Urinary kallikrein activity in the hypertension of renal parenchymal disease

To learn more about the regulation of blood pressure in renal parenchymal disease, 57 subjects (18 normal controls, 25 patients with essential hypertension and 14 with renal parenchymal disease and hypertension) were evaluated for peripheral renin activity, 24-hour urinary kallikrein activity and whole-blood volume. Blood volumes were significantly lower in patients with essential hypertension (P less than 0.001) and those with renal disease and hypertension (P less than 0.001) than in normotensive subjects. Renin activities (measured after the subjects were standing) were also lower in patients with essential hypertension and hypertension due to renal disease (P less than 0.01 and P less than 0.02, respectively). Kallikrein activity was similar in subjects with renal disease and those with hypertension (P less than 0.05) but markedly diminished in both groups as compared with normotensive subjects (P less than 0.001 and P less than 0.01, respectively) when glomerular filtration rates were taken into account. The kallikrein-kinin system may be involved in the hypertension associated with renal parenchymal disease.