Gestational Age and Renin Converting Enzyme and Kallikrein-Like Activity in Amniotic Fluid

Abstract

Electrolytes, angiotensin-converting enzyme and kallikrein-like activity, renin activity, active and inactive renin and angiotensinogen concentrations were determined in amniotic fluid from normotenslve pregnant women during early (17–20 weeks) and late (35–40 weeks) stage of pregnancy.

Sodium and protein concentrations were lower whilst potassium and creatinine were higher in late pregnancy. ACE activity was lower by 85% at late stage when compared to early stage. Active renin concentration and renin substrate decreased by 60% and 45% respectively in late pregnancy. Gestational age had no significant influence on renin activity, inactive renin concentration and the ratio total/active renin. Kallikrein activity was lower by 70% in late pregnancy. These results demonstrate that increasing gestational age is associated with consistant decreases in the concentration of most components of the renin-angiotensin system and in kallikrein activity