EFFECT OF UREA ON THE INACTIVATION OF ANTIDIURETIC HORMONE BY THE INNER MEDULLA OF THE RAT KIDNEY IN VITRO

Abstract

ABSTRACT Inactivation of antidiuretic hormone by slices and homogenate from rat kidney inner medulla was inhibited during a 2 hour exposure to urea in concentrations over 0.5 M. Guanidine and thiourea in equimolar concentrations had an inhibitory effect which was 2 and 1.6 times more marked, respectively, than that of urea. The possible implications of these findings for the function of the concentrating mechanism of the kidneys during different states of hydration are discussed.