Tissue kallikrein activity in pregnancy.

To determine tissue kallikrein (TK) activity in black African women with hypertensive disorders of pregnancy; 140 women were recruited and divided into the following groups: group A--35 preeclamptic women, group B--35 mild to moderate hypertensive pregnant women and group C--35 normotensive pregnant women, and group D--35 normotensive non-pregnant healthy women. The activity of tissue kallikrein was determined from a random untimed urine sample using a selective, synthetic chromogenic tripeptide substrate having the sequence H-D-Val-Leu-Arg-pNA (S-2266). Urinary sodium and potassium levels was determined by flame photometry. Tissue kallikrein activity was decreased in women with preeclampsia (1.54 +/- 0.95 vs 3.05 +/- 0.83 ngTK/microg protein; p < 0.0001) and mild to moderate hypertensive group (2.03 +/- 0.76 vs 3.05 +/- 0.83 ngTK/microg protein; p < 0.0001) compared with normotensive pregnant women. There was also a significant difference in tissue kallikrein activity between the pregnancy groups (1.54 +/- 0.95 vs 2.03 +/- 0.76 ngTK/microg protein; p < 0.001). No difference in tissue kallikrein activity was observed between normotensive pregnant and normotensive non-pregnant healthy women (3.05 +/- 0.83 vs 3.14 +/- 0.88 ngTK/microg protein; p = 0.51). There was no difference in the excretion of urinary sodium and potassium in pregnancy groups compared to normotensive pregnant group. Tissue kallikrein activity is decreased in hypertensive disorders of pregnancy.