Effects of dietary potassium and race on urinary excretion of kallikrein and aldosterone in man.

Urinary excretion of kallikrein by 16 normal and 8 hypertensive subjects was studied at three levels of dietary potassium: 85 meq/day for 5 days, 185 meq/day for 7 days, and 25 meq/day for 10 days. Excretion of kallikrein varied directly with potassium intake and paralleled excretion of aldosterone in both normotensive and hypertensive subjects. Mean levels of excretion of kallikrein at 85, 185, and 25 meq intake of potassium were 10.8, 19.1, and 5.8 esterase U/day (EU/day), respectively, for the normotensive subjects and 8.8, 13.9, and 6.1 EU/day for the hypertensive subjects. Mean levels of excretion of kallikrein were significantly higher in white that in black subjects among normals and hypertensives [13.0 vs. 5.9 EU/day for normals (P less than 0.05) and 13.7 vs. 4.0 EU/day for hypertensives (P less than 0.05) on the 85 meq/day diet]. The parallel changes in excretion of kallikrein and aldosterone support the hypothesis that changes in effective levels of aldosterone induce changes in the excretion of kallikrein. Because of racial differences in excretion of kallikrein, matched groups should be used for comparisons of the kallikrein system in disease states.