QUANTITATION OF 5 FORMS OF HIGH-MOLECULAR-WEIGHT ANGIOTENSINOGEN FROMHUMAN PLACENTA

In addition to the well characterized predominant form of plasma angio tensinogen, which will be termed low molecular weight angiotensinogen (LM(r)A), significant quantities of a high molecular weight angiotensi nogen (HM(r)A) occur in the human pregnant state. HM(r)A is the predom inant form of angiotensinogen in the placenta and amniotic fluid. The ratio of HM(r)A/LM(r)A is elevated in approximately half of the women who develop pregnancy induced hypertension (PIH). This report document s a simple two step methodology for the separation and quantitation of different forms of HM(r)A. The two steps are gel filtration and ion e xchange chromatography. The application of this methodology to amnioti c fluid and plasma from normotensive pregnant women and extracts of am nion, chorion, and placental tissue has shown five distinct forms in t he tissue extracts and amniotic fluid, but only three significant form s in plasma. The elution position of all forms of HM(r)A are highly re producible and are the same for each tissue or fluid studied, thus len ding support to the concept that the three forms seen in plasma of nor motensive pregnant women are the same as three of the forms of HM(r)A seen in extracts of placental tissue.