentrations opposite to those usually seen in mammals.