Urinary kinin excretion following alterations of vasopressin levels in man and rat.

To investigate the interaction between arginine-vasopressin (AVP) and the renal kallikrein-kinin system (KKS), urinary excretion rates of bradykinin (BK) and lysyl-bradykinin (LBK) were monitored in humans following water-loading, and in conscious diabetes insipidus (DI) rats during the infusion of AVP. In humans, the excretion rate of both BK and LBK decreased markedly 90 min after the water load. There was a close positive correlation between plasma AVP levels and urinary BK excretion, while urine flow was correlated negatively with the excretion rates of both kinins. In DI rats infusion of AVP caused a significant, reversible increase (from 14 +/- 2.8 to 35 +/- 5.1 fmol/min) in BK excretion. These results further implicate AVP in the regulation of the activity of the renal KKS.