Investigation of the role of kidney kallikrein on bumetanide induced diuresis in rats.

Administered to anaesthetized, laparatomized rats bumetanide (10 mg/kg intravenously) evoked a rapid and large diuretic response. This was associated with three to five fold enhancements of urine kallikrein (kininogenase) excretion. In addition bumetanide slightly decreased (approximately 10 mmHg) the blood pressure and temporarily increased renal blood flow (less than 10%). The capacity of bumetanide to increase urine kallikrein excretion was inhibited either by pretreatment with chlorazanil (3 mg/kg intravenously) or by the infusion of aprotinin (5000 KIE/kg/min). Kallikrein inhibition did not significantly modify bumetanide induced diuresis, natriuresis, kaliuresis, lowering of blood pressure or renal vasodilating effect.