Quantitation of the five forms of plasma high molecular weight angiotensinogen in women with pregnancy-induced hypertension

In the human pregnant state a high molecular weight form of angiotensinogen (HM(r)A) is present in significant quantities in addition to the usual low molecular weight angiotensinogen (LM(r)A). In a previous study involving a small number of white women, it was found that women who had developed pre gnancy-induced hypertension (PIH) had significantly higher levels of plasma HM(r)A. It has been determined that there are five isoforms of HM(r)A. The objectives of this study were to expand the previous study with the inclus ion of black women and to determine which isoform(s) of plasma HM(r)A are e levated in PIH. Plasma LM(r)A and HM(r)A were quantitated in 24 normotensiv e pregnant women and 65 women with PIH. The PIH group had higher levels of HM(r)A and somewhat lower levels of LM(r)A than the normotensive group. The HM(r)A/LM(r)A ratio was elevated in 47% of the PIH group. The five isoform s of HM(r)A were quantitated in plasma from 10 white women with PIH, 10 bla ck women with PIH, and 6 normotensive: pregnant white women. Half of both t he white and black women with PIH had an elevated HM(r)A/LM(r)A ratio. The relative proportion of the HM(r)A isomers was similar in all groups. These studies show that half the women with PIH have a distinct abnormality in th eir renin angiotensin system. Both white and black women show this abnormal ity. In those women who have an elevated total HM(r)A, all five isoforms of HM,A are equally elevated. Am J Hypertens 2000;13:221-225 (C) 2000 America n Journal of Hypertension, Ltd.