Plasma catecholamines and angiotensin-converting enzyme activity in hypertensive subjects with positive rollover...

The rollover test is useful in predicting and identifying subjects developing hypertensive disorders of pregnancy. The mechanisms responsible for positive tests are unclear, but a greater release of pressor substances occurring in subjects with positive tests has been proposed. The authors measured and compared heart rate, diastolic blood pressure, plasma norepinephrine and epinephrine levels, and serum angiotensin-converting enzyme activity in ten pregnant subjects with positive rollover tests and seven control subjects with negative rollover tests at 29 to 36 weeks' gestation. Resting levels of epinephrine were significantly lower in subjects with positive rollover tests than in the control group. Plasma levels of epinephrine increased significantly during the positive rollover tests. Basal angiotensin-converting enzyme activity was significantly increased in subjects with positive tests and may play a major role in the altered cardiovascular sensitivity to pressor substances resulting in positive tests.