The renal tubular handling of aldosterone and its acid-labile conjugate.

Stop-flow studies using infusions of aldosterone-(3)H or its (3)H acid-labile conjugate were done on five rhesus monkeys. The aldosterone-(3)H urine-to-plasma (U/P) ratio decreased in the same distal urine samples as sodium. The (3)H acid-labile conjugate U/P-to-inulin U/P ratio increased in the more proximal samples either with conjugate formed endogenously during aldosterone-(3)H infusions or with labeled conjugate infused alone. Aldosterone reabsorption occurred at a distal site in the renal tubule, and secretion of its acid-labile conjugate occurred at a proximal site.