ISOLATION, IDENTIFICATION AND PHYSIOLOGY OF A POSTULATED HORMONE CAPABLE OF INDUCING EXCRETION OF SODIUM
MICHIGAN UNIV ANN ARBOR
Pagination or Media Count:
Normal young men before and after administration of aldosterone and patients with aldosteronomas were studied using a standardized saline infusion test. Tests were done after standard dietary preparation with both high and low salt diets. Before infusion tests, measurement of plasma volume, extracellular fluid volume, total exchangeable sodium and total exchangeable potassium were done simultaneously by means of a technique developed in this laboratory. Endogenous creatinine clearance, PAH clearance and rates of excretion of sodium, potassium and chloride were measured. During infusion the mean maximum rate of sodium excretion in normals was 0.72 mEqmin 180 mEq Na diet prep. and 0.14 MEqmin 8-10 mEq Na diet prep.. Twentyfour hours after aldosterone administration 1.0 mg IM q 8 hr the rate was 0.36 mEqmin on the high sodium prep. Seven days after starting aldosterone, with no further change in extracellular fluid volume or GFR, renal escape had occurred and the rate had increased to 1.53 mEqmin without elevation of blood pressure. This value is similar to that found in patients with aldosteronomas 1.63 mEqmin. The results suggest that renal escape from sodium retention is not dependent upon changes in GFR, ECF or blood pressure and that a renal sodium-losing mechanism was activated secondary to aldosterone administration.