TRANSPORT OF ALDOSTERONE AND OF THE ACID LABILE CONJUGATE OF ALDOSTERONE BY TUBULAR CELLS OF THE KIDNEY

Abstract

ABSTRACT Stop flow experiments on dogs receiving continuous infusions of radioactive aldosterone were carried out in order to determine the tubular sites of reabsorption of aldosterone and the tubular sites of secretion of its metabolites. Sodium, p-aminohippuric acid, creatinine, inulin, radioactive aldosterone, radioactive tetrahydroaldosterone and the acid-labile (hydrolyzable) conjugate of aldosterone were analyzed in the urine samples collected after the stop periods. The results of the experiments indicate that aldosterone is mainly reabsorbed at a distal tubular site, that the acid-labile conjugate is secreted mainly at a proximal tubular site, and that tetrahydroaldosterone glucuronide is neither secreted nor reabsorbed by tubular cells. Predominant distal reabsorption of aldosterone is suggested as being a possible reason for the predominant distal sodium-retaining effect of this hormone.