Prokallikrein and kallikrein inhibitors in human urine.

Kallikrein activity (KA) and kallikrein inhibitors (KI) were evaluated in urine from normal subjects and essential hypertensives. Kallikrein inhibitors were almost completely removed by dialysis against water, confirming previous reports of their low molecular size. The negative relationship found between KA and KI in urine samples from 12 normal subjects suggests that KI might play a role in the modulation of KA excreted by the kidney.