Prostaglandin I2 has more potent hypotensive properties than prostaglandin E2 in the normal and spontaneously hypertensive rat.

The blood pressure lowering effects on PGI2 in the normal and spontaneously hypertensive rat are described. Comparison of dose response curves for PGI2 and PGE2 indicate that PGI2 is twice as potent as PGE2 in the normal rat and 3--4 times more active in the spontaneously hypertensive rat. Furthermore PGI2 is equiactive through intracarotid and intrajugular administration indicative of the complete lack of pulmonary inactivation. These findings supported by evidence of enhanced PGI2 synthesis in aorta during hypertension support the notion that PGI2 could participate in blood pressure control mechanisms.