SERUM NITRITE AND MALONDIALDEHYDE IN HYPERTENSION AND MYOCARDIAL-ISCHEMIA

To understand the role of endothelially derived vasospastic superoxide anion (SO) and vasodilatory nitric oxide (NO) in vascular disorders s uch as essential hypertension (EHT) and atherosclerosis, malondialdehy de (MDA), a stable end product of lipid peroxidative damage, and nitri te, mostly derived from NO, have been estimated in the serum of hypert ensive patients and in patients suffering from myocardial ischaemia (s table or unstable angina or acute myocardial infarction (AMI)). An inc rease in serum MDA together with a decline in serum nitrite was observ ed in patients with EHT, indicating respectively heightened activity o f oxygen free radicals (OFR) and diminished NO production. Similarly, patients with stable or unstable angina or AMI had elevated levels of serum MDA while serum nitrite declined only in unstable angina and AMI . These changes in MDA and nitrite probably occurred as a result of an endothelial response to extravascular factors such as angiotensin II and dyslipidaemia or mere endothelial dysfunction in EHT and atheroscl erosis. In these patients, other disease states such as diabetes, arth ritis and other inflammatory disorders associated with OFR generation were excluded.