Urinary kallikrein activity during rat pregnancy

Changes in urinary kallikrein activity and its possible correlation with changes in blood pressure and renal excretory function during pregnancy were studied in the rat. To establish a possible physiological role of kallikrein in this condition aprotinin, which inhibits kallikrein as well as other serine protease was administered to pregnant rats. Urinary kallikrein activity was markedly increased during pregnancy and correlated positively with urine volume and electrolytes excretion, but not with blood pressure. Aprotinin administration almost completely inhibited kallikrein activity, however, blood pressure levels, urine volume and electrolytes were not changed after one day of aprotinin treatment. In conclusion, although renal kallikrein is highly enhanced during pregnancy, its physiologic role in this condition remains elusive.