Inhibition of Toad Bladder Sodium Transport and Na++K+Stimulated Adenosinetriphosphatase by Extracts of Human Urine: Studies of Patients with Virilizing Adrenal Hyperplasia1

ABSTRACT In order to detect the presence of a possible sodium transport inhibitor, urine extracts were tested directly in 2 in vitro systems: (A) sodium transport across the urinary bladder of the toad and (B) Na++K+ stimulated adenosine triphosphatase (Na-K-ATPase). The sodium transport across the toad bladder, which remained 60 min after urine extract was added, was compared to the sodium transport before the addition and expressed as a ratio, R60. The R60 in children with virilizing adrenal hyperplasia (VAH) (R60=.33±.05) and in normal adults (R60=.39±.08) was significantly lower than normal prepubertal children (R60=.79±.03), indicating more inhibitory activity in the former 2 groups. The effect of urine extracts on Na-K-ATPase was similar to the effect on the bladder (children with VAH-46.9±7.0% of control ethanol additions, normal adults 46.8±7.7% of control, and normal children 75.6±2.6% of control). Among the children with VAH, there was no difference in the inhibitory activity of urine extracts f...