Plasma levels of 6-keto-prostaglandin F 1α in normotensive subjects and patients with essential hypertension

Abstract

To assess the pathophysiological role of prostacyclin in essential hypertension, plasma levels of 6-keto-prostaglandin F 1α (6-keto-PGF ), a stable, nonenzymatic metabolite of prostacyclin, were assayed in patients with essential hypertension and 25 age-matched normotensive subjects. Supine plasma levels of 6-keto-PGF 1α were 270±14 (SE) in normotensive subjects and 203±14 pg/ml in the patients with essential hypertension. The difference was statistically significant (p< 0.001). There was a significant negative correlation between plasma levels of 6-keto-PGFand systolic blood pressure (r=−0.44, P< 0.002), diastolic blood pressure (r=−0.55, p< 0.001), or mean blood pressure (r=-0.56, p< 0.001) in the pooled subjects. The same relationship was found in the hypertensive patients. There was no definite relationship either between plasma levels of 6-keto-PGFI and plasma renin activity (PRA) in the supine position, or between changes in plasma levels of 6-ketoPGF 1α and changes in PRA after 60 min of upright posture. These results indicate that circulating prostacyclin is reduced in patients with essential hypertension as compared to normotensive subjects. This reduction of plasma prostacyclin may participate, in part, in the maintenance of blood pressure elevation in patients with essential hypertension. It is also suggested that upright posture is not sufficient to elevate circulating prostacyclin.