Although the PGE2 receptors EP1 and EP3 are vasoconstrictive in mice, the EP2 and EP4 receptors are vasodepressive [27]; experiments using PGE2 synthase knockout mice subjected to salt-loading, angiotensin II, or aldosterone-induced hypertension indicate that endogenous PGE2 is, in the aggregate, anti-hypertensive [27]; and exogenous PGE2 lowers arterial BP through both vasodepressor and natriuretic effects in experimental animals and human subjects [57–64]. This evidence concerns the gene PTGER1 and Hypertension.