Effects of Prostacyclin Infusion on Blood Pressure and Plasma Renin Activity in Patients with Essential Hypertension

Abstract

The effects of prostacyclin infusion (6.7 ± 2.7 ng/kg/min, 3 to 10 ng/kg/min) on blood pressure, plasma renin activity (PRA), and 6-keto-prostaglandin F_1α (6-keto-PGF_1α) were studied in 7 patients with essential hypertension (4 men and 3 women) with a mean age of fifty-eight ± eleven years (forty-six to seventy- four years). The baseline value of 6-keto-PGF_1α for patients with essential hypertension was not lower than in healthy subjects. Blood pressure immediate ly dropped following prostacyclin infusion. Systolic blood pressure returned to the baseline value after prostacyclin infusion was discontinued. However, di astolic blood pressure and mean arterial blood pressure were still significantly decreased thirty minutes after termination of infusion. Heart rate did not change during prostacyclin infusion but decreased significantly when infusion was ter minated. PRA was not significantly affected by prostacyclin infusion. The 6-keto- PGF _1α level was about 8 times higher than the baseline value thirty minutes af ter initiation of prostacyclin infusion and approximately twice as high as the base line value thirty minutes after termination of infusion. The decrease in mean arterial blood pressure coincided with the increase in 6-keto-PGF_1α. There was no correlation between mean arterial blood pressure and PRA, nor between PRA and 6-keto-PGF_1α.

These results demonstrate that production of prostacyclin is not reduced in patients with essential hypertension, and heart rate and PRA are not changed by prostacyclin infusion, although prostacyclin decreases blood pressure.