Antihypertensive lipids from the kidney: alkyl ether analogs of phosphatidylcholine

Four types of lipids with potential antihypertensive properties have recently been derived from the kidney. These consist of prostaglandins (PG), a renin inhibitor, a neutral lipid, and alkyl ether analogs of phosphatidylcholine. PGI2, mostly renocortical, and PGE2, mostly renomedullary, may aid the antihypertensive function of the kidney by decreasing renal vascular resistance and shunting blood toward the juxtamedullary zone and the renal papilla, where the renomedullary interstitial cells (RIC) are located. Several analogs of the renin inhibitor are available. The neutral lipid is a natural product derived from fresh renal medulla and from RIC grown as monolayer tissue culture. The alkyl ether analogs of phosphatidylcholine (formerly designated as the antihypertensive polar renomedullary lipid or APRL) are orally active vasodilators. They cause a prolonged depressor effect due to a decrease in peripheral vascular resistance. The latter may be partly due to alpha-adrenergic antagonism.