Urinary kallikrein in normotensive subjects and in patients with essential hypertension.

Basal 24 hour urinary kallikrein excretion of 20 patients with uncomplicated essential hypertension did not differ significantly from that of 18 normotensive age-matched control subjects. 4 of the 20 hypertensive patients, however, had low kallikrein excretion. Furosemide (40 mg i.v.) caused an increase of urinary kallikrein excretion in the normotensive subjects and in most of the patients with essential hypertension. The stimulating effect of furosemide was less pronounced or even absent in 7 hypertensives. No circadian rhythm of urinary kallikrein excretion was observed. There were weak correlations between 24 hour kallikrein excretion and urinary volume (r=0.59; p < 0.05), and potassium excretion (r=0.51; p < 0.05) in the normotensives. In the hypertensives correlations were found between 24 hour kallikrein excretion and potassium excretion (r=0.51; p < 0.05), aldosterone excretion (r=0.57; p < 0.01), and creatinine clearance (r=0.59; p < 0.01). Our findings do not support the concept that the renal kallikrein-kinin system might play a primary role in the pathogenesis of essential hypertension.