[Effect of blood pressure on the plasma renin-angiotensin system]

The relationship of systolic and diastolic blood pressure (BP) to the peripheral blood renin-angiotensin system (RAS) has been examined. BP has found to be inversely related to the concentration and activity of plasma RAS components. It has been shown that angiotensin-converting enzyme (ACE) affects BP more greatly than do other plasma RAS components. It is suggests that RAS activation or depression is an adjustment to BP elevation or lowering. Altered BP triggers the biochemical mechanisms responsible for regulating vascular tone, cardiac output, and water-salt balance. All RAS components under study show a weak association with BP in some patients. It is concluded that the laboratory plasma RAS test is of low informative value in diagnosing hypertension and hypotension in clinical practice.