Urinary kallikrein excretion in normal and hypertensive pregnancy at term.

To study the urinary kallikrein excretion before the delivery of term pregnancy we measured its excretion preterm (between 32-36 gestational week) in 13 patients with normotensive pregnancy and 17 patients with pregnancy-induced hypertension and one to five days before the delivery at term in 18 and 22 patients, respectively. In normotensive pregnancy urinary kallikrein excretion remained unchanged during the late third trimester until delivery (12.6 +/- 1.7 ncat in 24 hours in preterm, 10.8 +/- 1.2 before delivery). In pregnancy-induced hypertension and particularly in pre-eclampsia urinary kallikrein excretion was lower than in normotensive pregnancy and the decrease became more marked as the time of delivery approached (respective values: in pregnancy induced hypertension 9.2 +/- 1.2 and 7.0 +/- 0.7; in pre-eclampsia 7.6 +/- 1.3 and 7.3 +/- 0.9). The decrease in urinary kallikrein excretion suggests progressive disturbances in the interactions of renal vasoactive systems (the kallikrein-kinin system, the renin-angiotensin system and prostaglandins) with resultant changes in renal hemodynamics.