Urinary kallikrein excretion and sodium metabolism in hypertensive patients

Urinary kallikrein excretion was measured in 21 healthy subjects and 44 patients with various types of hypertension. The kallikrein activity was determined by the method of esterolytic assay. The excretion rates in normal subjects were 112.9 +/- 11.1 (S.E.) EU/day. The kallikrein excretion was decreased in patients with essential hypertension, the mean estimated values were 75.2 +/- 10.0 EU/day. In this disease, however, an enhancement of urinary kallikrein was observed after sodium depletion. An obvious increase in kallikrein excretion was found in the primary aldosteronism. In primary aldosteronism and renovascular hypertension, one of the secondary aldosteronisms, there was a good correlation between the urinary kallikrein output and the urinary sodium excretion. The present data indicate that the renal kallikrein-kinin system, one of the renal antihypertensive factors, is suppressed in essential hypertension and is under the influence of mineralocorticoid levels.