Presence of an Aldosterone Stimulating Substance in the Urine of Rats Deprived of Salt

Abstract

These experiments are concerned with the study of a substance found in the urine of intact and adrenalectomized rats deprived of salt which when injected into intact hydrated rats caused a decreased excretion of sodium. As the substance was present in the urine of adrenalectomized rats, it obviously was not aldosterone. The substance responsible for sodium retention was thermolabile at pH 7, extractable with butanol and did not dialyze through a cellophane membrane. To determine whether the sodium retention by the assay rats was due to an increased excretion of aldosterone, the following experiment was done: feces of intact rats were collected during a control period. Feces were collected during a second period when the rats were injected daily with urine from adrenalectomized rats deprived of salt. Aldosterone was determined in the feces in each of these periods. The aldosterone excretion was greater during the period when the rats received the urines from the adrenalectomized rats deprived of salt. The authors conclude that the sodium-retaining activity of the urine of adrenalectomized rats deprived of salt was due to the presence of a substance capable of stimulating the adrenals of the intact rats to produce aldosterone. The substance was not present in purified ACTH.