The role of antihypertensive polar renomedullary lipid in the pathogenesis of hypertension.

One-0-hexadecyl-2-0-acetyl-sn-glycero-3-phosphorylcholine (HAGPC), a component of semisynthetic antihypertensive polar renomedullary lipid (APRL) reported by Muirhead et al. in chemically treated rabbit renomedullary lipid had a strong hypotensive action, a cardiosuppressing action and an apparent anti-norepinephrine action. 3-(N-n-octadecylcarbamoyloxy)-2-methoxypropyl-2-thiazolio ethyl phosphate significantly inhibited the hypotensive action of HAGPC, whereas the hypotensive activities of prostaglandin I2, prostaglandin E2, bradykinin, histamine and acetylcholine were not affected by this drug. The blood pressure of rats with established hypertension produced by clipping one renal artery and contralateral nephrectomy normally decreases rapidly after unclipping the renal artery, but the initial rapid decrease was significantly inhibited by an intravenous infusion of 3-(N-n-octadecylcarbamoyloxy)-2-methoxypropyl-2-thiazolio ethyl phosphate. This shows that endogenous 1-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine participates in the rapid decrease of blood pressure after unclipping the renal artery in one-kidney, one clip hypertensive rats.