The excretion rate of urinary kinin was estimated in 71 patients under various clinical conditions. The estimated values ranged from 5.3 to 36μg per day in 14 healthy persons. No significant change in the kinin output was recognized in 32 patients with bronchial asthma, dermatological, neurological or pancreatic diseases in which kinin is generally considered to play an etiological role.
The kinin excretion was investigated in man during the intravenous infusion of kallikrein or bradykinin, or in dogs during the bradykinin infusion into renal artery. No correlation was demonstrated between the kinin level in circulating blood and the kinin excretion in urine in six patients. It was concluded from these experiments that circulating kinin is not excreted in urine, and urinary kinin is produced and secreted by the kidney, perhaps by the tubular cells.