Oxygen free radical scavenger system intermediates in essential hypertensive patients before and immediately after...

Oxygen-free radical intermediates/scavengers were measured in 43 patients with essential hypertension who, although under antihypertensive therapy (without angiotensin-converting enzyme inhibitors), still had high blood pressure values. Measurements were taken before and 30, 60 and 120 min after sublingual administration of 25 mg captopril. Both systolic and diastolic blood pressures were reduced significantly. Twenty normotensive healthy volunteers were used as controls. The hypertensive patients had lower glutathione peroxide activity (GSHPx), higher superoxide dismutase (SOD) and serum glutathione reductase activity (GSHRx) compared with the controls. After captopril (30, 60 min) the glutathione and GSHPx increased compared with the pretreatment values. SOD and GSHRx remained high compared with the controls, while whole blood glucose-6-phosphate dehydrogenase remained low. Another group of 19 essential hypertensive patients, free of any antihypertensive medication (for at least 3 weeks), had lower GSHPx, SOD and higher GSHRx than the normal control group. Our results show significant differences in the oxygen free radical scavenger system of hypertensives compared with the normal subjects. It may be that captopril has a concomitant scavenging action together with its antihypertensive effect. Our study raises the question whether cell/organ damage will occur in hypertensive patients exposed to oxidative stress during periods of low antioxidative capacity.